Chainset question

[perry]

You might be able to use a longer thread bottom bracket for downhill use such as a Hone and space it out to the right , leaving the left cup against the frame without any spacers .

 

[Augustus]

You might be able to use a longer thread bottom bracket for downhill use such as a Hone and space it out to the right , leaving the left cup against the frame without any spacers .

interesting.

 

[MikeD]

I don't think that'll work either. The road cranks will be designed for a 68mm shell - make the BB wider by spacing one side out and you'll start to run out of axle to attach the other crankarm to...

 

[perry]

I don't mean widening the width . I mean moving the left cup so it's against the frame and having all the spacers on the right to get the crank as far over as possible ( essentially offsetting the shell to the right ) You will need a wider set of cups though as the normal ones will leave about 5mm of thread to go into the shell and the thread doesn't even start at the edge .

 

[pigman]

Ive banged a 42-53 chainset on the pub/shop bike (its a 90's GT steel thingy that my neighbour gave me). I had to stick a washer behind the fixed cup to ensure the 42 ring ring cleared the chainring. I'd say get the inner chainring as close to the chainstay as poss without the possibility of touching as it bends under strain.

I used to run a 42-52 campag chainset on a rockhopper frame as a commuterbike a few years ago.

both work ok, with no chainline problems. BUT both bikes only use(d) a 6 speed block at the back. Obviously 9/10 speed will have a wider span, but providing you dont use the extremes (all big or all small) you'll be ok

edit : having just read all the thread (durrh) I dont know relevant this is given mine was all square taper stuff. personally, if its just about the sram labelling, i'd forget it. if its about the gearing, get a 110 LX/DX chainset with some bigger rings and drop the inner. Depends whether its gonna be a poser or a clunker ??

 

[MikeD]

I don't mean widening the width

Oh yes, sorry. I guess it depends if 2.5mm is enough, then

 

[perry]

yeah it wont be much but every little helps

 

[garethrl]

External BB road cranksets are all for 68mm BB shell I believe. 68/73mm is mtb only. So if your frame has a 73mm BB shell then it's a non-starter.

You can sort the chainline easily enough, just a different length axle.

Problem will be with the front mech and indexing. The indexing is slightly different, and the shape of the front mech's cage is different, 'cause road rings are bigger.

Although I see Shimano R440 road thumbies are £15 in the CRC sale.

modern extrenal bb set up. axel is fixed.

Think i may walk away from this impending headache and just tippex SRAM on the back of my cranks to get the desired effect....(such a tart).


:cry: