Single Speeding And 29"ers: Which Method Is Best?

All along, single speeding and 29 inch wheeled bikes have seemed to be like “pie and ice cream”, like they just belonged together. Certainly there are reasons for that, but since a preponderance of single speed mountain bikes are 29″ers these days, it has come to my attention that the method of chain tensioning is not at all agreed upon, nor does one method go hand in hand with 29″ers.

Let’s take a quick look at the contenders for the tensioning job and point out some pros and cons.

raleighcxss 011
A stainless steel faced track end.

Track Ends: Track ends, or horizontal drop outs, are the oldest method of tensioning a chain for a single speed drive train on a bicycle. It is extremely effective and extremely simple. Most commonly used on bicycles built to be ridden in velodromes, or “tracks”, the track end got its name from this use, but now you see this type of drop out in wide use today on fixed gear bikes and some mountain bikes. Track ends require the use of bolt on axles for the most part.

Pros: As stated, these are simple. There really isn’t much you can do wrong here, unless you get the wheel bolted in crooked. The track end is mechanically sound, and speaking of sound, it is silent in use. They are durable too, and with no moving parts to get lost or futz with, these seem to be the perfect solution to tensioning a single speed bike, unless………..

Cons: Well, unless you are running disc brakes, have trouble with slipping the axle forward, and if you want to have the versatility of running gears. Disc brakes are really the biggest problem here. (Karate Monkey owners all say “Amen!”) When you change gearing on a disc braked single speed with track ends, you also have to adjust the rear brake caliper. This also may or may not come into play while removing a wheel, where some issues may arise with getting your rotor to clear the caliper. Sometimes loosening the rear caliper is necessary. Another con is having to use a chain tug, which is necessary if you are getting axle slip. This adds complexity to what is supposed to be dead simple. Not a deal breaker, but also not great. Finally, running geared will require some sort of additional piece on your drop out to accommodate a derailluer, or if the frame is like a Karate Monkey, and has a integral derailluer hangar on the drop out, you may need to use a special “plug” to keep the axle from moving from the ideal position in the track end. More futzing! Not to mention the fact that you probably will need to carry a wrench to remove the wheel anyway.

osblackbuckg-teds 008
Eccentric bottom brackets come in many variations. Here is a split shell type.

Eccentric Bottom Brackets: No, we’re not discussing bottom brackets with odd behaviors, this refers to an insert in an oversize shell with an offset threaded aluminum hole that you thread a traditional bottom bracket into. This then can be rotated, and effectively “swings” the bottom bracket in an arc that can be used to tension a chain. The method of securing the aluminum insert into the over sized shell that is part of the frame varies. Some use an internal expanding wedge, like a Bushnell eccentric bottom bracket. Some use a “grub screw”, or pinch bolt that essentially pushes the eccentric into the frame from one side. Then there are split shell eccentrics which, as the name implies, have a split outer shell that is fitted with threaded bolts that pinch down upon the aluminum insert, preventing unwanted eccentric rotation. All use a traditional vertical drop out in the back that allows for easy wheel removal and the use of quick releases.

Pros: Eccentric bottom brackets allow for the use of a traditional drop out in the rear of the bike which means you can use a traditional quick release instead of a bolt on axle. No chain tensioners, no messing with disc brakes, and if the drop out has a derailluer hanger, conversion to a geared set up is a breeze. So, why isn’t this the best method?

Cons: Eccentric…creak…bottom brackets can….creak!…be noisey, which can be rectified, but usually requires a tear down of the bottom bracket assembly. Not easy. Sometimes they are prone to seizing up, which can be really annoying, and the opposite, slipping, is also an issue. Some eccentrics, especially the pinch bolt type, can cause a frames EBB shell to ovalize, thus ruining the frame. Not to mention that in general, frames are heavier with an eccentric bottom bracket.

Sliding drop outs, like the one shown here, have been widely used as a chain tensioning solution for single speeders.

Sliding Drop Outs: As the name implies, these drop outs move, or “slide” in a slot to achieve tension on a chain. Like the eccentric bottom bracket, sliders allow for the use of a quick release. There are several versions of sliding drop outs in use, but in principle, they are all basically the same.

Pros: Sliding drop outs can be set up to have the brake mount be part of the slider. This makes for trouble free wheel removal. Of course, a quick release can be used, and adding a slider with a derailluer hangar is usually an option. So why aren’t sliders the way to go?

