Changing Chainring

FishFish

I'm getting a new Boardman MTB (29 pro if you are interested). It has a Sram GX crankset and a 32 T 1*11 setup. I currently run 38 T or 36T and it was my intention to fit one of these - say the 36 and get rid of the 32 as it is too undergeared for me. My instinct is that this will not require a new chain and the back is 10 to 42 and I doubt I'll use the lowest gears.


Will I need a new chain because of the larger front? My instinct is to use a larger ring around here - Thetford forest and put the smaller one on when going to mountains, trails but was wondering if I needed a chain for each setup.


....Halfords is offering bike discounts and a trade in for any bike against a new one - 10%.

fenix

Are you riding a 29 at the moment ?

cooldad

You will need a longer chain.

The Rookie

If the current chain is correctly sized, as CD says you will need a longer chain (another pair of links for 36T and one or two pairs for 38T), it may be its too long and you don't need to add any, if its too short the rear mech gets pulled into the cassette and wrecked so it's not a good idea.

nobby_chobbly

I got the same bike new from Halfords last year, and also replaced the 32T ring with a 36T. The chain that came with it had 114 links which was plenty long enough to cope with the 36T/42T combo.

FishFish

Fenix wrote:

Are you riding a 29 at the moment ?

Yes, a Bizango 1*10

FishFish

I guess you are right! I suppose that as the pitch size of the chain is still half an inch then the difference between 32 and 36 is 4 teeth = 2 inches. Certainly don't want to wreck the rear mech or worse - the cassette which is ridiculously expensive.

I presume that it has a clutch mech too which adds to the chain tension.

I'll but another chain and use it with a larger ring or find out where nobby_chobbly lives and steal his.

The Rookie

Right idea, poor application, the chain wraps round half the chainring, so the current 16t becomes 18t for the 32 to 36.

The clutch adds no chain tension, it just controls the spring.

cooldad

I'd just measure it properly.

The Rookie

Of course, as its not uncommon for OE chains to come out too long.