Archive for October, 2008

An Experiment In Front End Geometry: Final Thoughts

October 30, 2008

The long journey has finally come to a close. The “Experiment In Front End Geometry” series was a lot of fun. I got a lot of positive feedback on this, and I think we all learned a few things along the way.

Sick of this bike yet?

I have to give credit to OS Bikes for making such a fun machine to do this test with. The bike was a hoot, but I’ll post some final thoughts on it in a separate post. In all, I tested eight different forks on the Blackbuck throughout the duration of this test. The bike never flinched, although I did a couple of times!

Muddy Blackbuck

When this test began I never thought I would really like anything other than the On One CabonSuperlight fork that I had on it when I started this testing. I can honestly say that there were some forks that I tried that I could have lived with for a long, long time. There were a couple I just didn’t prefer, but in the end I found out something that I thought perhaps would show through before all of this testing began.

Lenz Lunchbox

It all started after the 2007 Interbike trade show where I rode this bike belonging to Mike Curiak. The geometry was not known to me at the time I rode the bike, but when I found out after the fact what it was, I was astounded. How could a bike with such slack angles and high trail figure handle so well? Maybe numbers weren’t all they were cracked up to be? How could geometry lie though?

Through some e-mails traded back and forth with Mike, I came to a vague understanding that 29 inch wheels were to blame. Yes, the wheel size lets you defy science……well, not really! It would be more accurate to say that the dynamics of the wheel trump the geometry a bit. That is to say, the gyroscopic effect of 29″er wheels allows for things to happen in conjunction with geometry that can not happen with smaller wheel sizes. For one thing, a wider range of fork/front end geometries “works” than with smaller wheeled brethren.

For instance, I was running axle to crown heights anywhere from 430mm to over 500mm and all were rideable on the same frame. I was using these forks with offsets from 38mm to 51mm and all were rideable, which shows that a wide range of fork geometries is acceptable on a 29″er. It may not be your preferance depending upon the specific set up, but the front ends of 29″ers can definitely be tuned to a preferance. The window of opportunity to do that with smaller wheels is much more limited.

So, numbers do not necessarily mean what they did on 26″ers. In fact, you can throw out everything you knew about 26″er geometries, because 29″ers are a whole different ball game. If there is only one thing you take away from any of this, let it be that 29″ers need there own set of parameters. Not only in terms of front end geometry, but in every component made for the big wheeled bikes.

Following are the links to all of the posts relating to this series for quick reference.

Introduction
The Baseline Fork
Fork #1
Fork #2
Fork #3
Fork #4
Suspension Fork #1
Suspension Fork #2
Suspension Fork #3

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An Experiment In Front End Geometry: Suspension Fork #3

October 29, 2008

This is the third suspension fork for the Blackbuck and the final fork in the experiment overall. Let’s see how the Spinner 2Nine stacks up against the previous forks in the test.

Blackbuck with the Spinner 2Nine fork

The Spinner fork is an 80mm travel fork that will reside on the Blackbuck for an extended period for testing. Look for update on this fork in the future.

Head Angle- 72.0 degrees
Axle To Crown- 490mm (unsagged)
Offset- 44mm**
Wheelbase- 42.5″
Bottom Bracket Drop Range (EBB)-51.5mm-62.5mm
Approximate Trail*- 81 mm (unsagged)

Changes Made: This set up was nearly identical to the Reba/Blackbuck set up. Again, the same issue with the saddle and the dynamics of suspension existed with this set up not being quite “optimal” in terms of what I could achieve with the rigid forks in this test. That said, all the suspension fork set ups were very similar.

Handling Characteristics: The first ride out, I wasn’t very happy with the handling at all. It wasn’t very easy to get settled in to the Blackbuck/Spinner combo. It felt almost identical to the Fox/Blackbuck set up in that the steering wasn’t very snappy. This I ended up attributing to a poor fork set up. (I take the blame there!) So, I ran the settings slightly differently and gave it another try. Well, things were much better the next time out! This fork seems to be a rather nuetral geometry on the Blackbuck. Nothing really outstanding in terms of “slow versus quick”. I would say that the current move by manufacturers to the 44mm to 46mm offset range is definitely justified. The Blackbuck shows me that this range is where the handling becomes the most nuetral.

