Raise pedals???

[EebStrider]

Ok, here goes! I keep grounding out the pedals over tree roots, and before anyone says I need to learn to ride, yawn, I’ve had mountain bikes for over 30 years, and this has never happened on any other bike I’ve owned, despite riding the same trails.

Are there any simple fixes for this, or do I need to look at raising the suspension? I’m not heavy, at just under 12 stone, and the preload is set correctly for my weight, so I’m trying to work out a fix, as this is pissing me off.

 

[Zimmerframe]

Don't worry, you're not the only person who does this.

With the emtb you find you end up pedalling in places you never would have before, it takes time to re-adjust to that ..

Most people just go with shorter cranks.

I think you have the Cube Stereo Hybrid 140 ... can't remember what the crank length is though

 

[Benbenben]

Little more air in the shocks would keep the ride height up a bit, lower profile pedals will help as can shorter cranks.
Does your ebike have longer travel than your previous bikes? that could be the issue.

 

[Gary]

Ok, here goes! I keep grounding out the pedals over tree roots, and before anyone says I need to learn to ride, yawn, I’ve had mountain bikes for over 30 years, and this has never happened on any other bike I’ve owned, despite riding the same trails.

Ok. so are you completely closed to the suggestion you "might" benefit from learning a NEW riding skill? on your NEW Ebike
Even if it does bore you, there really is only one reason a pedal hits a root while rolling over it.

Ideally you want to time your pedal strokes so that each pedal is out the way of any pretruding object below the bike. BECAUSE you have a motor it's actually EASIER to manage this while holding momentum over rough ground. partly because you can get a boost of momoentum on approach and freewheel longer with your cranks level and partly because a motor adding assistance can make a ratchetted pedal input deliver greater forwards motion. Full pedal strokes over technical terrain require timing and weight shift to pull off cleanly. it's honestly a skill worth developing

As for your bike, What is it?
It seems incerdibly unlikely if it's a modern mid motor FS Emtb that it's BB would be overly low with recommended sag simply because there are no Emtbs with genuinely low BB heights. But... having said that, your suspension "could" be set up badly or for some reason lacking midstroke support and "could" be wallowing under rider inputs or "trapdooring" on square edge hits.
A bike with a whack regressive leverage curve can act like this too but again this is highly unlikely as most manufacturers nowadays do actually know not to design those anymore.

 

[Flatslide]

I have the same issue as my RM has 170mm cranks and the suspension setup I prefer is at the second lowest BB height. On a local 2-way narrow track named-Fir Trader, there are many rock and root sections that I can easily clout my pedals into. The trick for me is to either carry speed uphill into them, and/or use part pedal strokes in a mid gear. I'm becoming more proficient at this, so whenever I pedal or crank-arm strike, it's my own doing-or should that be undoing...

 

[EebStrider]

Don't worry, you're not the only person who does this.

With the emtb you find you end up pedalling in places you never would have before, it takes time to re-adjust to that ..

Most people just go with shorter cranks.

I think you have the Cube Stereo Hybrid 140 ... can't remember what the crank length is though

Yep, I’ve now heard that a few people have the same issue. Glad it’s not just me. What are the implication of shorter cranks? Any?

And, yep, it’s the Stereo Hybrid 140.

 

[EebStrider]

Ok. so are you completely closed to the suggestion you "might" benefit from learning a NEW riding skill? on your NEW Ebike
Even if it does bore you, there really is only one reason a pedal hits a root while rolling over it.

Ideally you want to time your pedal strokes so that each pedal is out the way of any pretruding object below the bike. BECAUSE you have a motor it's actually EASIER to manage this while holding momentum over rough ground. partly because you can get a boost of momoentum on approach and freewheel longer with your cranks level and partly because a motor adding assistance can make a ratchetted pedal input deliver greater forwards motion. Full pedal strokes over technical terrain require timing and weight shift to pull off cleanly. it's honestly a skill worth developing

As for your bike, What is it?
It seems incerdibly unlikely if it's a modern mid motor FS Emtb that it's BB would be overly low with recommended sag simply because there are no Emtbs with genuinely low BB heights. But... having said that, your suspension "could" be set up badly or for some reason lacking midstroke support and "could" be wallowing under rider inputs or "trapdooring" on square edge hits.
A bike with a whack regressive leverage curve can act like this too but again this is highly unlikely as most manufacturers nowadays do actually know not to design those anymore.

