Race results AFTER switching to shorter cranks ?2

Triathlon Forum
1

would like to get some info from anyone who made the switch to shorter cranks and what type of results did you get during the bike of your races. Did you get faster, stay the same or slow down?

I made the switch last winter to 155 from the stock 170 on my bike. The short of it was that i could never get into a good position with the 170 without closing off my hip angle. So I made the switch.

my bike was 12 min slower this year(2:32 vs. 2:20)…same course…same conditions…guys in my age group who i have beaten every time at this race the past 5 years all biked around the same as last year so I know conditions did not play a factor…yet i was slower than all of them. My run stayed the same…1:35

Thanks for any feedback…seems like a no brainer that it has not been a good decision to make the switch…always looking for the extra 1 minute may have caught up to me.

2

How’s your training been? Do you have a power meter? If so, how did last year’s power compare to this year’s? Finally, with the shorter cranks, if you didn’t raise your cups, you may now be exposing more of your back and be in a less aerodynamic position. Lower isn’t always better

3

I was slower with shorter cranks too but I didn’t do a race to prove it to myself.

I trained on them for about 6 months before I switched back, when I did it seemed like I was magically able to put out more power. Weird thing is that I’m small and I thought for sure the shorter crank would be better.

I think for most people it doesn’t matter though.

jaretj

4

A power meter is really useful as it will help answer the question of whether power was affected, where race speeds doesn’t.

If the goal is to open up the hip angle, you also need to adjust the seat and bars to match, maybe something about the fit got screwed up in the process?

Did you raise the seat and bars, and get the seat setback figured out?

5

I have a PM and going from 172 to 150 on the TT bike made no difference in power (that is comparing max efforts of 23-56 min duration), and felt a lot better. That was with little adaptation. I raised the saddle 22mm and left the bars where they were.

Your results don’t look promising, but if you are basing everything off one ride… you can’t. You say you switched last winter… you should have plenty of data for comparison.

6

I tried 150mm cranks, trained with them for several months. Did a TT where I was beaten by a number of riders I had beaten the year before, the winner was 2:27 ahead of me. After that I went back to my old 175mm cranks and immediately put out 30W more power on a max effort training ride. The 150mm cranks only saved me 0.01 CdA at best, so 30W more power was more than enough to make the 175mm cranks faster. Did a TT with the 175mm cranks and was nearly a minute faster than the rider who had beaten me by 2:27 with 150mm cranks.

Edit: I’ll add that the problem for me seems to be that I can’t spin fast enough for the short cranks, so it feels like the force I need to apply is immense and beyond my ability. I think you need to be able to increase your cadence for short cranks to work, but I don’t seem to be able to increase it enough.

7

I think saddle height and leg extension are important considerations.

When I switched to short cranks last year, I raised the saddle and kept leg extension the same as with long cranks. Cadence only rose a little, so I was probably pushing down harder… which was easy to do. But this year I’ve set the saddle height back the way it was before, so leg extension is ~22mm less, and I’ve not been able to produce the same power… at least not yet. Cadence is up also, so it makes sense that applying higher force is tough.

I shortened the cranks ~13%, so to produce the same power I need to increase cadence, force, or force effectiveness in some combination that results in +13%. It seems that this is difficult unless the leg extension matches what you had with long cranks. Possibly a longer adaptation period is needed.

8

I got a lot faster, but I blame training, bike position and set-up for most all of it. BUT, I think shorter cranks has allowed my to ride a little more aggressive without penalty.

I’m 5’11" riding 165mm cranks. IN race condition I do tend to naturally select a high cadence, but I don;t think it’s much higher than where I was at before switching.

In both the races I’ve done this season since switching, I’ve run really, really well of the bike. But again, that could just be training and better bike pacing. I really can’t compare fairly.

9

Thanks for the feedback guys
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10

Many think its a straight forward shorter cranks = faster cycling. It’s not that direct. It’s actually indirect. Some don’t need to go to shorter cranks. If fit is optimal, and you are comfortable and as powerful as you can be, then there really should be no reason to change.

I went shorter on my road bike a few years ago. I don’t race, much any more so I can’t tell you if it made me faster - but it sure made me more comfortable, and a felt better on the bike. That was a enough for me!

11

The primary advantage to short cranks is to compensate for short legs and to get into a more aero position. If you are not in one of those two categories then I can’t imagine they would help. In fact, they could be a hindrance for some.

I have short legs and run three different crank lengths on three different bikes. The TT bike has 155s, the road bike has 162.5s, and the track bike has (stock) 165s. I won’t do a direct speed comparison between the three because it would be apples to oranges but… I push the biggest gears at the highest cadence on the TT bike. I push the least on the track bike and a cadence that would not caused trouble on the TT bike had me bouncing all over the place and slamming my knees into the handles bars and my chest on the track bike in a sprint. I also see the less back pain with the shorter cranks, especially versus when I used to run 170s. I would love to tell you specific power numbers but I am waiting to get my new used powertap repaired before I can make that comparison. At the moment, the road bike (162.5) is the only one wearing a PM. My TT results over a particular course (raced 8 times in three years) show a massive improvement but again, a weak measure as my coach gets at least 75% of that credit.

When I get that PT fixed, I can give you a very real apples to apples comparison across the different lengths.

12

Six months ago I went from 200m cranks on my bike trainer to 175’s. I had heard shorter cranks help ones running. I switched my race bike over from 200’s to 175s 2 weeks ago.
I have seen no real change in my bike times one way or another. But, I am setting new run PR times at races I have done for years. I just did a 1 minute run PR at Folsom yesterday
in the 10K in 39:10 with like the 4th fastest run for an old guy at 57. (First time every to break 40) So for me, the shorter cranks have seemed to help my running such that I am sticking with the 175’s for now.

