300 PT stability...

[Terry Ferguson]

Just started using a 300 PT and am having a little trouble adjusting the resistance. If I'm increasing, I seem to have to go past my desired load and then back it down. Do your units dial in easily? I have not calibrated it yet nor looked at the cables. I did tighten down the v-brake springs, but that did not seem to help.

Part dos - Have you found a use for the brake lever? Like maybe to adjust it so that it gives you close to the correct power for a short sprint? You could just grab the lever for the sprint and release at the end???

TIA,
TF

 

[mullerrj]

Just started using a 300 PT and am having a little trouble adjusting the resistance. If I'm increasing, I seem to have to go past my desired load and then back it down. Do your units dial in easily? I have not calibrated it yet nor looked at the cables. I did tighten down the v-brake springs, but that did not seem to help.

Part dos - Have you found a use for the brake lever? Like maybe to adjust it so that it gives you close to the correct power for a short sprint? You could just grab the lever for the sprint and release at the end???

TIA,
TF

I have the 300 PT too, and also do MAP tests with it. Yes, the resistance knob is VERY touchy. There is a definite lag too, to what you dial in. When I first used it, I would always go past my desired resistance and have to back it down..now, I use smaller increment gains as it's easier to make small increases to get to my desired output. Also, what I did to make dialing in a setting easier was put a white paint mark on one of the arrows on the perimeter of the knob. That way, I know that two complete knob rotations will put me in the 200 watt range. Just helps when you have to dial in a setting FAST for say sprints or Critical Power tests such as CP1.

Part II, nah, brake lever equals emergency stop only. Although, if there were a way to hold it in a certain position (where it absolutely won't move) you might have something there. Rob

 

[J-V]

Rob pretty much nailed my experience with it in his post above. It is very finicky, and you need to learn how much to rotate it, being especially careful not to go too far, as it's nearly impossible to get 'back to where you started' in any reasonable period of time. I, too, color-coded the little arrow heads with different colored markers over a 'silver' Sharpie. Over time, your calibration mark 'moves' (due to cable stretch?), and I needed to be referencing a different mark after awhile.

As far as the brake lever is concerned, I absolutely have learned to use it to increase resistance for shorter periods of time. Also, if you accidentally move it's cable with your left hand, it will increase the resistance, annoyingly. Or, you could potentially view it as a 'feature' if you wish to slightly increase the resistance...

When I was initially troubleshooting all this last winter, I removed the water bottle holder to get a view of the mechanism underneath. It's basically a 'mixing unit', to which both the brake and resistance cables attach. Unfortunately, when either is made taut and then released back to where you started, the mechanism seems to refuse to return to that initial point. no amount of lubrication or fussing with it on my part would solve it, it's just a marginal design.

The 300PT is a great tool, however, and it changed my cycling life in ways that just about nothing else could have.