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Hi,
I'm setting up a bike for some trials messing around. I'm going to be running a 22 tooth chainring on the inner of a triple crankset with a bashring in the outer position.
So I was looking at some second hand Saints for something hopefully bombproof. Now I've figured out that the Saints come with two spindle lengths. One for 68mm/73mm bottom brackets and one for 83mm bottom brackets. Now I've got a 73mm frame, but using the 83mm version of the cranks would move my 22 tooth chainring outward giving me a better chain line and more frame clearance.
So finally getting around to the question, if I get the cranks with the longer spindle, can I just get some 24mm dia. spacers (presumably 10mm, but I can't find spindle lengths anywhere) and put them on the axle? If I do this will the right part of the spindle run on the bearings in the 73mm bottom bracket or will they be too far in board?
Cheers,
Mikey
Saint HTII cups have a longer driveside threaded section so you should be able to use 2.5mm HTII BB cup spacers to space them wider out on that side side.
whether you can get the BB where you want it. I couldn't say. but I'd rather space the cups than the axle. (the crank arms themselves have a seal/spacer recessed in the end of each arm)
1" headset spacers work, I did this to get my long spindle saints on my old Demo 8, which was a bit weird in having a 73mm bb.
See, I'd prefer to space the crank rather than the BB. I don't know why, it just 'feels' like that would be the less incorrect thing to do. Maybe 5mm on either side would work better than a single 10mm spacer?
Thanks for the thoughts.
A bit of research suggests the axle on the 83mm cranks may be 15mm longer than the 68/73mm version. So on my 73mm frame I might put an additional 2.5mm bottom bracket spacer each side of the bb, like you would on a 68mm frame. This will gain me 5mm without taking the threads too far out. Then I'll add a 5mm spacer on the axle each side. Having looked at a normal Hollowtech II axle it looks like the bearing section of the axle is about 5mm longer than needed so hopefully this is OK too. It doesn't solve the problem of the seals that Geex points out but I'll just have to keep on top of the maintenance! I like the idea of using 1" headset spacers which I'll probably go with, although apparently Raceface used to do a conversion kit for their cranks which had 3x5mm in them so might see if I can source one of those.
Cheers
Let me get this right, your buying new to you, second-hand saints, the wrong size for your bike, and want to adapt them to fit?
unless i'm missing something massively, why don't you get the correct size saints for the job?
or failing that, new slx or zee cant be much more than 2nd hand saints? i'd do that personally!
Haha, sort of!
There is some logic behind the idea. It's all about chain line. I'm running a hope single speed hub so the closest towards the centre of the bike I can get my sprocket is equivalent to 4th on a 10 speed set up. This means that using the 22t chainring on the inside tabs of a triple doesn't give me a very straight chain line.
I'm thinking that the wider axle helps the chain line, by shifting the ring out, ut it might not. I need to look into that next. Might be I'm better off with a boost chainset.
In the end though I might just go standard as you say!
Nah, bodging is best!
On SRAM cranks the axle is only the correct ground diameter in the region where the designer expects the bearings to be.
Are you going to be using the axle in a way that the axle is under sized where the bearings are in this modified set up? Or do Shimano ones not do that?
Cheers for the info on the SRAM cranks. I've had a look at a standard length Hollowtech axle and it is constant diameter throughout (24mm from what I understand). There is a smooth section at each end though, which I guess is the bearing length, and a slightly textured central section. The smooth section is longer than needed for the standard bearing position by about 5 or 6mm or so. If the axle for the 83mm version is similar the bb bearings should still be on it. Maybe they've set it up so you can get away with bodging it - OK, probably not!