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Hi bizmarqua,

Shorter cranks aren’t always better. They’re only better when they’re … better.

We wrote an article about that based on the published research and practical experience with Cervelo TestTeam riders and our triathlon pros. The article includes some practical guidelines and wind tunnel data as well. Here it is:

http://www.cervelo.com/en/engineering/ask-the-engineers/crank-length.html

Cheers,

14

I liked this last bullet which is what I seem to be finding.

“They can run better. Triathletes say the initial part of the run feels better coming from shorter cranks”

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Hi bizmarqua,

Shorter cranks aren’t always better. They’re only better when they’re … better.

We wrote an article about that based on the published research and practical experience with Cervelo TestTeam riders and our triathlon pros. The article includes some practical guidelines and wind tunnel data as well. Here it is:

http://www.cervelo.com/...rs/crank-length.html

Cheers,

(Edit: fixed for all the typos from my phone based posting)

I tried 165’s for 8 months in 2010 and was no faster and was producing slightly less power. I come from a fast twitch sport background so inherently my body tends to lean towards more force per stroke.

My best climbing was on 175’s and my best TTing was on 172.5. I have been on 170’s for the last 4 years. I am pretty short (168 cm). Due to some neck injuries, I don’t have an option to “go lower”. I am already literally sitting up like a sail, so if my RPM is going to stay pretty well the same, a longer crank gives me more torque for the same pedal force, resulting in more power. For now, I might put 175’s on my Computrainer TT bike as an experiment and leave 170’s on my road TT bike.

I have powercranks set up at 175mm on my road bike with a fairly closed hip angle (more closed than my TT bike) as cross training to help my running. I don’t have a powermeter on that bike, so don’t really know the power. I do know that on timed hill climbs, my best results were on 175mm even taking into account doing the climbs in a 34x25 on 175’s and 34x27 on 170’s. Technically the 34x27 on 170’s is a lower gear, but the way my body interacted with the bike it did not play out. Also my best St. Croix times (high crank torque course unless you come with a 34x32) have been with 175’s (again with 25 tooth, not 27 or 28 as I have done with 170’s). Patrick Evoe and I were talking about this topic at St. Croix. Like me, he is a small rider and in theory we should perform better off shorter cranks, but neither of us was entirely sure if our bodies delivered on the short crank promise even though we both gave it a good run.

Also part of my disappointment on short cranks may have had something to do with racing Wildflower, Mooseman, and Ironman France on the 165’s. All courses with long and steep grades where you’re out of the aerobars anyway. I did St. Croix once on 172.5 and once on 175’s and 3x on 170’s. The three slowest years were on 170’s even though I came equipped with lower gearing. Too bad, I don’t have power data from the 172.5 and 175 years. So by sticking some 175’s on the Computrainer bike and riding in the aero position, I can finally get some data from both 170’s and 175’s off the same fitness as I am simultaneously adapted to both (current riding 175’s on powercranks on road bike and 170’s on TT bike)

I think my other problem is that I road for around 20+ years on 172.5 on my road bike and 175’s on my mountain bike and perhaps my brain and firing patterns are better suited for that range. Hard to know.

16

Damon,

Thanks for the link. I had seen and read this article of yours before I decided to make the change. I am only 5’4" and have short legs (obviously). My Cervelo P2 came with stock 170’s on it. I was always uncomfortable in just near any position unless sitting up…I always just worked through it and was able to scratch out some good bike times but would always feel really bad during the run…as if I was in a box all day…Hence my decision to switch to the shorter cranks. I immediately felt better while riding and running was without question much easier. The run I did this weekend while similar to last years time was much easier on me. But to give up 12 minutes on the bike to run the same (yes I could have gone harder but I wore a skirt during the run as I knew my day was toast after the bike) isn’t worth it…

I’m left trying to debate/figure out what to do…go back to 170 for a better bike time and just feel uncomfortable on the run or stick it out on the bike with the new shorter cranks and hope it had nothing to do with the 12 min difference this weekend…

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You need more data points. How long have you been training on the shorter cranks? How many bike miles? I did like 6 months, 1 hour a day before I tried racing. For me, the bike times are about the same, but better running.
Each person just needs to find the best fit for them, and crank length is one part that needs to be dealt with.

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Hi bizmarqua,

Glad you’ve already referenced the article. Based on your height, you might be interested to know that Emma Pooley, at 5’ 2," is one of the best time trialists and triathletes around, and she’s one of the main reasons Rotor offers shorter cranks than many other brands.

As Dev points out, people are different. On the other hand, as Dan points out, we’re usually more similar than different. And as Fleck pointed out, if there’s no problem with longer cranks, then there’s no problem.

But your reasoning for switching to the shorter cranks is valid. Your unusual 12 minute slower bike is probably not related to the crank length. Maybe consider what other variables could have had an effect on your bike performance.

Cheers,

Damon

P.S. And good for you for wearing a skirt on the run. The skirt is a powerful garment, and sends a strong message to the wearer, and those who see you wearing it. I for one can respect anyone who wears a skirt.

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Define short? I am short, 5’4" but sort of long legs for a short guy (30" inseam). I did get 165s for the TT bike. Its hard to find shorter, I have thought of trying 160s.

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Damon,

Thanks…If I had a pic of my run in a skirt I would certainly send it to you :slight_smile:

Any chance I can PM you to ask a few more questions and try to figure out what to do ?