Archive for the ‘29er School’ Category

Going Tubeless: What You Need To Know: Questions And Answers

July 21, 2009

One of the readers of Twenty Nine Inches- “Mickey”, had some great questions that were posted in the comment section of the last article. I thought I would break them out into their own post and share the answers with all of you readers. Here are some day to day issues one might face going tubeless.

What (do) you do with (old) sealant then, throw it away? Probably yes, but how?: This question can be answered in a few ways depending upon which sealant you are using. If you are using a latex based sealant and it dries up, there really isn’t any clean up necessary. Usually the sealant dries into “interesting formations” which Stan’s users have a rather uncouth name for. (!!) These can simply be discarded. If the sealant isn’t dried out though, it can be re-used. Recovery of old sealant from a tire usually is easiest when using a “syringe” type instrument such as the unit available from Stan’s or a similar product from CaffeLatex. Draw out the old sealant and mix it in with new sealant, then add it back into a new tire.

contiking09 036 An injector/syringe tool aids in sealant recovery as well as injecting sealant into tubeless tires.

Glycol based sealants are usually still wet after several months, but may be dried up to a thicker, gooey consistency. If you are switching out tires, it generally will be easier to wipe up the old sealant with an old rag or sponge. After getting the majority of the sealant out, you can wash with a soapy water solution and rinse with water to get any left over residue out. Your rag or sponge could be washed, or discarded with other hazardous waste.

How do you clean tires inside when changing to another (pair)?: Again, in a similar way to what I describe above. Just remember to discard the old rags or sponge with your other hazardous waste.

How do you put the tube (in) when the puncture is too big and you are on the (trail) ?
Once you have determined the sealant isn’t going to seal the puncture, you should release all the air in the tire, break down the beads from the rim, and remove the tubeless valve stem. All rather simple things to do, but the whole process is complicated by the mess of sealant you will encounter within your tubeless tire. I have experienced this a couple of times. My advice is to carefully install a slightly inflated tube and push the bead of the tire over the rim without removing the sealant out on the trail. (Of course, making sure you do not have a foreign object in the tire yet, or a tear that requires a tire boot.) Keeping sealant off the trail and off you is the best way, if at all possible.

In the case of Bontrager’s TLR rim strip, you will also want to make sure you have a long stemmed presta valve to allow good purchase with your pump or CO2 unit after installing the tube. I have also found that carrying a multi-tool with a pliers type tool helps in loosening the tubeless valve stem nut, which is generally too tight to remove by hand. (Make sure you pick up your valve stem and stow it before you ride away!)

How (do) all those sealants work during a winter time? Sealants that are water/latex solutions will freeze up. Sealants that are glycol based are much less likely to freeze up, but may become too thick to really seal any punctures depending upon how cold it is out and the particular sealant in question. Some home brew sealants use windshield washer solvent, which aids in keeping the solution from freezing. In my experience, tubeless tires will still work in winter, but you may not see the puncture protection benefits that you do in summer, or during warmer weather.

Okay, that’s a wrap on Mickey’s questions. Thanks Mickey for writing those in the comments section. Remember, if you have any questions, just put them in the comments. I try to answer all of them and I may use one of yours in a future post.

Going Tubeless: What You Need To Know: Day To Day

July 19, 2009

Now following up on the last post on Going Tubeless, here is a post dealing with your day to day living with a tubeless tire set up. This assumes you have a set up that is successfully sealed and ready to roll.

contiking09 033The difference between using a dedicated system and a mixed and matched set up is huge in the world of tubeless tires.

Using A System Or A Mixed “Rider’s Choice” Set Up: The way your tubeless tire set up will work depends upon what components you have chosen to work with to a large degree. A “system”, such as Bontrager’s, Stan’s, or a system using UST type components, will typically be much more successful and safe than a tubeless tire set up that draws from different systems or uses non-tubeless parts. Differences may include the ability to stay sealed, tire bead/rim interface issues, or even poorer tire performance.

Tubeless systems from Bontrager, Stan’s, or the UST developed rims and tires are not infallible systems, but they do require less fussing around with. Set ups using parts of other systems, or non-tubeless tires and home made sealing systems have success rates that vary about as much as the different combinations. It seems that a lot of folks have their particular favorites or have learned through trial and error to tweak out the bad and keep the good. However; one must discern whether they are willing to take the risk of possible failure and have the ability to take responsibility for their experimentation. For those who are not willing to take that gamble, then the systems that are offered now are your best bet. The good news is that several wheel manufacturers are working on tubeless rims/rim strips for their 2010 lines, so the list of choices will blossom soon.

bonty29-3-09 007Systems such as Bontrager’s Tubeless Ready System are very reliable typically.

