Let’s talk crank arm lengths…

Question for XL riders only. Would you benefit from higher BBs to accommodate longer cranks?


  • Total voters
    10

Monty Dog

Member
Jan 7, 2023
47
31
Weybridge, Surrey, UK
SOLVED.
I totally get it now.

There are actually two quite different groups on this thread…

1) Those who recognise why the move towards lower BB clearance and shorter (160mm or less) cranks for all - for all rider heights - poses a problem for the lanky ones.

2) Those who see no problem at all. Think that all the talk about leverage, using full range of muscles etc simply not relevant when talking about powered EMTBs. And anyway, everyone’s moving towards shorter cranks these days, so what’s your problem. .

The reason for the split came to me when I read this excellent thread… Has your EMTB made you fitter, or kept you as fit, as your regular MTB?
Because everyone on this thread are also similarly split right down the middle.

Basically… both discussions are split according to whether you ride EMTBs for fitness - fun is a byproduct. Or ride EMTBs because it’s social and it’s fun - fitness is secondary.

Crank length (and therefore BB clearance) DOES matter if your aim is to get a full workout. But not if fitness is less important. (Also not an issue if your average height of course - fitness fanatic or not).

Someone on the other thread put it nicely…

“I think you'll find two types of cheater riders. The ones that want to work for it and just need a boost, but intend to ride with an analog mindset (e.g. SL). The other camp are the lazy fucks that want all the power they can get and don't mind the bulk.”

So….
It looks like the subset of riders who are a) 6’3” and taller, and b) ride EMTBs primarily to push themselves physically are simply too small a group for bike manufacturers to care about.

I get it now. But still frustrated….
 

emtbPhil

Well-known member
Jun 20, 2021
408
452
UK
Yeah that's just complete nonsense

See Rob's latest video - he test rides emtb's for a living and reviews them, he's tall, he rides an XL - he runs 160mm on everything and says that longer cranks offer zero benefit

You can continue beating the drum of leverage and full range of muscles and stuff - even calling everyone who "doesn't get you" not interested in health gains - but it's nonsensical unless what you're targeting is pure muscle growth in which case you wouldn't have an emtb at all.

The whole point of an emtb is to ease climbs, and hoon down hills. Neither of those activities require leverage, if you have 80nm of assist and still don't have the leg power to crank an emtb there's a serious issue.
Both of those activities though DO require crank clearance, you can't pedal up a rocky climb if you're smashing your pedals on every rock.

Personally I've got a lot fitter, I get a better cardio workout on an emtb because I'm out for 4hours instead of 1 and I'm pedalling up things I would normally walk up. It honestly just sounds like you're trying to make an emtb fit where a road bike should be.
 

rzr

Active member
Sep 26, 2022
396
250
bcn
SOLVED.
I totally get it now.

There are actually two quite different groups on this thread…

1) Those who recognise why the move towards lower BB clearance and shorter (160mm or less) cranks for all - for all rider heights - poses a problem for the lanky ones.

2) Those who see no problem at all. Think that all the talk about leverage, using full range of muscles etc simply not relevant when talking about powered EMTBs. And anyway, everyone’s moving towards shorter cranks these days, so what’s your problem. .

The reason for the split came to me when I read this excellent thread… Has your EMTB made you fitter, or kept you as fit, as your regular MTB?
Because everyone on this thread are also similarly split right down the middle.

Basically… both discussions are split according to whether you ride EMTBs for fitness - fun is a byproduct. Or ride EMTBs because it’s social and it’s fun - fitness is secondary.

Crank length (and therefore BB clearance) DOES matter if your aim is to get a full workout. But not if fitness is less important. (Also not an issue if your average height of course - fitness fanatic or not).

Someone on the other thread put it nicely…

“I think you'll find two types of cheater riders. The ones that want to work for it and just need a boost, but intend to ride with an analog mindset (e.g. SL). The other camp are the lazy fucks that want all the power they can get and don't mind the bulk.”

So….
It looks like the subset of riders who are a) 6’3” and taller, and b) ride EMTBs primarily to push themselves physically are simply too small a group for bike manufacturers to care about.

I get it now. But still frustrated….
well... a lot of text, but conclusions inaccurate ...
Shorter cranks are everywhere, on road bikes as well !, and it's not connected to fitness or strength...
read articles from last 10 years, which clearly states that there is no advantage of having longer crank arms (also you can look and link here articles that say otherwise ....)

