1x8, what size chainring?

[Grannygrinder]

I'm cobbling together my GT avalanche for general riding duties. I want to run one front chainring and 8 on the back. Will a 32 tooth chainring be enough or would it be worth sourcing something slightly larger? Ta.

 

[Dr S]

I run a 1x9 setup on my Hei with a 32-12 on the back and a 34 on the front which suits me fine around here. Depends on the terrain. If it's somewhere flatter than here I would run a 36 but with a closer ratio cassette too.

Si

 

[Mr Panda]

My current "commuting" bike with 8sp rear, is rarely off the middle ring unless I specifically want to get a move on. That ring is 34t. That gets me up a 1in7 hill on the way home without going on the lowest rear sprocket, and I am no means a fitty.

If going for a single front with 8 rear, I wouldn't have any less than 34t or your going to lose out on the flats and downhill. Depends on your local terrain really but i'd say 32 is too low.

(Got the shifters BTW - ideal, now bolted up and ready to roll )

 

[jimihendrix]

I ran a 32 on the front with a 12-32 cassette on my LTS far a while, found 32-32 fine for even steep stuff, could have been doing with 11-32 or a 34 ring for road sections and flat fire roads though.

A 32 on the front is a good starting point though.

 

[Xesh]

On my ATB I've got a 36 tooth front and an 11/25 Ultegra cassette on the back. Ok, yes it's a 9 speed but the principle is the same.

 

[stevek]

Dr S, do you have any problems with the chain dropping off the front when it gets a bit bumpy and your at or near the extreme end of the cassette? Do you use a front mech, bashring, unramped ring or what to keep the chain on?

I only ask because I wanted to make my Yeti a 1x9 without front mech etc but ended up going for the Middleburn Duo set up using a front mech. Not as clean looking.

Thanks
Steve

 

[Xesh]

I use one of these on the front (although mine doesn't have the bash guard on it).

 

[stevek]

Yeah, seen them thanks Xesh. Just not over keen on them. Picky git aren't I?

 

[Grannygrinder]

Short cage mech

Have you tried a short cage mech? Might give a bit more chain wrap, just a thought.

 

[stevek]

Yeah, shortcage r/mech might work, getting the tension and length just right on the chain... unramped chainring and Bob's your Auntie's Husband...