Anyone gone to 165mm cranks and regretted it?

I inherited a set of 165mm XT cranks on a new-to-me bike. I don't notice any difference to the 170s on my other bikes TBH. That particular bike has a slightly low BB so every little helps. I'm 187cm, if that matters.

I went 165 a few years ago due to knee problems, I haven't found any disadvantage, I am 6'2". One of the bikefitter videos on youtube  suggested that shorter cranks for taller people can cause putting more weight on the bars, I haven't noticed it on MTB or gravel bikes.

chucked them on my top fuel, not sure i can notice any difference. 

I have 165mm cranks on my MTBs, works well for me with my short legs. No issue going back to 172.5mm on gravel bike.

The only downside for me is the loss of leverage is more noticeable than I expected, so my lowest gear is a bit harder on steep stuff.

Do you feel any power loss?  Do you need to run a smaller chain ring or anything? 

Worked well for me, lowest gear is slightly high but I wanted to increase that so it saved me buying a new chainring.

It is only 1cm difference but pedal strikes are virtually a thing of the past now, very weird.

One of the bikefitter videos on youtube  suggested that shorter cranks for taller people can cause putting more weight on the bars, I haven't noticed it on MTB or gravel bikes.

The logic makes sense as shorter cranks places your COG slightly higher as saddle should be higher to maintain the same leg extension. All marginal though, I'm not sensitive enough to notice it 😀 

I built a bike last summer. Modern geometry 29er 1x12 gear etc (previous bike 26 inch 2x etc etc). Reading about crank length recommendation was go a bit shorter (at the time I was running 175 cranks). So I went with the recommendation and got 165mm. I have not noticed a jot of difference and seeing this post was really the only thing that reminded me.

The logic makes sense as shorter cranks places your COG slightly higher as saddle should be higher to maintain the same leg extension. All marginal though, I'm not sensitive enough to notice it

Another benefit is it effectively gives you more drop on your dropper post.

Do you feel any power loss?  Do you need to run a smaller chain ring or anything? 

Couldn't say re. power loss, and "maybe" to smaller chainrings.

I am firmly on 28t for my trail and enduro bikes (10-46t cassette). Used to sometimes be on 30t.

Another consideration about changing cranks to reduce pedal strikes. It's marginal again, but some crank arm designs give better clearance than others. Hope EVO cranks are more squared off and have less material beyond the pedal hole, so in theory more clearance when cranks are at 6 o-clock position. Marginal though.

was out on my 165mm cranked full sus last night for the first time in a while, my hardtail which Ive been riding a lot has 170mm, my other bike has 175mm

About an hour in to the ride I remembered I was on shorter cranks,  pretty hard to tell any difference, especially compared to things like suspension, tyres , weight of wheels etc,

I'm now running 165mm cranks on three bikes - gravel, full sus and hardtail. I find pedalling slightly spinnier and generally more fluid. It has the added plus on my FlareMax, with its slightly kinked seat-tube, of allowing me to us a BikeYoke dropper that was, with 175mm cranks, just slightly too long.

The biggest downside for me was that once I found I really got on with shorter cranks on the Cotic, I ended up swapping two more sets from 175s, I think. Fortunately there are some cheap deals around at the moment and selling off the old cranks meant it wasn't too costly overall. I run 170mm on an old cross bike and the difference from that to 165mm is less pronounced. I didn't even know what length they were until I looked at the stamping on the crank arm tbh. When I was running 175mm on my hardtail still, it felt slightly, erm, 'stampy' by comparison.

So yeah, personally I can feel a significant difference, but some people are very adaptable to changes in their position / crank lengths etc and just absorb those alterations without batting an eyelid, others are more sensitive. For me it's been a really positive change, but YMMV as per some of the answers above. 

On my road bikes i've gone from mostly running 53/39 to 52/36 when switching to 165 (i have a few road oriented bikes) and it fairly much drops me into the sweet spot for ratios using the new, smaller rings and shorter cranks.

On the MTB i've been doing major tear ups at the same time, so i've no idea (mostly going from 2x10 on 175 cranks to 1x11 or 1x12) the only one i did a direct swap, the cassette was wide enough that i didn't change anything, and haven't had any issues.

