Help with replacement bottom bracket/crank sizes
 

Working on an older bike here (peugot mtb). I pulled the stock BB that is basically 2 open face bearing cages and a square taper shaft. I would like to replace this with a sealed cartridge type bb. I was hoping to replace just the BB, but I am having trouble finding one this size. It is a 68x133, but is threaded. I did not measure the threaded portion, of course. 68x110 or 113 seem to be more popular, and also all the ones I see use crank bolts instead of a nut to hold the crank on.

So, I was thinking if I could find a reasonable price replacement set, crank and bb, I might do that. I am completely stupid though on knowing what size BB I can use with what crankset. Or does it matter, or what? Basically at this point I am lost.

I should mention, this is a single speed conversion that has gotten out of hand. I knew I shouldn't have taken the whole thing apart!!!

Thanks for any help.

It's an old nut type spindle.You sure you just measured end of taper to end of taper? I have never heard of a 133. If you use something shorter,the chainrings will interfeer with the chainstays. You are best off buying a crankset where you know what BB spindle length it takes,otherwise it can be trial and erroe finding the right one. Unlees someone knows what the crank takes.

Before you invest too much time and money in the conversion, make sure you have an English/ISO bottom bracket. If your Peugeot was made in Asia or Canada, this is guaranteed, but older French-made Peugeots have harder-to-find metric (French until about 1980, Swiss thereafter) BB threading. Phil Wood makes superb cartridge BBs and offers all four major thread standards, but these are pretty pricey for your bike.

WEll, I had bought a Chinhaur 68x111 before I was fully aware of all of this off ebay for .01, and it threaded in fine.

Attached a crappy pic I took with my Palm Pilot to show the length.

anyone ?

What??..............

If its too narrow, you will know when your crank arms strike the chainstays.

...or the chainrings, and even if everything clears,the derailer may not be able to swing in far enough, without hitting the seattube.

Yeah, you have opened a can of worms... how are you single-speeding it? do you have the replacement cranks on hand? The way you're going about it, you're not going to get good chainline without a lot of trial and error.

OK, so not really getting any help here. Seems people aren't reading everything I wrote.

1. not worried about a derailer because it is SINGLE SPEED!
2. I kindof figured that too narrow would hit stuff, thank God for college.
3. Trial and error sucks
4. Like I said, considered new cranks, don't have anything yet.
5. Bought a new rear wheel with a SS conversion kit designed to place the cog at the 5th position according to the instructions.
6. The 'anyone" was because a few replied and then nothing so I was wondering if "anyone" had something to contribute.

If I took this to the shop and dropped it off I doubt they would just go around grabbing BB and cranks and trying stuff until it fit. There has to be some system here. I don't see BB width listed anywhere cranks are sold, so I am assuming BB width is more a product of the bicycle design and cranks are somewhat "universal" as the less changing part of the system. If that is not true, then can someone tell me how I can tell what size BB a certain crank is designed for?

I did go to the shop and told them what is up, but the bike was not with me of course. They seem to think I am stuck with the BB as wide as it is. I wonder if there isn't some way to replace just the bearings with a sealed cartridge bearing. That would be my biggest issue, I don't like the open cage design.

I hope I don't sound too ungrateful, but I just get worked up when people reply without either reading or understanding or when they just throw out the "your screwed" comment. I would rather nothing. I sincerely appreciate those who have tried to help. Thank you immensely.

Cranks aren't universal.Every crank made has a spindle length that goes with it to give correct chainline.Some small variation is possible.You want to know about the most popular current stuff, like shimano and campy,get their catalogues or go to their website.Most other makers have websites.Learn to use Google. Sheldon Brown has a crank/spindle data base,which is far from complete.Want to know about older stuff. Fiddle with alot of bikes and put it all in your database. Have something you don't have a clue about,experiment.You can't replace just the bearings on that type BB with cartridge bearings.You could get a cartridge type BB, if you can find the corect length,which i don't think exist.

Well, I have been using Google since before anyone knew what Google was (8 years at least). I have done hours of research on this and stil not found what I need. I am somewhat new to bikes, but I know how to research.

I find it interesting that none of the online shops list anything about spindle length with any of their cranks. Seems that is something that should be listed if it is this big of a deal. TruVativ does list their SS cranks as working best with a 113-118 spindle I just discovered (thanks for that tip), so I guess they are not going to work here. Shimano has a crappy website design and I am not finding much. I might do some fitting with what I have and see what I see. Anyway, thanks for all the woderful help :D . This inviting attitude is sure to draw in the masses!

I guess here is a question no one has addressed. So, I have this 68x111 BB sitting here, if I were to buy a crankset designed for this BB size, would it work? I am guessing no.

hate to tell you, but when you try to do single speed with a bunch of mismatched parts, esp those not designed specifically for single-speed/track application, it is a lot of trial and error. At my work, probably one of the most common things said to customers looking for "standard parts" is that nothing is standard.

If you bought a new wheel, which i'll assume is cassette since i've never heard of a single-speed kit for a freewheel wheel, and you buy a crankset that is supposed to take a 118, and your frame is straight, then yes, theoretically you'll have an OK chainline from the middle chainring to the "5th position on the cassette," which is more or less the middle, assuming this is a 8,9,10-speed wheel. Theoretically.

what kind of dropouts do you have?

I had a freewheel wheel, but being so old it wasn't worth truing up when I could get some new OE pull offs for pretty cheap. They are freehub design.

so you have a 68×111 that "threaded in fine". i assume that you mean you were able to reassemble the bottom bracket, tighten the adjustable cup/lockring properly and have a nice, smooth-turning spindle with no side-to-side or up-and-down play. okay. now you want to attach a pair of cranks to this spindle, correct? have you tried the cranks that came with the bike orginally? dafydd is correct that trial and error is an inevitable part of what you are trying to do.

the only reason i can think of for not using the cranks you already have is that you cannot physically put them on the spindle. the perfect combination of cranks/spindle is not a matter of life and death; there are things you can do with the rear wheel to improve your chainline. in fact, i can guarantee your rear wheel will need some fussing with. if the cranks you have are totally useless, find another cheap set somewhere, preferably from a bike someone is throwing away. this is the essence of "do it yourself". good luck!

The 68x11 threaded in, but I didn't full assemble it. Someone had mentioned checking the thread sizes. I have not tried to attach the cranks to it yet. Right now the paint is drying and I can't attach anything for a few days.

Right now I am thinking I am going to repack the bearings and slap everything together and ride the darn thing. I have had it since Labor Day and still haven't done that.