JIS/sq taper VS. ISIS .... JIS bottom bracket choices?

[psyber_0ptix]

hello all, i've been recieving mixed reviews about either systems. some of my friends swear by sq tapers, and online a lot of people seem to like the isis. i've had a run of badluck with some hussefelts where the splines got worn quick. yet my howitzers on my urban bike are holding up like a dream.

i'm looking into a set of the middleburn cranks, but the ultimate decision comes down to preference of bottom bracket.

there are a million + 1 options for ISIS, but how about sq taper? do they wear out any quicker? how about adjusting chainline?

i'm also worried since i'm novice, that i wont be able to figure out how to adjust chainline on the burns. the site says it uses a 48mm chainline for xc nd 50mm for dh. but nomention for trials.

/just to throw inanother question/ thinking of using a surly rear hub w/ WI eno fw. what bottom bracket, or how to adjust chainline? just play around with different spindle lengths? (costly)

any insight is greatly appreciated

[jmkimmel]

Generally, I'd suggest isis for trials, but if you're stuck on square taper, all you need to know is Shimano UN-72. They come in a ton of sizes.

I've beat the shit out of them on 4 different bikes (including an old-school DH bike), and none gave up, either breaking, or wearing out bearings. And, you can pretty much walk into any bike shop and pick one up for under 30 bucks.

[THEDEMOLITIONMAN]

For square taper, all you need to know is Shimano UN-72

I've beat the shit out of them on 4 different bikes (including an old-school DH bike), and none gave up, either breaking, or wearing out bearings.

The XT of BB's, the UN-72 is a nice BB, for what it is.A splined BB is the way to go, your not going to get any play in the cranks and the fit is going to be solid.Also, eventually your cranks are going to get rounded, where it slides onto the splindle of the BB.


I would just use what you have for now and then move on the splined BB.

THEDMAN

[goose]

Given a BB, you can adjust the chainline with BB spacers to increase, and washers under the chainring to decrease. You shouldn't do more than 2mm of adjustment with either type of spacer, which means you should chose your BB wisely.

Before you buy your BB, you need to measure the white-ind/surly combo. Then you need to measure your ISIS cranks on an ISIS BB of known spindle length. Make up the difference between those two measurements with a longer spindle and spacers. When you measure it, you'll know what size to buy, as your only choices are 113, 118, 123, 128. You are trying to line up the granny ring with a singlespeed hub/freewheel that is designed to line up with the middle ring of a standard mountain bike, so you will likely need a longer than normal bb spindle. 118 minimum, 123 or 128 is more likely (my guess of course).

You gotta measure the chainline with a some straight edges an accurate ruler. And see if you can borrow/try an old BB to get a measurement.

Middleburns are great cranks, but a heck of an investment:)

[psyber_0ptix]

curious, are there any choices available for the shimano octalink/hollowtech (original) setups?

i'm ona 113 spindle, but maybe if the cranks dont frag themselves i'll keep them fora bit, till i at least get a rear wheel built with a freewheel

[StaggerLee]

you can pretty much walk into any bike shop and pick one up for under 30 bucks.

I find the opposite to be true. I can't find a un72. Plenty of my lbs have un52's or lower. They have un92's but in road length's, no 113's. I have a pile if square taper cranks too. Today when I'm at the shop I'm gonna ask if they can get me a couple of un72's. I have a pair of lime green raceface's I'd like to put on my fixed.

I've destroyed lots od un72's, mostly riding mtb and road. But they were so friggin cheap it didn't matter. I now have isis and x-type bb's and cranks.

[r464]

There are some good square taper BBs out there. Phil Wood is the top of the line, but the new IRD Quad BBs look very nice (they come in 103, 107, 110, 113, 115, 118, and 122 widths). They are actually Japanese made by Tange Seiki.

I still see Shimano UN-52, UN-53, UN-72, and UN-73 models in all sorts of widths available from the online shops. I also see Action Tec, American Classic, Real, and White Ind from time to time. Stay away from the cheap Truvativ one, but if you can find an old Race Face Taperlock buy it.

A good square taper BB will last you a long time.

[Keith Courage]

Wow.
Am I in OTN anymore? I feel like I'm reading some fixed gear forum.
The term JIS should never appear in this forum.

I realize that some people are partial to certain things but if you go square taper and plan on progressing as a trials rider, YOU WILL ROUND it.
I've rounded square tapers XC riding.

Why make an investment into something that will without a doubt go bad when you can get ISIS/splined/Xtype and have a 98% chance that both the crank and BB last for 10 years?
How many trials riders have been riding a the same square taper set up for the past 5+ years?

PS Mod or stock?

[psyber_0ptix]

thanks for the responces, the only reason i was asking was because on mtbr, a lot of people are complaining about ISIS bottom brackets not holding up well, and i guess in particular, truvativ splines cranks. and i've had a set of isis cranks that i'd retighten after every ride. to the point where i didnt trust them staying on anymore.

yet i a trialser i met recently has gone 3 years problem free on his monty using a square taper.

i guess its all in the quality of cranks.

i think i'll shoot for ISIS because the whole load->rounding issue.

things to consider about the burns warranty:

*Warranty excludes tapers, splines and threads.

so with any crank, if it wears, it wears.

[KeepRollin]

How many trials riders have been riding a the same square taper set up for the past 5+ years?

I put 3 ish years on my bonz square tapers and they were definitely getting bad.

[r464]

I have had a Real Designs square BB for 8 years that is still smooth.

[cogmog]

It all depends on if you ride like TRA or a mortal. Im definetly a mortal but have still managed to go through 3 bottom brackets in 4 years with my Bonz square tapers. Love the cranks, hate the squares. My most recent BB breakage led me to three different bike shops looking for a un72. Apearently they still make the un 72 but it is now shipped with a plastic cup instead of the aluminum cup. I luckily threw all my old aluminum cups in my parts bin over the years, so I should be good for a while. I guess this is Shimanos way to force you to move towards their spline drive system so they dont have to keep maufacturing a inferior product. ....just my two cents.