Crank and PM fix for my Supersix HM

Discuss light weight issues concerning road bikes & parts.
Post Reply
Percival1
Posts: 3
Joined: Sat May 25, 2019 5:14 pm

by Percival1

Hey all, new to the forum. Am a UK based racer and hill climber riding 2015 SS Evo HM.

Over time I’ve come to believe my cranks are too long due to some functional issues on bike.

Am 5’6” female and all the calculations suggest 165mm cranks are best but this bike came with 172.5mm cranks. Have ridden before on 170mm cranks on an old Supersix which felt better.

Now for the real issue.... before I latched onto crank length as a problem I went out and bought a Stages 3 L power meter, factory fitted to Cannondale SI crank. So now, if both the PM crank and regular cranks are too long, looking for advice as to cheapest way to change to 170mm or 165mm (harder to find) crankset and replace the PM - open to other PM types but Stages is obvs ideal for weight.

Stages PM L on Cannondale SI doesn’t look like it would sell for much second hand :( ... ideally don’t want to move from Cannondale SI set up as it is what’s meant to be on the bike!

Thanks all! :)

alcatraz
Posts: 2220
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

For 5'6" 172.5 isn't completely out of your range if you are a low cadence rider that enjoys climbing out of saddle and doesn't struggle to do so.

If you are having fit issues or pain then you could try lower but without such issues, going 165mm would mostly benefit your breathing and cadence in aero situations. That wouldn't necessarily improve your climbing ability other than make it a little easier to ride out of the saddle. (Mtb bikes often have a little longer cranks to give better leverage. Road - aero - shorter.)

I think that for long climbing efforts (several hours) you need to be able to comfortably transition in and out of saddle to be competitive and use all available muscle groups.

If we are talking moderately long climbs below an hour then maybe staying seated is good enough and thus 172.5mm is ok, and maybe even desireable if you like more muscly lower cadence riding amd have no problem standing for short intervals.

I'm not explaining my point well but I hope some of my thinking comes across. You needing 165mm depends on your riding style/requirements.

(I'm not a fitter. Above recommendations are from my own observations.)
Last edited by alcatraz on Mon May 27, 2019 12:31 pm, edited 1 time in total.

by Weenie


CrankAddictsRich
Posts: 1735
Joined: Wed Jan 27, 2016 1:39 pm
Contact:

by CrankAddictsRich

I don't think her question is whether or not she can run the 172.5's. It sounds to me like she's already decided that she wants to switch. I think the question is, how can she make the jump swaping crank and powermeter for as cheaply as possible.

Unfortunately, I don't think that will be super easy... The second hand market for 165mm stff is definitely limited. Everyone so often i see one pop up, but not often. my guess is you'll have to get lucky or buy new. If you can find some women's cycling groups with more serious riders/racers, your chances might improve if people have old stuff to unload. The Cannondale Si might be a trickier sale too.. I think there's Si and SiSL... so most people will want the SL stuff because that's the lighter, higher end stuff?.. I think. I'm not sure on the Cannondale parts, but I'd imagine that markets is more limited as well... compared to say somthing like an Ultegra crank or Dura-ace.

Percival1
Posts: 3
Joined: Sat May 25, 2019 5:14 pm

by Percival1

Thanks to both there. I’m not 100% sure I should change but the rest of my team are on way shorter cranks. I think it sounds that 2nd hand is going to be the way... even for a Stages 3 which would be super rare on 165mm .... otherwise £££

User avatar
Dan Gerous
Posts: 1115
Joined: Sun Aug 12, 2007 6:28 pm

by Dan Gerous

Hollowgram cranks are really nice, light, stiff, but as we all know, expensive, even if you only bought the arms alone and kept your spider/chainrings... And harder to find in sizes shorter than 172.5mm.

Maybe you could try to find a SRAM BB30 crankset instead, much more common, cheaper (depending of the powermeter option) and easier to find used too. A Red BB30 is not too heavy either and there are Stages powermeters for it, or one with a Quark maybe.

mikemelbrooks
Posts: 51
Joined: Wed Jun 16, 2010 10:58 pm

by mikemelbrooks

Percival1 wrote:
Sun May 26, 2019 9:05 am
Hey all, new to the forum. Am a UK based racer and hill climber riding 2015 SS Evo HM.

Over time I’ve come to believe my cranks are too long due to some functional issues on bike.

Am 5’6” female and all the calculations suggest 165mm cranks are best but this bike came with 172.5mm cranks. Have ridden before on 170mm cranks on an old Supersix which felt better.

Now for the real issue.... before I latched onto crank length as a problem I went out and bought a Stages 3 L power meter, factory fitted to Cannondale SI crank. So now, if both the PM crank and regular cranks are too long, looking for advice as to cheapest way to change to 170mm or 165mm (harder to find) crankset and replace the PM - open to other PM types but Stages is obvs ideal for weight.

Stages PM L on Cannondale SI doesn’t look like it would sell for much second hand :( ... ideally don’t want to move from Cannondale SI set up as it is what’s meant to be on the bike!

Thanks all! :)
Get a bike fit to decide what length crank would be best for you, then decide on a power meter, a pedal based one will give you the flexibility to switch between cranks or indeed bikes.

by Weenie


alcatraz
Posts: 2220
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

My wife has her weight centered lower than me. That means heavier legs = more muscle = lower cadence. I'd imagine a heavier legged person gravitates towards a bit lower cadence and maybe prefers that feeling of leverage of a longer crank.

I'm 5'8" and I've tried 172.5 170 and 165mm cranks. I had high expectations with 165mm but coming from no pain the difference was rather marginal. I was a spinner before going 165mm and on 165 my legs felt like they wanted to do 120 cadence which would be too much for my lungs on long efforts

Maybe I'm completely wrong and a heavy legged rider should use short cranks to up the cadence. In any case just thought I'd mention some thoughts.

Either try to explore new traits you think you should have, or optimize the ones you already have. Try a crank without a pwm before making the investment. That would be the safest bet. Go out on a known route and try to beat your previous time.

Post Reply
  • Similar Topics
    Replies
    Views
    Last post