Need to check Tire Pressure while on Bike Trainer?

Mark Cardinale

I have been using training road for my preseason workouts and plan on using it for my OS as well. As a result my road bike has been locked in the trainer for about the past 3 weeks. During that time I have been wondering if I can keep it pretty much locked into the trainer indefinitely, or is it a good idea to periodically remove it to check tire pressure. I know exactly the number of rotations I have on the resistance crank, but despite this I’m concerned about removing the bike and adjusting anything that might put me in a position where I’m no longer comparing apples to apples. Is that possible to do by changing the tire pressure? On the flip side I’m wondering if by not checking tire pressure, might I be encountering some unintentional drift caused by slowly losing pressure over time.  Then again, I might be way over thinking things….Would welcome any input or advice from the team. Thanks!

Coach Patrick

I can pump my rear tire without taking it off the trainer...can you bring the pump to the bike? Or am I missing something here?

levijones

I have found tire pressure plays a role.

I was wondering the same thing last year when I was leaving my bike on the CT, so I started tracking the calibration drift (measure of rolling resistance) . Each consecutive ride I would see a drop in this number. Leaving the bike on the CT and inflating the tire to the recommended pressure would put me right back to the original numbers.

Multiple pieces contribute to the rolling resistance; the roller, your tire, how many turns you have on the resistance crank, temperature and tire pressure. By leaving the bike in the trainer (and inflating the tire there) you eliminate some of these variables.

Al Truscott

 I'm not sure what is meant by "leaving the bike on the trainer" My TT bike stays on the trainer during the OS (outside rides on my road bike). But i release the resistence roller each time, worrying about subtle pressure and warpage to the wheel rim and damage to the tire. Every couple of wkos, I pump tire to 110. Since I have a CT, I re-calibrate to 2.00 after a 20 min warm-up each ride. This requires adjusting the resistence precisely each time.

Scott Alexander

Same here as Al, I leave the bike on the trainer all OS, but only release the flywheel from against the wheel/tire after every workout.

harrast

Tire pressure certainly changes power measurements. I ride a CT and top up my tire every couple of days. Like Al, I generally recalibrate for each ride. As long as I keep my tire pressure at the same number, my calibration numbers are similar. If you don't top up the air, your measured watts will likely drift higher than your actual watts. I have a training bike that I leave on the trainer and have never had any issues with tires or rims flaking out. I do use a trainer specific tire and love it because it doesn't shed all that black junk onto the floor.

Peter Greagg

I also use a CT in the OS and inflate the tyre to 110 every WKO and calibrate to 2.0 — without exception.
I want to give myself the "right" dose of work each time.

Mark Cardinale

Posted By Patrick McCrann on 31 Oct 2012 12:33 PM

I can pump my rear tire without taking it off the trainer...can you bring the pump to the bike? Or am I missing something here?

Well it seems so simple when you put it that way!

 

Thanks everyone.  What you have said makes sense.

I'm using a KK Road Machine and i don't have the ability to calibrate beyond the number of rotations i apply to the resistance knob.  My take away from your feedback is no problem keeping the bike in the trainer, but release the resistance knob after each use.  Then check tire pressure regularly to maintain a constant PSI.

This is the first time i have spent any extended time using a trainer so i appreciate everyones patience with my start up questions!

Thanks, all!

 

 

rmiller

I pump the tire up to a consistent pressure before every ride.. bike tires lose pressure fast, and pumping up just before hopping on it the best way to make it consistent day to day.

cgres123

Pheewww..

William Jenks

Power is power is power.

As far as your legs are concerned (if you have a PM), it doesn't matter if your tires are filled with nitrogen, air, or applesauce....or if you have a few playing cards on the spokes to make that cool motorcycle sound. Seriously. This is the same thing as if you are riding into the wind or on a bad road or whatever.

If you are NOT using a PM, then getting the pressure and tension all equal is what you ought to be trying to do.

Now, having said that, your gearing and "speed" will change for a fixed power if your tire pressure and tension are not kept constant. I saw a guy do a measurement of how much faster he was going on rollers at fixed power with different tire pressures, and that was pretty dramatic, but rollers also exaggerate the difference.

Al Truscott

 @Wm...for those machines which internally vary the resistence based on preprogrammed signals, like the CompuTrainer, maintaining a reproducible constant tire pressure is important to having the consistency needed for our workouts. If my tire pressure drops, the pedaling gets easier, and I have to try and adjust the CT resistence on the fly to maintain a steady power output... Can't do it via changing gears. Ditto the calibration number which Peter referenced.

William Jenks

Pardon me for misunderstanding the question. Agree that if the system uses feedback for resistance (a la computrainer) that is absolutely right.

Mark Cardinale

Thank you both for the continued dialog.

Just so i am clear...In addition to the computrainer, this would also apply to virtual power, i.e. trainer road, correct?

robin sarner

good questions.

For computrainer, where power is measured through the device, calibration is important.

for a regular basic trainer, if you are using a crank or wheel power meter, or Trainer Road, things like tire pressure should not matter???

Or does not matter for the bike power meter but does matter for Trainer Road???