Cons: Sliding drop outs can slip, making your chain tension go slack, and can cause you to throw a chain. Not only that, but on bikes with tight tire clearances, a slipping drop out can cause contact with the tire and frames chain stay. Getting a slider to stay tight requires extra washers sometimes, and getting enough tension on the slider bolts without stripping out threads or rounding out bolt heads can be tricky with some designs. Sliders look clunky to some, with the bolts and modular pieces breaking up the lines of a traditional seat stay/drop out/ chain stay look. Some designs are cantilevered out from the junction of the seat and chain stay to the point that breakage of the frame is a concern.

Conclusions: While each style of single speed chain tensioning mentioned here is popular, not one can be agreed upon, and each has its detractors and fans. All are in use on 29″ers. I have used all three extensively and in several variations. I have experienced problems with all three, and have had great success with all three on separate bikes. In my opinion, I like the EBB or slider best because I can use a quick release. Of those two, I like the way an EBB system looks the best, but I have ridden creaky EBB’s that drive me nuts, so that isn’t always a great way to go. That said, in my opinion, my choice for the best chain tensioning device is the split shell eccentric bottom bracket. I do like several sliding systems, and the new style that will be coming on the 2010 Superfly SS is very intriguing. That said, I’ll be happily single speeding on about any of these styles of chain tensioning devises on any given day! They are all great when they work, and besides, I like bicycles!


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No Responses to “Single Speeding And 29"ers: Which Method Is Best?”

  1. Lee T Says:

    I have to say that the track ends on the 2009 SS Superfly are pretty awesome – the disc mount is about as friendly as it gets. The ’10, as you point out, will be intriguing as well. My Fly never creaks, and has not, so far, lost tension, even with QRs.

  2. dblspeed Says:

    Track ends a la On One and you’re golden, no more wheel slipping forward under (disc) braking, ease of caliper aligning etc. Much better than plain horizontals and no creaking like ebb, easier to setup than Paragons. And if you want to run gears all you need to do is slap the wheel all the way forward.

  3. Willie Says:

    GT-What about the derailleur type swinging chain tensioner type? I hope you know what I mean. FYI, I think the sliders look way COOL! Plus, they are the most versatile type of system.

  4. Guitar Ted Says:

    @Willie: We’re discussing original equipment solutions, not conversions of geared frames, but yes, I am aware of derailluer hangar mounted tensioners. Tensioners such as these, or the White Industries ENO hub are outside of the scope of my post here.

  5. Dogdude222 Says:

    GT – You forgot one more disadvantage of the EBB. Adjusting chain tension can sometimes require adjustment of saddle position.

    Another advantage of sliders: one can minimize chainstay length, while still maintaining a comfortable level of tire clearance with the seattube/derailleur/stays.

  6. GenghisKhan Says:

    Sliders on my On One–not too bad, but certainly not perfect. Easy to tension when changing rear cogs and no adjustments to the brake are necessary. Though, as GT mentioned, certain not the prettiest set up, but I soon forget about that when I start riding!

    Peace! Now, get out and ride more!

  7. MG Says:

    I’ve found my El Mariachis (I have two of them), which are well-built Bushnell EBB-equipped bikes, to be noise-free and totally trouble-free over their entire life. I haven’t had to do any unnecessary maintenance to them whatsoever. My oldest El Mariachi, the green one that’s almost two full years old and is my dedicated singlespeed, has only had the EBB pulled to be lubed once, and it remains creak-free to this day. I just adjusted it last week when I changed cogs on the rear and it was super smooth and easy to adjust. When people complain about EBBs creaking, slipping and doing funky stuff, I just don’t know what they’re talking about, because it simply hasn’t happened to me over the two years I’ve been thrashing the piss out of the two I own. I know a quite a few other guys who have ’em too, and I don’t hear them bitching about ’em on rides either, which suggests to me that they’re holding up for them too.

    That’s all I know… Horizontal dropouts work OK too, if you beef up the drive side so the QR doesn’t let it slip. That’s why things like Monkey Nuts exist — because QR skewers aren’t strong enough to hold tension on rear wheels in dropouts. They certainly are good from a cost and weight standpoint though.

    Sliders need gnarly washers to hold them in place… The Kona I had slipped pretty badly with the stock washers it came with. I found some hardware store solutions that worked OK though…

    There are some interesting swinging dropouts that might offer new options. It’ll be cool to see where that goes.

  8. MG Says:

    Dogdude222… The saddle position thing doesn’t really work out to be that big of a deal. I’ve been surprised at how little I’ve had to mess with my saddle position on my El Mariachi as I use different gears and EBB positions, and I’m a notoriously finicky saddle positioner.