Tires and Sealants: Tires and sealants are also part of the picture here and once again, we see tubeless ready tires, UST tires, and several sealants available or being concocted for use. Not everything out there is workable in a tubeless situation. Getting non-tubeless tires to seat, seal up, and stay on are probably the number one problems here. It can even run counter to what benefits tubeless tires are supposed to offer in terms of pressure. Non-tubeless ready casings often do not have the support to carry a load without the tube inside resulting in the rider needing to use higher pressures rather than the lower pressures one is supposed to be able to use when going tubeless.

Care And Maintenance: Tubeless tire set ups will require similar maintenance to tubed tire set ups. Pressures will have to be checked, inspection of the tires should be done on a regular basis. The only real difference here is maintaining your sealant. Some sealants will outlast others, but predicting what you will experience is difficult. The climate, the conditions your wheels are stored in, and whether or not you regularly get punctures will all affect how often you will need to replenish your sealant. A good rule of thumb is to check your tires every three months or less. You can shake the wheel, and perhaps hear the sealant sloshing inside. Otherwise a visual inspection will be necessary which will include letting the air out, breaking the bead, and looking inside.

A note on mixing sealants- While I have not dabbled in the mixing of sealants, some readers have asked me to comment on this. It is my opinion that latex type sealant and glycol based sealants should not be mixed together. I do not see any benefit in doing so. Some folks do add glitter, or some other small particles to aid in sealing punctures. There may be some positive benefit to this. (Actually, Slime Tubeless product actually has small bits of rubber in it to do exactly this.) My experience bears out that there isn’t anything wrong with using sealants as recommended. Slime, Stan’s, CaffeLatex, and others all do what they claim without assistance. Adding anything beyond some glitter to aid in sealing seems to my mind to be a gamble at best.

Next time: I’ll wrap up the series with an overview of where tubeless tire technology is now and where it should be headed.

Going Tubeless: What You Need To Know: How To

July 12, 2009

After getting to know why you would want to go tubeless, we now will delve into the “how” of going tubeless with your “wagon wheels”. There are a couple of standardized systems out which I will cover first. Then I will touch briefly on the typical ways folks are turning components meant to be used with tubes into their own tubeless systems.

But before that, we need to understand a couple of key things that must be done by any company or individual that attempts to attain a state of perfect “tubelessness”. Without making sure these things are secured, disaster, possible injury, and even death may result. Really!

First, a way to seal the rim well must be found, and usually this means sealing off a bunch of spoke holes drilled into the rim. Of course, if you can find a way around drilling all those holes, it makes this job a lot easier, and in fact, that is why a UST standard rim is so appealing. Unfortunately, only pre-built wheel sets are available with this sort of rim, so unless you buy into a complete system, the UST rim isn’t an option. Other ways to seal a traditionally drilled rim have been done, and usually in conjunction with a specific rim extrusion.

BontragerTRSwheel 007Bontrager TLR rim strip, tubeless valve stems, and bonus skewer image!

Stan’s NoTube system consists of a specially extruded rim that features a “bead socket” for the tire and a rim well designed to assist in making a tubeless tire air up without much effort. The spoke holes are covered with a specially developed rim tape, thus sealing off the holes in an effective manner. Bontrager does something similar with its Tubeless Ready System, but instead of a tape, they developed a rim well and plastic strip that mate together. The rim can be built on any hub, then the plastic rim strip is snapped into place, sealing off the spoke drilling. In fact, a tubeless tire set up on this system actually seals against the strip, and not the rim.

Now you’re almost there. You will need a special tubeless valve stem to finish off the job. Bontrager, Stan’s, Mavic, and others make these, and home made ones will also work. The valve- usually a Presta, but not always- is made to have an inner seal of some sort. Either an “o” ring seal or a rubber type collar around the valve on the inside is employed with a nut that threads on to the outside which pulls the inner seal against the rim strip, sealing off the valve hole in the rim.

Crossmax29er 010Mavic’s Cr29ssmaxx were the first UST rims available for 29″ers.

Okay, now the final piece of the puzzle is the tire. A typical folding bead tire isn’t made to keep air inside its carcass- that is the job of the inner tube. So tire manufacturers either do one of two things- they make a true, air tight casing and bead, or they make an airtight bead with a casing that requires sealant to become air tight. A standard developed by Mavic and other tire manufacturers called “UST” is one way this can be done, but most manufacturers have eschewed this avenue for their own systems which all are of the “tubeless ready” type requiring sealant to become air tight. The common denominator of all of these though is a tighter rim bead diameter standard and special bead construction. Without holding the rim bead dimensions to tight tolerances and reinforcing this critical area of the tire, blow offs and other failures would result and cause possibly catastrophic results for riders.

bontragerxr2008 007Special beads are part of a tubeless ready tire and make them safe to use tubeless.

