Change Triban 3 Chainring for Youth Cycling

photonic69

Hi all.

I've just bought my 10yr old son a 2nd hand Triban 3 (the good red one!). He cycles with a local Saturday morning team but is interested in entering British Cycling Youth races but they have gear restrictions. Currently the FD is locked off so he can't get onto the big ring and likewise at the rear with the smallest sprocket unavailable. The Triban comes with 50/39/30 chain rings on an Ounce 170mm crank.

However, this still leads to chain-rub even with a 9 speed chain fitted. The sound annoys him (and me). Is it possible to fit a smaller big ring such as a 44 or 42t ring on this crankset? I've seen a couple on CRC but need advice if this is possible or not before going further.

Thanks

Nick.

arlowood

Quick google suggests that the Triban3 came with a square taper BB with a standard 68mm thread - probably English.

If that's the case then one solution would be to replace the BB with a Shimano Hollowtech II (Tiagra/105/6700 - they're all pretty cheap) and fit a cyclocross chainset with a 46/36 chainring combo.

http://www.chainreactioncycles.com/shim ... lsrc=aw.ds

You should still be able to run your 9-speed chain with that set-up tho you may have to find a double front derailleur. However the triple may work OK with the CX chainset - worth a try anyway.

photonic69

I was hoping for a simpler/cheaper/quicker/reversible solution if there is one?

Would this work?
http://www.ribblecycles.co.uk/sp/road-track-bike/chainrings-stronglight-dural-130mm-shimano-8-9-10-chainring/strochri300 with the 44 or 46 tooth options?

arlowood

PhotoNic69 wrote:

I was hoping for a simpler/cheaper/quicker/reversible solution if there is one?

Would this work?
http://www.ribblecycles.co.uk/sp/road-track-bike/chainrings-stronglight-dural-130mm-shimano-8-9-10-chainring/strochri300 with the 44 or 46 tooth options?

Do I understand correctly that you want to swap the 39 tooth chainring for something bigger so that he does not need to rely on the smaller sprockets on the cassette to get some decent speed?

If that is the case then it should certainly be possible to use a 42 tooth replacement. The BCD of the 50 and 39 chainrings is 130mm so the 42 ring in the link you gave should be fine.

A bit more unsure about the 44 or 46 option you suggest because of the gap between the inner 30 tooth chainring. There will be a maximum tooth difference built into the design of the FD and I'm not sure it will cope with a 14 or 16 tooth difference between the inner and middle rings.

Others with more experience may be able to confirm or refute the above doubts.

photonic69

No. You seem to have misunderstood my query. Perhaps I wasn't quite clear.

I'd like to remove the 50t and replace it with the smallest tooth ring I can that is still bigger than the 39. So anything 42,44,46 really. For kids they like to get them to up their cadence and spin rather than push big gears as it is better for their development and less likely to result in strain injuries/knee problems etc. The restriction for age groups also levels the playing field so that large/early developing kids don't have an advantage over smaller ones that cannot push the bigger gears. Hope that makes sense?

Salsa

I used the same brand of ring on a friends sons bike for exactly the same reason. It worked fine, I just lowered the front mech. His was a double though, only issue I can see is whether shifting middle to top and back would be smooth because of the smaller outer chainring.

arlowood

PhotoNic69 wrote:

No. You seem to have misunderstood my query. Perhaps I wasn't quite clear.

I'd like to remove the 50t and replace it with the smallest tooth ring I can that is still bigger than the 39. So anything 42,44,46 really. For kids they like to get them to up their cadence and spin rather than push big gears as it is better for their development and less likely to result in strain injuries/knee problems etc. The restriction for age groups also levels the playing field so that large/early developing kids don't have an advantage over smaller ones that cannot push the bigger gears. Hope that makes sense?

Sorry for the misunderstanding. In your first post you stated that the FD was "locked off so that he can't get on to the big ring" - I read that as meaning that he could only use the 30 and 39 tooth rings

No reason than that you can't swap the 50 ring for any of the sizes you suggest - 42,44 or 46. they're all relatively cheap so I would be tempted to buy the 44 and 46 rings and try each one to see what he prefers. FD shifting should be fine as you're reducing the gap between the middle and large ring in terms of the tooth count

keezx

Just leave the big ring off and and change the middel for whatever you want.

Mike03776

Should be fine, you might need to shorten the chain slightly though.