A Note On The Forks Ride: See my recent post on the Spinner 2Nine here.

Final Thoughts: Again, the offsets being proffered by today’s 29″er fork manufacturers make a lot of sense to me. It is quite obvious that the 44mm to 46mm offset is the sweet spot for a “nuetral” handling geometry on a 29″er. In the dynamic world of suspension, I think the manufacturers got this one right. Of course, in rigid forks, I do not necessarily believe that this same offset range needs to, or should be adhered to.

**Note: The manufacturer has not gotten back to me on the exact offset of the example I tested, but I am led to believe by them that it is 44mm. Once the offset is confirmed, I will post an update.

*The trail charts I used all gave slightly different answers and of course, your tire selection will also affect the trail figure slightly. Take my trail figures with a grain of salt. Your mileage may vary!

This ends the testing phase of the “An Experiment In Front End Geometry” series. Thanks for reading throughout the Summer and Fall! Look for a wrap up on these tests soon!

Xtracycle : Quasi Moto's

October 29, 2008

While tinkering with the Xtracycle last week I decided that swapping out the No Tubes ZTR wheels for Blunts would be a smart move before loaded touring/camping.  While doing this I thought to myself “boy I have a lot of clearance, I wonder if I could fit in a 2.0 knobby tire.”  Fit it did, with clearance too if I decided to go mud racing or something with the xtracycle.

Disclaimer: This is a 700c Xtracycle kit.

Here are some photos to show the clearance :

The ride on the road was suprisingly comfortable.  My commute up to work, with 45 lbs of gear and 2.0 knobby tires, only took 40 minutes longer than on my geared commuter biked.  2 hours and 15 mins vs 1 hour and 30 mins.   I don’t think that is bad at all, even if it didn’t have the knobby tires on it I think the time would be good.

I’m really impressed how the 650b handles on the Xtracycle.  I’ll be throwing something comprable on in a 26″ for a week or two soon to be able to really judge.

Edge Composites XC Rims: Update On Wheel Build

October 26, 2008

Well, all the parts and pieces finally came together for the wheel build on the Edge Composites XC rims/ American Classic hubs wheels. I had a devil of a time getting the right length spokes, as the combination of the American Classic hubs large diameter flanges and the deeper profile of the Edge rims made for an odd length spoke. I wanted something light, and well…..weight weenie-ish. So, the choices were limited, but I got the job done. Here are the results.

Edge rim, American Classic hub
American Classic hubs

The spokes ended up being DT Swiss Aero Lite spokes. I know, I know! Some of you may think it is a crazy choice, but I was going for a sub 1500 gram build, and that was the only choice in stock at the places I normally deal with in the lengths I needed. I am quite confident that since these are race wheels that they will hold up just fine. Edge touts their rims ability to have higher than normal spoke tensions, and with 32 spokes in each wheel, things should go well. But…….that’s why we test things here! We will certainly find out soon enough. Edge claims these rims are strong. DT Swiss claims those spokes are amongst their strongest ones. So we will see just how it all holds together.

It should be noted that the nipples are a special design that resemble a flange-less alloy type nipple.They seat against a molded pocket in the inside of the rim cavity, so no part of the nipple is exposed outside the rim. This means that you must true and tension the wheels through the spoke holes in the rim well. Fortunately a proper sized nut driver will suffice in getting the job done since the alloy nipples provided were of a hexagonal shape. One end of each nipple is rounded to mate wih the spoke interface on the rim. The other end has an insert, not unlike a DT Swiss Pro-Lock nipple, that resists the spoke wanting to back off and unwind from the nipple after tensioning.

