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Pedal strikes

32 posts & 23 voices | Started 1 year ago by headfirst | Latest reply from deadlydarcy

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headfirst - Member

So I've put up with these for a while but I'm fed up with it now. I'm not in the market for a new bike and I really like my Stumpy apart from this issue. I've taken my SPDs off (M515's) after yesterday's ride and put my old V8's on, this obviously won't stop the pedal strikes but might make them 'jolt' less?!

I'm also considering swapping my 175 cranks for 170's, the SLX for £99.99 at CRC seems like a good buy.

So anyone had a similar experience (I've done a bit of a search and know stumpy01 has) or have suggestions on cheapish fixes? I suppose another thing to do would be to pump my shock up a bit too?

(EDIT: Oops wrong forum... )

Posted 1 year ago #
brooess - Member

dial in stiffen up the suspension and bring up the BB?

Posted 1 year ago #
bassspine - Member

I used to get a lot with my Enduro ('06) so I fitted the higher bb shuttle and learned to time my pedalling to avoid strikes. I don't use the Enduro any more (the frame's in my cupboard) but I still find that learned pedal timing skill useful.

Posted 1 year ago #
Garry_Lager - Member

Pedal strikes suck, but they have to be considered in the context of the whole ride. A low bb has to be pretty fundamental to the frame geometry, so if you're liking how the bike handles in general then I'd put up with them.
I've just moved on from a CDale rush that had a low bb, noticeable pedal strikes. Great, great handling XC bike - occasional bash of the pedals easily worth putting up with.

FWIW I've just got that slx 170 chainset fitted as part of an emergency replacement when I was on holiday - don't like that crank length at all. It's always dodgy to assume you're really noticing small differences in MTB components, so happy to be told I'm talking bolex, but I felt like I could feel the difference in pedal stroke immediately.

Posted 1 year ago #
molgrips - Member

Don't pedal over rocks?

Or, more pressure and/or compression damping or platform damping.

FWIW I notice a big difference between 175 on the MTB and 170 on the road bike.

Posted 1 year ago #
BigJohn - Member

Get some big tyres and pump them up.

Or lower your saddle

Posted 1 year ago #
oreetmon - Member

half crank over anything 'rough' or coast and keep them level.
if thats not easily done,,,, get a new frame as you current is not good enough for you and your locals.

Posted 1 year ago #
1freezingpenguin - Member

I use to get it on my Enduro and then later on on my Demo7. Just learn where you can pedal and where you need to coast like over rocks.

Posted 1 year ago #
pitduck - Member

i do it all the time on my 2004 enduro, worth it for the low centre of gravity in my op

Posted 1 year ago #
PeterPoddy - Member

I'm not in the market for a new bike and I really like my Stumpy apart from this issue

It's a Spesh. They all do that, sir!

You get used to it. 5mm off the cranks will make BUGGER ALL difference.

Posted 1 year ago #
geetee1972 - Member

Oooh where's TLR when you need him?

Posted 1 year ago #
GW - Member

sorry, but stumpjumpers don't even have really low BBs, it's your riding that's to blame.

but 5mm will make a difference PP.. I've been running 165s on my lowest bikes for years and would never go longer than 170 on an MTB crank.

Posted 1 year ago #
buzz-lightyear - Member

Try some taller tyres and thinner pedals - it might just clear up the worst of it.

Posted 1 year ago #
brooess - Member

You don't hear people saying that about Orange Fives

Posted 1 year ago #
Cougar - Member

I'm a martyr to pedal strikes as well (and Spesh also).

Though, every time I do it, I think "fk, I need to stop doing that" rather than blame the bike.

Posted 1 year ago #
Scamper - Member

I've got a stumpy. First thing i did was put on some superstar pedals which took about 1cm off. Made a big difference. Then I went down to 170 cranks which also made a difference, although had to adjust to being sat higher on the bike.

