Hello,

I’m starting to build up a carbon hardtail xc race bike and need a bit of a advice regarding chainset / cassette options.

The bike will be for xc NPS races and a couple of marathons.

Should I go for 3 or two rings up front? I’m a strong climber but I like the idea of being able to suddenly drop into the granny ring if required, rather than slowly clicking through lots gears to get there.

Which cassette options? 11-32 / 11-34 / 11-36? (I’ve no idea how these numbers affect the ride)

Any suggestions very much appreciated.

3×10 if you like the granny ring. 22/32/44 with an 11-28 cassette?

If you need a granny when racing, get off an push – it’ll be quicker 🙂

Personally I’d look at 2×10 c/w 11-36, no lighter than an equivilent (ie all XT say) 3×9 c/w 11-34 but a better spread of gears.

if you are claire from mad i would recommend 22-32-44 chainrings and 32-11 cassette

2 x 10 with an 11/32 or 1 x 10 with an 11/36

I’d use 2×10 with anything you like at the back 32 or 36 if you need the range. chainline is rubbish on 3×10 unless you only use the middle ring. You’d probably struggle on some courses 1×10 unless you change the front ring according to course.

I use 1×10 36 front 11-36 rear on a 29er, can just about manage all UK courses on that, I did the WC at Houffaliaze and no way could I have got around on a single front ring, unless it was a 32, way too steep but using a 32 left nothing for to pedal against on the flatter sections.

1 or 2×10 with an 11-36 block, no advantage in going for a narrower block IME, triples don’t offer anything either these days.

I use 24/32/44 with 12-27 for most things, occasionally swapping to 11-32. It suits me, but that’s mainly for 24hr racing, sometimes you are so knackered you just need to twiddle the granny ring just to keep going. For sub-2hr XC races I can’t remember the last time I used the granny, double should be fine for XC, maybe triple for longer maarathons.
Also, NPS courses tend to be fairly flat. Margam isn’t but even that’s fine with a double. However, if any of your marathons are somewhere really hilly a triple would be good, for example the first climb I ever did in the Alps was 1hr45, all in the granny!

But a double with a wider block will give a lower gear anyway – 26-36 < 22-27

All a narrower block means is more shifting on the front, I found it really annoying. Ymmv.

I agree with Nick on this…..I ran a 9 speed road cassette when I was racing with a triple up front-a narrow cassette just means that you will shift 3 gears at a time on a mtb. 2×10 with an 11-36 for a wide range of gears. -‘d go 1×10 or 1×11 if I could afford were I to race xc again.

I raced last season regional XC and 12hr solos with a 2*9 40/28 up front and 11/36 on the back, spins out a little on fat road but otherwise fine not missed the granny at all.

As others have said the question should be “one or two rings up front?” not “two or three?”

Personally I love the simplicity of 1×10 for short, fast rides/ races but will probably revert back to 2×10 for the Summer longer events (unless of course I get magically strong on the bike between now and then) 🙂

1×11 in an ideal world of course…

Thanks for all the feedback, it was a great help.

2 x 10 it is!

What size wheel is this for?

The wheel size (between 26 and 29) will throw it out by about 1 gear.
ie same chainring, a 36t on 29″ about the same as 32t on a 26″ wheel?

Other way round – 32t on a 29er is about the same as 34t on a 26.

Gee’s right – roughly 10% ‘harder’ gearing on a 29er.