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MountainBikeReview.com's Forum Archives - Singlespeed
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BB width, chainline, etc (8 posts)
|  BB width, chainline, etc | VetteRacer
Apr 17, 2002 5:03 PM | | I am thinking of getting a new frameset for my bike. And making my current ride into a SS for the hell of it.
I have a 3x crankset that is spare, was thinking of making it a 1x. But I am wondering how chainline (and BB width) come into effect when I change the rear out. I havent looked at any 135 SS bikes to see how everything lines up. I am wondering if you use the same BB width as the crank recomends (113) or if a wider one is needed (I have a 120 also).
What ratio is a good one to start with? The crankset is 22/32/42.
Also, without starting a new topic or trying to find old stuff, can someone do a brief description of what these EBB's do for you?
Thanks all
Matt
BTW, for those that saw my other post (Full susp SS), I have a Trek Y33, so chain length doesnt vary, so I should be ok there. |
| Start with... | SS_MB-7
Apr 17, 2002 5:24 PM | | Try 32:16 to start with. Most SS' use a 2:1 ratio.
What are you going to be using as a rear wheel? A converted geared-MTB wheel or a SS-specific wheel?
If you are using a converted wheel, chainline won't be too much of an issue since you can use spacers to move the cog left/right to match your front chainline. SS-specific wheels require a specific front chainline that can only be achieved by a longer/shorter BB spindle and/or mounting the ring the inside/outside of the spider.
If you are going with the converted geared wheel, get a Shimano DX cog. These are non-ramped and have longer teeth so they'll minimize chain-throws. But, if you are using a wheel with an aluminum freehub body, be careful as the single cog can dig into the body.
E-BBs (eccentric bottom brackets) are bottom brackets within an oversized shell.
E-BBs allow disc brakes to be used on singlespeeds. Instead of using the rear wheel for chain tension, the e-BB allows the bottom bracket to rotate in the oversized BB shell to achieve chain tension. Since the rear wheel is in vertical dropouts, the rear caliper and rotor are always aligned. Some SS builders opt to use horizontal dropouts with disc adapters, etc. but IMHO, the e-BB is the ideal solution. I've been racing on mine for 1+ year and I haven't had a single issue with it.
Ride Hard,
Mike B. |
| Start with... | VetteRacer
Apr 17, 2002 8:32 PM | | I would like to use the standard hub, since if I go SS it will be out of spare parts for the most part, and like to do it as cheap as possible right now, new wheelset is pushing it.
Whats a good SS site to visit for parts like that?
So you rotate the BB everytime you replace the wheel?
Matt |
| Start with... | Chequama Mama
Apr 17, 2002 9:04 PM | | Just to make sure you understand, an e-bb requires a special frame with a bigger bb shell.
For dx cogs, non-ramped chainrings, cog spacers and possibly a tensioner go to your lbs. If you don't have an lbs, www.webcyclery.com has ss stuff.
Non-ramped Front chainrings aren't as important, but are nice. Engagement rings (from QBP) are pretty cheap and most shops can get one. Or you can just make do with ramps. I raced an entire season on a ss with ramps on the front ring with basically no problems. A little chain dropping problem in once race but that was it.
DX cogs-do it, not ramped workes way better and they're <$5
While I'm at it. Gearing doesn't necessarily need to be 2:1. Depending on where you are you might want to go easier. I run 32:19, but 32:18 would be a lot easier to find parts for.
You may not need a tensioner. There's a website that will help you figure out which gear combos might work with your chainstay length. I believe it's
www.peak.org/~fixin
but I could have the url wrong.
If you do need a tensioner. You can either:
1)use your rear derailler with the limit stops screwed in or with a piece of cable ala keith bontrager (go to his website and rants and look for the singlespeed one)
2)use your existing derailler and modify it. there are a couple of ways to do this. Maybe some other folks can post pics if they've got 'em.
3)go buy a surly singleator, or paul melvin
of course also check out
www.sheldonbrown.com
he knows his shiznit.
I think that's about it
Paul |
| Thanks... | VetteRacer
Apr 17, 2002 10:13 PM | | I am aware about the EBB being frame specific. Had seen posts below talking about it, just couldnt figure it out.
These are the cranks I plan to try out, going to make them a single speed crank, they are 32 tooth. Here
That Surly one looks like a winner to me! Should work for what I want. I gave a buddy the XT cassette of my bike when I went to XTR, the one he took off had individual gears, not sure if ramped or not. I'll give him a call and grab those. What can I use for spacers?
Thanks again all
Matt |
| I knew I was forgetting something | Chequama Mama
Apr 17, 2002 10:54 PM | | You can get spacers in a ton of different places.
One option is to take apart old cassettes by punching the pins out of them and use the spacers from them. You can also use pvc pipe sections. You can go down to your local bike shop and mooch misc. spare parts to make it work (this is what I have, parts of coaster brakes, and a bunch of other stuff, including honest to goodness cassette spacers). |
| I knew I was forgetting something | VetteRacer
Apr 17, 2002 11:15 PM | | Lol... I'll have to hit up my friend/LBS owner and see what he has. He runs a SS with a freewheel, so he's not too usefull for my idea :P
PVC sounds good. I will also have to check my campy cassette spacers, see if they fit on a shimaNO hub :)
Matt |
| You only touch the e-BB when... | SS_MB-7
Apr 18, 2002 4:27 AM | | Nope, you only touch the e-BB when you either change gear ratios or you want to tighten your chain due to chain-stretch. This is easily done on the non-drive side via 4mm allen key, which loosens the e-BB shell, and either a pair of Park spanners or your fingers to rotate the e-BB within the shell. Then, tighten.
To remove the rear wheel, just simply loosen the axle bolts or quick-release and drop the wheel out. No fiddling with adapters, etc.
Ride Hard,
Mike B. |
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