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Short cranks and single speeds. Who's tried it?

6007 Views 45 Replies 23 Participants Last post by  edubfromktown
Any of the single speed crowd try really short cranks in order to reduce knee stress? I use 155mm Canfields on my trail bike with a Wolftooth oval and I LOVE that setup. But that's a bike with a fairly active suspension and work great for sitting and spinning. So much easier on my knees while sitting and spinning.

I have 170s on my single speed and the very nature of single speeding is rough on the knees. I'm not sure going to 155's would be a significant benefit for my knees in a single speed scenario? I'm afraid going from 170 to 155's would just throw off my gearing and not really give any benefit to ease the effort on my knees. A hard effort ride on my single speed and I can definitely feel it walking up the steps to my office the next morning. If I didn't have an oval on my 155's I'd swap them over for a couple of rides to try out. It uses a zero offset direct mount chainring and at minimum I would have to find and but a new chainring just to try them out. Trying to decide if it's worth the time and effort to test out.


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Any of the single speed crowd try really short cranks in order to reduce knee stress? I use 155mm Canfields on my trail bike with a Wolftooth oval and I LOVE that setup. But that's a bike with a fairly active suspension and work great for sitting and spinning. So much easier on my knees while sitting and spinning.

I have 170s on my single speed and the very nature of single speeding is rough on the knees. I'm not sure going to 155's would be a significant benefit for my knees in a single speed scenario? I'm afraid going from 170 to 155's would just throw off my gearing and not really give any benefit to ease the effort on my knees. A hard effort ride on my single speed and I can definitely feel it walking up the steps to my office the next morning. If I didn't have an oval on my 155's I'd swap them over for a couple of rides to try out. It uses a zero offset direct mount chainring and at minimum I would have to find and but a new chainring just to try them out. Trying to decide if it's worth the time and effort to test out.


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Some input from my end. How is your seat height and position fore/aft over the BB between the two bikes. If you used the exact static measurements between the two, since the FS rear sags it will not be exact that same as the hardtail once you sit on the FS. You may have found the sweat spot on your FS, but those exact measurement to the hard tail may not translate to ideal. Of course the shorter cranks would make things easier, but I would probably really look at bike fit first. Also what type of pain are you experiencing in your knees, front, side, back? I see you are on flat pedals, do you use flats on the FS also. Also are the cranks between the two bikes the same spindle width. One problem I have run into if switch between bikes with different spindle length or pedals and just go by look on the pedal to place my feet, the width my feet are apart will not be the same. If my feet are further apart then ideal I will get knee pain. Therefore on the bike with wider spindle/pedal interface I have to be conscious that I put by feet more inward on the pedals.
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I’m down to 165 on one of my SS MTBs (used to run 180 on SS 20 years ago). 170 on the other. I also run ovals on all my singlespeeds. I’d say try it out with the cranks and ring you have. You can adjust the chainline to work with the zero offset ring. Ideally though, go to Sheldon Brown’s gear calculator and figure out the gain ratio you have with your 170 cranks, and then match that with the 155 setup. You’ll probably need a bigger cog.

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Also what type of pain are you experiencing in your knees, front, side, back?
I'm not experiencing pain. Instead I would describe it as feeling the extra stress on the knees. The next morning when I walk up the stairs and my muscles are still cold I can feel a bit of stiffness in my knees like a sore muscle that needs to be stretched out.
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I’m down to 165 on one of my SS MTBs (used to run 180 on SS 20 years ago). 170 on the other. I also run ovals on all my singlespeeds. I’d say try it out with the cranks and ring you have.
You can run an oval single speed without some type of chain tensioner? I was thinking that would cause problems with constant changing chain tension.
I'm not experiencing pain. Instead I would describe it as feeling the extra stress on the knees. The next morning when I walk up the stairs and my muscles are still cold I can feel a bit of stiffness in my knees like a sore muscle that needs to be stretched out.
How long have you been SSing and how often? Can take quite a while for your body to adapt. When I first started SSing, it took me at least 6 months of consistently SSing to no longer have that fatigue. But agree with CCSS, just swap once what you have.
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You can run an oval single speed without some type of chain tensioner? I was thinking that would cause problems with constant changing chain tension.
Absolutely. You will have a two slightly tighter spots during a rotation of the ring, and two slightly looser spots. Just tighten the chain to your normal SS chain tension on one of the tighter spots. If you tighten on one of the looser spots, it'll be too tight in the tight spots.