BTW, not regretted it at all. Still converting more bikes as i go. Next one will be the winter training bike...

The biggest downside for me was that once I found I really got on with shorter cranks on the Cotic, I ended up swapping two more sets from 175s,

This is also the downside i've found... Cost

I've gone 155 - no regrets, seems to climb better if anything

Seems all round positive vibes!

I have 172.5mm on my road and gravel bikes (I think), god knows what’s on the commuter and cargo bike, so I’m probably overthinking this….

I’d love a set of Hopes but I’d rather spend that money towards upgrading the brakes at some point. 
The drivetrain is Slx, annoyingly can get 170mm at £50 (£80 XT) but 165 SLX is £79. 

6ft, long legs (34" cycling inseam), ridden 175mm for years. Went to 170mm last year and the only negative thing I've noticed is slightly less torque on very steep slow and technical climbs. Descending feels a lot better.

I'm super sensitive to bike setup and could tell you if my seatpost was 1mm lower or bars rotated 1 degree forward or back from what I like and there was definitely a few months of transition period where things felt 'different.' Overall I'm happy with the change but it wasn't the night and day difference I thought it would be.

I went 175 > 165. Feels a bit "off" for the first 15 minutes of the first ride and I've not thought about it since. 

A minor beware, and I am unsure if it applies to the current crop, but I have a set of SRAM GX 170mm cranks that I ordered that length from Cotic as I wanted to be shorter than 175, on my 2019 Flaremax. Main driver for me was ground clearance... Turns out that they only made one size of GX crank arms, just repositioned the pedal drilling for the 170! So the arm wasn't actually any shorter. Grumble. 

The logic makes sense as shorter cranks places your COG slightly higher as saddle should be higher to maintain the same leg extension. All marginal though, I'm not sensitive enough to notice it 😀 

I was wondering that when looking at the Pro's super short cranks, I'm sure they've done some testing to validate their choices but my first reaction was surely you'd keep the saddle at roughly the same height relative to your peak torque? Oval rings put the peak just after 3 o'clock, so logically the saddle to BB height should be about the same?

If you raised your saddle you'd be constantly in the bottom half of your old range of motion.  Same with saddle set-back, presumably if your cranks are 10mm shorter then the saddle needs to be 10mm further back to keep your knee pushing in the same position. 

I have everything from 172.5 to 155 (on my tt bike) and can't notice any real difference at all.

I need to get some shorter cranks to avoid pedal strikes on a new(ish) bike. Want to stay with Shimano but can't see any cheap 165mm crank deals. Anyone seen any deals that I may have missed.

So the arm wasn't actually any shorter.

But the pedal is higher, so theoretically less chance of strikes. (And if it's an aluminium crank, you could just take the end off...)

Oval rings put the peak just after 3 o'clock, so logically the saddle to BB height should be about the same?

Only if you only use the front (and back) 90 degrees of pedal stroke. Rule of thumb seems to be about a 2/3rds of the change in crank length higher and 1/2 back from those few convos i've had with fitters who've dealt with this.

needs to be 10mm further back to keep your knee pushing in the same position. 

This is KOPS thinking, and not really that important.

Nope, in fact I actually like 155 cranks even more

SLX 165mm ordered 😎 👍 

The only regret I had was that I had to swap to 165 or less on my other 4 bikes! 

P20 - where from, how much? Merlin seem to have lots of cheap 175mm's but not 165mm's...

I went to 170 on all my bikes about 15 years ago and appreciated a difference in how my legs handled the slightly smaller circles and my knees generally seemed happier.  More recently I've started to notice the odd knee niggle and bit of tightness in the legs, there could of course be multiple causes, however I am building up another Gravel/Road ("Groad"?) bike and decided to go with a cheap (off-brand) set of 160mm cranks jus to see how I go on quite a "sit down and pedal lots" type of bike.

I've yet to actually ride them but I'm honestly intrigued to see how it affects things, reducing the range of motion/stress on my joints vs the (actually quite minor) reduction in mechanical advantage, will I like it enough to swap all/most of my bikes to 160mm?  We shall see...   

