Inaccuracy of Pro 300PT indoorbike with powertap due heating up flywheel - Page 2

sorry to hear about the fever . Let us know when you're back in the saddle or have heard from Saris.

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rmur

I second that for what it's worth PMD your one hour TT reports convinced me to try it I just did my first one on the KK and I like it better than 20 min TTs. The pace was more comfortable I still had enough breath to tell my wife to leave me alone if I had to but I didn't. I did 19.7mph=249.86 watts FTP (fuzzy numbers but improving fuzzy numbers)

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I have the Pro300 PT as well and have also noticed the problem. I think I have a way around it as I warm up for around 20 minutes at a fairly good pace and then zero the torque. If I zeroed before the warmup and then after warmup I see a value of about 7-10 on the computer module after warmup. Once the torque is zeroed after warmup the 1-2 hour ride is fine. I've even looked at zeroing during the 1-2 hour rides and found 0 every time in the torque setting.

At the moment I still don't have a reply from Cycleops. I am going to send them a second email.

I am very dissapointed that this is a design problem of the Pro 300PT. All Pro 300PT flywheels heat up and all hubs will be inaccurate after 30 minutes of use.

Now all my logfiles are worth less, when I look at them I understand why my heartrate drops 10bmp between minute 30 and minute 60 I thought that it came due a good warming up of my body. When I knew these problem of the Pro 300PT I wouldn't have bought one. I hope Cycleops has a good solution but I am afraid that they haven't. The only other solution is that I get my money back so I can buy a regulair spinningbike with an isis bottombracket so I can install an SRM pro on it.

yeah I hear your frustration there. Decreasing HR indoors would certainly confirm the power drop as I believe most folks would increase or at least plateau but not drop at constant power. I have hundreds of ergo workout records and doubt if there's a single one showing HR decrease over time.

What about the suggestion by Attybiker? I use a CT and warmup at tempo power for ~ 15min before performing 2-3 rolling resistance checks and accepting the 'calibration' (more of an offset rather than calibration). Perhaps a similar routine would enable your 300PT to give you acceptable results.

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rmur

Yes, it's a good suggestion but for an indoortrainer of 1850 dollars it shouldn't be necessary. And for me the problem is that I have bought the indoortrainer because I have less time to train. I have appr. 40-60min. A 20 minute warming up to get my trainer more accurate was not what I was thinking about when I bought it.

Paul, ditch the emails and try calling them - if you call during hours, you'll actually get to speak to a live person.

At weightweenies.starbike.com Jesse Bartholomew readed my post. After I private messaged him I got an reply from Jereme Noffke:

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Hey Paul,

Here's another experiment you might wish to try (provided that you have the time): set the zero offset, then pedal against no resistance for 30 min or so while periodically rechecking the zero. If the problem is truly due to heat-induced drift, then you should find no change. OTOH, if the zero offset is drifting for some other reason - and there have been reports of some hubs showing this behavior - then you should (may) still see some increase.

Just a thought...

If I can get some time tonight, I can try and do both of these tests (Paul's and Andy's) and report back on what happens with my PT300.

that lines up with the previous estimates.

re the flywheel -- well steel or alu alloy conducts heat pretty darned well. Cooling will be lessened near the hub due to the lower radial velocity at that point. I can't see their point to be honest unless there's an insulating layer of sufficient thickness to retard heat conduction from the 'rim' inwards.

Andy's test sounds good as well to confirm it's a heat problem and not something else with the hub.

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rmur

Paul,

FWIW, I have seen no such drift issues with my 300PT. Always reads "0" at the beginning, always reads "0" at the end.

However, what I have noticed (and I believe I wrote in the forums awhile back) is the decrease in resistance over the course of the ride (i.e. for a given cadence, the power drops off maybe 20 watts over the course of 1 or 2 20-min. L4's, necessitating continually tightening the resistance setting). Saris told me this was brake pad/caliper heating.

But, it sounds like you have a different issue, and I'm sure they'll take care of it, though at what inconvenience to you I can only guess. One thing you might consider is contacting the local shop you bought it from (if so), or a local shop that sells them. When my flywheel went out of true, my LBS handled everything (even though I didn't buy it there), including swapping the flywheel from stock (they ordered themselves a new one), and even picking up and delivering the unit back to my home.

Good luck!

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'07 S-Works Tarmac SL, Polar CS600+Power
2008 Cervelo P3C, Zipp 900c+808

'07 Specialized Epic Marathon w/Crossmax SLRs
CycleOps Pro 300PT Indoor Cycle Trainer (my winter ride)

@acoggan: Yes, this week I have enough time for this kind of experiments. I just cycled 30 minutes without any resistance. The zero torque stayed 0 the whole 30 minutes. But I discovered that PowerAgent and CyclingPeaks can't read the file on my cycleops CPU. According to the cycleops CPU I did 30 minutes with an average of 6 watts . But in poweragent and cyclingpeaks I only see 24 seconds.

@warnerjh: That's good to hear (you don't have this annoying problem and for me maybe there is a solution). But how is the temperature of your flywheel after one hour > 200 watt? After the post of attybiker I was thinking that it was a common problem with the Pro 300PT. Because due the design the powertap has to increase in temperature during a workout.

@cPritch67: I am very curious what your Pro 300PT does with the zero torque after a workout. If I was you I shouldn't ride 30 minutes without resistance, my torque was fine afterwards. But I am very very curious if your zero torque will change after 30 minutes with more than 200 watts. Especially because warnerjh says he has no problems.

The flywheel is always roughly the same warmth after any given ride (warm to the touch but not downright hot), whether it's my wife's 1/2-hour workout or a 1x60 at 260+ watts. Try getting in touch with Robb Zbierski at Saris, he'll get you going down the right path.

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'07 S-Works Tarmac SL, Polar CS600+Power
2008 Cervelo P3C, Zipp 900c+808

'07 Specialized Epic Marathon w/Crossmax SLRs
CycleOps Pro 300PT Indoor Cycle Trainer (my winter ride)

Quote:

Originally Posted by warnerjh The flywheel is always roughly the same warmth after any given ride (warm to the touch but not downright hot), whether it's my wife's 1/2-hour workout or a 1x60 at 260+ watts. Try getting in touch with Robb Zbierski at Saris, he'll get you going down the right path.

At the moment Jereme is trying to help me. But I think that his first thought is that I am doing something wrong. His first line was that it was not due heat because the powertap is nowhere close to the braking surface of the flywheel. His second line was how I determined the temperature increase of the flywheel. I hope he will soon take my problem a little bit more serious. He has probably never ridden a cycleops indoortrainer because due the friction of 300 joule / second during 3600 seconds a lot of energy goes as heat into the flywheel and with metal as a good conducter of heat the compleet flywheel becomes hot. You don't have to be an expert to find out that the temperature of the hub is increasing a lot.

He also asked about hub calibration. But what those number say, I don't know:
Cooked 0000
Offset 0509
Raw 0509