I just performed a Ramp test, and as I was getting into the higher wattage outputs (about 350 watts), then go to the next minute of needed higher power, my cadence increases, but my wattage actually goes lower.
I know I can play with the pressure of the trainer, and the tire pressure, or maybe even take the heavy flywheel off during a ramp test. Before I do all of that, I figure that there must be someone else out there who has already gone through this and could help.
Here’s my current setup:
Gatorskin tire 700x23 always pumped to 100 psi
Kurt Kinetic trainer with the optional heavy flywheel attached
Calibrated prior to ramp test
Removing and reinstalling the pro flywheel is not a good idea. You need to test and train with the same setup. I don’t know for certain, but I expect real changes to be felt when testing and training with a difference setup between the two. Just not a good idea IMHO.
I had a practice of using rubbing alcohol on my tire at least once a week, to keep it clean and it seemed to reduce wheel slip. So, I’d suggest a good tire cleaning if you haven’t already done so.
I haven’t used the heavy flywheel. But I always had slip at high torque (usually a transition to a high wattage) until I switched to a trainer tire and tightened the Kinetic down pretty hard.
Same as jpowers pretty much said. I don’t have the big flywheel, but do have a KK. I have always tightened the clamp 5 1/2 turns after first contact with the wheel, which is considerably more than recommended. After tightening the clamp grab your rear wheel and yank it forward and back. There shouldn’t be any slippage. And then hopefully you’re good to go.
I wonder if, over time, the tire “polishes” the drum and makes slipping more common? If so, you could try shifting the whole rear wheel contact point over to a fresh patch of metal by adjusting the tightening knobs at the apex of the frame. (e.g., loosen the non-drive side a few turns, then tighten the drive side, to “walk” the rear wheel over a half inch or so.)
Woah! I keep my tire at ~110psi and tighten 3.5 turns; never really had a problem with slippage with wattage steps like in the ramp or even “normal” interval jumps. I could definitely see a possibility of slippage happening in burst type sprint/VO2max efforts but have not yet experimented.
I hear ya. The knob always alerts me to tire pressure – if I’m having to turn it more than usual, I know pressure is down. And yes, do the tire yank test to make sure it’s all locked in.
With my setup, I could drop in to a 1000 W seated sprint in Zwift without slipping, but that was cutting it a bit close. Stomps or transitioning to a really hard standing effort could still make it slip a bit.
At least what I saw before I started using a trainer tire is that the trainer flattens and polishes the tire, and tire material transfers on to the trainer. That has less grip than if both parts are nice and clean.
I am not too worried about the sprint efforts so much. It’s just frustrating when putting out a constant effort towards the end of my ramp test (breathing hard…sweating…burning…), and seeing less wattage…and knowing my FTP isn’t being calculated correctly. Thanks for your input.
This was not a problem in the past but since my FTP has increased and I am having more Vo2 rides with huge jumps in power, my wheel is slipping as well. I will try cleaning the tire and the drum. Getting a trainer specific tire is probably a good idea but I only have one wheel so would have to change it each time I go for an outside ride.
I see some say they are not keeping a consistent tire pressure and not using a consistent number of turns on the knob. Anytime your pressure or knob is not the same as your FTP test, you will not have consistent measurements for your rides. I set tire pressure at each trainer session to 100PSI and 5 half turns, not full 360 degree turns.
But I am not going to change trainer type as I like how it is a low cost alternative to a SMART trainer. And I have to be the smart one to adjust my cadence and gearing to achieve the proper FTP target. More like the real world.
I’ll echo the statement about cleaning with rubbing alcohol. That will absolutely help, if not resolve the issue. I also strive for consistency in tore pressure and knob tightness.
Thanks for the help. I think the issue is resolved. I cleaned the tire and the roller, and then brought the tire to pressure and started at 5.5 turns.
I then pulled up the Kinetic app to calibrate. It told me to loosen the roller, and after 3 tries decreasing 1/2 turn each time, it calibrated. Much tighter than I was running.
I tested it out, and it seems to be working and holding at higher wattage.
someone may have already said this but its definitely worth picking up a cheap rear wheel and putting a rubber trainer tired on it for dedicated trainer use. slippage is almost completely eliminated for me with 3.5 turns on the adjustment knob. Ive had the same tire for 3 years and its still very grippy
Sry for high jacking the thread, but here seems to be alot of Kurt kinetic people. So I ask here instead of starting a new one.
I have a Rock’n roller, and it leans to the left. Anyone have any suggestion how and what to change? I have the feeling that I have to punch it to the right sometimes to get the feeling of being straight.
Today I think i changed it so much so the resistance changed depending on how much I leanded.
Thanks
I keep my tire at ~110psi and tighten 3.5 turns; never really had a problem with slippage with wattage steps like in the ramp or even “normal” interval jumps. I could definitely see a possibility of slippage happening in burst type sprint/VO2max efforts but have not yet experimented.