Triathlon - Tri vs. Road Bike Cadence?

I have two bikes - a trek road bike (700c) and a tri(650c) bike. As it's off-season, I'm mostly riding on the trainer.

I just had my tri bike professionally fitted...and my road bike has fit great since I bought it.

What I've noticed is that I can sustain a high cadence spin (120 rpm) on the road bike in the drops for a reasonable period of time but the same cadence in the tri's aerobars is very difficult to maintain.

I think the gearing is roughly comparable.

So....is it the wheel size that's making the difference; the forward aero position on the tri bike; gearing?

it could be the wheels but im not sure. the distance traveled pre pedal stroke is less with the 650's because they are smaller which seemingly makes it less efficient

My money is on the steeper angles on the tri-bike working the muscle groups differently.

-R

I am getting used to my new tri bike and have found the same to be true. I can maintain a higher cadence on my road bike than on my tri bike. On the tri bike I tend to spin less and push a slightly bigger gear.

My money is on the steeper angles on the tri-bike working the muscle groups differently.

-R

That's it exactly. Tri bikes save the hamstrings for the run and are used much less than on a road bike.

isn't 120 rpm kinda high? I always thought the target zone was around 90-100 rpm

isn't 120 rpm kinda high? I always thought the target zone was around 90-100 rpm

Good catch. I didn't see the cadence first time. Yeah, the ideal road bike cadence is around 80-100 for most people. Tri cadence is closer to tt and should be 75-85 to produce max poer over a limited course length. That doesn't mean you need to ride/train at that cadence but that's the range that's best for most riders when racing.

edit" of course, there's lots of individual varaition with that

Yes....120 is high. My normal cadence is about 90. But, I wanted to compare high speed spinning on the two bikes and found that I really can't spin the tri bike for that long. However, even at around 90...the road bike seems to be easier.

Good catch. I didn't see the cadence first time. Yeah, the ideal road bike cadence is around 80-100 for most people. Tri cadence is closer to tt and should be 75-85 to produce max poer over a limited course length. That doesn't mean you need to ride/train at that cadence but that's the range that's best for most riders when racing.

edit" of course, there's lots of individual varaition with that


I would say the 75-85 for sprints or really short distances, as you get into the halfs and olympic distances you would want that higher cadence around 90 or so. There is no way I can pedal at 120 cadence in the aero bars, maybe sitting, but its probably the position you are in.

Are your cranks the same length? I have read that tri/TT bikes often use longer cranks, this makes for a larger circle which might slow you down.

It could be hip angle. If your hips are closed more on the tri bike that will keep you from spinning as comfortably as on the road bike. Do you have the same leg extension on both bikes? Your tri bike might have a bit more extension than the road bike, causing your hips and core to lose stability at higher rpm. Too little extension can do the same thing.