calamarichris

Any idea how to prevent belt-slippage on a belt leading from rollers to resistance fan? It's the little orange belt ahead of the front wheel, ("Headwind").


Old picture from a build project.


Anytime I sprint over ~700W, the speed & cadence continues to rise, but the wattage decreases, making me believe the belt is slipping. It's a fresh belt with less than 1000 miles on it, and I've tried cleaning the belt and pulley with a wet rag and drying it.
Make the belt or pulley stickier? Less smooth? Any other ideas?

Wheever

As a musician, my first thought was this stuff. Violinists use blocks of it on their bows to give the horse hair "tooth," And is used as a "tackifier" for many other things. (tennis, apparently) Probably would be a little messy, in that it would shed some powder, but it's non-toxic and not sticky for easy cleanup. I bet it would work well, and you probably wouldn't have to use much.

[EDIT: Oh, duh, I bet automotive belt dressing would work, too. Don't know how toxic is might be for indoor use, though.]

fietsbob

Automobile V belt dressing There should be a Product data sheet online listing what is in it.

Maybe a shorter belt? drum have a groove for a second belt on the other end?

maddog34

i'd be CLOSELY inspecting the belt and/or pulleys... i spent way too many years working on various machines that utilize belts... once the sides of the belt no longer contacts the walls of the pulley grooves tightly, you must REPLACE the belt to prevent slippage... Tighten the worn out belt, and it just slips less, then begins slipping even more, and pulley wear rate increases too... typically, if a V-type belt isn't high enough in the V pulley to stick up out of the V on the pulley, it's shot, or nearly so. Be aware, there ARE different V belt angles, too, so verify the new belt is CORRECTLY DESIGNED for the pulleys involved.
there is one other thing to consider... "Aerodynamic lock"... similar in nature to hydraulic lock... you may be exceeding the limits of airflow through the fan when you spin up to warp 9..........

calamarichris

Thanks for the helpful suggestions. Guess I'll order a spare belt and use this one to experiment with tackiness solutions.

I've read a few complaints about the noisiness of these Kreitler "Killer Headwind" fans, but I've found that coating the outside surface areas with adhesive foam pads (which ordinarily coat the inside of plastic motorcycle fairings, to contain the mechanical noise) does a nice job of quieting things down. And it's pretty neat--the harder you pedal, the more cooling air blows on you.

OshkoshBiker

Alcohol can take the gloss off of a rubber belt.

Andrew R Stewart 

At one time Kreitler published the power draw of their Headwind systems. This was in the early years of trainers. I don't remember the specs but I wonder if 700 watts is towards the max lever intended. I also remember back then that there was some talk about the belt's ability to drive high levels of power.

But this brings up the question as to the best purpose of a set of rollers. Us old timers never viewed rollers as a power training device to start with.

I will agree about the noise though. Andy.

calamarichris

Thanks very much again for the responses. Turns out the belt is indeed not slipping at all. It's mostly likely the hydrodynamic lock you mention Maddog. As soon as I noticed how well the belt actually grips the pulley, I experimented with the intake aperture on the fan, and the more open the intake, the higher (slightly) watts it will attain before "slipping"--it can only move so much air at once.
I've had these Kreitlers nearly a decade, but have only recently started riding track and haven't needed to spend much time above 400 watts before this.
Guess I'll have to quit slacking & get out to take advantage our our famous weather more often.
Thanks again and ride safely!