While I sort of get what you’re saying, if you’re riding fast technical tracks, picking your way through tight gaps, turning on fast hairpins at speed, there just isn’t time to stare at the ground.

 

[EebStrider]

Little more air in the shocks would keep the ride height up a bit, lower profile pedals will help as can shorter cranks.
Does your ebike have longer travel than your previous bikes? that could be the issue.

I can’t see how that would raise it that much though. Not enough to avoid what I’m hitting!

 

[Benbenben]

I can’t see how that would raise it that much though. Not enough to avoid what I’m hitting!

I guess it all adds up as would larger volume tyres, between all of those things you might gain an extra inch or two depending on sag.

 

[EebStrider]

I have the same issue as my RM has 170mm cranks and the suspension setup I prefer is at the lowest BB height. On a local 2-way narrow track named-Fir Trader, there are many rock and root sections that I can easily clout my pedals into. The trick for me is to either carry speed uphill into them, and/or use part pedal strokes in a mid gear. I'm becoming more proficient at this, so whenever I pedal or crank-arm strike, it's my own doing-or should that be undoing...

I avoided quite a few today, using that technique, but it’s not always possible. Annoyingly, after my crash last week, my shoulder is more sensitive, so every clout went right through me today. Not fun.

 

[Gary]

While I sort of get what you’re saying, if you’re riding fast technical tracks, picking your way through tight gaps, turning on fast hairpins at speed, there just isn’t time to stare at the ground.

Yeah. and that's because you should be looking ahead, scanning and taking in everything you're aproaching and adjusting body position as necessary. Not staring at the ground at all. If you honestly struggle doing that then slow down until you can.

Scanning ahead and judging foot placement is a pretty important life skill. Without it you'd be black and blue from tripping over kerbs and walking into lamp posts every time you walked down the street.
Why would you think this to be any different on an Ebike?

 

[flash]

I bought a set of 165 and 155 cranks for my Merida to try out as the 170's were striking much more when I reduced my tyre volume (2.8 to 2.5). I ride very rocky and rooty trails. I don't pretend to be a technically great rider although I'm slowly improving.

Definitely less strikes the shorter I go. Obviously. I didn't notice much difference with the 165's but the 155's definitely are less efficient (ie: I need to pedal a bit harder and my cadence is up) and I feel I get a small but noticeable drop in battery range. I'd never go 155's on an acoustic. But on an e-Bike I don't see a problem with shorter cranks.

OTOH I found the shorter cranks very comfortable to pedal. Maybe I've got short legs? I do prefer higher cadence than grinding up a climb. I'm still riding the 155's although I think a 160 would be ideal, for me.

Gordon

 

[Zimmerframe]

What are the implication of shorter cranks? Any?

This seem to depend very much on the rider, riders height, riders experience.

On my Shimano I dropped to 150 Mirandas as I seemed to spend half of my time landscaping rock. I'm crap, inept, amazed when I stay on - so historically, don't have the time to appreciate the trail in front of me The Shimano bike also had a particulalry low BB, 5cm's lower than the Kenevo.

When I ordered the Kenevo I ordered 140 cranks as I'd heard it had a low BB and knew I was still inept. I rode the bike on the standard cranks, 165 I think, and it was actually fine .. no strikes. But changed anyway because I'd bought them.

When you first change, for a couple of km's it feels like you're riding on a tiny little hampster wheel.

Interestingly, until two days ago when I let someone ride it with the power off, no ones ever mentioned the shorter cranks on either bike.

I'm 5'10, I think if you're taller, the shorter crank effect becomes more unusual and difficult to adjust to.

It arguably gives you a smaller platform on which to stabilise and control the bike with your weight - I'm fortunate in that stabilise and control are never states which occur when I'm riding.

