"The 33"-Road Bike Racing - Problem switching between crank sizes?

Hey guys,

I currently have two road bikes that I alternate riding time between. Both have 172.5mm cranks. I'm planning on selling one of them and buying a Six13 that comes with a 175mm Si crank. Will it cause any issues for me to ride/race two bikes back to back that have different crank arm lengths? I'm 6' tall so I'm on the bubble as far as crank arm fit. Let me know what you think.

-Stephen

fwiw -

i used 170s for years.

last year i got a new bike, and went with 172.5s

last summer i borrowed a compact crank that was 175 for a couple of weeks.

went back to the 170 crank bike from oct-march (my winter bike).

never really noticed any difference.

Just lower your saddle height 2.5mm on the new bike and you'll be fine.
I've gone from 180 to 170 before and only barely noticed it for the first ride, then that sensation was gone.

If you go longer you'll feel like you can roll big gears on the roller climbs. You'll lose some rpms. Little cranks you feel like you lost some power but you spin like mad. It depends on how much riding you've done and what you're doing now. When I switched cranks (170->175, same make/model) I spent about 3 months getting used to them but it was my first crank length switch in about 10 years of racing. Now they're natural.

I'd try and get longer cranks to try also, just as a point of reference. When setting up things (like suspension or tire pressure settings on cars), you put in some extreme (but still safe/driveable) numbers first to get some reference points. Then you narrow down to optimize the trade-offs. I'm about 5" shorter than you and have short legs for my height. I use and love 175's (and I've used, over 15+ prior years of racing, 165-167.5-170's). My friend who is 6'2" went to 180's and he likes them a lot, ditto another who is about the same height (both use about a 60-63 cm traditional frame).

cdr

I have several bikes with different lengths and even though I try to notice a difference I can't YMMV. As long as the saddle height is correct as was mentioned.