Bottom bracket

[Zubanoid]

Hey all.

I am / trying to replace the bottom bracket in my old Giant AC2. It has a Raceface bracket with a sort of octalink shape for the cranks. When I looked at prices for a new one I figured a whole crankset might cost just as much - 2nd hand mainly...

My question is if my bottom bracket is a Raceface Brittish thread 68mm / 113mm, what will be a similar or compatible type of crankset to replace it with? I'm thinking of a hollow BB like on a Shimano XT crankset.

Here's a link to basically what my BB is: http://www.wiggle.com.au/race-face-srx-isis-bottom-bracket/

Here's a link to what I'm thinking of getting: http://www.ebay.com.au/itm/2012-Truvativ-Stylo-mtb-170-mm-crankset-/171051651481?pt=AU_Cycling_New_&hash=item27d3791199&_uhb=1

 

[moorey]

Abort abort!!
The raceface is ISIS inboard, the shimano is outboard.
On your RF the cranks attach to the bb. On the truvativ the crank and spindle go through the bb.

Xtype RF cranks will fit a shimano outboard bb, but if your RF cranks take the bb in the first pic, no dice.

 

[moorey]

I don't think I explained that well. Basically, if your cranks fit the bb in pic one, they are 2 separate crank arms that attach to the ISIS (International Splined Interface Standard) bottom bracket.
They are expesive and non serviceable.
I would get a whole new (or SH) crank/bb with outboard style bb. Cheaper in the long run, and a sensible upgrade. Slx would be a good place to start, without knowing what riding you do.
If you are buying online, as it appears, see what's on special at torpedo7, crc, wiggle etc. plenty of good SH sets on here also.

 

[willsy01]

Like the ones in that ebay link?

 

[moorey]

Like the ones in that ebay link?

Yes, captain surly, like the ones in the link, not that I think they are a particularly good crank, and for $140, you could do a lot better.
My main point, if it wasn't clear, was not to bother spending half of than on a RF bb, which historically don't have much of a life span....aside from the 9yo one on my Dh bike.

 

[Zubanoid]

So, basically any crankset with a BB that is an English thread is compatible?

I usually ride XC / light DH / all mountain.... not heavy riding for sure.

 

[moorey]

Yep. You can get new xt with bb for $170 delivered. Perfect all round option.

 

[silentbutdeadly]

Yep. You can get new xt with bb for $170 delivered. Perfect all round option.

Or SLX for about $130...unless you want 2x10 because less is always more.

 

[moorey]

Or SLX for about $130...unless you want 2x10 because less is always more.

Yep. I'd have to agree, and take a slx 2x10 over the XT if you wanted to run front mech, but if you then want to go 1x, you can't mount the bashie on the outside :third:

 

[mik_git]

Yeah if you want a new BB you don't need to get a race face one, just an ISIS compatible one (Not shimano) with the same measurements (BB width and axle length.
If oyu buy a new crank with external BB then you just buy whatever you want/afford, the BB should have spacers to fit 68/73mm shells, you just screw in the BB, slide the driveside crankarm/axle through, then slide on the other arm and do up the pinch bolts.

Edit: but then again it seems all ISIS BB are stupid expensive!

 

[moorey]

Edit: but then again it seems all ISIS BB are stupid expensive!

Yep. I considered grabbing a spare for when the 9yo eventually dies, but I decided that it will be easier to bang other cranks on when the time comes. Captured market i guess :noidea:

 

[mik_git]

Its funny (going OT) that the ISIS stuff, all there seems to be for sale (from a quick look on wiggle and crc) are high end stuff. But you can only get lower end octalink 2 BBs...

 

[silentbutdeadly]

Its funny (going OT) that the ISIS stuff, all there seems to be for sale (from a quick look on wiggle and crc) are high end stuff. But you can only get lower end octalink 2 BBs...

Hardly off topic. Same shit happened to me. ISIS BB driving a cheap SRAM crankset decided to chuck it in after just a couple of thousand kays. I could buy the crankset new for $50....but the BB was lucky to be less than $60 - and all of what was available seemed to be boat anchors made for downhill or AM work. Couldn't find the basic OE Truvative BB anywhere.

Yet an SLX 3x10 crank could be mine for a smidge over $100 (on sale at the time) with a BB. So the SRAM set went to the alloy scrap bin known as my parts box and the bike got the SLX...

 

[toofar22]

Honestly speaking, i am confused as hell when it comes to bottom brackets. I didn't want to start a new thread, so am hoping someone can help me here. I have a vague understanding of BB30/GXP on modern bikes, but throw in a older bike and my head spins a little.

Here are my questions.

What kind of bottom bracket is on my old giant ATX870? It's the exact same year / colour as this bike here --> http://www.rotorburn.com/forums/sho...nt-ATX-870-Frame-Second-Hand-Make-Me-an-Offer!

What kind of bottom bracket can I install on this bike? Can a modern BB30 or GXp be installed?

It has 2 different brand crank arms on the bike at the moment due to a product failure whilst I was living in Japan. The bike is over 10 years old and has hardly been ridden over the last few years. Is it worth replacing the bottom bracket whilst I am freshening up a few other things on the bike? (it will be a commuter for me)

Or would you leave it until something fails?

Thanks in advance for putting up with my numb nuttedness.

 

[willsy01]

Measure the shell width of the bb housing. Bear in mind that anything more modern thatn you've got now will require new cranks.

 

[The Duckmeister]

It will be a 68mm x 1.37" BB shell, AKA a normal English thread. You cannot use BB30 as it's an entirely different shell size. Any screw-in type bottom bracket will go in; the crucial thing is that it mates to the crank. The two most common these days are Shimano Hollowtech 2 and SRAM/Truvativ GXP. They're virtually identical except for one factor which makes them incompatible with other cranks: GXP has a stepped spindle, with a smaller diameter at the left end. No other crank format will fit through a GXP BB. FSA Mega Exo is dimesionally the same as the Shimano system, so independent aftermarket BBs will work with most cranks.

Fully internal cartridge systems such as square taper (which is most probably what's in the ATX), ISIS drive & Shimano Octalink have been largely phased out & generally relegated to lower-spec components - except as previously mentioned ISIS drive, which is only available in Bloody Expensive levels.

 

[redbruce]

Honestly speaking, i am confused as hell when it comes to bottom brackets. I didn't want to start a new thread, so am hoping someone can help me here. I have a vague understanding of BB30/GXP on modern bikes, but throw in a older bike and my head spins a little.

Here are my questions.

What kind of bottom bracket is on my old giant ATX870? It's the exact same year / colour as this bike here --> http://www.rotorburn.com/forums/sho...nt-ATX-870-Frame-Second-Hand-Make-Me-an-Offer!

What kind of bottom bracket can I install on this bike? Can a modern BB30 or GXp be installed?

It has 2 different brand crank arms on the bike at the moment due to a product failure whilst I was living in Japan. The bike is over 10 years old and has hardly been ridden over the last few years. Is it worth replacing the bottom bracket whilst I am freshening up a few other things on the bike? (it will be a commuter for me)

Or would you leave it until something fails?

Thanks in advance for putting up with my numb nuttedness.

If it still has the original STX cranks then its a square taper and if the BB is still in good nick, leave it alone until it fails.

If its not then buy a new SLX crankset of CRC.