I like to push myself, I do emtb climbs with HRm>90% (however I doubt i'll be fitter from emtb, as I do 600-700km (and 12-13km elevation) per month on a road bike as well) and I don't see any problem with 160mm cranks, naybe it was strange a bit first weekend. I have 170mm on a road bike. 181cm height, around 86cm inner leg.

also I gave you an example, Sir Bradley Wiggins - 190cm was using 170mm crank arms, Is he strong? or maybe only fit? I don't know ...
 
Last edited:

Monty Dog

Member
Jan 7, 2023
47
31
Weybridge, Surrey, UK
Yeah that's just complete nonsense

See Rob's latest video - he test rides emtb's for a living and reviews them, he's tall, he rides an XL - he runs 160mm on everything and says that longer cranks offer zero benefit

You can continue beating the drum of leverage and full range of muscles and stuff - even calling everyone who "doesn't get you" not interested in health gains - but it's nonsensical unless what you're targeting is pure muscle growth in which case you wouldn't have an emtb at all.

The whole point of an emtb is to ease climbs, and hoon down hills. Neither of those activities require leverage, if you have 80nm of assist and still don't have the leg power to crank an emtb there's a serious issue.
Both of those activities though DO require crank clearance, you can't pedal up a rocky climb if you're smashing your pedals on every rock.

Personally I've got a lot fitter, I get a better cardio workout on an emtb because I'm out for 4hours instead of 1 and I'm pedalling up things I would normally walk up. It honestly just sounds like you're trying to make an emtb fit where a road bike should be.
Thanks emtbPhil - but no need for complete dismissal as 'complete nonsense'. Are you also 6'3" / XL rider?

You say "the whole point of an emtb is to ease climbs, and hoon down hills". That's a big part of it, but some riders - me, for one - also want to ride long distance, such as South Downs Way (over a couple of days). I've done this on an analogue hardtail a few times, but now I'm older and fatter I could do with a helping hand.

Five hours of that sort of riding is different to what many others (incl you?) do. Am in a minority? Yeah, sure. But does that mean I'm talking rubbish to say that tall riders who want to ride long distance aren't being properly catered for? No, I don't think so...
 
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SwampNut

Well-known member
Oct 26, 2022
298
353
Peoria, AZ USA
It's bullshit to categorize at all, really, because if nothing else, we ride in vastly different environments. One mistake we all make (all humans, on all topics) is to base something on our own reality. I just had a conversation with a friend about a depth finder/SONAR for his boat. I started down a recommendation that was important for me, then learned that his lake is mostly flat with a max depth of 17 feet. I had my boat in a 500' deep lake with extreme variations. Totally incomparable needs.

On mountain biking, I have a lot of nearby areas with deep and difficult sand. I simply cannot pedal in it on an amish bike, and even with the eMTB with wide tires, it's often at the end of my limits. Putting the bike on boost is not about lazy, nor am I cheating; I just would have to stop and walk it otherwise. That sort of thing is where going to a shorter crank scares me.

Then a few minutes later, I can be on the side of a very rocky hill, where I don't need a lot of help, but I need clearance. I have to time my strokes around rocks, along with being in the moment for a hard climb after a drop through a rocky bed. So this is where shorter cranks appeal to me.
 

Monty Dog

Member
Jan 7, 2023
47
31
Weybridge, Surrey, UK
It's bullshit to categorize at all, really, because if nothing else, we ride in vastly different environments. One mistake we all make (all humans, on all topics) is to base something on our own reality. I just had a conversation with a friend about a depth finder/SONAR for his boat. I started down a recommendation that was important for me, then learned that his lake is mostly flat with a max depth of 17 feet. I had my boat in a 500' deep lake with extreme variations. Totally incomparable needs.

On mountain biking, I have a lot of nearby areas with deep and difficult sand. I simply cannot pedal in it on an amish bike, and even with the eMTB with wide tires, it's often at the end of my limits. Putting the bike on boost is not about lazy, nor am I cheating; I just would have to stop and walk it otherwise. That sort of thing is where going to a shorter crank scares me.

Then a few minutes later, I can be on the side of a very rocky hill, where I don't need a lot of help, but I need clearance. I have to time my strokes around rocks, along with being in the moment for a hard climb after a drop through a rocky bed. So this is where shorter cranks appeal to me.
Agreed.
 