  9. trainwreck Says:

    here’s a question. why have we not seen a sliding verticle dropouts with a post mount? the thing that drives me nuts about all these single-speed hub interfaces is that clunky looking disc adapter that has to be used. now yes i could go with an IS mount rear brake, but i don’t like the adjustment capabilities i get with them. am i missing something? it seems like it would be relatively easy to do. only one i’ve seen so far is on those Civia bikes.

    and what is this new superfly dropout you are talking about? did i miss the pic somewhere? or is it on MTBR or something?

  10. OptimusGRRR Says:

    You forgot mine: magic gear ratio!

    Pros: Awesome.
    Cons: None, unless you don’t ride 32:20 on a Niner AIR9 exclusively.

    Word Up.

  11. Kid Riemer Says:

    The method that works best for singlespeeding with 29’ers is to pedal your bike. If the trail becomes too steep and you no longer turn over the cranks, you should dismount and push your bike to the top. Once there, remount your singlespeed 29’er and continue pedaling.

  12. jimmythefly Says:

    Probably not a big deal for mountain 29ers, but for city 29ers or for city bike internal hub conversions having vertical dropouts is nice when also running fenders.

    Speaking of, are there any 29ers with good ol horizontal dropouts, like an old road bike?

    I’m intrigued by the magic gear ratio concept, especially considering that you can get half-links for your chain. Google “fixmeup” to find one that shows a nice chart of available ring/cog combinations that’ll work with whatever chainstay length your bike has.

  13. MG Says:

    Opti… I use the Magic Gear scenario on the one little wheel bike I still have built — my ti Bontrager — and it’s a sweet setup.

  14. Jeff Says:

    All of the above mentioned chain tensioning methods work.. which is good. More options is good.. I have my favorite.. you have yours.. life is good. I like my SS.

  15. Spanky Says:

    If your EBB creaks take it out clean it and give it a good coat of antiseize compound. I did it to both of my bikes and haven’t heard a peep out of them since.

  16. mtbboy Says:

    I have ridden all as well and my New Waltworks has the paragon sliders and they don’t slip. Love them. Simple and quiet. Easy to adjust. Home run. Thanks Walt!

  17. Shop Mechanic Says:

    @trainwreck The reason why you don’t see rear post mounts is because it is expensive to do and not really any lighter. Because the brake mount is on a plane that is inboard from the inner dropout face it requires that if you are doing a machined dropout you have to start with material that is twice as thick and machine away most of the additional material which gets expensive. In the end you have the same basic structure minus 2 bolts. It would definitely look better though! Doing a cast or forged dropout is also more expensive because of the increased complexity of the varying thicknesses of the mount verses the dropout, and extrusion is out of the question unless you want to do a lot of machining on top of it. I know, its a bummer. But I think that many manufacturers are going to make the investment because that is what riders want and might be willing to pay for.

  18. trainwreck Says:

    argh! i am ready to pull the trigger on a handmade frame and don’t know what system to use so this is a relavent article for me. i own a pinch EEB and verticle sliders already. i prefer the verticle sliders, but want the cleaner look of the post mount.

  19. GenghisKhan Says:

    @trainwreck: “You can’t always get what you want… but if you try sometimes you just might find you get what you need…” ;o) Good luck!

  20. Guitar Ted Says:

    @GenghisKhan: A good Rolling Stones reference is always appreciated! 🙂

  21. GenghisKhan Says:

    @GT: Not to be contrary, but as old as Mick is/looks, I was born in 1162 AD, thus you might want to let the Rolling Stones know that they have made a good Genghis Khan reference… 🙂

  22. jonnyB Says:

    @trainwreck: trek 69er SS has post mount sliders. The sliders look different then all the others with their vertical tension bolts. But they do a great job. However that bike only half belongs a mention on this site 😉

  23. grannygear Says:

    Am I the only one who finds the Paragon sliders homely? they may work well, but they are sure not complimentary to a sleek and clean look.

  24. Jeff Says:

    I like paragon sliders, almost as much as a low maintenance wife. . they have a lot in common.

  25. Optimus GRRR Says:

    I didn’t know someone was making low maintance wives. Probaly not made in the US.

  26. chuckc1971 Says:

    Anyone ever checked out the Black Cat Cycles tensioners?

  27. BearSquirrel Says:

    If you use a irregular shaped rotor, you don’t have to adjust the rear caliper on the Karate Monkey. The Avid Roundagons are perfect for the job. Just rotate the wheel to one of the “low” points and the wheel comes right out.

    If you do have a “just plane round” rotor. You can use a grinder to produce a small flat spot in the rotor and get the same effect.

  28. Wheezee Says:

    Don’t do what I did, and pull out your ebb before checking your chain ring bolts.

    Just because it’s creaking down there, and ebbs are creak-prone, doesn’t necessarily mean your first suspicions are correct!

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