I have ovals on my SS cross bike and both of my SS mtbs. And pretty much everyone in my SS circle has switched to oval over the last 10 years. I suspect you may like the oval ring more than the shorter cranks :)
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Absolutely. You will have a two slightly tighter spots during a rotation of the ring, and two slightly looser spots. Just tighten the chain to your normal SS chain tension on one of the tighter spots. If you tighten on one of the looser spots, it'll be too tight in the tight spots.

I have ovals on my SS cross bike and both of my SS mtbs. And pretty much everyone in my SS circle has switched to oval over the last 10 years. I suspect you may like the oval ring more than the shorter cranks :)
I'm going to have to remember this inasmuch as I'm in process of building up a singlespeed as we speak.
I've never tried oval rings but have heard everything from, "I couldn't tell much difference" to "They're amazing -- I'll never go back to round."
Seems and oval ring would make the most sense on a SS.
But I've got round rings in the parts bin so that's what I put on for now.
It should be ready to ride in about a week... got a couple small parts on order that'll arrive by then.
=sParty
I'm going to have to remember this inasmuch as I'm in process of building up a singlespeed as we speak.
I've never tried oval rings but have heard everything from, "I couldn't tell much difference" to "They're amazing -- I'll never go back to round."
Seems and oval ring would make the most sense on a SS.
But I've got round rings in the parts bin so that's what I put on for now.
It should be ready to ride in about a week... got a couple small parts on order that'll arrive by then.
=sParty
I'm part of a big SS group here in Austin (we're juvenile so we call ourselves A*S*S). The vast majority of the folks I ride with are in the the "I'll never go back to round" camp. Personally, I rode a buddy's SS around a parking lot 7 or 8 years ago after he'd switched to an Absolute Black oval and I didn't like it. I could feel the ovality and thought it felt weird. So I held out on trying it until mid 2019, and then I went with a Wolftooth oval because it has slightly less aggressive ovality and clocking. And on the first ride on the first hill I literally got angry with myself for waiting so long. I'll never go back :)
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I have 165MM cranks on one of my SS bikes, And 180MM on another SS. Although I'm 6' with a 34" inseam I much prefer the 165MM cranks. It's a much smoother spin and my knees are much happier.

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I have two SS’s, one on 170 another on 175 both shimano XT non oval xt ring. I definitely prefer the 175s, added feel and leverage is my best reason, I ride both bikes a lot, 5’9, no pain or discomfort on either, I’m not sold on this short crank hype.
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short cranks with tall socks... who's tried it? :)
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I've only been SS for a month, but I definitely get some knee soreness that the OP mentioned. I think it is starting to go away though, or at least I hope so. I also only switched to hardtail from FS 6 weeks ago, so I think that could also be contributing to the knee aches. My knees instead of a rear linkage are taking the hits when the trail gets chunky.

I have a oval ring on 170mm cranks and am 5'10".
I've been SS for a couple or three months now. I've been getting soreness just above the kneecap. The trails around here have a lot of punchy climbs so there is a lot of out of the saddle climbing. I just switched my cranks from 175 to 165, only one ride so far, but I think that I like them better. My knee didn't have the pain above the kneecap just a general soreness that comes from getting a good workout. I'm 6'1" with a 33" inseam and 58 years old. I've been riding for 30+ years, 2-3 times a week for the last six years.
One thing that I noticed when climbing is that it actually seems as though I have more power since I'm spinning smaller circles. I left the gearing the same, only difference is the shorter cranks. I suppose that an oval ring might do the same but I already had the cranks so I'm gonna run it like this for a while. I'll report back after a few more rides.
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Why Shorter Cranks Are Better (According To Science) Pinkbike Goggle it.
I’m down to 165 on one of my SS MTBs (used to run 180 on SS 20 years ago). 170 on the other. I also run ovals on all my singlespeeds. I’d say try it out with the cranks and ring you have. You can adjust the chainline to work with the zero offset ring. Ideally though, go to Sheldon Brown’s gear calculator and figure out the gain ratio you have with your 170 cranks, and then match that with the 155 setup. You’ll probably need a bigger cog.

Give us a ride report if you try it!


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I think your cranks can be too long for your body, causing knee stress. this is true on any bicycle, SS or geared or fixed-fear. It seems unwise for the dimensions of my legs to use cranks longer than 170, so I don't. go as short as you dare to spin faster and avoid pedal strikes, and adjust your gearing accordingly. it's not any more complex than that.
Interesting thread as I’ve been chasing some recent pain myself.

I have too many variables…went from 175 to 170, changed frames, and changed my workout routine during Covid…to diagnose. But am interested to see some of the comments here to help me isolate.

One thing I’d dispute is that SS is inherently worse for your knees.


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