BJC

New Member
Jan 17, 2023
5
0
Peaslake
I thought 170mm would have too many pedal strikes. But you learn to ride differently and avoid big lumps. Just get them you’ll be fine.
 

SwampNut

Well-known member
Oct 26, 2022
298
353
Peoria, AZ USA
I thought 170mm would have too many pedal strikes. But you learn to ride differently and avoid big lumps. Just get them you’ll be fine.

Again, we're all different in different riding areas. YOU might be skilled at this, and *I* am not, even close, yet. My 165s concern me. One place I can't really figure out is uphill sweeping areas where you must pedal, and you must turn at the same time, so one side is much closer to the ground. I try to get off the bike, but again...not all of us have all the skills.
 

BJC

New Member
Jan 17, 2023
5
0
Peaslake
Again, we're all different in different riding areas. YOU might be skilled at this, and *I* am not, even close, yet. My 165s concern me. One place I can't really figure out is uphill sweeping areas where you must pedal, and you must turn at the same time, so one side is much closer to the ground. I try to get off the bike, but again...not all of us have all the skills.
I don’t really have the option tbh. Skills don’t come into it. I can’t get on with standard 160s. It’s a tall thing. Haven’t tried 165
 

emtbPhil

Well-known member
Jun 20, 2021
408
452
UK
I don’t really have the option tbh. Skills don’t come into it. I can’t get on with standard 160s. It’s a tall thing. Haven’t tried 165
Skills do come into it. With pedals level they have same clearance as the BB

If you’re smashing that on rocks there’s a huge issue lol

I was crap when I started now I’m better at timing my pedalling around obstacles on rocky stuff
 

emtbPhil

Well-known member
Jun 20, 2021
408
452
UK
Thanks emtbPhil - but no need for complete dismissal as 'complete nonsense'. Are you also 6'3" / XL rider?

You say "the whole point of an emtb is to ease climbs, and hoon down hills". That's a big part of it, but some riders - me, for one - also want to ride long distance, such as South Downs Way (over a couple of days). I've done this on an analogue hardtail a few times, but now I'm older and fatter I could do with a helping hand.

Five hours of that sort of riding is different to what many others (incl you?) do. Am in a minority? Yeah, sure. But does that mean I'm talking rubbish to say that tall riders who want to ride long distance aren't being properly catered for? No, I don't think so...

I do it all. A lot of bike parks, downhills, jumps etc…. But also done multi day 4-8hr rides XC and bridle ways.

Have a converted van with leisure battery and inverter so I can do multiple day rides and charge inbetween.

I enjoy bike parks and technical stuff more but do a lot of XC and bridle ways for fitness.

I’m 6ft. Ride a large. Have 160mm cranks.
I swapped from the 165s that came on my bike down a bit. I’d love to try shorter. More clearance.

I don’t have any issues and like I’ve been saying since this mad thread started it’s such a personal thing and so cheap to change it doesn’t make any sense to argue that manufacturers should relate crank length to frame size.

Loads of people have mentioned that crank length is not related to leg length in the way you think. Rob is your size and always uses 160’s.

Just fit what works for you, crank arms, bars, stem, risers, seat post etc… and enjoy. Life is too short for 4 pages of arguing because you feel the bike industry is victimising you over a very personal opinion
 

Monty Dog

Member
Jan 7, 2023
47
31
Weybridge, Surrey, UK
Yep - I guess you could call it skills. I just know that you get used to avoiding pedal strikes. Obvs more of an issue with 170mm. Less of an issue for shorter height / reg cranks.
 

BJC

New Member
Jan 17, 2023
5
0
Peaslake
I do it all. A lot of bike parks, downhills, jumps etc…. But also done multi day 4-8hr rides XC and bridle ways.

Have a converted van with leisure battery and inverter so I can do multiple day rides and charge inbetween.

I enjoy bike parks and technical stuff more but do a lot of XC and bridle ways for fitness.

I’m 6ft. Ride a large. Have 160mm cranks.
I swapped from the 165s that came on my bike down a bit. I’d love to try shorter. More clearance.

I don’t have any issues and like I’ve been saying since this mad thread started it’s such a personal thing and so cheap to change it doesn’t make any sense to argue that manufacturers should relate crank length to frame size.

Loads of people have mentioned that crank length is not related to leg length in the way you think. Rob is your size and always uses 160’s.