All this means that if your Edge rimmed wheel set needs tensioning, you would have to remove your tire and rim tape to do the job. Same goes for a spoke replacement. Not a huge deal if you are dedicating these to race duty only, but it might be a problem for every day users. This also would not be encouraging for those thinking about converting these to tubeless duty.

Edge Composites XC wheel set

All this is a little easier to swallow when you see the weights. Front Wheel: 670 grams, Rear Wheel: 770 grams. Looks like my goal was met for weight! No doubt the American Classic hubs had something to do with this. The whole package is just amazing to hold in your hands. The lack of weight is astounding when put in the context of 29″er wheels.

Now we’ll finish off the ensemble with a cassette, rotors, and some tires and (yes folks) tubes! Then we will be seeing how these ride and perform in a variety of conditions and locations. Stay tuned for another update coming up soon!

Specialized "Captain Control" 29"er Tires: Out Of The Box

October 24, 2008

Today’s report filed by Grannygear from Southern California.

Tires make it happen. You can have a frame made of the latest wunder-metal and all the spiffy, high bling parts but if the rubber ain’t meeting the road in the way you need it to, it all means a crummy day on the trail.

Enter Specialized and the Captain Control tire. Along with the Eskar and the Fast Trak, we will be looking at these closely, mounting them up, and getting them dirty. I began with the most versatile of the bunch, the 2.2 2Bliss Control version. This is not the lighter and more fragile ‘S’ version, but the everyday tire that I imagine most will choose to roll with.

The Captain Control
2Bliss

To begin, I weighed the samples at the local bike shop:

720G/750G

Not too far off from the tires I am currently using, a Maxxis Ignitor front and Maxxis Crossmark rear, both 2.1s, but the Captain has quite a bit more knobs going on there then either, especially the Crossmark.

Before I mounted the Captains, I measured the Ignitor/Crossmark to see how the new 2.2s stacked up.

Do they measure up?

I measured the casing width, tread width, and height (including the rim) with calipers. It was easier to measure around the tire and rim and I really am just looking to compare numbers anyway.

Tire model Tread Width Casing Width Height

Ignitor 2.09” 2.1” 2.85”

Crossmark 2.065” 2.08” 2.74”

Captain Control 2.135” 2.085” 2.80”

As you can see, it is pretty much the same size as the Ignitor. I would not mind if it was bigger, but it looks bigger to the eye, likely because of the more aggressive, deeper tread blocks. As well, tires can grow after time, so I will re-measure after a while and see if they grow.

They mounted easily on the Stan’s Flow rims and took a nice, final push to get over the rim. Even better, they aired up with a floor pump, no compressor required. THAT is very nice. They have a nice look to them with a good center set of blocks and pretty large side knobs, and with the dual compound tread, they should roll well and last a decent amount of time. The sidewalls on the non-‘S’ version seem quite sturdy with a shiny layer of rubber over the cords.

Mounted and ready to rage!

How will they perform? Stay tuned.

Titanium, News, and Rumors

October 23, 2008

Way back in April, we reported about On One’s newest project, a titanium Inbred 29″er. Well, after much delay, it is about to become a reality on trails in the U.S. In a short note sent out by Brant Richards, head honch at On One, he had this to say:

The Ti29er frame is now in finishing at Lynskey Performance, and is available to US customers at $1700, shipped within the USA. See more details here:-
http://www.on-one-shop.co.uk/?p=1324.

So, pretty short and to the point, but it looks as though these will finally become a reality. In other titanium rumors and news, we have heard of a new titanium rigid fork that will soon become available with a price tag of around $375.00. We don’t know much more as of now, but we are digging! Stay tuned for any further updates on that fork. Also, we are hearing solid news that another Lynskey produced titanium 29″er is about to be unleashed under another brand name any day now. The very first frames are arriving in a U.S. based warehouse and further details will be released soon. Again, we are staying on top of this story and will post any updates when it is cleared by my sources.

