MissP and Others update on your change to 165 mm crank

Triathlon Forum
1

Just wanting to hear how things are going for those that went down to 165’s.

I went from 172.5 to 170 in August and it has been great. My biking based on a bunch of TT’s is slightly faster, but that could be completely due to the fact that I am focusing on shorter harder rides (90K or less) vs May-Jul when I was ramping mileage for Ironman LP. But what I have noticed, is that all my runs in training and racing have been consistently faster since going to the slightly shorter cranks. Again, it could be due to less long riding in my program, but my biking overall load is not much different…just a lot more intensity. Overall, my knees feel 200% better on the slightly longer crank lengths (they have been bothering me off and on for 4 years now).

For those that went to 165’s, I know everyone is saying you have not lost power, but interested to know if you are running any faster on account of moving your hip flexors and hamstrings through a smaller circle. Just intersted to know as I contemplate getting my powermeter cranks swapped for 165’s. Its going to cost me around $200 for that, so not a huge expense given the big picture and if it makes my knees feel better than I will be happy guy.

Dev

2

After speaking with both Jordan and Fleck extensively (thanks guys) I switched from 172.5s to 165. I built up a P2C early this spring when I was living in DC. Shortly thereafter I moved to Newton, MA and was introduced to real hills. I am decent tri-cyclist (so like a crap real cyclist, haha) but a fairly good runner. Typically place in my age group in sprint/olympic distance races and top 10-20 overall for such races.

However, the bike was always a matter of just hanging on and dealing with discomfort. I suffered a compression fracture in my L3 vertebrae about 5 years ago and have since dealt with some lower back stiffness/discomfort. Typically late into long rides, when riding hills, or when riding into the wind for extended periods of time my low back would flare up. After moving, I decided compact cranks were more appropriate and this was around the time there were several post on ST about shorter crank lengths. I talked with Jordan and he suggested trying 165s. I was worried about switching both the gearing and the crank length at one time, but his reply was, “If your bike was 2 sizes too big, would you first get a bike that was just 1 size too big before buying the right size?” Point made.

I picked up some Ultegra level compact cranks in 165 from Nashbar. Not much adjustment time, standing felt weird the first few rides, but I got used to it, plus we shouldn’t be doing a whole lot of standing climbing during tris anyway.

Have the cranks made me faster in and of themselves? Probably not. But what they have done is made me more comfortable, which has allowed me to ride harder, for longer, while staying in the aerobars. So a 3 hour ride is 3 hours in the bars (other than some steep climbing) instead of 1 hour in the bars, 1 hour on the bullhorns, 1 hour getting up periodically to stretch my back.

The other thing is, my pedal stroke certainly feels a lot less tight at top dead center. Whenever I would hold one leg at 12 o’clock for any period of time, a long sweeping turn with the inside leg raised, coming into transition and holding one leg at 12 while reaching down to un-velcro my shoe, etc., I would get a little cramp/spasm in my hip flexor, and that is no gone.

So I’d say the cranks have made me more comfortable, which has thus made me faster.

3

Thanks for the info. Jordan will immediately tell me that 170 is still 2 sizes too large for me, which I tend to agree with. I have noticed the ability to stay aero for longer which is a good thing as a tri cyclist. Just going from 172.5 to 170’s has helped my knees and that is a good thing. I’d like to really hear from others if they have noticed feeling better while doing day in day out training runs, while maintaniing a high cycling training load.

So at the moment, just waiting in the wings to hear some more stories before I retrofit my SRM with 165’s. I’m a bit hesitant to do it before Clearwater, just as I was hesitant to go from 172.5 to 170’s before LP, but frankly I guess I should not as I adapted to 170’s quickly in less than 10 days of training before Timberman.

4

I wouldn’t be too hesitant about “adjustment” periods.

If you were wearing pants that were a 34 inseam even though you were a 31, would you keep them just because you were used to them even though they were the wrong size :slight_smile:

Seriously, I went from 172.5s to 165, a quick saddle height adjustment, a couple rides where standing felt a bit weird and then never thought about the change again.

5

After speaking with both Jordan and Fleck extensively (thanks guys) I switched from 172.5s to 165. I built up a P2C early this spring when I was living in DC. Shortly thereafter I moved to Newton, MA and was introduced to real hills. I am decent tri-cyclist (so like a crap real cyclist, haha) but a fairly good runner. Typically place in my age group in sprint/olympic distance races and top 10-20 overall for such races.