Cookeaa which brand did you go for?  I’m looking for some cheap ones to stick on either my hardtail or pumptrack bike as they have 175mm cranks. 

Posted by: burko73

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P20 - where from, how much? Merlin seem to have lots of cheap 175mm's but not 165mm's...

bikeparts.co.uk but you have to pay a premium for the shorter cranks. They’re £79

https://www.bikeparts.co.uk/products/shimano-slx-fc-m7100-slx-crank-set-without-ring-12-speed-52-mm-chainline-165-mm

I just don't get it. If someone 5' 2" with size 6 feet and someone 6'7" with size 12 feet both go for a bike fit, why would 165 cranks suit them both? I'm 5' 11" with size 9 feet. I used 170 on road for decades and felt the 'spinny' benefit on long club rides. I've only ever had 175 on mtbs and, given the need to climb out the saddle in bottom gear, the last thing I need is shorter levers to grind up steep slopes. Surely such things should be tailored to rider size and type of bike / terrain?

5' 2" with size 6 feet 

Should probably be on 155 or shorter. I bought my girlfriend ( who is only 5ft) a new bike a couple of years ago, an xs canyon grail, iirc it actually came with 170mm cranks swapped them out for some 155 and she was much happier, I think I could easily have gone with 150 or even 145.

Surely such things should be tailored to rider size and type of bike / terrain?

Some things make a big difference like saddle height some things are far less critical. Crank length seems to be one of those less person specific things. I've ridden 90mm cranks (not on an MTB) a fair bit and they felt weird to start with but once you get used to they are great for spinning fast.

Fairy nuff but there's gotta be an efficiency cut-off point somewhere? Nobody is doing an Audax on this.

Posted by: downshep

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Surely such things should be tailored to rider size and type of bike / terrain?

That's my train of thought too, hence why the enduro bike has 165's, the trail bike 175's and the gravel/road bike has 170's.  Takes a minute at most to adjust when switching between them.  

Surely such things should be tailored to rider size and type of bike / terrain?

Nah.
its a whole pile of biomechanical stuff around spine, hips, knees and ankles. Plus proportions of thigh/shin and a bit of cleat/foot position and the degrees of flexibility.

Leonard Zinn is the man for "cranks proportional to leg length" though his logic and testing regime is, errrr, a bit odd.

Fairy nuff but there's gotta be an efficiency cut-off point somewhere?

Funnily enough, as long as you can handle the level of movement and knee/leg extension there is virtually no drop off in sustainable power between about 100 and 200mm, the curve changes (sprinting on 100s ain't no fun). There are a few studies that have been done on this as well so not just guess work.

Nobody is doing an Audax on this.

There are a couple of people doing triathlons and ultra distance events on 150 and shorter. Even seen a guy doing events on 120s i think (he has a hip impingement though and virtually no range of leg motion).

I went for 165mm cranks on my newest bike and can't say I noticed a difference. Given the supposed benefits of shorter cranks then there isn't much to lose. Fwiw I'm 6'5" and long of leg so most crank length calculators suggest I should be running 180mm

Cookeaa which brand did you go for?  I’m looking for some cheap ones to stick on either my hardtail or pumptrack bike as they have 175mm cranks. 

You won't want these, they're scummy AliExpress jobs, finish is not awesome, they're not particularly light, but it was a cheap way to try stumpy cranks. 

https://a.aliexpress.com/_EHx2Jvw

Should have said before,  I'm 5'10"  so by conventional wisdom I should be on 'normal' length cranks... Conventional wisdom seems to change, especially whenever there's a chance to sell everyone new kit. I'm not surprised it's only 175mm cranks on discount, nobody wants them anymore... 

I just don't get it. If someone 5' 2" with size 6 feet and someone 6'7" with size 12 feet both go for a bike fit, why would 165 cranks suit them both? I'm 5' 11" with size 9 feet. I used 170 on road for decades and felt the 'spinny' benefit on long club rides. I've only ever had 175 on mtbs and, given the need to climb out the saddle in bottom gear, the last thing I need is shorter levers to grind up steep slopes. Surely such things should be tailored to rider size and type of bike / terrain?

