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Apologies if this has been done recently. I searched the forum but couldn't find anything newer than a couple of years ago.
I'm replacing some components on my XC / trail bike (Transition Spur) and looking to pick up a new crankset. Bike came stock with 175mm cranks (size large), a size which I've ridden since I first got into mountain biking ten years ago. Hpwever, I'm noticing though that a lot of new bikes in the 120mm "downcountry" category with similar bb heights are coming with 170mm cranks e.g. Trek Top Fuel, Ibis Ripley, Revel Ranger to name a few).
I'm 6ft exactly, relatively normal proportions (33.5" cycling inseam) and don't get any knee or hip pain when I ride. I've read all the articles online re the benefit of shorter cranks but I do fairly long rides on my Spur (30-50 miles is a typical ride for me) and the old saying "if it 'aint broke....." comes to mind.
What cranks lengths are people running on here, for more XC / lighter trail duties? I'd be interested to hear experiences before I commit.
Hope say we should all be running 155 !!!
https://www.pinkbike.com/news/hope-say-their-super-short-155-mm-cranks-are-the-sweet-spot.html
I'm 5ft 8in with stumpy legs (28in inside leg).
I went to 165mm SLX cranks on all my MTBs, as I'd liked them on one of them and I valued the extra pedal clearance.
It's fine, but I think I prefer the feel of 170mm (my previous default) for pedally rides - and it does make the gearing harder (I'm not on super-wide-range 12sp cassettes).
Choosing again, I'd probably stick to 170mm for trail bike but have 165mm for enduro.
So if you really like 175mm, stick with that for the Spur. They tend to be cheaper anyway, as everyone wants shorter now.
I'm down sizing on everything.
XC, road, CX, trail.
Used to be 170 road/175 MTB, as that's what my bikes always came with.
165 has been a revelation to knees and muscles. It's not even like i had an issue before.
(32" inside leg, 5'9".)
Given how low bottom brackets have become, I'd not run longer than 170 but I do ride mostly in the Peak where it's pretty rocky.
I use 170mm, but on the low setting on my Enduro I still get rock-strikes. I'd go shorter in an ideal world, but cost of change, inertia...
Given how low bottom brackets have become, I’d not run longer than 170 but I do ride mostly in the Peak where it’s pretty rocky.
Maybe the key determining factor for OP is whether they're smashing pedals on stuff at the moment or not.
I certainly found going 175 to 170 helped with that.
All depends where you ride mainly imo.. I've switched to 165 on my stumpjumper and its a massive help being able to pedal through sections where you wouldn't risk it on longer ones.
Think im running 170 on a Mojo3 which are good also.
Bb height should be factored in when deciding i think.
Wouldn't got back to 175 again on my mtb's.
Maybe the key determining factor for OP is whether they’re smashing pedals on stuff at the moment or not.
Very, very rarely. My local trails are all smooth / hardpack stuff with very little in terms of rocks or roots. When I do smack a pedal its always my fault.
I'm 6ft also, use 170mm on anything I pedal for a long time apart from the SS that's still on 175. For a FS MTB that was more DH biased / anything but an XC bike I'd go 165mm.
I'm 5'11" so similar to the OP, 175mm on all bikes, geared and ss.
I did have one 175 and one 170 on a commuter for ages and it wasn't a problem, not sure it makes that much difference if 5mm isn't even noticeable side by side
I'm 182cm. Trail/enduro rider rider in current parlance, but I'd describe myself as an all mountain rider.
Used 175mm cranks for 15 years and never felt the need to change, ran 170mm cranks for a bit of extra clearance and preferred them. Ran 165mm cranks and hated them.
165mm changed the torque and relative gearing and impacted my riding technique in chunder, felt too spinny and had me shifting gear even more than I already did.
YMMV.
I've used 165, 170 and 175mm. I don't know if I could tell them apart with a gun to my head.
Same leg length as you (I'm shorter but have long limbs) and I'm running 165mm on both bikes (a geared eMTB and a singlespeed hardtail). I had 170mm on the my last hardtail (which had gears) and changed to 165mm when I got my new one (which isn't always going to be a singlespeed but that's how it's started out) because my faulty knee (caused my ankle of limited mobility) seemed to prefer the shorter cranks on the Levo.
I don't know if shorter cranks are for everyone but I think there's both an adaptation period and also a gearing issue - if you switch to shorter cranks without moving to a smaller chainring then you are raising your gearing because you can spin a shorter crank faster but it won't generate quite as much torque.
165mm all the way.
5'10" with 33" inseam.
I've run 165mm on everything for several years now. This was initially driven by a knee issue, but I found that I much preferred the shorter cranks. Kinder to knees and hips. No loss of torque. Evidence around these claims is building (Start with Phil Burt maybe).
Only down side is that you need to raise your seat to compensate for leg flexion/extension at bottom of pedal stroke. Possibly move it back fractionally too. Or pull your cleats back a few mm for a proper win/win situation.
I buy cranks as short as I'm able to, but the minimal benefits on performance usually are outweighed by price or what value I'm getting. I'd rather buy a set of 170 cranks at 50% off, than a set of 165 at full RRP for example.
188cm, 33.5" inseam, riding 170 cranks on all bikes. Was tempted to try 165 but haven't got around to fitting them.
Recently fitted 170mm Hope EVOs to my big bike. Profile of ends of the crank arms - flattened/sqaured off - gains an extra few mm clearance over other cranks.
Hardtail Party did quite a good video where he compared quite a few different lengths of Canfield cranks from extremely long to extremely short. He compared them back to back on the same bike.
Personally I have always preferred shorter cranks 165. My current
Urgent bike has 170 and I think I’d like to switch out to 160 or 165.
i went from 175 to 165 to reduce pedal strikes. i didn’t notice any difference other that my foot naturally sitting in the “wrong” place for the first few rides.
current riding is big climb followed by a descent.
edit: i was concerned about the change before i made it
My current bike has 170mm cranks and they just feel wrong to me having always had 175 or 172.5mm.
I get the logic behind it, but it's not right on a hardtail where the BB isn't that low anyway.
For FS bikes, maybe it makes slightly more sense, but depends where you mostly ride, I used to get stuck with pedal strikes all the time in North Yorkshire*, but it's a non-issue in the Chilterns unless you're on the Ridgeway.
*other locations with horrible stepped and rutted climbs are available
6'2" and a +35" inside leg, swapped to 165's on my FS last year - staying on.
Only downside was having to raise the saddle.
Does wheel size play a part in crank length choice, seeing as 27.5 are quicker off the line, I know some people felt a difference in shifting when they first jumped on 29ers cos the wheel takes longer to fully rotate, is it worth considering or am I gonna get roasted for saying something stupid.
I’m 6’4” or 194cm in new money, but inside leg is 33” or 84cm. But I’m longer in the thigh, hip to knee, than knee down. I’m shaped like a badly shaved gorilla.
I prefer 180mm cranks. Rare as unicorn poo though.
I thought it is mainly down the Hip Flextion capabilities? I was told this by my favourite bike fit dude. Some people 6'+ = little cranks as they have zero flexibility and vice-versa...
“Does wheel size play a part in crank length choice”
Kind of because 29” tyres raise the gearing (vs 27.5 or 26) and so do shorter cranks. So on my 29x2.4” I’m running 30:18 gearing with 165mm cranks. That ratio on a 26” bike with 175mm cranks would be pretty spinny.