 Hrm.

I’ve been wondering if I should go shorter armed as well. I’m moving from a regular to compact crank, but I’m still at 175 for the crank arms (33" inseam, 5’10"). Maybe I should change out the arms for 170’s as well.

Although every sizing engine I’ve found recommends 175 crank arms, tho.

John

6

The so-called “sizing engines” told me the same thing, about 6’1" and a 32.5" inseam.

But the 165s made a world of difference. What is leading you to consider the change? That is the question? Jordan, accurately pointed out that I had too issues, my leg clearance was tight at top dead center, and more importantly, my back would flair up under high torque applications (long hills, riding into the wind, etc.) The shorter cranks reduced the torque that was aggravating my back.

So basically I went from a poorly tuned, Mustang V8, to a finely tuned Honda Civic Si :slight_smile:

7

So basically I went from a poorly tuned, Mustang V8, to a finely tuned Honda Civic Si :slight_smile:

Did you put a huge pipe on the back? :wink:

.

8

how do you go about figuring sizing. i’m interested in a change that might make me more comfortable on my tri bike, and if the crank is an option the offseason is a good time to give it a go.

does this hold for road cranks as well?

FWIW, I’m running 172.5 on my tri bike, and 175 on my roadie. 5’11", 150#.

9

My experience with the 165’s has meant my 50 year-old knees stopped hurting.

The jury is still out as to whether or not I have lost speed; having no speed to start with means nothing to lose!

IMAZ will be my testing ground, unless photographing Finman cutting the bike course gets in the way! Ah, the sacrifices I make to appease the guardians of SlowTwitch!

10

Like you, I went to 170’s. But I’m 6’3" with a 36" inseam.

I was convinced to make the change by testing using adjustable PC’s. I found that I was *much *better in the aero with shorter cranks. With longer cranks I was really catching at the the top of my pedal stroke. It wasn’t noticeable to me using normal cranks but it was very noticeable with PC’s (I think that’s part of the reason people struggle to adjust to riding aero with PC’s. Their cranks are to long). Since the switch I feel much better, can hold aero more comfortably, pedal harder (subjectively, I have no power metre) and longer.

11

Dev,

The mid-term report on the shorter (165) cranks is all good for MissP.

  • More comfortable
  • Can ride longer in the aero position
  • Back pain gone
  • No jamming at 12:00
  • Smoother pedal stroke all around
  • Faster bike splits
  • Feels better getting off the bike and running

Please note that these last two points are not why you do this - you make this change for the first 5 points and then the last two points follow in succession.

12

Bump for another round of discussion…

So is there any more feedback on the crank-length discussion, namely going to shorter-length?

For my particular situation, my road and TT bikes both came with 175’s, with no discussion ever about what would be the “appropriate” length crank. My 20+ year old mountain - now commuter bike - came with 170’s and I can “feel” a smaller circle when riding that bike.

I am 6’ 1", with a 33" inseam. I also have some medical issues that include typically tight IT bands and an occasionally balky right Achilles tendon that flairs up in the heel area after particularly hard bike sessions (biking lots in hills, for example).

Since my race plan for 2010 is to go longer again (IMMOO), I know that I don’t want to be surging with lots of power on the TT bike, but keeping a nice, steady cadence and power output through the training and racing.

I’m thinking of perhaps trying 170’s on the TT bike. Don’t want to be too radical…

13

I’m jumping in late on this, but is the gist just switch to shorter cranks and see what’s what? I’m about 5’6" and I think my inseam is like 29", does that matter?

14

I’m the same height and have the same inseam. Have 165’s on my road bike to prevent excessive compression at the top of the pedal stroke (at 73-74 deg. seat tube angle). I also have 165’s on my fixie/commuter bike. On my TT bike, I have 172.5s (which were stock) and don’t have those fit issues (at 80 deg. seat tube angle), so I haven’t swapped those out for shorter cranks. I don’t notice a difference in feel between the bikes.

15

Seems like stopping on the IMAZ course to photograph finman is more important than the impact of 165mm cranks.

When I went from 172.5 to 170’s my knees were also happier. Anyway, I will get a cheap pair of 165’s (Bullteproof taper square cranks available from Harris Cyclery for $40) and put it on my commuter bike for the winter and slap that bike on the computrainer to see the impact on any power gain/loss (I’ll set the bike up in the aero position). Assuming this goes fine and I like the feel, I’ll drop the $200 to change my tri bike SRM cranks to 165.

Dev