Chainset problems

[Anthony]

I have some cranky questions for you sages out there:

I’ve been trying to set up an XT M737 chainset, but the inner ring fouls the derailleur plate. My first thought is that maybe the 110 bb axle that I’m using might be too short. So question 1 is what length axle does an M737 need?

But then the second thing on the M737 is that it seems odd that the gap between the granny and the middle is bigger (by 1.5mm) than the gap between the middle and big ring. I’ve never seen that before. So question 2 is can this be right?

So next I fished out an M739, only to find that its middle ring was wobbling. Took it off and found that the bolt sleeves were 7mm. Looked at some other cranks and some sleeves were 6mm and some were 5mm, and either seem to work fine. Ah, but I’ve got those spares, haven’t I? Found them – 7mm! So question 3 is are 7mm sleeves any use for anything whatsoever, or were they invented just to try my patience?

 

[Harryburgundy]

Anthony, I don't know the answers to all your Q's, but I successfully ran an M737 chainset and my 94 Kilauea with an 107 length bb axle.
Carl

 

[Tallpaul]

M737 cranks are fine on anything from 107 to 113mm. No idea on the ring spacing though, it should be the same as any compact shimano crank, including the M739 you also have? :?

 

[guybe]

On the '96 Cindercone I build up recently is using Shimano LX 68mm x 113mm B/B on Shimano LX cranks with no problems, maybe try 113mm one.

Is the chainrings on your cranks is the same make? different make of chainrings do various in sizes and shapes, I would try keep all the three chainrings in the same make to avoid complication. OR do you use spacers for the granny chainring?, if yes then try for some smaller ones.

Good luck

 

[Anthony]

Good luck is indeed what's required in my case young Guy!

Confession one is that having now bothered to check both a Curve and a Strongarm = Sugino, both use 7mm sleeves, so now I know what they're for - and I have a beautiful set of five inners and five outers in alloy to go in my sale one day!

Confession two is that I'm using the M737 with one of those awful modern top-swing fms , and I wonder whether maybe they prefer proper retro conventional-swing.

And yes I confess I'm mixing makes of ring! How much money do you tthink I've got? You'll be expecting me to buy something new next! :cry:

 

[P20]

Which chainrings, including size? Which front mech? Any pics?
From memory the 107 and 113mm bbs sound right

 

[Carsten]

"stock" spindle length for the M737 is 106mm so i would assume that the problem is due to a too long spindle. distance of the chain rings is pretty much fixed by the spider. no washers etc are required - except maybe for those very thin ones Shimano has used to fine tune the centering of the rings. just bolt the rings on and you're good to go.

what ring sizes are you using?

Carsten

 

[dyna-ti]

Unlikely i know but could the front mech be too low?

 

[Anthony]

Which chainrings, including size? Which front mech? Any pics?
From memory the 107 and 113mm bbs sound right

Shimano 22, 42, Curve 32, modern LX topswing, can't find the number.

I'm now wondering whether the Curve could be part of the problem, as it does use separate spacers, so maybe it's not the same thickness as a Shimano. Surprised it could make that much difference though.

 

[Anthony]

"stock" spindle length for the M737 is 106mm so i would assume that the problem is due to a too long spindle. distance of the chain rings is pretty much fixed by the spider. no washers etc are required - except maybe for those very thin ones Shimano has used to fine tune the centering of the rings. just bolt the rings on and you're good to go.
what ring sizes are you using?
Carsten

106!!! Not with this FM - I've always found conventional-swing FMs have more clearance to the rings, so maybe that's what I need to use here.

Many thanks for the picture Carsten, will copy that.