[doctorbangbang]

Hey there, I'm upgrading my drivetrain (BB, Cranks, rings, cassette, chain) and wondered what are the pros/cons of square taper VS ISIS providing BB is the same as the cranks??

 

[Kris]

ISIS is stiffer, square taper lasts about a thousand times longer. Replacing the ISIS bb on my cross bike is an annual affair (same with my outboard bearing mountain bike), my square (UN54) on my SS beater which sees lots of nasty conditions is 3 years old. My square (UN73) on my Middleburn equipped hardtail is also 3 years old. Both spin super smooth with a fraction of the drag of any of my other setups.

Major downside of square is that they are more prone to snapping under massive abuse. IE, I wouldn't freeride on square.

 

[Germany_chris]

Hum...I used to replace square taper every 3 months because of bent spindles...ISIS every year from orn out splines...I have never replaced an outboard bearing BB in 5 years...I know SS love middlebun cranks and square taper but I do not...I think out board bearing and disc brakes were the best thing to happen to mountain bikes in the last 15 years..

 

[doctorbangbang]

The isis middleburn set up is also a bit lighter. I'm no weight weenie but thats a good enough reason to use ISIS again! I've also never had any issues with my previous splined system. Thanks for the feedback guys! So the plan is... Chris King BB with Middleburn triple chain ring and cranks.

 

[Bikinfoolferlife]

The isis middleburn set up is also a bit lighter. I'm no weight weenie but thats a good enough reason to use ISIS again! I've also never had any issues with my previous splined system. Thanks for the feedback guys! So the plan is... Chris King BB with Middleburn triple chain ring and cranks.

How are you going to use a King bb with an ISIS or square taper crank?

 

[doctorbangbang]

Yeah, the CK BB and middleburn cranks won't go together will they! I might rethink the BB choice...

 

[zarr]

Whichever one is easiest to get replacement parts for.

 

[fcojavier]

ISIS SKF bottom brackets are long lasting ones.
Mix of balls and rollers (in the drive side) running directly over the spindle for better sizing, and good seals.
A little on the heavy side, 300g. for a 113mm M15 BB, is also available with a M12 spindle.

 

[mlloyd007]

The isis middleburn set up is also a bit lighter. I'm no weight weenie but thats a good enough reason to use ISIS again! I've also never had any issues with my previous splined system. Thanks for the feedback guys! So the plan is... Chris King BB with Middleburn triple chain ring and cranks.

The ISIS Middleburn cranks are about 25 g lighter than square taper, but the ISIS Ti BB's are about 50g heavier than a light square taper (like Phil Wood), so the ISIS crank+BB is about 25g heavier. I just got a ISIS Middleburn crank and FSA BB and I'm going to return for a square taper. Added advantage of Phil Wood is you can adjust the chainline by up to 5mm.

 

[Bikinfoolferlife]

Yeah, the CK BB and middleburn cranks won't go together will they! I might rethink the BB choice...

Might also rethink your assumptions about weight. Total weight of an external type bb crank is comparable to that Middleburn plus ISIS bb.

 

[MadDuc916]

Doctor BB,

I just finished a bike build and after a lot of research, I went with the American Classic Ti BB and the Middleburn 2 x 9 R8 crankset. Previous to this I had run the American Classic Ti BB for close to 10 years with no failure. In talking with my LBS, they did say that the external BB required at least a rebuild every year. I am close to 240 with gear on and I have never bent a a square taper ti Spindle FWIW. This set up is pretty much bomb proof and is very light. I am very pleased with the Middleburn cranks as are most people that have posted on the forum that I have seen. Here is a picture of my current 2 x 9 Middleburn/American Classic set up. If you have anmy questions, let me know, I am happy to help with any details.

Hoipe this helps.

 

[Prophet Julio]

i'm with Fcojavier

I replaced a couple of ISIS BB's until I switched to SKF. 3 years and smooth as silk. Bombproof. They make square taper as well. The secret is in the seals and the combination of ball bearings and roller bearings.. Oh and it's all stainless!

Use a power washer if you want, no problem.

 

[morbergsmed]

Doctor BB,

I just finished a bike build and after a lot of research, I went with the American Classic Ti BB and the Middleburn 2 x 9 R8 crankset. Previous to this I had run the American Classic Ti BB for close to 10 years with no failure. In talking with my LBS, they did say that the external BB required at least a rebuild every year. I am close to 240 with gear on and I have never bent a a square taper ti Spindle FWIW. This set up is pretty much bomb proof and is very light. I am very pleased with the Middleburn cranks as are most people that have posted on the forum that I have seen. Here is a picture of my current 2 x 9 Middleburn/American Classic set up. If you have anmy questions, let me know, I am happy to help with any details.

Hoipe this helps.

Where did you buy the crankset?

k

 

[MadDuc916]

Middleburn Cranks

morbergsmed,

The only place in the states that has them is Mountain Tandems. They had everything for my 2 x 9 in stock and shipped it immediately. They were very good to deal with, no hassles, got everything I wanted in a timely fashion. Here is the link to there site, giv'em a try.:thumbsup:

http://www.mtbtandems.com/Middleburn.html

 

[peedrama]

If you're running an ISIS setup, the two ways I'd suggest to get more than a couple years out of your BB is either buy an SKF (if you can find them) or buy a crank brothers and make the most of their 3 year warranty.

 

[Prophet Julio]

mtbtandems.com

That is where you can buy the SKF BB.