Sealant is the last bit needed before most systems will operate safely and effectively. Usually some sort of latex based sealant is introduced into the tire carcass which seals off the carcasses porous inner walls making it air tight without using an extra layer of rubber as UST tires do. This results in a lighter, more supple casing, and a heightened level of performance in most cases. Sealants come in many forms, some being glycol based, and even home brews are popular with many riders.

fargotest08 078Most sealants are latex based such as this Geax product.

DIY Tubeless Set Ups: Note: Twenty Nine Inches does not endorse any of the following. It may be dangerous and cause a crash leading to personal injury and even death. Taking any of these measures to set your bike tires and wheels up tubeless is done at your own risk:

Many riders have been doing their own conversions of standard tubed wheels and tires using home made sealants and rim strips for years. Most of these systems use some sort of combination of reinforced packing tape, a foam backed tape of some sort to fill in deeper rim wells, and home made valve stems. Some folks use split open tubes as rim strips as well. Sealants based on mixtures of commercially available sealants, or mold building latex mixed with an ammonia based substance like windshield washer solvents are common. The tires used are typical tubed tires resulting in various levels of success ranging from bulletproof reliability to hit and miss successes resulting in occasional failures, crashes, and injuries.

Mixed Systems: Some riders will try “mixing and matching” systems or components with each other, and may even do this while introducing their own “home brew” solutions as sealants. Generally I have found that some things work, and some things don’t. Here is a short list of my personal findings in messing around with tubeless systems. Your results may vary.

-Bontrager TLR tires: Works with decent reliability on Stan’s rims and I have heard enough about failures with Mavic/UST rims that I will not use TLR tires on those types of rims.

-Bontrager TLR Rim Strips/Wheels: Works really well with Specialized’s “2Blis” tires. Geax tires are waaay too tight and will not work at all with the plastic strip installed. A Stan’s strip in a TLR rim will work with a Geax tire, however. Continental tires work well on TLR rim strips. TLR rim strips have also been used by myself in Velocity Blunt rims with Rampage tires with good results.

-Stans ZTR Rims and Strips: Works great with Specialized, Bontrager, Continental, and some non-tubeless tires. GEAX tires are just too tight to be field serviceable. I won’t use a Geax tire on a Stan’s rim for that reason. Stan’s strips: I have used these only on ZTR rims with the exception of some DT Swiss TK 7.1 disc rims and that works flawlessly.

contiking09 037CaffeLatex valve stems for tubeless tires and the injector for their sealant. This is the best sealant and system available on the market.

Sealants: I have used Bontrager’s Super Juice which seals a tire casing really well but is very poor at sealing punctures. Slime Tubeless Sealant works very well, staying wet for well beyond six months. Stan’s sealant works well initially, but dries out in a span of three to four months, still keeping the carcass air tight, but the puncture protection falls off dramatically, as you can imagine. Hutchinson Fast Air- Seals up casings really well, but does not stay liquid very long at all and does not provide very good long term puncture protection. Geax Pit Stop works almost exactly as the Hutchinson product. (Note: To be fair, the Hutchinson and Geax products are for inflation/quick repairs. Both companies have a product that claims long term puncture protection.) CaffeLatex: This has been the best available solution I have used so far. It is easily introduced through valve stems and seals punctures very well. It claims the sealant foams up while riding to provide better sidewall protection. While I can not vouch for that yet, it does foam out of my valve stem when I open it. In my still ongoing tests, the CaffeLatex product remains wet going on month five now. Homebrew- I have a home brew that I will not divulge here, but has outperformed everything else on the market I have tried so far with the possible exception of this new CaffeLatex solution.

Next time I will get into the day to day care and feeding of your tubeless tire set ups. Stay tuned!

Going Tubeless: What You Need To Know- Why Tubeless?

July 6, 2009

The tubeless tire discussion really can not begin until we cover the “why” of the tubeless tire choice for cycling. While it may seem obvious to some, this may enlighten a few first timers and there may be a few surprises along the way.

First of all, the cyclists worst enemy is a flat tire. Nothing ruins a rides flow like a flat tire. Tubeless tires can puncture, rip, and leak, of course- so does a tubeless tire help in regards to the flat tire problem? Is it worth setting up your tires tubeless for this reason?

