Shimano M8000 single ratios

strauss_jon

Hi all.

I'm trying to figure out which ratio to go for with the xt m8000 single.

11/40 cassette with 32 chain ring or
11/42 cassette with 34 chain ring

Yes, i've seen loads of posts about this (well, mainly about 10 speed cassettes) but i'm finding them very difficult to understand (especially since they're are loads of opposing views) - and i think they're mainly written by the racers which ain't like me. I want to make sure i get this right so looking for a simplistic view.

I'm not competitive but keen none the less. Mainly xc on the south downs, UK - but a fair bit of flat also so I dont want to lose too much top end speed. 26 inch hardtail.

Is there much between the 2?

I think my problems is...i know how the teeth affect the behaviour individually on the cassette and the chain ring but when i combine the 2 - i get ultra confused. If it's not proper mountain climbing - just a bit hilly with a few short steepies - will a 34 be ok or would it be too difficult? I'm quite fit, but don't have a lot of leg leverage

(Simple) views would be much appreciated. Thanks, Jon

The Rookie

Crikey, for me 11-42 and a 36T chainring given the usage you describe.

I'm currently riding an 11-34 with a 32T and its pretty much fine for me but I am going to 11-40 (can't fit a 42T with 9 speed realistically) and a 34T to give a little more range and climbing ability - and I'm 49 and not that fit.

codfather

I currently run 11-34 and a 36t ring and that feels like plenty for me. Knowing what sort of setup you're currently using might help us advise on the best choice for the new ratios, but either of those pairings will give a low enough ratio to winch up almost anything.

swod1

depends on how your using your current gear setup, are you only ever using the middle chain ring of say a triple chain set which is usually 32t?

As the 34 will be a little better on the flat parts of your ride.

I'm using on my bike a 32t up front as my front mech is broken (soon to be changed to 34t n/w) with a 11-36 cassette and find it is fine getting up hills around my area but do lose a little on the flat parts but I'm bothered for.

BigAl

I run an 11-36 on a 36T chainring.

Works for me.

If I can't get up a hill on a 36-36, then I'd rather bleeding walk!

rockmonkeysc

Other people suggestions are meaningless. They might be more or less fit. They could have bigger or smaller wheels and they might prioritise downhill speed over easy climbing.
Consider the two changes separately rather than as one combined change. It's not that difficult to work out how it will work.

strauss_jon

Thanks all, very helpful.

I've been riding for ages, but for some reason always bought straight off the shelf without knowing or caring about any configurations. If it looked like it had some street cred and was smooth - i bought it. Kept it for years, then any replacements were just off the shelf once again, not knowing what i was replacing. Now in my 40's i'm starting to give a damn. My last bike was a 2007 stump jumper hard tail - 26 inch wheels. I'm rebuilding this and now comes the groupset. My old slx triple was a 22, 32, 34 with a 11*34. Really raving reviews for the deore xt m8000 but i think it only comes in 32 11*40 or 34 11 * 42. I can't see a 36 (as a groupset package i mean - cheaper this way)

My 22*34 could get me up anything (if anything it was overkill) and the 32*11 i think would be too slow on the flat. So guess it's a 34 11* 42. I probably should go for the double chain ring if i was being sensible (more versatile) but i'm a stickler for simplicity and getting rid of the front stuff would be really good. I'd also love to be forced to work a bit harder .... plus i've got a road bike if i feel the need for speed. So I think i've answered my own question. Just has to be a 34 (although 36 preferred) as the 32*11 would be a bit too slow. I would have thought xt would come in more than 2 combo's though? If it doesn't, can i just buy a 36 ring and stick it on the xt crank? Excuse my brain dump - hope it's not too confusing.

Thanks again

strauss_jon

Rockmonkey - just seen your comment. You're absolutely right. However i was looking for an easy answer initially - then i did some more reading, compared with my existing middle ring and it started to make more sense. I would like to see the 36 for sale but i dont know if thats possible as an all in 1 deal - e.g.

http://www.mantel.com/uk/shimano-deore-xt-m8000-single-groupset

Cheers.

The Rookie

Just swap the Shimano ring for a proprietary one, they are a standard fitment.

The Shimano one is to cope with a wide range of riders and riding, your riding is relatively flat (you say) so you can go bigger in the chainring.

strauss_jon

Thanks for your feedback all. Gone for a 34 11*40. Much appreciated and happy 2016 riding

strauss_jon

Sorry to bother you again. Was just about to get this (hence last post) and saw that it a long cage

Shimano XT 11-speed Rear Derailleur RD-M8000 SGS Shadow RD+

Use: MTB
Group: XT
Model: RD-M8000 SGS
Cage: long
Mount Type: Direct Mount
Technology: Shadow RD+
Gear: 11-speed
Compatible Chain: HG-X 11-speed
Max. teeth large sprocket: 40T / 42T for 1x11 only
Min. teeth large sprocket: 40T
Min. teeth small sprocket: 11T
Max. Front Difference: 18T
Total Capacity: 47T

I read that for a single, it should be a short cage:

“Single- and double-ring drivetrains will use a GS cage, while triples require the longer SGS option"

Is that derailleur the incorrect size then...even though it comes boxed with the single configuration? If so, probably a copy / paste error in the description - or is there something about the xt cassette teeth range that requires it to have a long cage?

Cheers

The Rookie

Capacity is the key bit, that has a capacity of 47t, you need no capacity at the front (single ring) at the rear you need a capacity of 42-11=31, a shorter cage will be lighter, have better ground clearance and control the chain a bit better, so while the large will work, a shorter cage with the right capacity would be better.

strauss_jon

Thanks very much...