News from Niner: From Niner’s latest web-letter, we have the following tidbits. The figures on the new R.I.P. 9 are just mind blowing. We know it was reported at Interbike, but this bears looking at again. Also, notice their take on 29″er forks, which I have been writing about here for at least a year now, so you know that I happen to agree with them! Here is their text:

70% stiffer tapered headtube – tapered forks available from Fox and Marzocchi and we have verbal agreements from Rock Shox that they will be making a tapered fork, too! Marzocchi option is a 100-140mm travel fork recently developed by Marzocchi with input from Niner. The improved ride quality of the tapered headtube is so noticable that we believe that other 29er makers will quickly follow suit and that this will become an industry standard.

55% stiffer bottom bracket

· 80% stiffer rear end

· Replacable dropouts available to work with quick release,
12 millimeter thru axle, Maxel or Rohloff hub options.

· Hydroformed top and downtube

· Forged links and dropouts: top link is now one piece instead
of 7 and lower link is now one piece instead of 7. Simpler
systems are the most reliable.
Alloy hardware replaces steel axles

· New larger pivot bearings move easier under full compression

· Pivot bearings moved to outboard position to handle loads

· Due Jan-Feb 2009 – contact your nearest Niner Dealer to
pre-order yours now!

· Pricing $1,799 includes headset, Fox RP 23 shock

Other Niner news includes a complete J.E.T.9 offering. Again, from the Niner web-letter:

We are very happy to announce to you we have our first complete fast XC / race bike – the JET9 – now in stock. We’re all hard riders and wanted to spec this bike out right from the very beginning so it could be ridden to it’s full potential right out of the box – Stans Arch rims, Fox F100 RL fork, WTB Prowler tires, etc. MSRP is $4099.

In news from Twenty Nine Inches, we have just taken delivery of a sweet pair of Easton XC-1 single speed specific wheels. Look for an “Out Of The Box” post on these tomorrow. Also, we will have an “Out Of The Box” post on some Specialized tires coming up from Grannygear, a wheel building post with the Edge Composites rims we are checking out, a final post on the “Experiment in Front End Geometry” series, and more. Stay tuned for a busy couple of weeks, and beyond!

Raleigh "Conversion" Professional

October 23, 2008

Joel is Guitar Ted‘s co-worker.  These words and photos are from Guitar Ted’s arsenal!

bike

A little background on Joel and his rig: This is a Raleigh Professional circa 1974. Joel has had it since the late 70’s. Joel has been a racer, bike shop mechanic, shop manager, and now teaches Spanish at a local community college and works part time at our shop. He has been commuting regularly on this bike for 10 years.

For all of that ten years, and actually going back to approximately 1985, Joel has had this set up with 650B wheels. He got them off of a Raleigh Tamarack, a circa 1984 Raleigh “Mountain Tour” rig. (I actually owned a 650B Tamarack for awhile!) The rims are still the same, but Joel laced up a different set of hubs some years ago now. He recently got the Rolly Polly’s on it and loves them!
Joel rode it in just for me on a raw, windy, drizzly day with temps hovering around 50 degrees. He was pretty chilled when he arrived at the shop, but he’s excited about any interest in his bike. He wanted me to wait for him to clean it p, but I started snapping off photos right off, saying it looked “real” if it was dirty.
Notice the lack of a lock ring on the track cog. Joel explains that he always has ridden fixed this way. He never goes without hand brakes and doesn’t do any “tricks”, so he feels perfectly safe without a lock ring.  The bike weighs at 22.5lbs, by the way, with flashlight and soaked Brooks Pro saddle!

Spinner 2Nine Suspension Fork: Update

October 20, 2008

It has been awhile since I have put the Spinner 2Nine suspension fork on my Dos Niner. I made a switch to my OS Bikes Blackbuck recently and have some more to say about the fork. So, sit back and check out the latest!

Spinner on the Blackbuck

With the Spinner 2Nine on the Blackbuck now I have a little better understandng of how this fork stacks up against the “big dogs” of the 29″er world. I have already tested the Blackbuck with a Fox F-29 and the classic Reba fork everyone is familiar with. How did it fair? Well, It isn’t really in the same league as these forks, nor was it intended to be.

