I installed a new cassette (10spd, 11-36t) and chain.
The distance between front chain ring and rear derailleur is 45cm
Front chainring is 34t
I calculated online that I'd need 108 chain links or 137cm or chain.
When installing it looks really too short and I can't shift to the biggest cog.
What have I done wrong?
by Cold-Purple-6388
9 Comments
Yes your chain is most definitely to short
1x with a smaller cassette (meaning not a mountain bike dinner plate) is pretty flexible, I just guestimate the chain length. I’d add a link in
On a hardtail bike as long as you can shift into the biggest cog and there isn’t resistance when pedaling, it’s ussually if but if you can’t shift (and it’s not a limit screw issue) its too short.
https://mtb.shimano.com/stories/determine-chain-length
Which sprockets are the chain on? If it’s the two big ones, then maybe not.
For a 1x setup, the chain actually doesn’t seem too short to as you’re still seeing bending around the jockey wheels (instead of being so short that it’s straight).
If you can’t shift to largest cog on a new cassette, I have to ask what size the old cassette was. And what kind is rear derailleur is that? To me, it seems like the derailleur may not be designed for the range of the cassette. If size compatibility is not the issue but you have sized up, then you need to adjust the B screw and probably play around a bit with the tension/limits if you haven’t already.
When going to bigger than normal cassettes there is a B Screw that sets the gap between the big cog and derailleur pulley. Turning it in increases the gap. Some times a longer screw is needed.
I would say the chain is not too short.
You could try a Shimano Zee M640 FR deraillauer.. An MTB part with a short SS cage, and a clutch feature. It’s rated for 11-36t You’ll gain some ground clearance too. Thery’ve been run with up to 11-42 on HT bikes.
There is a good park tool video on how to measure chain lengths, I’ve always used that method. On my 1x setup it seems pretty short like that also, but I’ve never had issues.
I’d say you need a few more links to make everything last longer as you’d be putting unsure stress on all the components
It’s about 2-4 links too short, from what I see. That would be about 5.5 cm…about 4 teeth of cog.