thook

i haven't measure anything, but the driveside seems visually more outboard on the driveside than the ND side. i have $30 shimano cartridge. what would cause this and what would be the solution? iow's, is there an adjustment i'm unaware of? i'd assume the cartridge style is just plug and play, but i've run across mentions of shims?

thanks!!

Bill Kapaun

They come in different lengths for different cranks.
You need the correct one.

JohnDThompson 

Different crank and chainring configurations need different amounts of offset to provide proper clearance. Your specific crank and configuration (single, double, triple) determine the amount of offset needed and thus the specific spindle or cartridge required.

Phil_gretz

Start with the crankset that you have. What brand and model is it? You can determine the correct crank spindle length from there, using any number of on-line resources. VeloBase being one of the easiest.

Iride01 

Some bikes from the get go have that crazy looking space between the bb shell and crankarms. Typical of square tapers on some bikes.

Is this original equipment or did you change it out?

thook

none of the parts are original. its '89 miyata triple cross i bought as a frameset on ebay. i have deore dx crankset on it, and the bottom bracket is something i bought and ran on the cross check i had years ago. i don't even recall what shimano model or length the bottom bracket is

Iride01 

You either have to live with it or change the spindle length. That's one of the things you can do with a square taper. They come in all sorts of spindle lengths. And different cranks sit differently on different brands and types of square tapers.

But if these are Octalink or something else, your options might be a little more limited. And I'd suppose you likely have a 72mm bb in a 68 shell or something. But cartridge BB's I have little experience with. When I left cup and cone square tapers I went to 2 piece cranks and the once painfully confusing BB stuff became easy.

thook

it's a deore dx crank from the early 90's. so, square taper i'm not sure what the length is on the shell, either. the frame is designed to run a triple with up to 38mm 700c tires, though

i guess the adjustment/shim thing is for more modern BB's like the octalink, etc?

Phil_gretz

That's twice that you wrote that you're not sure of a length measurement. Do you own a set of digital calipers yet? $10 and you can measure anything to 0.1 mm with ease. Great for, let's see... seatpost diameter, seat tube inner diameter, seatpost bolt length, quill stem diameter, stem reach, handlebar clamp area diameter, rear stay spacing, BB spindle lengths, BB shell width, chainline, bolt circle diameter, among others.

EDIT: early 1990s Deore LX cranksets are compatible with 113mm spindle lengths. Your BB shell is very likely 68mm.

thook

first i wrote i wasn't sure on the BB length. second i wrote i'm not sure on the shell. i had not considered the shell when i initially wrote. i have calipers. i intend to investigate once i know what's going on..ie. i have the info i need to understand what i'm doing. relax?

thook

okay, thank you all. i get it now. i see what all you're saying. honestly, i've never bothered minding details on cranks/bottom brackets aside from "oh, i need a short for the double and a long one for the triple." i hope you understand. i just read a thread, yesterday, and someone mentioned the BB being too long might the source of the OP's trouble. that's why i started this. new'ish territory for me

without pulling the crank, the BB does appear to be a 113. and, the shell is indeed 68mm. however, i have a donor mtb with the same width shell and the BB also appears to be 113. the crank (7spd alivio) is still on there, too. (gotta find my crank extractor).
anyway, on the donor mtb, the crank arms are seated closer inboard to the shell than the crank arms on the miyata. it just seems like they should be closer on the miyata than they are. i didn't think to measure the differences when i was out there, but i'll do that later. i guess what i'm seeing might be what Iride01 was alluding to in post #7.
maybe i'll just nab the BB off the donor, put it on the miyata, and see what happens

ps. i have yet to look at an online calculator, but i will do that as well

thook

i just read sheldon brown's run down on BB's and cranks. i understand completely, now

the BB for the donor/alivio may actually be a bit shorter than what i have on the miyata. i'll know for sure once i find my extractor and can measure with the arms off. but, sheldon's chart says to use 110-113 BB for that alivio crank. the chart also says the DX crank should use a 122.5. i'm pretty certain the BB i have on the miyata is not that long. i will check. but, if the BB on the alivio is also too long, i'll have to look for a 107 BB, at some point. or....live with it.

KCT1986

Suggest that you measure the chainline (Sheldon's site has info on this). If the chainline is about OK than the DS is fine, despite appearance.

You could also check the thread distance (Q factor) and see if this also checks out.

Also check how the rings and crankarm are in relation to the chainstay.

thook

everything is clearing on the miyata quite generously with the chainstay. the arms (at the spindle) are close to twice as far from the shell as the arms (at the spindle) are on the donor mtb. i really think i should be able to get the miyata crank in closer. q factor and i think it'll help with some drivetrain shifting/noise
i'll get those measurements, regardless

cjenrick

had the same issue, went from Suntour Superbe cranks on a 68 BB shell, to Suntour Superbe Pro cranks, which apparently were not too often isntalled on a 68 shell but probably more often on a 70 shell. there was unequal space between L and R crank arms, the right side hung out more, the pro cranks are a little beefier and thus push the peddle out further for the same taper spindle.

i bought a spindle for a 70 shell and i think it made the problem worse. so i posted up and the guy said "just ride it, you won't notice" so that is what i do. i think i will go back to a new 68 spindle in there as the old one had some wear. it is only a few mm difference, and i do not notice anything just like the man said i wouldn't. body's are not that symmetrical in the first place. LeMond had on foot that took a size larger shoe. had to buy two pairs to et one until he hit the big time sponsor thing.

or i could go back to Superbe cranks if i can find some NOS 175s, which is next to impossible. i do like the looks of the Pro cranks a bit better and i worry less about snappage. I guess it is best to keep the original cranks and spindle setup that the bike maker shipped the bike with.

JohnDThompson 

The original Superbe crank used an asymmetrical spindle, with more offset on the drive side. The Superbe Pro crank used a symmetrical spindle with the same offset on both sides. Mounting a Superbe Pro crank on an asymmetrical spindle results in the drive side arm being located further out than is ideal.

thook

conclusion, a month later.....
i finally took everything apart and it turns out the BB i had on the miyata says "117.5mm" printed on there. i put a 110mm bottom bracket on the things are much, much better

shelbyfv

thook