pauliewalnuts

Hi,

I have the chance to buy a very nice Sugino crankset for a fraction of the price they retail at. Only issue is I am 5 foot 6 with a 30 inch inseam and the crank arms are 175mm. Will I be fine with this length of crank arm length or should I avoid? I cycle to work and hope to do a couple of light tours with the bike.

Cheers,

Paul

Jicafold

Don't sweat it. You'll be fine.

PoorInRichfield

I personally would avoid spending the money. You won't die with 175mm cranks, but if you watch some of the many videos on crank research these days, there's a trend towards shorter cranks (like 165mm or shorter). If the new cranks are "blingy" and make you happen, then by them, but I think you'd be wasting your money.

Eric S.

I don't know Greg LeMond's inseam but he's 5' 9" and preferred 175mm in his racing days.

I'm pretty tall with about a 32" inseam and ride 180mm on all my bikes.

canklecat

175 might work for you but expect to make some bike fit adjustments over time to find what works.

I'm 5'11" and have 170, 172.5 and 175 cranks. For a few years I was in the "makes no difference" crowd. But the past year I notice, probably due to injuries and age. With the 175 cranks it's really easy to develop knee strain either from the saddle being too low for the knee angle at top of stroke, or lower back/hip pain from hyperextension with the leg fully extended. I still have and use 172.5 cranks but prefer 170.

If I was 5'6" with a 30" inseam, I wouldn't get 175 cranks. I'd go for 170, 172.5 at most, maybe even shorter if I could find 165 or shorter.

When I first tried 170 cranks they felt less efficient. My leg didn't seem to be working as much. But in fact I was consistently faster and less fatigued during and after rides.

CliffordK

Cranks have been discussed off and on. Here is a recent discussion.

https://www.bikeforums.net/classic-v...reference.html

Depending on your application, you're probably fine with the 175's, but they are probably long for your height. Some people like longer cranks, some don't. It will be up to you.

pauliewalnuts

I've read up a lot and there seems to be no definitive answer. Although if I had a choice I guess 165/170 it would be considering I'm so short. Now whether it is worth taking a risk buying a crankset with arms at 175mm for 150 euro cheaper than it is elsewhere is another thing...

AnthonyG

I'm in the camp that reckons that 165mm is the longest that will really work for you although others may differ.
False economy as far as I'm concerned.

pauliewalnuts

Thanks for this. And I agree, absolutely no point in going for this deal if I then have to spend another 100 or so on new crank arms. I will reluctantly pass!

Germanrazor

In all honesty, the only real way to know is try it. If it’s a good deal and doesn’t cost much go for it. If it fails......sell it.

canklecat

Yeah, wait awhile, the right crankset will turn up. I waited a few months for an old Dura Ace crankset with 170 or 172.5 cranks to show up. For months, nothing but 175. But I snagged the one I wanted a couple of weeks ago.

Another oddity I noticed -- probably related to age (62) and injuries (hit by cars twice, lotsa stuff busted up) -- is I like Biopace chainrings, but only with 170 cranks. When I switched the 52/42 Biopace rings to 172.5 cranks my knees started twinging within a couple of rides. And it felt herky jerky. Yeah, Biopace already feels a bit odd -- there's a surge effect along with a bit of leverage during the power phase of every stroke, then it eases as we approach the narrower portion of the oblong chainrings. But it felt way too herky jerky with the slightly longer crank.

You wouldn't think 2.5mm would matter much, but it sure did with the Biopace rings. Switching back to 170 cranks fixed that problem.

My Univega hybrid has 175 cranks and a 50/40/30 triple. I don't push hard on that bike, it's my casual and group ride bike, and the one I ride when I'm supposed to be doing a recovery ride. I tend to push too hard on my road bikes, but I'll relax and just spin and loaf along at 12 mph on the Univega. But the few times I have pushed harder I can feel either knee twinges or lower back/hip pain until I get the seat post height jusssst right.

I'm building up another road bike from a donor frame from a friend, a nice 2010-2012 era Diamondback Podium with an aftermarket 175 Ultegra crankset. It's such a nice crankset, better than the factory original (FSA, I think?), I'm gonna try to make it work. But I suspect I'm gonna hafta pay very close attention to saddle height and position, and maybe shim the cleat on my right foot to avoid injury. My right leg is very slightly "shorter" -- technically it's the same length, but a hip/lower back injury from a 2001 wreck causes a tilt that can cause knee twinges if I'm not careful.

