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Anyone try shorter cranks and not like them?

bootsie_cat

Oct 29, 09 16:34

Post #1 of 10 (316 views)

Anyone try shorter cranks and not like them?	Can't Post

I have been running 167.5 cranks on my tt bike for a couple weeks now. I am 5'10, with a saddle height of 72.5 (with 167.5 cranks) and 72.0 (with 172.5 cranks). 172.5 is my regular road crank length.
When I made the change, I did as other have suggested. Raise saddle 5mm, move saddle back 5mm, raise bars by 5mm, shoter extensions to maintain same cockpit length.
When riding easy-ish the shortcranks feel fine. They also turn over nicely and feel open in the aero position.
However, when I need high power or cadence drops- they feel "weak".
Do I need to suck it up and ride them more?
Go back to 172.5?
Split the difference and try 170?
Anyone else have the same experience?

roady

Oct 29, 09 16:46

Post #2 of 10 (304 views)

Re: Anyone try shorter cranks and not like them? [bootsie_cat] [In reply to]	Can't Post

I'll put this in the 'cautionary tale' file. The first time I tried the short cranks, I put them on my bike the week before the season-opening 10 miler and road them for 5-10 minutes on the trainer. Race day I did my typical 20 second warm-up for the race. Next ended up being my peak 20 minute power for the year.

A month later I decided to do some 5:00 intervals on the TT bike and my power has absolutely horrible. I then thought "maybe I was just lucky or something and on a good day--and these cranks really suck". I bailed on the third interval, went home and got my road bike, that re-started the intervals. My power still sucked... As it was, I was just a little tired...

In short, 'subjective feelings' often don't count for much, and if your power is down, don't automatically assume it's the cranks.

My .02.

bootsie_cat

Oct 29, 09 17:30

Post #3 of 10 (284 views)

Re: Anyone try shorter cranks and not like them? [roady] [In reply to]	Can't Post

Thanks- It is possibly true that I was having a bad day.
Is it safe to assume form your response that based on my saddle height (72.5cm), that 167.5 would be an appropriate tt crank length?

(This post was edited by bootsie_cat on Oct 29, 09 17:43)

roady

Oct 29, 09 17:37

Post #4 of 10 (271 views)

Re: Anyone try shorter cranks and not like them? [bootsie_cat] [In reply to]	Can't Post

In Reply To:

Thanks- It is possible true that I was having a bad day.
Is it safe to assume form your response that based on my saddle height (72.5cm), that 167.5 would be an appropriate tt crank length?

Yep. My saddle height is almost identical (729mm) and I'm using 160's. I'm using 170's. on my road bike, so a 10mm difference between the two bikes.

psycholist

Oct 29, 09 18:24

Post #5 of 10 (236 views)

Re: Anyone try shorter cranks and not like them? [bootsie_cat] [In reply to]	Can't Post

I tried 'em for a few weeks. Like you, went from 172.5 down to 167.5. Scored some close-outs and swapped out my TT bike and my road bike. Made the adjustments to saddle as you described. Hated it. Just never felt right. I don't use a power meter, so I can't quantify that they were really bad. I just couldn't get comfortable with it on either bike. When I changed back, it was like ... aaaahhhhhh, that's it!

.
Bob C.

Mito Chondria

Oct 29, 09 18:24

Post #6 of 10 (235 views)

Re: Anyone try shorter cranks and not like them? [bootsie_cat] [In reply to]	Can't Post

My road bike came with 172.5 and I don't like that at all. Replaced them with 175 PC's and it's so much better. Never tried shorter than 175 on a TT bike.

MoodBoost Drink : Mood Support + Energy.

bootsie_cat

Oct 30, 09 13:24

Post #7 of 10 (156 views)

Re: Anyone try shorter cranks and not like them? [roady] [In reply to]	Can't Post

Just went out and checked slope on SRMs for both my road bike and tt bike- road bike was dead on- within .2%, tt bike- not so much. It was 2.5 % different than slope I was running. So power was actually better than I was seeing. I will check it again in the next few rides. I suspect the changes could have resulted from crankarm and chainring changes. It is a Specialized SRM for their cranks- they come without rings or arm mounted on them. So given that, the power I am making with the short cranks is close to what I put out on the road bike for a similar effort.

Boudreaux

Oct 30, 09 13:51

Post #8 of 10 (142 views)

Re: Anyone try shorter cranks and not like them? [psycholist] [In reply to]	Can't Post

Bob - don't want to go through a gazillion posts...aren't you over six feet. Or are you a little fark? I've forgotten.

"you know, aero trumps training ;-) "
R10C 10/09

psycholist

Oct 30, 09 14:01

Post #9 of 10 (140 views)

Re: Anyone try shorter cranks and not like them? [Boudreaux] [In reply to]	Can't Post

Or are you a little fark?

Not sure what a little fark is, but since I'm nowhere near six feet, I guess I must be one. I'm of somewhat freakish proportions. Long torso and short legs, but surprisingly long femurs. Odd combination of attributes. Also incredibly handsome, talented and modest.

Boudreaux

Oct 30, 09 14:06

Post #10 of 10 (134 views)

Re: Anyone try shorter cranks and not like them? [psycholist] [In reply to]	Can't Post

Also incredibly handsome, talented and modest

Ahh, but that's a given...and fast also!

"you know, aero trumps training ;-) "
R10C 10/09