Dropouts with Powertap Comp Wired


New Member
May 20, 2010
Hey guys,

I'm getting consistent power and speed dropouts with my Powertap Comp Wired setup. I seem to get about 4-12 dropouts per hour. This occurs with two different wheels, 4 different wiring harnesses, and I have fresh batteries in both wheels and the head unit. This is my second head unit as well.

The link symbol does disappear when the dropouts occur and my cadence and hr still register.

Do the rest of you guys with wired setups still get dropouts or should I keep looking. Going with the wired setup, I was really hoping there wouldn't be any dropouts like those I was getting with my Polar.

Something isn't right, I've had 4 wired PT SL wheelsets on different bikes and have only had a few dropouts over the years, mostly related to cold weather and old batteries.

FWIW, the sharkfin style pickups work best when placed as close as possible to the PT hub with the round 'bump' facing in towards the hub. That's different than the older square style pickups that worked best when placed further from the hub as described in the manual.

Make sure the locknuts on your PT axle are snug, loose locknuts can lead to data dropouts.

Good luck,
Thanks for that info Dave. I have the shark fin style and have tried as close as possible and parallel (per the manual). Every time I think that I've figured it out, I start getting drop outs again... I'll check both hubs.

Two different wheels, 4 different wiring harnesses, and two different head units? Hmmm.

Do they occur in the same spot?
I know. No, the dropouts do not occur in the same spot(s). Nor do they occur with similar efforts or terrain. None of the equipment has ever been wet either...

Thanks for the thought,

I've been told by Saris that bumpy roads can cause dropouts. They also said, contra Dave and their own manual, that it's best to put the old box style pickups as close to the hub as possible. Maybe that has something to do with the most recent generation of wired hubs. Anyways, it helped in my case.
I did install all 4 harnesses myself. This occurs with older and brand new harnesses. The cadence sensor keeps working during the drop out.

As for bumpy roads, it occurs on perfectly smooth roads and sometimes over bumps. That part doesn't seem consistent either.

Saris hasn't been able to offer much insight as to why its occurring so I wanted to get input from other users. So far, my case still seems odd.

When I first got my (wired, pre-shark fin) PT I got a fair number of drop-outs until I re-positioned the receiver. In my case it was kind of trial and error but right now the little bulb on the old-style rectangular receiver is 2-1/2" up the stay from the axle and canted in toward the hub (i.e., it's not parallel with the bike's axis). I can still get dropouts but they're rare and almost always location-specific: for example, there's a telephone pole and a spot on the road with buried cables that consistently produce dropouts. I've heard that the shark fin needs to be placed differently but since I don't have one I'm not sure.
Thanks, I've been trying different angles on the shark fin sensor and that has made some difference, but I still get drop outs... Very irritating...

Yes, I can imagine it's irritating.

BTW, I thought of something else: I don't know what kind of stays you have but the original bike I mounted my PT on had slightly thicker stays than the bike I have now. When I first moved the harness over the receiver was a tad loose and it jiggled a bit and I got dropouts on my first ride. Then I made a little conformable "shim" out of a piece of old inner tube, which made the mounting much more stable. I don't know if that will work in your case but it couldn't hurt ...
Thanks for the thoughts Mr. Chung. The 4 harnesses are on 4 different bikes, carbon, steel, and AL so none of the stays are the same. It happens on all 4 bikes. I'll check to make sure that none of them are loose / vibration prone.

Thanks again,

I just found this post, so you probably have the situation rectified by now but FWIW, mine was doing the same thing. It was the battery holder! I learned I really had to push it in hard to get good contact with the little tab sticking out of the hub. At first it was no big deal, and then it got worse and worse. Every flat tire would end in frustration because I would have to stop mid ride (numerous times) and pull off the cover, press the holder in HARD, reinstall the cover and hope it worked. Saris sent out a new holder (they have EXCELLENT customer service!) but that was no help. Finally it would not read at all so I called them and am sending it in now. If you care, I will let you know what they find.
Back when wired PTs were the newest version this came up a fair bit on the forums.
For mine, I took a thin piece of packaging foam and put it between the frame and the sensor, held in place with zip ties.
That little piece of foam resolved all the issues with intermittent readings.
I still have a wired PT and experienced this a few times. Mine started doing this the other day and I changed batteries. Prior to drop outs I was getting a low battery signal, I changed all is good. Also check the wire from sensor to cradle, perhaps you have a cut from vibration? or just order a new cradle and sensor
Just bought a wired model. Installed it to find it dropping data about 40% of the time. Getting pretty annoyed until I read this. After putting new batteries in the hub and CPU and removing the battery from the Cateye wireless transmitter that I had kept on the bike "in case" the powertap didn't end up working, everything appears to be fine.

Other wireless units truely can interfere with the PT wired unit. BION. :)