As @Gary says, ideally, we all learn to become better riders. For me this helps as an interim measure to keep me and the bike safer until that never happens.

 

[OldGoatMTB]

A little practice does make a difference. When I first got mine I was having four or five pedal strikes per ride and now it’s probably more like one. I’m still thinking about getting shorter Kranks.

 

[Rosemount]

Ok. so are you completely closed to the suggestion you "might" benefit from learning a NEW riding skill? on your NEW Ebike
Even if it does bore you, there really is only one reason a pedal hits a root while rolling over it.

Ideally you want to time your pedal strokes so that each pedal is out the way of any pretruding object below the bike. BECAUSE you have a motor it's actually EASIER to manage this while holding momentum over rough ground. partly because you can get a boost of momoentum on approach and freewheel longer with your cranks level and partly because a motor adding assistance can make a ratchetted pedal input deliver greater forwards motion. Full pedal strokes over technical terrain require timing and weight shift to pull off cleanly. it's honestly a skill worth developing

As for your bike, What is it?
It seems incerdibly unlikely if it's a modern mid motor FS Emtb that it's BB would be overly low with recommended sag simply because there are no Emtbs with genuinely low BB heights. But... having said that, your suspension "could" be set up badly or for some reason lacking midstroke support and "could" be wallowing under rider inputs or "trapdooring" on square edge hits.
A bike with a whack regressive leverage curve can act like this too but again this is highly unlikely as most manufacturers nowadays do actually know not to design those anymore.

I am the owner of a 2019 Cube Stereo Hybrid 140 SL .
And it has an extra low bottom bracket and pedal strikes are definitely a pain in the ass .

My new 2020 Stereo 160 has 20 mm more clearance and I notice the difference . I was talking to the mechanic @ the LBS he said he has another guy who gets his Stereo Hyb 140 serviced there and he always wondered why his pedals and cranks were polished from rock / root strikes .

I also raised the sag on my bike . Did make a very small difference but it is a characteristic of that bike .
Pros and cons . Low BB means low centre of gravity . Leads to fast cornering and stability when jumping . Gotta trade off some where though ...


So yes it is a real phenomenon . And you need to adapt your riding to compensate .

 

[Gary]

I am the owner of a 2019 Cube Stereo Hybrid 140 SL .
And it has an extra low bottom bracket

No it doesn't!
it has a BB height of 343mm which is considerably average for a 140mm trail bike (infact verging slightly on the high side)
it's 15mm higher than my Esommet while static and the Cube has 20/30mm less travel.
Meaning the Cube's sagged BB height is considerably higher when riding. and a whopping 39mm higher when bottomed out.
any difference you've noticed may well be partly in your head from misunderstanding the numbers.

pedal strikes are definitely a pain in the ass .

They're also definitely self inflicted.

My new 2020 Stereo 160 has 20 mm more clearance and I notice the difference .

your 2020 stereo 160 has 20mm more travel.
If it's static BB height is 20mm higher it is to allow for the extra 20mm the BB will drop when fully bottomed out.
Your stereo 160 if set up with the same percentage of sag is actually LOWER than your 140

I was talking to the mechanic @ the LBS he said he has another guy who gets his Stereo Hyb 140 serviced there and he always wondered why his pedals and cranks were polished from rock / root strikes .

Tell the mechanic it's because the other guy isn''t looking where he's going, planning ahead, timing and positioning his cranks well on aproach to rocks and roots


[EDIT] Cube list the 2019 cube stereo hybrid 140s static BB drop as 15.5mm, While they list the 160s as 12.5mm.
This being the case your 3mm higher 160 is actually 2mm lower than your older 140 at 25% sag and should ride considerably lower throughout its remaining travel.

 

[Rosemount]

Go ride one and come back with a report bro .

I gave mine . Backed it up with an anecdote from my mechanic . How many miles you done on a Cube Stereo 140 ? The thread is stacked with Cube 140 owners . And you know better ?
Real word vs drawing board .

