Singlespeed & Fixed Gear - Using BB Length to Adjust Chainline?
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01-31-07, 01:32 AM
I'm an idiot...Mod please delete this thread.
01-31-07, 06:56 AM
This is something I was going to post but I wanted to see what info was out there before doing so.
This is something I would like for someone to confirm.
A newbie like me needs this info.
I am beginning to believe that this is the case.
But what are the mechanics behind it?
01-31-07, 08:18 AM
Briareos - post what you did here as this is useful info for some.
01-31-07, 02:12 PM
I found this on the everything2 website.
Us newbies can benefit from info like this. It's the reason we join forums.
"Adjusting chainline can be done at two locations, of course: the cog or the chainring.
At the chainwheel end, you can change a number of things to adjust where it will pull the chain. Bolting the chainring on the opposite side of the crank spider, using chainring spacers, and using a different chainring (if it has more than one) are all easy, cheap ways to move your chainring around to the left and right. If you are desperate for a nice change, you'll have to remove your cranks (requires special tools), remove the bottom bracket (requires special tools), and get a new bottom bracket with a different spindle length or just a new bottom bracket spindle and install these (special tools required), and reinstall your cranks. As you can tell, this is a difficult and somewhat expensive process if you don't already own the tools needed. Luckily, your LBS will probably be happy to help you for a more reasonable price. If you want a perfect chainline that looks like the bike was built for, this is the way to go.
At the cog end, you can do very little. The only thing you can really do is push the cog a little bit further out from the hub with a spacer, such as a large washer or an old bottom bracket lockring (availabe at your LBS, of course). Another possible alternative is to adjust the spacers on the axle itself. This will push the entire wheel to the left and right, so you have to watch your tire clearance. Moving the wheel around will affect the look of the bike drastically, and may affect the ride itself. Most people would recommend moving the chainring instead, but if you've already reached the end of your wallet and need to get a little bit more, try moving the wheel. Don't say I didn't warn you."
You guys may know this. I posted it for those who need to.
01-31-07, 02:18 PM
a couple things that weren't mentioned. although i think it's a janky solution, you can get bottom bracket spacers for your drive side.
also, phil wood bottom brackets are adjustable so you can dial in your chainline.
for most of us, the way to go is to either guess and check with bb lengths, or do our homework. where else...
01-31-07, 02:21 PM
A little off topic but to dial the chain line on my bike. I tried moving the chain ring frst to the outside and it was way off, when on the inside it hit the chain stays. Thanks to someone on line I got the idea to flip the spindle in the BB so the short end was on the drive side and then run the chainring in the outside and it came out perfect!!
01-31-07, 02:32 PM
These are all great Ideas!
They make me less "anal" when it comes to chainline.
01-31-07, 04:20 PM
[I deleted my thread because I already posted a similar one and quickly after I wrote it, I checked Sheldon Brown and it explained to me one of the things I was wondering about]
I was curious if I could use a BB with a shorter spindle so I can place the chainring in the proper position outside of the crankset. Furthermore, it would allow me to put my chainring back on the outside of the crankset, where it rightfully belongs!
I may run a geared bike with one chainring, so if I can get the outside ring of the crankset to be in the middle position relative to the gear cassette, I'd like to. I may use a track crankset if I can. This is for my next fantasy build: time-trial bike, that will be simple or fixed-gear.
I am an idiot...Because I already asked a similar question a while ago which answers lots of questions, and features Sheldon Brown.
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