The short answer? Yes! Tubeless tires, while vulnerable to flatting, are far less likely to flat, and if you use sealant in them, they are even less likely to lose all the air in your tires. Here is why: A tube in a conventional tire is not part of the tire casing, obviously. Because of this, the tire casing can pinch the tube between it and your rim edge, or “bead”. This can happen when you strike an object hard enough that the force applied overcomes the pressure in the tube to withstand that force, allowing the tire carcass to pinch the tube against the rim. This is commonly referred to as a “snake bite” due to the usual pattern of two punctures on each rim bead directly across from each other which reminded someone of a snake’s bite, thus the name.

november08testing 049Geax Saguaro TNT tires: Tires that can be tubeless or tubed!

A tubeless tire has no tube, so nothing to pinch against the rim means no pinch flats……usually! One still can pinch the sidewall against the rim beads, but this is very unusual.

But what about punctures? Well, this is where sealant comes in. Sealant- some substance that seals punctures and seals up non-UST tire carcasses so they can be air tight, is a product that comes in many forms. Usually some form of latex sealant is most popular, however glycol based sealants are also somewhat popular for cycling. At any rate, the sealant seals up punctures, small tears, and holes….sometimes…and allows you to finish out the ride.

So, sealant combined with a tubeless tire greatly reduces the chances for flat tires. This is perhaps the single most popular reason for average mountain bikers to run tubeless tires, but there are other benefits.

Tubeless tires, since they do not pinch flat very easily, can be run at slightly lower pressures, enhancing traction. Also, since there is no tube to cause rolling resistance, this makes lower pressures even more attractive. A tubeless tire run at a slightly lower pressure than a tubed tire can get better grip, ride smoother, and have similar or less rolling resistance than the tubed tire. Reduce the pressure on the tubed tire to match and generally you will increase the likely hood of a pinch flat and greatly increase the rolling resistance.

Weight was an early reasoning for going tubeless, but this is not necessarily the number one priority of off road cyclists. Tubed tires, if the tire is a very lightweight folding type, can weigh less by far than a similar model that is tubeless. The extra butyl rubber necessary to make the casing air tight is the culprit. Now days though, there are a vast number of cyclists who convert standard tires to tubeless use by way of sealant. This has met with varying degrees of success and should be approached with caution. We’ll cover a few of the techniques used to do this in a later post. At any rate, tubed tire to tubeless tire weights are very similar these days, especially with conversions to tubeless type set ups.

To recap- Tubeless tires are a great way to avoid flat tires, get better performance characteristics, and may save some weight over a standard tube and tire set up. Now that you know why, we’ll delve in to the “how” of tubeless tires next time. Stay tuned!

Handmade Bicycles: The Custom Experience- Choosing Materials And Builders

March 4, 2009

Editor’s Note: In this series, Grannygear introduces us to some custom frame builders and takes a closer look at the process of making and delivering a custom, handmade bicycle to a customer.

Part 2: The Who, What, Why, Where and When of a custom framenot necessarily in that order.

Why: In the first part of our series I pointed out that a production, ‘off-the-rack’ bike works very well as a viable path to cycling happiness and bliss. So why go the custom route? Well, there are several main reasons that I can think of:

-You are very tall, very short, or have odd body dimensions such as short legs/ long torso, long legs/short arms, etc.

-You have specific needs that a production bike does not meet, such as a certain touring set-up with integrated racks.

-You have been riding enough years to want a very specific set of handling characteristics derived from specific angles, fork offset, frame material choice, etc. and no production bike quite gets there.

-You just want one because you want one. Nothing wrong with that. There is a certain cache’ that goes along with a custom frame.

When: There is some timing involved in the frame buying process. There will always be a wait for the frame since it is being built from scratch…duh…but the time from the first contact between builder and client and the date of frame completion varies a great deal. For a hot builder much in demand, the wait can be a year before you see a frame. The lesson here is do not put yourself (and the builder) in the position of having a drop-dead date that HAS to be met or your trip of a lifetime, racing season, goals for the year, etc, will be ruined. That will just add to the stress level and perhaps cause some very bad blood if things go late. Remember, many of these guys are one man shops. Anything can happen.

What: You will need to decide what you want your bike frame made from. As well, you will need to know, and this is obvious, what kind of frame you want: Cyclocross, road, mountain, geared, singlespeed, rigid, FS, etc. For our purposes in this article, we will be headed towards a 29er hardtail singlespeed. But what should it be made of? There are three main players: Steel, titanium and aluminum.

Steel Steel frame

Steel is by far the most popular material for small shops to work with. There are lots of choices in tubing diameters, butting (the wall thickness of the tube will change over its length), shapes, strengths, ad-nearly-infinitum. This allows for tons of options as far as how the bike will look and perform. Steel is easy to weld/braze and manipulate, requires little prep work, paints or powdercoats well, and, in the hands of a skilled artisan, can produce a fabulous and long lasting ride. It is easy to repair as well. The bad? It rusts and it is not as light as aluminum or as chi-chi as titanium. In my opinion, steel is the standard all other materials are compared to.