I have learned to compensate for the wider Q of an Ebike crank axle and what I perceive as the lower clearance of the cube 140 . The axle length + low / longer crank arms means if you are not perpendicular the crank bites the rocks . 2019 140 has 170 crank arm .2020 160 has 165 . Add a wide pedal and cruncho !
I am more aware of where my pedals are now than ever. I use changes of cadence and half pedal ratchets to stay clear of rocks . Still my pedals and cranks on my 140 are butchered .

The trails I ride are littered with baby heads , roots and logs . Some eroded with narrow gullies .
Most pedal strikes are when climbing these sort of trails .

After a week of riding the 160 I can tell the difference .
I deliberately bought more compact pedals for the 160 to help with ground clearance when exiting turns . And sneaking between gaps in trees and rocks .
I run the suspension quite firm . I weigh 60 KG . Soaking wet .

I recently went to Derby Tasmania and rode a Turbo Levo and a Trek Power Fly for a lot of miles both seemed to have more ground clearance than the Cube 140 .

 

[Gary]

Instead of anecdotes from a mechanic about some other clumsy guy who continually smashes his pedals off everything, how about you actually measure the BB height on both of your bikes?
You're arguing with the manufacturers BB drop specs I posted so by all means go ahead and prove the manufacturer wrong.

The Q factor on your Stereo160 is 175mm - pretty much exactly the same as any standard trail/enduro mtb so you needn't have worried about choosing more compact pedals for it really.

 

[Rosemount]

I measure it every time I ride .
Not by theory .

Just checked seems to me the older gen BOSCH motor has wider Q ? and the 2019 has longer cranks .
Those factors could be the difference , also when climbing the arse end squats more too ?
So pedals get closer to the ground ? That`d be suspension kinematics and wheel travel direction and geometry ? Yeah ,beyond my pay grade too ...

 

[Rosemount]

@Gary

I just read an interview with Nico Vouilloz .
Says he uses 160 mm cranks to avoid pedal strikes ! OMG !!!

10 time world champ , but uses shorter cranks on his ebike to avoid pedal strikes . But Gary can clock up infinite miles and never touch the pedal on a thing ...

Interview: Nico Vouilloz Goes Down the Rabbit Hole on Bike Setup & Design - Pinkbike

 

[urastus]

I never had pedal strikes on my accoustic (26" 120mm) trail bike with 175mm cranks. With 165mm I'm probably down to one each ride on my ebike? When I started riding my ebike I was striking all the time. I don't know what it is - I never bothered to look. There is something definitely different with emtb though. I assumed it must be the bb height? If not, and most other things are equal re heights and suspension bob etc, then it must be something to do with momentum and the need to spin on an emtb? I adjust suspension and tyres for the ground I ride - it's a 140 so I want to get everything I can from it, and it's rocky where I ride. I'm not going to increase pressure in suspension or tyres to limit pedal strike (casing is also a concern). I subconsciously have alarm bells go off when I think I could strike, so don't. Sometimes though I'm still truly surprised when I do strike.

 

[R120]

Its pretty simple - Ebikes require an adjustment in your technique to avoid pedal strikes - its very common to get pedal strikes when you first get an ebike, but you learn to adjust and soon the problem goes away. Having said that IMO 160mm cranks are the sweet spot for an EMTB, as you are not going too short as to cause stability problems by shortening your static peddling platform when descending, but gaining enough clearance to help.

Irrelevant of how @Gary puts his point, he is right, once you get the technique right if you are relatively new to "proper" mountain biking, or recalibrate your technique if you are an older hand, the problem goes away.

I find that many riders find themselves on an accelerated learning curve when they get an ebike, and start both riding terrain they never would have on a normal bike, or progressing their riding into more challenging terrain than they ever have before, and as such start having issues that they didnt have before.

Shorter cranks are not a miracle cure for pedal strikes, lets face it we are talking MM here, they do help, as do lower profile pedals, but if you are getting constant pedals strikes then its technique, not the tool, that needs improving.

Think of it as a challenge to get better, rather than something to overcome, because improving your technique also means having more fun on your bike.

 

[Gary]

I just read an interview with Nico Vouilloz .
Says he uses 160 mm cranks to avoid pedal strikes ! OMG !!!

