Help me out here, I switched from 175 cranks to 170 this year. I am 5’10 and 1/2. I am a year more experienced with triathlon, did my first Ironman at Florida last year and went 5:30 on the bike. I am running faster and swimming faster this year than last year. So far this year I have more training under me at this time of the year than last year and have more experience, yet, all of my times this year so far on the bike are slower. Bike set up is the same except the change in crank length. I now conditions vary, things happen, but I am starting to get worried. Help me to check off the possibilities. Could the change in crank length make a difference? I do feel that I have always preferred to push a bigger gear as opposed to higher cadence. Anyway, tell me what yall think and thanks.
PS I dont have a power meter, I know that would make this question a lot easier to answer.
1st… without a power meter, how do you know you’ve lost power? A LOT of variables are unaccounted for most likely.
2nd question… how much has your training morphed? Did you ride a lot heading into Florida? (most IM racers put in long rides) compared to now?
175 to 170 isn’t terribly drastic. You say everything is the same except crank length. I assume you meant you changed saddle height to compensate though.
My bike power is always lower in April than it is when I am “peaking” for a fall race. Especially when I am putting in IM training miles/time. Plus I weigh a bit more as well…
The research has shown that there is little to no power loss, over a wide range of crank arm lengths with the same cyclist, so whatever changes you’ve been experiencing are not a result from the change in crank length.
If you can borrow a PT from someone you could do your own testing with both cranks.
Too many variables, for some a “perfect” crank may be shorter but then changes fit. If you don’t get the fit that is right for you after the change then it may not be better.
Going to shorter cranks may result in less torque applied but then you may also be able to spin faster thus resulting in a similar power.
I would guess if it did indeed result in a power loss it would be because you are not used to spinning faster. Although I think this is probably minimal and not the cause.
Going to shorter cranks may result in less torque applied but then you may also be able to spin faster thus resulting in a similar power.
I would guess if it did indeed result in a power loss it would be because you are not used to spinning faster. Although I think this is probably minimal and not the cause.
The bike’s drivetrain is a series of levers, two of which are the gearing (front and rear). In other words, you can apply the same force at the same cadence and produce the same power on any range of crank lengths, provided you shift up or down to compensate. The only time changing crank length can affect your available leverage is in your easiest and hardest gears.
Even though 5mm shorter cranks do not sound like a big change, it really is. You will need to raise your saddle 5mm and then possibly move it forward (depending on the bike). If you have a 76deg seat angle, you may need to move the seat 2-3 mm forward. If you are very sensitive to your fit position, you may need to raise your bars by 5mm as well to keep the saddle to bar drop unchanged.
Your not over biking and pushing a big gear like you were, so your running faster at the cost of slightly slower bike times. Giving up 1 minute on the bike to run 2 minutes faster or even 1:10 faster is ALWAYS and good compromise.
I know that my best week cycling this year was while I couldn’t; run due to an injury. Since I started running again, surprise, surprise, I’m more fatigued and not hitting the same metrics on my rides or improving as much. Have patience.
Thanks for all the input guys, yes I moved my seat up 5mm. Other than that everything has been the same. Maybe I am just freaking out and looking for an easy excuse to why I feel slower. Thanks for all the input.