Hi all,

Just toying with the idea of changing my crankset on my Boardman 650b TEam FS.

The main reason is that i’m struggling with some climbs compared to my friends, and on investigation, it appears my climber gear is quite high compared to everyone elses (11/36 cassette with 27/42 up front), but also the FSA BB’s are silly money for some reason and the shimanos are a third of the price.

At present its running an FSA Comet up front, but im thinking of going for this … http://www.chainreactioncycles.com/shimano-xt-m785-10-speed-double-chainset/rp-prod67200

Im thinking of going for the 38/24 with the bottom bracket to match.

Is there anything i should be aware of? Will this play ball ok with my current setup at the rear, and chain? Anything else I will need to change?

Cheers all 🙂

You’ll never go wrong with a shimano crank, basically. But you do need to be sure it’s the right BB. That’s pretty much it!

It’s not a massive reduction in your lowest gears, that. Noticable, but not huge. You said you struggle on climbs, this might sound daft but are you always in the lowest gear when that happens? Sometimes the pace or shape of a climb leaves you in a higher gear, you’re absolutely buckled but not because of running out of ratios.

Why not just change the rings?

Yup i have been told its the right BB…. I found this out when i was looking at an alternative bottom bracket when my fsa mega exo gave up.

With regards to changing the rings, id have to change both as the tooth diff between bigger and smaller is already at its limit (as i understand it), and at £25 ish a ring id be at about 50 quid, and still stuck with a rubbish BB that will prob give up again after a few muddy rides.

@northwind, regarding the climb… my issue is that on the really steep stuff i just don’t seem to have a low enough gear to get me going without killing me sometimes. I am unfit and a heavy weight, which will hopefully change, but i just want a bit more spin available for some of the steep stuff. I’d rather have that than the top end gears which are barely used on a MTB, not for me anyway. 🙂

Makes sense then… I think if I was you I might be tempted to try and find a 22/36 chainset instead, proportionally that adds more on the bottom than it takes from the top. It’s a very low bottom gear but, better to have it and not use it, than not have it and want it I reckon. But I reckon 24/38 will do you alright too.

Ahh ok ta …. Is it right that a 14 tooth difference is the limit between rings at the front?

Get an SLX 2×10 crank and BB and you’ll be laughing.

@mikertroid… the slx is less than £20 cheaper than the XT at the mo, and that’s with no BB. My thinking was that at that price its better getting the XT with BB for £93. Would you not say the same?

http://www.chainreactioncycles.com/shimano-slx-m675-10-speed-double-chainset/rp-prod83170

OP i was in your shoes when i had my boardman. I went shimano 36/22 for a while and found that too spinny before going 38/24 and eventually up to 38/26 as i got stronger.
Def think it’s a worthwhile change. When you come to swap do measure the chain properly but you’ll end up taking a couple of full links out.

Are you stalking me!?

I made pretty much this exact post a few weeks ago..on a different forum!

I just switched to an M675 38/24T.

It fits fine with the BB that’s included in that set.

I noticed a big difference in ratios too.

Things to look out for:

1) Chain length, I removed a whole link as it was too long, 1 whole link is 3 teeth so going from a 27 to a 24 makes sense.

2) Front mech height. The direct mount front mech wont really go low enough and I am experiencing some chain rub and the extremes of the gearing. I have borrowed a low clamp mech from a friend to see if it will fit and if it will make any difference, not tried yet though

3) Getting the BB off might be hard, my torque wrench goes to 100Nm and that wasn’t enough to get it off, it’s only supposed to be on at 40-50Nm. I had to buy a breaker bar in the end.

Had my bb off already, so that won’t be an issue 🙂

Interesting re derailleur height as it’s a fixed frame mount isn’t it? 🙁

When you say it fits with bb in set, do you mean the fsa one that comes on the bike?

yeah the FSA BB fits with the shimano cranks

I meant the shimano bb that comes with the new cranks fits the bike fine. I ditched he FSA one as it was worn, expensive to replace and got very poor reviews.

The front mech is a direct mount yes, there is a small amount of vertical adjustment offered but the elongated mounting hole. However mine was already as low as it would go with the old cranks.

I recently ditched my chainset off my Boardman, mainly because of the jump from 42T to 27T was so big. I looked into changing rings but the comet rings only seemed to be 42t and 27t and they are a 3 bolt fixing so not compatible with anyone else. mine is the 2012 frame (26″) and the from mech is not direct mount luckily so it was pretty easy. Went with 32t and a 24t (I think), but to be honest I haven’t used the small ring as I don’t really need it round here.

Cheers all…. Can anyone comment on SLX vs XT?

Ahh i made an error … it looks like the SLX does come with a bottom bracket too, so that is a saving 🙂

Think i’ll go SLX.