That's not exactly what Nico said now is it?
How about quoting what he said instead of trying to make it fit your argument?
Fwiw I run 165s on most of my bikes. Including my roadbike (so obviously not for pedal strike clearance).
Nico is a good bit shorter than me.

 

[Rosemount]

Point is Gary a 10 time world champ runs short cranks to avoid rocks .
You tell stories about the 10 s of thousands of KM without as much as a brush . I think that is an anomaly .

Not every one has the skill or the eyesight to plot such a course . That standard is a bridge too far for even a 10 time world champ .

Though clearance and the way the suspension works and the terrain are all variables . I`m riding the same trails on the Cube 160 and not scrapping the pedals in places I did on my Cube 140 !?? How is that ? Did my skills and eyesight suddenly improve ? At 54 yrs old I doubt it ...

 

[Gary]

You honestly think if Nico ran 5mm longer cranks (the length I do) he'd be smacking his pedals off everything?
Sorry. But if you think that you're deluded.
Read what he wrote again. Or have someone explain it to you.

 

[HORSPWR]

Ideally you want to time your pedal strokes so that each pedal is out the way of any pretruding object below the bike.

No shit Sherlock!

@Gary

I just read an interview with Nico Vouilloz .
Says he uses 160 mm cranks to avoid pedal strikes ! OMG !!!

10 time world champ , but uses shorter cranks on his ebike to avoid pedal strikes . But Gary can clock up infinite miles and never touch the pedal on a thing ...

Interview: Nico Vouilloz Goes Down the Rabbit Hole on Bike Setup & Design - Pinkbike

That's coz Gazza is the legend of all legends ?

 

[deksawyer]

Not that any of you fuds will haud yer weesht afore ye get yersel in tae a stooshie! Here's my findings on pedals strikes.

I've modded my Haibike (shut up Garry) from 120mm F/120mm R to 140mm F/130mm R and I have very little to no pedal strikes. Even before the travel incease they were rare. Cranks are 170mm and BB is around 370mm now. I prefer rooted forest singletracks and the accociated adjoining pleasure of cycling all the way there. Some deep ruts are gonna get you....no matter how short your cranks are.

I think its a combo of incorrect suspension setup and poor riding ability that causing all this spraff!

 

[Rosemount]

Irrelevant of how @Gary puts his point, he is right, once you get the technique right if you are relatively new to "proper" mountain biking, or recalibrate your technique if you are an older hand, the problem goes away.

I find that many riders find themselves on an accelerated learning curve when they get an ebike, and start both riding terrain they never would have on a normal bike, or progressing their riding into more challenging terrain than they ever have before, and as such start having issues that they didnt have before.

Shorter cranks are not a miracle cure for pedal strikes, lets face it we are talking MM here, they do help, as do lower profile pedals, but if you are getting constant pedals strikes then its technique, not the tool, that needs improving.

Think of it as a challenge to get better, rather than something to overcome, because improving your technique also means having more fun on your bike.

You honestly think if Nico ran 5mm longer cranks (the length I do) he'd be smacking his pedals off everything?
Sorry. But if you think that you're deluded.
Read what he wrote again. Or have someone explain it to you.

Errrr yeah yeah . NAH !

 

[Rosemount]

No shit Sherlock!


That's coz Gazza is the legend of all legends ?

He does know some things .
I have read enough of his posts to realise this . But ,,,

 

[R120]

Read this article.

What’s the best crank length on an E-MTB?

The trail in front of you gets steeper and you don’t want to lose your momentum, so you start pedalling like a maniac. Then you hear a loud clunking noise and everything comes to an abrupt halt… the next thing you know you’re flying over the bars! What happened? Chances are you jammed your crank […]

ebike-mtb.com

This thread is a bit depressing really, along with several others on the forum at the moment, because being a good rider actually has very little to do with the equipment you have, and everything to do with skills and technique, and there are no shortcuts to achieving this - yes certain mods help improve certain situations, but riding any mtb well and dealing with issues different terrains throw up is ultimately about rider skill, and as I have said before a bit of coaching or a skills course is a far more effective remedy than chucking money at upgrades that have no benefit unless you have the abilities to make use of them.