Titanium Titanium frame

Titanium is the next material most used by custom shops. Ti is very sexy, lasts nearly forever, is known for a compliant and smooth ride (although that depends a lot on tubing selection), and has a lot of bling if that matters to ya’. It is notoriously hard to produce the raw tubing and it is hard to machine, manipulate, and weld the finished product so it is a big step up the ladder of skill for any frame builder wanting to build in Ti. In fact, a poorly constructed Ti frame is likely to fail rather quickly, usually from bad welding practices. The biggest hit against Ti is the cost. All that difficulty in the process from getting the raw tubing made to the last bit of hand work on the final frameset takes a ton of time and resources and you will pay for that. Beware of a very cheap Ti frame (typically an off-the-rack frameset). Assuming that the build quality is decent, it may not be any lighter or ride any better than a high end, custom steel frame despite the equivalent cost. However, any frame that is truly custom and Ti will likely not be cheap or a compromise in materials and design.

Aluminum Aluminum frame

Aluminum is the final material we will look at. Very common in off-the-rack bikes, it is not as widely used in custom builds. Aluminum is often considered to be the king of light AND stiff. It is very easy to build a light and fast feeling aluminum frame. But, it is much harder to make an aluminum frame that is light, stiff, rides smoothly, and will last. Aluminum is not considered to be an especially forgiving ride and often is favored by riders looking for certain performance characteristic such as a racy, stiff pedaling and solid feeling ride. As with any of the choices, the tubing selection and build approach can affect this quite a bit. A high end aluminum frame can ride nicer than a cheap steel frame. Aluminum has a shorter fatigue cycle than either steel or Ti so a good builder takes this into account when he lays out the design. A custom aluminum bike is a real lightweight weapon and has the potential to be a fast, smooth, stiff and nice piece, but it will take skill to get all of that in there.

Where: Where the builder actually resides is not that terribly important, but there are some considerations worth talking about. If I was an East Coast rider and my riding was best served by a bike built to deal with roots, boulders, quick transitions on tree lined narrow trails, etc, I would look for a builder who cut his teeth in that world and was building for that type of riding. Can a Colorado or California builder make a frame that performs well at Pisgah? Sure he can, but you may need to be a bit more specific as to what you want to get that certain result.

Who: Ah, here is the crux move. Once you have a good idea of what you want and why, it comes to choosing the right builder. This is not to be taken lightly, cuz this is a bit like a marriage relationship (without the perks). Both parties will need to communicate, there will be promises made, expectations will be high, there may need to be compromises and there is a financial commitment. So, here are a few bullet points to consider:

Do your homework first. A lot of the best info you will get about a custom builder will be word of mouth from happy customers. If you hear over and over again how great they were to work with, how they listened to the customer and made wise suggestions, they were on schedule, kept them informed along the way, etc, that is a good thing. What is the biggest knock against the custom builder? Lack of communication and/or over promising and under delivering.

Many builders have a niche or certain passion for a style or technique. Maybe they love a lugged frame or they have thousands of miles on touring bikes. Like that classic cruiser style? Some builders like it too. Perhaps they are a dedicated 29er singlespeeder. If that aligns with your focus as well, this can help.

If you are tall, a tall builder is not a bad idea and vice versa for a smaller person. The bell curve will prove this to not be a big deal, but it is something to think about.

Do you like them? There will be an initial conversation and continuing dialog between the two of you. If the builder is arrogant or seems indifferent, you may have just got them on a bad day or it may be a warning sign. In fact, if you can’t even get them on the phone or to answer an email, do you want to hand them your money and hope it all works out? Maybe not.

Do they have tenure? There are guys that have been building frames for more years than I have been riding them. That type of experience is hard to beat. On the other hand, someone who just hung up his frame builder’s shingle may be cutting his baby teeth on your frame. Or not. Often the newcomers are the guys that are innovating the most while the ‘old guard’ may be sitting around hand filing the perfect lug. Something to consider, in any case.

The last thing that I think is important, you may think otherwise, is the bike builder’s presence in the cycling world, both real and virtual (on-line). Are they involved in the local cycling scene? How about the internet? Is there a blog, website, etc that is up to date and accurate? I realize that many builders may not be computer guys or see the need for a strong on-line presence, but really…if I cannot go to the web for most of the answers I need about a company or product, I wonder what the person selling whatever it is must be thinking.

