Classic & Vintage - 70x113 Bottom Bracket for Square Taper Cranks

I have been scouring the internet for said Italian bottom bracket and the closest thing I can find is 70x115 (short of laying out the $$$ for a Phil Wood which I'd prefer not to do). Any ideas on where I might be able to locate a 70x113? If not, is the 2mm going to wreck my chainline? That seems like a big difference. . .

I used Sheldon's chart (http://sheldonbrown.com/harris/bottombrackets.html) to come up with the 113mm spindle length, as I would be putting on Shimano 600 cranks. If this isn't correct, please let me know. Thx.

IRD makes a 70x113, the link below is to the Soma page but most shops should be able to get IRD stuff. $25 is about the normal price. They're very nice rigs, hollow spindle and good bearings.

http://store.somafab.com/irdqubobr.html

Ah, perfect. Thanks so much. Think I'll pick up the Tange threaded headset from them too. Thanks again.

If anyone cares to confirm/deny the 113mm spindle length that would be awesome. Not that I distrust Sheldon, it's just that I'm getting some conflicting info. Thx.

What is the crankset, and what are you shooting for with the chainline? Also, the IRD's are JIS taper, I should have mentioned that.

Also, I'd be careful about that headset, the stack height is really big and they don't say if it's JIS or ISO. It's also about 80% overpriced, but that's soma for you.

Ah, thanks for the heads up on the headset. I'll keep looking.

Cranks are NOS Shimano 600's (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=230162404708&ssPageName=STRK:MEWA:IT&ih=013). And I'll admit I'm entering new territory here. . .Sheldon Brown is my main reference point, so I suppose I'm aiming for 43.5 chainline (?) I'll have a 9 speed Ultegra cassette on the back if that makes any difference. The frame is an early-80's Moser.

I asked the seller if 113mm was correct and here's his reply:
"That would depend on several things - mostly on your frame and front derailleur. A narrower BB was commonly used (108-111) when we had downtube shifters and narrower cassettes. This would give you a much better Q factor.

Shimano has made things much more standardized since STI came out. The newer front derailleurs work best if you have a wider bb. So yes, if you are planning to use this with STI and a newer FD, the 113 would be correct."

My plan is to use Ultegra 9 spd brifters, and I need a new FD b/c my old one was damaged in a collision.

From what I've read about people using 600's for fixed gear conversions, 113 is going to be about right. A mm or 2 is not going to be the end of the world for shimano 9 speed doubles, it's pretty tolerant by nature as each front cog has to be able to work with a lot of gears in the back. Worst case is you have to buy a newer, shorter BB for $25, second worst case is you need a $.50 bottom bracket spacer to move the crank out a little.

I'm intrigued by your choice of cranks, NOS 600 is a little odd to put on a 9 speed bike. If it was me I would resell them to someone who actually wanted NOS stuff from this era and get a 9 speed compact (50/34 or thereabout) double, it's a much more versatile set of gears for anyone but the strongest racers.

Sorry I can't help specifically; figuring chainlines has proven a riddle to me. As Landgolier says, sometimes you just have to try it out and see. Does your Moser take a braze-on FD or a clamped FD? If clamped, you may have to/want to find a period correct FD to go with the cranks. Because modern frames have much fatter seat tubes (or maybe I'm wrong about this), a slightly wider BB spindle may be necessary to get the cranks a bit farther outboard. With your setup, as the seller of the cranks pointed out, you may be better off going with something like a 108 mm.

Also, I'm not sure about this either, but the spacing on a modern crankset is probably narrower between the chainrings to prevent the modern narrow chains from dropping between them. So, STI on the front may not work as well as you hope. Again, I'm not sure, and have no practical experience with it. Just speculating.

STI front spacing isn't substantially different, at least for 9 speed, though some say weird things can happen with 9 speed chain on 8 speed rings. Probably mostly apocryphal, and Sheldon says you have to be shifting like a drunkard to make it happen.