I haven't found any 165 cranks but it's on my bucket list to try with another bike project. Should be easier on my knees as they age -- less extension and retraction per stroke, same effect I feel with 170 vs 172.5 cranks. Subtle but feels pretty good after adapting to it.

aclinjury

you're 5'6", use 165mm crank, not 175mm

dmanthree

Sounds long. I'd pass and wait for a more suitable model.

tkamd73 

The crank arms on the 6 bikes I ride on a regular basis vary from 170 to 180. I guess if I had a preference I’d pick 175, but not enough that I would pick one bike over the other, for any length of ride, 35” inseam.

friday1970

I'm in the camp that you stick on 165mm cranks. 175mm would kill your knees, and that may cost you later in life. Also with 165mm cranks, this allows you to raise your seat higher in relation to your handlebar height, if you so prefer a more aerodynamic setup.

grizzly59

Deals come, deals go. 175mm is prob too big. 165/170

CliffordK

Are these new cranks or used?

You could always buy them, try them out, then resell if they don't work out. There are always people looking for cranks of different sizes.

If you are a casual low cadence masher, they could well be fine.

If you are into spinning high cadences, you probably will never quite be happy with the cranks.

phughes

I wouldn't, I am 5' 11" and switched from 175, to 172.5, and despite the "small" difference, the difference in use was very noticeable to me. I can spin more fluidly with these, and that was apparent on the first ride. I would even go shorter, but will not go back to 175mm cranks. Mine are Sugino as well.

PoorInRichfield

I just ordered some 165mm cranks to experiment and see if the benefits that friday1970 mentions are true. My bike currently has 175mm and I've never ridden anything shorter than a 172.5mm because that's what usually comes on my bike. I'm 46 years old and my knees have been squawking for a few years, so less stress on my body has started to be a big consideration.

What is particularly annoying about 165mm cranks is that they cost more than the 172.5 or 175mm, at least for the Ultegra R800 crankset, and many online stores don't stock them at all.

SlvrDragon50

I will say that there are a LOT of good crankset deals if you don't care for a particular brand/model. I got a Praxis Zayante w/ an M30 bottom bracket for $105 shipped. Barely used. Plenty of Rotor 3D deals for ~$130-150 now too.

CliffordK

I'm in the camp that what doesn't kill the knees is good for the knees.

Korina

Ah yes, the hill I'm likely to die on. I'll skip the complaining and just support the OP's decision to go with 165mm cranks; his knees will thank him. Sugino makes a very pretty (and rather expen$ive) crank in a variety of short lengths, the XD600T. Also, here's a discussion of the topic from a PT/bike fitter.

Wileyrat

I'm about the same height as the OP, my roadie cranks are 170 by choice, and my mtn bike cranks are 175 by manufacturer default. I can't really tell any difference, and at the ripe old age of 61, knee pain is non existent for me.

Korina

You may have different proportions, i.e. longer legs.

Cyclist7485

I'm 5"10 with a 34" inseam. I have torn the meniscus in both knees. They are pretty sensitive. I rode 165mm for six months. I had to raise the saddle to compensate for the shorter crank, which gave me a relatively lower handlebar and a more open hip angle when my foot was at tdc. More aero as well. I was much more comfortable riding in the drops, but climbing out of the saddle was awkward feeling to me. I can ride 172.5 and it's not a big problem, but I am most comfortable at 170mm. 170mm is the sweet spot that gives me the best of both worlds.
Adult-sized BMX racers typically ride 180-190mm cranks, but they are standing the whole time, and rarely cranking on the bike for longer than a few seconds at a time.
If your money is tight, and you don't have any physical limitations or injuries, maybe try out that 175mm crank, but my instinct is that it's probably a touch on the long side for you. I've just not met any 5'6" people who have tried road cycling with anything longer than 170mm and it's unlikely that anyone can know for sure what length crank is perfect for you without watching you in motion on the bike.
Bottom line is, we are all unique physical specimens. What works for some may not work at all for others.
If you have discomfort, and can afford to do it, I recommend you get a fit done by an experienced fit tech. When I say experienced, I mean someone with more than ten years of making a living at it.