The Spinner 2Nine has to be viewed for what it is, an entry level suspension fork. In that capaity I think it fairs fairly well. It just doesn’t have the chassis stiffness that the Fox F-29 has, nor does it have that wonderfully tunable plushness of a Reba. The Spinner 2Nine isn’t terrible, but it isn’t to be seen on the same playing field as the other forks mentioned. What does it have going for it?

Well, it is easy to set up and it has a decent amount of travel that is useable. It feels a bit harsher than a Reba, more akin to the Fox in this regard. In the previous report, I mentioned having a bit of an issue with the mid-stroke of the suspension. I think that I have found a way to alleviate that issue now.

Rebound adjust

I mentioned in the earlier report that I was going to mess with the rebound and that I did. I ended up going to full slow, and it made a huge difference in the way the fork felt and performed for me. I also feel that now the fork is breaking in and coming into its own, which is also lending to the better feelings during compression that were not there before. Now the travel is much smoother and with the rebound set as it is, the fork seems much less harsh.

Overall, for the terrain I recently tested the fork on, it seems to be fine. In harsher, faster terrain, I still feel that the damper gets overwhelmed. The maxed out rebound gets a little “packed up” and the slight flexiness of the chassis shows through. This doesn’t make the Spinner 2Nine a “bad” fork. It is what it is, and it makes no pretenses otherwise.

Interestingly, I was able to chat with a representative of Spinner at Interbike and the company is very interested in feedback and improving the fork. I made my suggestions to them which included getting rid of the cantilever bosses, going to a 32mm stanchion for a stiffer chassis, and made some other suggestions regarding the lowers and aesthetics. It will be interesting to see if Spinner makes some changes. I am hopeful that they will.

I am going to give the Spinner 2Nine some more trail time and come back with a final asessment in a week or so. Stay tuned!

Edge Composites XC Rims: Update On Hubs

October 18, 2008

The first step in getting the Edge XC rims going is to gather some wheel building components and get to building these beauties up into a usable set of 29″er wheels. To that end, I contacted American Classic and purchased a sweet set of their new Disc 130 front and Disc 225 hubs to lace to these Edge rims.

American Classic Mountain Disc 225 and 130 hubs

These hubs are pretty light. As the names of each suggests, the numbers refer to how much each hub weighs in grams. The rear weighs 225 grams and the front weighs in at 130 grams. That’s not too amazing for a rim brake hub, but for a disc hub it is pretty amazing.

Another look

Just about every aspect of these hubs has been scrutinized for weight savings, strength, and performance. The hubs both sport 17mm axles and sealed bearings set as widely as possible within the hub shell. The large hub flanges help with shortening the overall spoke lengths. Those flanges are also milled out, with the exception of the drive side on the rear hub, for light weight. The rear hub features the patented cam actuated 6 pawl engagement system and (new for this year) steel inserts on the free hub body that prevent your cassette cogs from digging into the aluminum splines.

Cassette re-inforcements in steel

These spline re-inforcements are an ingenious way to alleviate a frustrating problem when it comes time to swap out cassettes, and it only adds a few grams. This feature is found across the entire range of 2009 American Classic hubs.

End view

The quick release levers are a new design for 2009 and are available in a chro-moly shafted version and a titanium shafted version. In terms of a 29″er, the steel quick releases are preferred, especially when we are dealing with disc brakes. The steel versions only add a few grams anyway. Well worth it for our intended application.

Stay tuned for our wheel build up, and then it is on to testing!

650b Tires : Outside Diameter

October 17, 2008

There is a great topic going on over at the 650b listserve.  Tires, depending on the manufactor, even with the same width might have a different outside diameter (OD).  This could be due to the rim it is on, the amount of rubber tread, thickness and so on.

Here is a list that Longleaf Bicycles started on Google Docs.

Do you have any information to add to this list?  Input on how some of these tires run? Let us know!