Turbo trainer go BRRRRRR (and loses resistance at high torque) - broken?

Have a Lifeline TT 02 fluid wheel on turbo trainer.

Have done 1500w sprints on it before, but after a 1 hr 250w effort tonight I did some 180 rpm high cadence sprint intervals and it suddenly went BRRRRRRRRRRRRRR and lost all resistance. It would still work at lower say sub 500w wattages and there’s no oil spill, tire was very well fastened and I try to tighten it even more to no avail.

Is it somehow overheating and losing function? Defective or perhaps just not beefy enough? Have it triggered some fail safe mechanism lol

I have no help or advice for you, I just love your title :rofl:

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I’d think in a fluid trainer the only real moving parts are the bearings. They could be going. If out of warranty maybe could pull and replace.

But this wouldn’t explain the sudden lack of resistance, something would have to uncouple, maybe a safety mechanism?

Likely issue is a fluid leak for a low or empty resistance unit.

Hm fluid leak leading to cavitation. I could see that.

No leaks!

More armchair engineering here. Assuming fluid trainers have similar design to the Kurt there are two chambers. It could leak from one to the other without being externally visible.

You probably did one of the following

  1. Boiled the fluid and turned some goo into different goo and gas. The gas is compressible or escaped past a seal. The impeller now cavivates
  2. Broke an impeller
  3. It is leaking oil through the o-ring, and you just haven’t notices.
  4. Your tire is slipping on the roller.

If you think you’ve got good resistance, I’d lean towards the tire. Try swapping tires and wiping down the roller with alcohol.

  1. Hard to say, if it’s silicone fluid the boiling point is 315 degrees C.
  2. Still works fine after cooling down so doubt its broken.
  3. Still works fine after cooling down so doubt there’s a leak, also a leak wouldnt explain the SUDDEN BRRRR sound that then goas away.
  4. No tire slippage, tried to clamp the tire as hard as it can go etc.

More likely what happened: if there are two plates held together magnetically like in the kurt kinnect and you apply too much force, the plates will slip and you wont benefit from the fluid resistance (plus it somehow makes a terrible noise and this is more likely when the unit is hot).

I have this too now. The trainer is 2.5 years old and I was just doing a race on Zwift. I pumped out a ton… of watts and the brrrr sound started. Did anyone ever to a fix for this or just go for a new trainer?