In the next sets of articles we will invite several frame builders to the table to answer some questions about their craft. Some will be wise old masters of the torch, some will be relative newcomers, but all will have been chosen as fine examples of someone you may want to consider for your next build. Stay tuned as we continue into the world of the custom bike experience.

Salsa Cycles Fargo: Getting Fit On Drop Bars For Off Roading

February 18, 2009

Good news! Salsa Cycles Fargo bikes and frames are starting to be delivered. With that in mind, and due to all of the questions I get about off road drop bar set ups, I thought it would be a good time to post my thoughts on fitting a bike with drop bars with the purpose of off roading in mind. Keep in mind that there are not many ,(or any) other production off road drop bar specific rigs available, so this is new territory for most 29″er freaks.

First of all, there are some things about drop bars for off road that need to be understood. Drop bars off road are not used like drop bars for road going bikes. Not at all! The positioning for your road biker is almost always “hood-centric’. Meaning that the primary position for riding is set up on how well the rider fits on the bike with his/her hands on the brake hoods. Not so with off road drop bar set up. In fact, the hoods are not even really a consideration here. When using drops for mountain biking, the primary posistion is based upon the hands being in the drops. Not on the hoods.

So, is the drop bar a waste of time? Why use one if you can not use the hoods? This is a question born out modern day thinking in terms of drop bars. In the early 20th century, drop bar users never dreamed of riding primarily ‘on the hoods’. Especially since they really didn’t have any hoods! Just bare brake perches usually. These riders understood that dropbars were easier to use on rough tracks and aligned their wrists, forearms and shoulders in the most relaxed, comfortable way without giving anything away to control on a rough road.

Drop bars for off road today reflect this same philosophy, but since most drop bar users are coming from today’s smooth tarmac type set ups, they have a hard time figuring this out. The tall stems, the odd frame angles. What is up with all of that? Actually, this is a great question, and worth looking into. Let’s take a look.

Comparison between drop and flat bar set ups.
In a comparison, the drop bars put your hands in a very similar place in space as they would be on the flat bar bike.

Since the ideal off road position for drops is to be “in the drops” or “in the hooks”, the bars need to be positioned higher than they would need to be with a flat bar set up. There are two main design features that can be employed to achieve this. One way is to use a “sky scraper stem”. A stem with a ton of rise that gets the drop bars up to a height where the drops are usable off road. The other way is to utilize a severely sloping top tube/longer head tube. This automatically gets the handle bars set in a higher plane, and unusual stems are not necessary. Another variation on the top tube/head tube theme is to also use a very long fork.

Custom drop bar bike
Here is an example of a long fork/tall head tube/severely sloping top tube design. It uses a standard Thomson 100mm stem.

These designs get the drop section up to a height where it becomes useable all the time. Your saddle to bar height should be determined at the point where your hand grasps the drop section. I usually go with about three inches from the nose of the saddle to where my hands rest. Take a look at this photo to get an idea.

Saddle to bar drop
The saddle to bar drop is determined at the point where your hands rest in the drops.

Notice that the bar top is higher than my saddle is. This is normal for an offroad drop bar set up. The bar tops are rarely used while riding. In regards to the proper saddle to bar drop, this is a function of the stem at this point. In addition to spacers, you should be able to achieve a great riding position with “normal” stems. Especially with the Fargo. You can see how the longer head tube and sloping top tube work to allow you to achieve this.

Side view
No goofy stems needed here!

Another thing that you can notice here is that by the time I put my hands in the drops to ride, the centerline of the grip section ends up being right about the same distance as the stem clamp on the steer tube is from the stem’s handle bar clamp. In other words, no need to sweat your reach to the bars because of the drop bar thing. If I were to ride on the hoods all the time, then it would be a concern. But as I have shown, that isn’t what the off road drop bar set up is about anyway.

Of course, if drops just don’t make sense to you off road, then none of this will either. That said, there are a couple of things to consider with off road drop bars. In the design of the Fargo, standover clearance is comprmised. If max standover is an issue, than the Fargo isn’t your rig. Also, the drop bars available that work well with off roading are not available in different widths. So if the width of an On One Midge, for example, doesn’t trip your trigger, then you are out of luck with that model. Choices in bars are limited. Finally, the shifting choices are limited as well due to the fact that drop bars do not accomodate mountain shifters. Some make do with road shifters or bar end shifters, but it is a limiting factor for some.

In conclusion, fitting a Fargo is as much understanding drop bars for off road as anything. Once you get a handle on that part, fitting Salsa Cycles latest 29″er will be a snap.

