TL;DR version: Own a Stumpjumper 650b, ignored the reviews about low BB, getting annoyed with pedal strikes, want new bike.

I just don’t feel confident in being able to pedal up to obstacles on rough terrain without pedal-striking on it.

Ideally I’d like another frame that I could swap all the components onto as I’ve just put new 160mm RCT3 Pikes on the Stumpjumper. Is it worth ‘re-framing’ everything or should I just cash in and get something new?

The way I see it I have 4 options:
• New bike
• New frame
• Shorter cranks and bigger chainring (to increase ground clearance and reduce cadence)
• Somehow adapt my riding style to counter the issue

Any advice?

Q1 why the pedal strikes? Is the set up right etc?
Q2 is the bb low or common with a lot of current bikes?

A1 Because taking into account for suspension travel/sag and raised terrain which you may be straddling, it’s a job to keep them off the floor. Even during the top section of Sixtapod at BPW over the weekend I was scraping the pedals and that’s pretty flat!

Maybe I just have to accept that I can’t pedal everything like I used to on my old Demo 8?

Q2 The BB genuinely is low, lowest in it’s class compared to every other bike released that year I believe (2015). Just for comparison, it’s BB height is 8mm lower than both the 26″ and 29″ versions of the Stumpjumper. So even if I fit 165mm cranks, the pedals will still be lower than the other two models.

For reference, HA and BB height of the Stumpjumper compared to other bikes in it’s class that year…

What length cranks and what size chainring are you running?

Technique needs to change.

Wasnt that the one where they used the 29er front end and put a spacer under the headset to lift it up. Like you say i dont think you can fix that with technique. It does give you scope to fit longer forks if you were inclined but as you say its not going to help a huge amount.

Try 165mm or 170mm cranks, if you’re on 175mm?

Fit some bigger tyres, maybe these new 2.6in “wide trail” jobbies?

Fit an eccentric BB to raise the crank axle?

http://wheelsmfg.com/eccentric-bottom-bracket-for-bb30-24mm-shimano-cranks-red.html

Or just buy a new frame. Life’s too short to ride the wrong bike.

What length cranks and what size chainring are you running?

Stock cranks are 170mm, and I’m on 32t at the moment. Wouldn’t go any higher than 34t though as that’s all my chain guide can take.

Wasnt that the one where they used the 29er front end and put a spacer under the headset to lift it up. Like you say i dont think you can fix that with technique. It does give you scope to fit longer forks if you were inclined but as you say its not going to help a huge amount.

Yes it was, and I already swapped the stock 150mm Revelations for 160mm Pikes and it’s made no noticeable difference.

I’m thinking a new frame might be the way to go, then I can get rid of the steep head angle and low BB in one go. But I’m worried the frame on it’s own would be un-sellable. lol

We have a 2016 S Works one and don’t have a problem with pedal strikes, run it with Bennies or Boomslangs which are thinish pedals. Think the cranks are 175 cranks

We have a 2016 S Works one and don’t have a problem with pedal strikes, run it with Bennies or Boomslangs which are thinish pedals. Think the cranks are 175 cranks

I think they redesigned the frames from 2016 inwards, 2015 was just a rehashed 29er frame though. Already got thin pedals.

I’ll double check the crank length later, because if I can take 10mm of the crank length that should sort it!

what sort of sag are you running?

ive seen a few people who are awesome downhill with 35+% sag. it all goes wrong pedalling over a rock garden though. I agree its low but were talking about the thickness of your thumb here.

I think they redesigned the frames from 2016 inwards, 2015 was just a rehashed 29er frame though

Website says 335mm BB height for the 2016.

New frame. That bb sounds like a fundamental flaw and shortening cranks etc is only going to tickle the edges of the problem. I have a Bronson which is 2 cm higher, and that seems low to me

what sort of sag are you running?

ive seen a few people who are awesome downhill with 35+% sag. it all goes wrong pedalling over a rock garden though. I agree its low but were talking about the thickness of your thumb here

I think it’s about 25% rear (with the smallest shock token) and 30% front with 2 tokens.

I’ve got another trip to BPW booked for Easter weekend, so I’ll see how that goes before I make any decisions.

Website says 335mm BB height for the 2016

Correct, and mine is 327mm as it’s a 2015 model.

New frame. That bb sounds like a fundamental flaw and shortening cranks etc is only going to tickle the edges of the problem. I have a Bronson which is 2 cm higher, and that seems low to me

Shortening the cranks will also increase the effort required to get the same speed in a given gear due to reduced lever effect.

Shortening the cranks will also increase the effort required to get the same speed in a given gear due to reduced lever effect.

There is often some gain back due to it being easier to spin the cranks and so actually put power down during riding.

e bike or HT 😀

Does anyone make what is effectively an eccentric BB for press-fit bottom bracket shells?

Yup, someone linked it above. Does limit crank choice though as it typically needs SS cranks without granny tabs.