Singlespeed & Fixed Gear - Finally, what BB length to match up with RX100 cranks?

Since I've been asking questions, I've narrowed the spec of my soon to be fixey down quite a bit, and even ran across a set of 170mm RX100 cranks. Now, the bike has a fancy new splined bottom bracket in it so that needs to come out. Since I'm buying specifically for a fixey, what spindle length would you fixey folks suggest? I'm going to run a White Industries Eccentric ENO hub in the back and the fine folks at White have already let me know that the offset from the middle of the bottom bracket to the chainring should be 47.5mm, which, for all I know, is a standard. Anyway, that's the latest question I have. Thanks for all the help so far. I hope to order parts this weekend and get this new toy built up sometime in the next week or so.

Since I've been asking questions, I've narrowed the spec of my soon to be fixey down quite a bit, and even ran across a set of 170mm RX100 cranks. Now, the bike has a fancy new splined bottom bracket in it so that needs to come out. Since I'm buying specifically for a fixey, what spindle length would you fixey folks suggest? I'm going to run a White Industries Eccentric ENO hub in the back and the fine folks at White have already let me know that the offset from the middle of the bottom bracket to the chainring should be 47.5mm, which, for all I know, is a standard. Anyway, that's the latest question I have. Thanks for all the help so far. I hope to order parts this weekend and get this new toy built up sometime in the next week or so.
I run a RX-100 on one of my bikes and I use a 113mm. If you can afford to spend a bit more, get the Phil Wood because the mounting rings that install the bb allow about 5mm lateral adjustment either way if you need to address chainstay clearance issues or chainline issues. The bb will last for the lifetime of the bike and they will rebuild it for cheap if you send it to them after 40,000 or 50,000 miles of trouble free riding.
fixedgearhead

Great tip. I looked at the likes of the Phil Wood, but I'm not sure that Wifey will go for an expensive BB and pedals. Since it's damn hard to ride without pedals, I might just start out with something a little cheaper between the crankarms.

Great tip. I looked at the likes of the Phil Wood, but I'm not sure that Wifey will go for an expensive BB and pedals. Since it's damn hard to ride without pedals, I might just start out with something a little cheaper between the crankarms.I started out with Shimano UN-72 and it worked well for me. They have them in 113 at http:\\www.lickbike.com
Good service and cheap.
fixedgearhead

lickbike is pretty cheap. I notice that Race Face has a tapered BB that offers some lateral adjustability as well. Might be worth checking out.

Go to Sheldon's website and search the chainline issues part. He has a listing of many BB/crank and rear hub lengths to check the proper BB length.

PJ

Have to admit, I haven't run across that yet and I thought I had been over the fixey stuff there a few times. I'll look a bit more. Thanks.

Start around here:

http://www.sheldonbrown.com/chainline/index.html

PJ

I guess im even more of a moron, how do you use this info?

Dura ace track cog+ suzu hub is 41.79mm, how do I use this info to determine the bb length?

Read the site man...

Seriously, from what I gather on there. You put a BB and crank on your bike no matter what the length. Measure that chainline (front chainline). Use the chart to determine the rear chainline # 41.79 to you I guess. Determine the difference between front chainline with the BB you have and extrapolate what length BB you would need to be closest to the 41.79

If I'm wrong someone tell me please.

PJBAZ

I think I'll just go with a cheapo 113 or, if my wife will go for it, a more expensive paul or Race Face that will give me some adjustability. It sounds like, from what the folks over at sb.com said in an email, 113 should be fine. I think it might be worth it to go with something that I can tweak a tiny bit and that has cartridge bearings, so I'll see what my LBS can do for me.

pjbaz, what you're saying sounds like what sb.com suggested.

Thanks for all the help, folks.

I got my info from Sheldon himself in an e-mail, although I paraphrased and extrapolated from his site.

Good luck,

PJ

Sorry to drag this up again, but I have those same cranks and a Suzue Promax hub, and I can't figure it out. Hub chainline is 42mm on the fixed side and 43mm on the freewheel. According to Sheldon the standard road double is 43.5mm (41mm inside, 46 outside). Shimano recommends a 107mm BB for these cranks, which would give me the standard. But I want the best compromise for fixed and free (about 42.5mm); if I remember correctly, 107 and 113 BBs have the same length left side, so the extra 6mm is all on the right, which would put it at 49.5 (47mm inside).

I'm off to the LBS in a minute, so I'll ask there, but shall I just put up with 41mm, or go with a 113 and use some chainwheel spacers, or are there BBs around 109mm?

Sorry to drag this up again, but I have those same cranks and a Suzue Promax hub, and I can't figure it out. Hub chainline is 42mm on the fixed side and 43mm on the freewheel. According to Sheldon the standard road double is 43.5mm (41mm inside, 46 outside). Shimano recommends a 107mm BB for these cranks, which would give me the standard. But I want the best compromise for fixed and free (about 42.5mm); if I remember correctly, 107 and 113 BBs have the same length left side, so the extra 6mm is all on the right, which would put it at 49.5 (47mm inside).

I'm off to the LBS in a minute, so I'll ask there, but shall I just put up with 41mm, or go with a 113 and use some chainwheel spacers, or are there BBs around 109mm?

You could get a RaceFace Taperlock at 110mm and use it's adjustment feature to get your chainline perfect. Other than you could get a 110mm and use the inside ring for a 44mm chainline.

Too late, the LBS guy said 107 would be fine, so that's what I have. Thanks anyway.