Just fit what works for you, crank arms, bars, stem, risers, seat post etc… and enjoy. Life is too short for 4 pages of arguing because you feel the bike industry is victimising you over a very personal opinion
Victimising? That’s a weird take. I get pissed off about pedal strikes too. Wouldn’t happen if i could go 160 but too short.
 

Monty Dog

Member
Jan 7, 2023
47
31
Weybridge, Surrey, UK
I do it all. A lot of bike parks, downhills, jumps etc…. But also done multi day 4-8hr rides XC and bridle ways.

Have a converted van with leisure battery and inverter so I can do multiple day rides and charge inbetween.

I enjoy bike parks and technical stuff more but do a lot of XC and bridle ways for fitness.

I’m 6ft. Ride a large. Have 160mm cranks.
I swapped from the 165s that came on my bike down a bit. I’d love to try shorter. More clearance.

I don’t have any issues and like I’ve been saying since this mad thread started it’s such a personal thing and so cheap to change it doesn’t make any sense to argue that manufacturers should relate crank length to frame size.

Loads of people have mentioned that crank length is not related to leg length in the way you think. Rob is your size and always uses 160’s.

Just fit what works for you, crank arms, bars, stem, risers, seat post etc… and enjoy. Life is too short for 4 pages of arguing because you feel the bike industry is victimising you over a very personal opinion
I started this thread under Canyon because I wanted that big 900wh battery for long long days out in the saddle. But I’ll prob go Specialized Levo instead, as that’s one of the very few bikes that you can raise the BB for a longer crank.

So I guess you could say that Specialized are catering to my ‘very personal opinion’.
 

BJC

New Member
Jan 17, 2023
5
0
Peaslake
I started this thread under Canyon because I wanted that big 900wh battery for long long days out in the saddle. But I’ll prob go Specialized Levo instead, as that’s one of the very few bikes that you can raise the BB for a longer crank.

So I guess you could say that Specialized are catering to my ‘very personal opinion’.
That’s what I ride.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,568
5,058
Weymouth
I know we all ride different terrain and some of us a mix of terrain but at the end of the day we are talking a bout full suspension MOUNTAIN bikes.
I alternate between my favourite forest trails with gravity runs to more cross country longer rides but my bikes are set up for the former so something of a compromise for the latter. If I mainly did those cross country type rides I would probably be better off with gravel bike or a hardtail emtb. In terms of reasons to ride at all.........simple........FUN. Exercise, fresh air, scenery are bonuses, although in terms of overall fitness blasting downhill is when my heart rate is highest and nearly every muscle in my body used. Dont really want huge thighs.....that leads to pulled hamstrings if you do other sports...and none of my shorts would fit:p
 

SwampNut

Well-known member
Oct 26, 2022
298
353
Peoria, AZ USA
If I mainly did those cross country type rides I would probably be better off with gravel bike or a hardtail emtb.

This brings up another term I don't really understand, in the sense of what it means globally, generally, or to others. My favorite ride is cross country, across the open desert with no trail. It would suck a lot on a hardtail. Here, it means you're on chunky terrain with a lot of crap coming at you, and a lot of wash crossings with sand and rocks. Apparently that's not what it means to some/most others?
 

Monty Dog

Member
Jan 7, 2023
47
31
Weybridge, Surrey, UK
In the UK I think of cross country riding as rolling hills, trail riding. Not extreme drops or gravity rushes. Somewhat technical, though not extreme. Somewhere between enduro and gravel riding. Can be done on a hard tail. Others may chime in with different views….
 

SwampNut

Well-known member
Oct 26, 2022
298
353
Peoria, AZ USA
In the UK I think of cross country riding as rolling hills, trail riding. Not extreme drops or gravity rushes. Somewhat technical, though not extreme. Somewhere between enduro and gravel riding. Can be done on a hard tail. Others may chime in with different views….

That is my impression of it, from watching videos. My part of the US is very rocky. My house is built on a monstrous multi-mile rock left from the ice age glaciers that swept the area. I can't dig in my yard without extreme effort.
 

SwampNut

Well-known member
Oct 26, 2022
298
353
Peoria, AZ USA
To take it even further, Scottsdale is 33 miles long, so around 52kM. You can actually find yourself in multiple different types of terrain depending on where you were. It could have been flat and soft, or vertical and rocky. So in all of these conversations about what is "best" it's important to realize how varied our planet is.
 

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