Front End Geometry For 29"ers: Set In Stone- Part II

February 15, 2009

In my first post on this subject, I got some questions in the comments section that I wanted to address in this post, along with some other related topics having to do with front end geometry. It seems that this topic is very confusing to some, of great concern to others, and some could simply care less. To the latter I say, “Go on out for a ride.” This post won’t be of interest to you.

To everybody else, I would suggest you all take a moment to read this short post about “trail as it relates to front end geometry. Once you have that down pat, we can look at head angles and where we are at with fork offsets. To better understand that, take a look at this article on offset. It will help clear up for you why more offset equals less trail/more unstable handling.

Now with the advent of the longer offset forks for 29″ers, what does that do to those older 29″ers that had 38mm offset suspension forks on them? Well, for that I would direct you to my series that I did called An Experiment In Front End Geometry. Looking through those links there, you will begin to see that a pattern developes. One that I think is unique to big wheelers.

That is the natural stability of the 29 inch wheel. It tends to overcome what would would result in an unrideable geometry for most folks in 26″ers. Done up in 29″er wheels, it is a different set of standards. The “window of what works” is a bit wider with the bigger wheels because of this “X-factor”, which is wheel stability caused by the gyroscopic tendencies in a 29″er wheel. So with more offset, we don’t see the instability with 29″er wheels that we might see with smaller wheel diameters.

WTB WeirWolf LT

So how will that affect a bike that has a 72 degree head angle and a newer 46mm offset fork? (A question I see popping up alot lately) Well, it will be a bit different than it was with the old 38mm offset Reba, yes. A bit easier to steer, really. For many folks, a few rides in and they will never know the difference. For some, they will crave the older handling, and either stay with an older Reba, or get a bike with a slacker head tube angle, but in my opinion, these folks will be the exception rather than the rule. I just feel that the “stability factor” of 29 inch wheels will make the changes acceptable for most, and for many it will be an improvement.

Front End Geometry On 29"ers: Set In Stone

February 1, 2009

Since the 29″er was first a reality with the introduction in 1999 of the Nanoraptor in 700c size, geometry for the wagon wheelers has been in flux. It was commonly known that the bigger wheel would automatically increase trail figures with the geometry carried over from the smaller 26 inch wheels. So, to gain back the quicker handling that had been honed in to perfection on the 26 inch side, various things were hit upon to make 29″ers more like 26″ers, at least in terms of turning.

Fox  F-29
Gary Fisher Bikes use a Fox fork with a 51mm offset, but don’t bet on that becoming the “standard” for 29″ers.

Of course, in the early days only a custom rigid fork would address the front end geometry needs necessary to get a big wheeler to steer in a manner that most riders craved. There were some early attempts to change suspension fork geometry for 29″ers, most notably Marzocchi with the special forks made for Fisher Bikes. Trouble was, at the time, most suspension fork manufacturers were loathe to make new forgings to reflect the offset needs desired by what was deemed a small, niche market. So other means were employed to gain some steering quickness back for 29″ers.

Reba crown
Until the 2009 Reba’s came out, all Rock Shox 29″er forks sported a 38mm offset.

Most commonly, the head tube angles were steepened. Most of the time 72 degree angles were used, but some bikes went as far as a 73mm head tube angle. While this worked in theory, the bikes tended to make suspension forks bend backward along the length of the legs instead of activating the damper. Finally the level of sales was attained that made getting fork manufacturers to make new forgings a possibility. The first salvo was launched by Gary Fisher Bikes, just like they did in the early part of the decade. They convinced Fox to manufacture a 29″er fork with 51mm offset. But not only this, Fox decided to also sell aftermarket forks with 46mm offset. This was actually the bigger story, as it turns out.

With Fox on board with 29″er geometry, the other 29″er fork makers were put on notice to make changes as well. Manitou changed their offset in conjunction with Fox, and then for the 2009 model year, Rock Shox announced it too would shed the old 38mm offset from the 26″er days. What Rock Shox did sealed the geometry for 29″er front ends for the future.

2009 Reba Team
2009 Reba’s have 46mm ofset

Now with Fox, Rock Shox, Manitou, and the up coming Marzocchi 44 fork all having offsets nearly identical to one another, it is safe to say that the front end geometry for 29″ers is likely set. The time for experimentation is over. Gary Fisher Bike’s G2 geometry not withstanding, this is the future for 29″ers now. Sure, we’ll see things like through axles, tapered steer tubes, and longer travel forks down the road, but the offset issue for 29″ers is over.

The 2010 Marzocchi 29″er fork will feature a QR15 front axle and an offset nearly identical to the current crop of 29″er forks.