I guess in some ways asking why people don't still use 175mm is a bit like asking why we're not all on 110mm stems anymore, most people accept that contact points and bicycle ergonomics were not perfected in 1988, so why have cranks remained mostly the same length since then?

To your question they should be tailored to rider and use, but:

1- component manufacturing companies, human factors, engineers, etc basically settled on 175(+/-5) as being "good enough" for the 95th percentile for a good long while and there wasn't a compelling enough financial reason for them to challenge it. 

2- Humans are pretty adaptable, you probably tolerate all sorts of imperfect ergonomics on a daily basis, particularly when you're younger and more flexible. 

3- There's definitely been an increase in understanding of bike fit, and how it's more than just translating rider height to frame size, fit matters more as you age and loses some of that joint mobility a d adaptablity, shorter cranks are one tool (amongst many) to relieve some stress on joints by reducing the required range of motion a bit. 

4- There's a commercial opportunity now, it's arguably easier to make a variety of lengths today, awareness and a bit of hype around the concept of tailoring this component choice has built demand, brands and shops can do the 'value added' thing and flog an aftermarket tweak, that original lack of financial incentive has changed to some extent. 

If your knees and hips are ok carry on as you are, if you're feeling some twinges it's worth looking into a bit further than "Man need big lever" (IMO). 

Prior to 1x drivetrains, there was really very little choice outside of Shimano and SRAM. Now you find far more new bikes with different cranks, more manufacturers means more diversity and more choice. It's certainly not Shimano driving change (I love them as a brand but they're rarely at the cutting edge).

I’m 5’8” with short legs and have a mix of 165mm and 160mm. They’re so much more comfortable for me than 170mm or 175mm, and I haven’t noticed any loss of leverage (I didn’t feel the need to ensmallen my chainring). 

So the arm wasn't actually any shorter.

But the pedal is higher, so theoretically less chance of strikes. (And if it's an aluminium crank, you could just take the end off...)

I find that with my shorter SRAM cranks I get less pedal strike but because, as mentioned, there is a lot of metal beyond the pedal axle, the end of the crank still hits rocks more frequently than if the crank end was squared off as per Hope, etc. 

Remember running 180 Race Face Turbines on my old mk1 Inbred SS. Mega leverage on the climbs!

I've said this before, but I don't get why 175mm is still the default cranks length? Anyone any ideas?

At this point I think it's more so they end up selling two sets of cranks rather than just one... It's also only really in the past few years there's been a more general shift in thinking that shorter is often better for most people and I guess bike manufacturers don't want to switch too early for such things but I can see it happening more over the next couple of years (assuming Shimano & SRAM also ramp up the amount of sub 170mm cranks they produce, otherwise they won't have enough to supply OEMs with anyway)

I've been thinking about going shorter on my HT (from 175 to 165).

Did anyone find they needed a smaller chainring when swapping to shorter cranks?

Surely shorter arms makes for less torque which equals having to apply more force?

I'm already looking at a smaller ring to help me put with the longer climbs (temporarily, until I get some fitness back) so wondering whether shorter cranks will kind of offset the gain from a smaller chain ring and put me back where I started in terms of effort on the hills.

I needed new cranks and have a very low BB on my hardtail, so the Hope EVO 155mm were my choice. 

Yes, it definitely changes the gearing - I'm going to get a smaller chainring for climbing days. I don't have short legs yet if feels fine, and somehow really planted in berms.

I do need to raise my seatpost to compensate, which seems to be seized, but that's another thread...

re chainring and shorter cranks

yer technically you should downsize the chainring due to the reduction in torque, in reality, i don't think anyone is ever giving a 100% effort in their easiest gear for extended periods of time, so adding a few percent effort can be adjusted to over time

I picked up a bargain set of x0? x1? idk 165mm carbons for £150 because they were DUB wide, which my bike was specced for anyway, just needed a chainring that would work with my hg+ setup (DMR chainring) 

First ride on the 165mm cranks. Definitely better on the pedal strike issue. There were still some strikes, but nowhere near severe. 
couldn’t really tell any power difference, but I’ve just come off half nights, so was tired anyway. 
Good service from Bikeparts, ordered Friday, delivered Sunday!