I’ve had some real tightness, pain coming off the bike in the anterior hip area and I’m convinced its coming from an aggressive time trial position where my hip angle is rather tight. Would going to a shorter crank arm relieve hip angle tightness? I ride a 167.5 and I am short at 5’6 with a 30 inch inseam. I get a fair amount of speed for watts so Id rather not tinker with my frontal presentation. Ive tried sliding my saddle a bit forward but then my anterior knee starts to take a beating.
How short would you like to go? I would think you would need to go smaller than 165’s. Do you have something in mind?
I can’t see changing 2.5 or 5mm making much of a difference.
jaretj
Yes I would agree. Would have to go at least to a 160 to even notice anything.I got to thinking when I saw an ad for cobb cycling with crank arms in the 140s! I didn’t know they even made them that short. Just curious if others have gone to shorter cranks and got relief from a tight hip. Ive read the threads where people insist that they don’t lose power on the flats.
Too bad someone like Cobb doesn’t make an adjustable crank that you can “borrow” with maybe a $400 deposit. Try different lengths, compare it to your power meter and see how it improves comfort, then the $300 is applied towards the new shorter cranks.
I think you’d need to go to 160mm to get a significant difference and you might find that as small as 155 is the right lenght for you.
Just my limited experience, but I went form 172.5 to 165 and I’ve been very happy with the results. My hips feel a lot more open in an aero aggressive position and some knee pain I’d been having on and off has gone away.
Starting with a 165mm crank, I just got a Cobb 145mm compact. I’m about your size, with perhaps a bit shorter leg length (size 32x29 pants). So far I have noticed no big difference in power, but a significant increase in comfort, as my upper leg no longer contacts my abdomen (Hip angle is opened up quite a bit). My cadence went up from around 80 rpm to 90+ or so, but still feels OK. I think this is because the foot speed is about the same for both cranks. 165 vs 145 is ~12% drop in circumference (the distance you foot travels in one rotation). 80rpm to 90rpm = ~ 12% increase in rotation rate. Looks like a wash as far as foot movement speed is concerned.
You might find this from Sheldon Brown interesting:
http://www.powercranks.com/...S_ursCFeFlOgodpHAAJg
All in all, I feel the shorter crank arms will be an improvement for me. (However, after spending $300 on the cranks, this could just be wishful thinking…)
.
I’ve had some real tightness, pain coming off the bike in the anterior hip area and I’m convinced its coming from an aggressive time trial position where my hip angle is rather tight. Would going to a shorter crank arm relieve hip angle tightness? I ride a 167.5 and I am short at 5’6 with a 30 inch inseam. I get a fair amount of speed for watts so Id rather not tinker with my frontal presentation. Ive tried sliding my saddle a bit forward but then my anterior knee starts to take a beating.
The short answer to your question is yes.
http://forum.slowtwitch.com/cgi-bin/gforum.cgi?post=4799515
7.5mm to 12.5 mm or more reduction in pedal arm (say 160 or 155mm from 167.5) should feel pretty significant. (it did for me)
Additionally, if you raise the front up 1cm, you will lose some aero (~3W?), but the tradeoff is a sustainable position. Your description sounds like you’re at the “uncle” point of the front end drop (Slowman’s description of what happens when he lowers the front end during a fit), and backing off is probably prudent.
g’luck
-J