I would just run a recent vintage Ultegra or whatever FD, you can get them in 28.6 and braze on and it will play nice with pretty much anything.

Thanks for all your help! Much obliged! And thanks for being cool about the fact that it's pretty clear I'm not 100% sure what I'm doing over here.

Those Shimano 600 cranks went out of my budget on ebay so I didn't pick them up. My new plan is to go Ultegra 6500 for the cranks which will (obvs) necessitate an octalink BB. This seems pretty sensible to me, but feel free to tell me otherwise.

I guess my interest in the 600 cranks was based around keeping it square taper to be at least psuedo-period correct (this is for an 80's Moser frame I just bought). And I've already got an Ultegra/Open Pro 9spd wheelset so I'm trying to build around that. The whole "period-correct" thing is out the window anyway with 9 cogs in the back, and I'm planning to put brifters on it, so I guess it doesn't really matter.

Oh, ok, I thought you'd won that auction. 6500 will be fine for this, you can get Italian BB's for those. It will be pricey though. There are also lots of good options for keeping it square taper, which as you say is kind of pointless for period-correctness, but will allow you to futz with the chainline if you need to. Old 600 cranks come up all the time on ebay and elsewhere, they will close at $50 or so if they're just plain old VG+ condition rather than NOS. There are also tons of NOS ("O" here being like 3 years old) square taper shimano 105 doubles around which are very good. FSA and Sugino also make great square taper cranks, I think Sugino look wonderful on older bikes. Depending on what kind of riding you do, you might want to consider a compact double (110 BCD crank, 50-34 gearing or thereabouts) instead of a normal 130 BCD with 52-39 or something like that.

Right on. I'll definitely look into the compact set-up. I had been riding with a 42/52 up front and it seemed to be working pretty well, although for climbing I'm looking forward to having a smaller inner chainring so I can keep the spin up more. Living in NYC, the only climbing I do is in the Palisades. This is such a process, I'm learning a lot tho. . .however I can't wait to post build pictures. . .

Totally off-topic, but do you have any 1" threaded headset recs?

Yeah, the compact setup can help you have a much better climbing gear, and in reality 50x12 is not much more usable by mortals than 52x12, so you don't lose much up top. I live in Chicago, though, so anything I say about climbing and gearing should be taken with a grain of salt -- I only shift on account of wind.

I don't get terribly excited about headsets, like so many things nowadays it's pretty hard to buy a truly bad one. The last one I bought was a $20 Tange, I've been very happy with both the finish and the function. Ritchey are fine as well, heck, they probably come out of Tange's molds. Be aware that there are ISO and JIS 1" threaded headsets, Sheldon has all the info on this but basically you just need to measure your frame or your current headset.

I might actually have one of these in my parts bin.

Want me to check?

If you want square taper, you should buy a Campagnolo double and a 111 Campagnolo bottom bracket. They are going cheap on ebay because everyone is freaking out about the new integrated units....

If you want square taper, you should buy a Campagnolo double and a 111 Campagnolo bottom bracket. They are going cheap on ebay because everyone is freaking out about the new integrated units....


That Campy square taper 111 works great for the Campy triple cranks. I have two bikes built with them, and they work very well. I would have thought the double would use a shorter one.......

My local bike kitchen has an Italian (we're pretty sure) threaded sugino bottom bracket that's square tapered, it's not sealed by in pretty good condition.

I might actually have one of these in my parts bin. Want me to check?

Thanks so much for the offer, I just found a NOS Tange headset in Brooklyn for $3. I don't know if I need JIS or ISO though, so hopefully it works out, we'll see.


My local bike kitchen has an Italian (we're pretty sure) threaded sugino bottom bracket that's square tapered, it's not sealed by in pretty good condition.

Thanks for throwing that out there. At this point I'm feeling pretty resigned to/leaning towards either octalink for Ultegras, or whatever is required for a compact double.

I'm aiming to be building it up in 3 weeks max. Many thanks for everyone's help and input, I'll keep you posted.