mixing chainring sizes

[tubbylee]

hello i need to replace a 9 speed 44t chainring with a 39t on a bike im fixing up for winter training,i can get a 39t 10 speed chainring,for next to nothing but im wondering will there be issues with shifting,between the 10 and 9 speed chainrings,thankyou

 

[Vapin' Joe]

Provided it fits the spider, no issues, no probs.

 

[HLaB]

Can the derailleur handle the jump from big to small chainring, I would guess so given that a typical double is along the lines of 53/39. I think the only things to consider are mech capacity, the bcd and bolt pattern and if it was the other way, 10-9sp it may have been marginally to thick at the teeth for the chain, but I'm no expert get a 2nd opinion.

 

[TheDoctor]

It'll be fine. I run a 9 speed chainsaw with 10 speed chain, no problem.