Trek Superfly New Crankset - Stupid Question

[Rudi Pollard]

So I want to upgrade the crankset on my Trek Superfly but I am a bit lost with all the specifications out there.

 

Currently I have the standard SRAM S1000 which came with the bike, but the problem is that it has a BB92. All the cranksets I have been looking at are either specified as BB30 or GXP.

 

What should I look at when buying a new crank in order to insure it will fit my bike?

[Rudi Pollard]

So was it such a stupid question or does nobody know the answer?

[Brian Fantana]

Read here:

 

http://www.parktool.com/blog/repair-help/bb90-bb86-bb92-etc-bottom-bracket-service

 

Some Trek frames have proprietary BB systems which is discussed in the link.

 

You refer to BB92. The BB92 is the bottom bracket type. You can still use standard cranks with a BB92. With BB92 the cups are pressed into the BB shell instead of threaded. The 92 is the width of the BB in mm, which id the same outer width as a normal threaded external BB.

 

This is a great opportunity to upgrade to a shimano crank

Edited June 19, 2013 by Brian Fantana

[Brian Fantana]

A GXP crank will fit into a Sram BB92 bottom bracket.

[MrFine]

Sorry just a another question on this thread about BB

 

Got new bearings for my Trek Superfly but cups that are press fitted were a bit worn out.I had to put some shim stock in befor fitting the bearings for a tight fit.

Will this method work.Looks to have done the trick.Thanks

[Rudi Pollard]

A GXP crank will fit into a Sram BB92 bottom bracket.

 

Thanks Brian!!! I have been looking at the specials currently on CRC, and was wondering if this will fit?

 

http://www.chainreactioncycles.com/Models.aspx?ModelID=78803

[Brian Fantana]

 

Thanks Brian!!! I have been looking at the specials currently on CRC, and was wondering if this will fit?

 

http://www.chainreactioncycles.com/Models.aspx?ModelID=78803

 

The one in the link will not work. It is a BB30 crank with 30mm spindle diameter.

 

For BB92 you will require cranks with 24mm spindle diameter.

[Rudi Pollard]

so

The one in the link will not work. It is a BB30 crank with 30mm spindle diameter.

 

For BB92 you will require cranks with 24mm spindle diameter.

 

so if I go GXP I should be fine. Just need to stay away from the BB30's?

[Brian Fantana]

so

 

so if I go GXP I should be fine. Just need to stay away from the BB30's?

 

Yes, but you need to remember that a GXP crank will be a Truvativ, which means it can only fit into a GXP press fit bottom bracket.

 

http://www.sram.com/truvativ/component/bottom-brackets

 

If you look at FSA, you will require a FSA press fit bottom bracket:

 

http://www.fullspeedahead.com/technology/8/Press-Fit

 

If you want a Shimano hollowtech ii crank, you will have to look at this BB:

 

http://www.chainreactioncycles.com/Models.aspx?ModelID=61801