What’s the magic ratios then?
32 up front and 11-42
Or what?
Going on a Krampus, with a less than average rider to pedal it..

Isn’t that 29-plus?

I’d start with 30t myself, unless you live somewhere flat.

Where do you ride most?

If Thetford then probably a 38 on the front, if around here (Borders) then a 28 (on a 29+) would probably be best.

+1 to what Chapaking said: For a 29er 32T if you aren’t used to it so for a 29+ a 30T seems right then if you feel strong enough move to a 32T.

I’ve a 30T up front and 11-42T rear end, XT M8000.

Mostly Peaks, Wales trail Centres and Scotish Borders. On an old fashioned 26″ wheeled MTB.

I’d have thought 28t. 30t max tbh

I might agree actually, bike’ll probably be quite hefty I assume?

30T up front, 10-42 Sram cassette, XTR shifter and mech is the perfect combo for me.

I was fine all Summer on 650b with a 32t, but the last couple of muddy rides have been a bit much. Considering dropping to a 30t.
(bike is 29lb)

I’d be sticking a 28T on there for a 29+ bike.

With those big tyres to push round lowest gear on 28t is 20″ and 32t is 22″
Highs of 76″ and 87″

Personally I’d go 28t you can always roll down a hill but not up one 😉

28 or 30 to start with and go from there.

Have a 32t Oval on my Trance which gets ridden in Wales/Shropshire and is about right, low enough to get up the hills and high enough that I’m not at the bottom of the cassette on every descent.

28T up front and 10-42 cassette, here in Scotland.

I’d be tempted to start with a 30t on a Krampus

Cheers all.
30t it is then..
I can always get off and push.
I’ve no shame in that.

Or run a front mech…

Knowing you Nick, and runninq 1×11 myself now, you could go for either a 30 or 28 fine, but on a 29+ I would opt for the 28 if you plan on riding any hills. If you are sticking in Delamere most of the time go for the 30.

Front mech would mean the chain rubbing the tyre when in the biggest sprocket.
29×3″ has 31″ rolling diameter, about 6.5% bigger circumferentially than a 29er and 20% over a 26er

I’ve gone 28t upfront with an 11-42 on the back. Would rather have that bail out gear if needed, that’s on a Santa cruz tallboy..

Or run a front mech..

Trying to avoid this Colin, as have Chainline issues at the minute.. When in the granny ring, it rubs on the rear Tyre?

Knowing you Nick, and runninq 1×11 myself now, you could go for either a 30 or 28 fine,

Going to be going to more than just Delamere Luke, and I’m a fair bit fitter than I was, so hoping I’ll manage on a 30t!

Where/ who does a 28 tho? You know, just incase… 😳

I’m running raceface aeffect cranks with a raceface 28t chainring. .

TBH there’s no way to know without trying- but do you already have the bike? If so, you have all the ratios you need to test it, no need to guess.

I’d be going 30T if I was you but, I am not.

Trying to avoid this Colin, as have Chainline issues at the minute.. When in the granny ring, it rubs on the rear Tyre?[/quote]Ah yes- I’ve “Boost-ed” mine to get round this.

Running 30T here on 2 29ers with 10-42 SRAM setups. To be honest, some places, I only just manage, but I refuse to get off and push until the slope is unrideable. Have been considering a 28T myself recently to take the sting away on the really steep climbs.

On a 29+ I’d not hesitate with a 28T…

Ah yes- I’ve “Boost-ed” mine to get round this.

Colin, what do you mean by this?
Sorry for sounding like a noob..

I suspect he means fitting a boost crank which moves the crankset out slightly to add clearance.

Play by the numbers

28×42 comes up the same as 24×36 so all depends on what you plan to do, there is no magic ratio