So, look for your 29″er to have some new fangled features in the future, but don’t expect too much change in the area of front end geometry anymore. Some folks will welcome that part with open arms, as just the mere thought of “offset”, “trail figure”, and “head angle” makes their heads spin. Others will lament the pasing of the “old geometry” for 29″ers, because they much prefer the way those early rigs handled. Whatever side of that coin you are on, one thing is for certain, this marks 29″er bicycles as being something that has come of age in the mountain biking world.

Question: Can You Put Road Tires On A 29"er Rim?

January 15, 2009

From time to time I get questions on the site in the form of comments, or e-mails that I like to address with a post. Today’s question is about putting road tires on 29 inch rims. Can you do it? Are they compatible? What sizes are recommended? There are a lot of confusing answers floating around out there, so let’s take a look and see if we can figure this one out………..

Easton XC One wheels These Easton single speed wheels are for 29″ers, but have a narrow-ish rim width suitable for road rubber.

The Fit Question- Diameter: Okay, let’ get this cleared up right away. It is commonly thought that 29″er wheels are a different diameter than everything else out there. I suppose the moniker, “29”er” is to blame, but make no mistake, it is 700c. 700c, or ISO 622mm is the rim diameter for both 29″ers and road racing bikes. In fact, the ISO 622 is a very common rim diameter that is used on a wide spectrum of bicycles. The term- 29″er- refers to the total diameter of the tire and wheel together, with the rim size being ISO 622mm, or as it is commonly referred to as, 700c. Okay? That part is the simple part.

Salsa Gordo rims
A wide 700c rim, like these 35mm wide Salsa Gordo rims, are not suited for road going rubber unless it is 50mm wide or wider.

The Fit Question- Rim Width: Now here is where things get a little dicey. To make it simple, you will need to match your tire width to your rim width after you determine that the diameters are compatible. So, what does that mean exactly? Let’s assume we are using only 700c/ISO 622 rims and tires to keep that part of the equation constant.

A typical road tire will measure around 23mm to 28mm wide. To support the tire properly, and to allow it to function in a way that is safe, the rim the tire is mounted to must be within a certain range. Too narrow and the tire will “roll” or squirm in corners, and too wide will cause the height of the casing to be to low in relatioship to the rim walls. This will encourage tire blow offs and more pinch flat problems, not to mention a higher likelyhood of rim damage. To properly support a tire in this width range, I would recommend any rim that was 19mm wide to no more than 24mm wide. Any wider and you will start to see a drastic increase in the problems I detailed above.

Some 29″er wheels have rims in this range. The Easton set, pictured above, has a 23.5mm wide rim, which should work fine with road tires in our 23mm to 28mm range. What about wider 29″er rims? Well, you would by necessity start to have to look at a wider tire.

A 24mm to 28mm wide rim, which covers a lot of 29″er rims, would probably work best with tires 30 to 35mm wide, the wider rims needing the wider tires in this range. Something on the order of the Gordo (pictured above) would require a much larger tire, say at least a 2.0 inch tire and on up.

I suppose some folks will say that these recommendations are too conservative, but in my mind, it is best to match proper components for the job at hand. (Of course, it could be said that running narrow tires on mountain bike rims is not matching up your components properly in the first place!) Putting a 25mm tire on a 28mm wide rim is not fitting that ideal in my mind, and I would not recommend doing that.

Conclusion: So, the answer to our question is a qualified “yes” with the qualification being that your diameters, while matching for rim and tire, are not the sole determination of whether certain combinations will work. Width of the tire and rim must match within a reasonable range also, or you will be inviting trouble.

Geax Saguaro UST and TNT Tires: First Impressions

December 18, 2008

The Saguaro tires in the UST and TNT versions have been ridden now a bit, so here are some things you can expect to find if you get these tires for your own 29″er.

Geax TNT in the snow

First of all, these tires are just a little bit different than the previously sold folding version. In a side by side comparison, it is easy to see that the TNT and UST versions of the tire are a bit “flatter” crowned than the original. This sets the edge knobs at a less severe angle in relationship to the center knobs. More tread hits the ground in corners because of this, so that vague feeling in transitioning from straight up and down to a lean angle going into a corner is muted. I felt that the tire gripped corners better due to this and no doubt due to the tubeless nature of the tire.

I also feel that the casing is a bit more voluminous, but I have yet to get a caliper on Captain Bob’s tubed folding bead Saguaros to confirm this. At any rate, the lower possible air pressures, different tread angle, and slightly wider casing all add up to an even better tire than before, in my opinion.

Once the trails clear again here in the Mid-West, look for updates on the Saguaros and we’ll do some more winter riding on them in the meantime. (So far, they are working out very well in the snow!) Stay tuned!