Posted 1 year ago #
GW - Member

um.. a 10mm slimmer pedal platform and 5mm shorter crank would cancel out each other :?.. WTF are you doing away up there? growth spurt?

Posted 1 year ago #
cruzheckler - Member

GW - 10mm thiner and 5mm shorter will bring the height up surely not cancel each other out

Posted 1 year ago #
Harry_the_Spider - Member

It's a Spesh. They all do that, sir!

You're not wrong! My FSR does it all the time. Once destroyed a pedal on my old Rockhopper doing it too.

Posted 1 year ago #
trailmonkey - Member

Sold my Spesh because of it.

Nightmare on technical climbs where you've got limited choice on where not to pedal.

Shame really because in all other ways it was a lovely bike.

Posted 1 year ago #
2wheels1guy - Member

I get that on my P7.
I've got 100mm rebas on it, I'm going to get 140mm revelations in a couple of months.
Anyone know what raising the front 4cm will do to the BB height?

Posted 1 year ago #
GW - Member

GW - 10mm thiner and 5mm shorter will bring the height up surely not cancel each other out
the top of a 10mm thinner pedal body will be 5mm lower with 5mm extra ground clearance (think about it?)
5mm lower (thinner pedal) + 5mm higher (shorter crank) = 0

Posted 1 year ago #
Lifer - Member

The pedal is 5mm higher too

Posted 1 year ago #
GW - Member

WTF are you on about?

Posted 1 year ago #
mboy - Member

sorry, but stumpjumpers don't even have really low BBs, it's your riding that's to blame.

but 5mm will make a difference PP.. I've been running 165s on my lowest bikes for years and would never go longer than 170 on an MTB crank.

What he said...

175mm cranks are "too long" (if you go by the correct way of working out ideal crank length) for about 80% of the MTBing public anyway. Far better would be for any medium sized bike and below to come with 170mm cranks fitted (and say XS size with 165's). Spesh do fit different crank lengths on different sizes in some bikes, but not in all, and most Mediums come with 175's iirc.

Anyway, correct shock setup, some 170mm cranks, and some slimmer pedals can make a difference... But it's mainly up to technique to dial out. I used to hate riding a bike with a low BB cos I wanted to pedal through everything. Now I wouldn't ride a bike with a tall BB for love nor money, bikes with low BB's handle so much better, you just need to learn where to pedal and where not to, and buy some tough/slim pedals!

Posted 1 year ago #
mboy - Member

The pedal is 5mm higher too

eh?

As GW has explained, if the OP uses a 5mm shorter crank, combined with a pedal that's 10mm thinner (so 5mm on either side), the top side of the pedal will sit in the same position that it did previously when the crank is at bottom dead centre, the underside of the pedal will now sit 10mm higher, giving it 10mm more ground clearance.

Does that make more sense?

Posted 1 year ago #
mightymarmite - Member

What model SJ is it? Have fitted RP23's on both the wife 07 and friends 08. Both were slightly longer shock bodies and stroke due to spec's original unique lengths. As a result also increased BB height, and travel. U-turns on the front to dial the original geometry back in. Have ridden the 07 a couple of times since and been very impressed with the improvements. Picked up the last shock for the 08 for £99 on ebay.

Posted 1 year ago #
Scamper - Member

Did not explain myself - agree with mboy. After firstly switching to thinner pedals, foot height is now back to where they started with the shorter crank, but i'be got overall 1cm more ground clearance. If anything its the confidence it gives you to spin the crank.

Posted 1 year ago #
Cougar - Member

I think what GW was referring to was

...although had to adjust to being sat higher on the bike.

... to wit, you'd be sat in the same place?

Posted 1 year ago #
Lifer - Member

Does that make more sense?

I was talking about the underside of the pedal too

Posted 1 year ago #
Scamper - Member

Yes, i was sat back in the same place, but this after 6 months of riding with just the thinner pedals!

Posted 1 year ago #
deadlydarcy - Member

I had to google "pedal strikes"

Posted 1 year ago #

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