PowerTap SL '07 - Hub coma?

gplama

I'm hoping someone can advise me on the issues I'm experiencing with my new PowerTap SL.

Model:
PT SL '07 (wired) with coded HR strap.

Issue:
Permanent hub dropouts. The hub works for the first 2-3 minutes of a ride then drops, the icon in the top left goes away and does not return for until the hub is reset. This issue is intermittent, but almost guaranteed to take place on my morning commute (4 out of 4 times so far)!

Further Detail:
Reception from the PT hub drops and does not return until the hub is reset, either by waiting 3-4minutes for the hub to shut off, or by removing and reinserting the batteries.

Troubleshooting to date:
- Head unit battery replaced.
- Hub batteries replaced.
- A different harness (on another bike) tested.
- Moving the sharkfin pickup from chain stay to seat stay (and
pointing the protruding circle outwards).

Other notes:
The hub reception is rock solid on the home trainer, 0 dropouts. The hub on occasion works flawlessly for road rides. 108km in the hills yesterday, 48km of short hill repeats today. I'm happy with a few "----"s then having the hub return within a few seconds, which happens on occasion with different pickup mounting points, but once the hub goes into 'coma' mode its game over. It appears the data stream from the hub itself is corrupted and only returns to normal once the hub is reset. All guesswork at the moment, as I'm not across the exact workings of the data transmission.

I've spent a few weeks searching for a resolution online and testing different pickup mount locations, to a point where I thought I had it nailed... but it wasn't to be. I chose the wired PT over the 2.4 to ensure I didn't have these kind of issues, but this one has been biting at me!

flapsupcleanup

I found my SL to be VERY sensitive to the sharkfin placement. Unlike my old PT Pro which I could put the sharkfin practically anywhere on the rear of the bike.

I put the bike on the stand and spun the rear tire. I then moved the sharkfin all around on the chainstay and by watching where I lost readings on the display came up with an optimum placement. It is quite close to the axle btw. I still get occasional dropouts but it works ok.

Have you called saris tech support? They are great.

gplama

I've found the same thing with the sharkfin placement. I've sent Saris an email with the details yesterday..

I've also firmewared the head unit to the latest ver 4.06, but since the transmission icon doesn't come back I guess its the hub.

lanierb

It sounds like a hub problem. Send it back. They will get it back to you within about 10 days. I have two PT SL's w/sharkfin sensors and they are not sensitive to sharkfin placement and they essentially never drop out.

fleshbroiler

I have a PT Pro and for the most part have not experienced drop outs, except twice. I thought it might be a battery issue based on posting to this forum. After experiencing several short drop outs on one ride I picked up replacement batteries. I was in a hurry to get out on the road the next day so I brought the batteries with me in case I decided to change them during the ride. I did in fact experience a major drop out during this ride so I stopped and opened up the hub. I was surprised to have the battery carrier practically fall out on me. I swapped batteries and reassembled the hub and continued with no further issues since, but I am still curious whether it was bad batteries or a loose connection. How secure was the carrier connected when you experienced the worst of your drop outs?

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mountaincycle

Do you have any type of wireless computer, heart rate or GPS on your bike?
I had the same problem. I found that my wireless computer was interfering with the Powertap CPU. I removed the batteries and the problem was fixed..
good luck,
M

gplama

Carrier is clipped in and going nowhere. I thought that may have been the issue before I'd opened up the hub cap to replace the batteries.

gplama

No. Although I've now put my Polar HRM and wheel sensor back on my bike to get reliable distance/time data.

Alex Simmons

Not that's it's been mentioned, but I have problems with PT signal when using my HID light. It is the signals emanating from the battery connector, rather than the light itself, that cause the problems. Sometimes repositioning the battery holder does the trick and I've even wrapped the connector/cable in alfoil to try and create a shield. Sort of works but not ideal.

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gplama

Today's ride: First 8mins normal operation, then the hub dropped out. I stopped for 5mins, then spun up the wheel, nothing. Not happy, but I can't let no power stop me training.

45mins later I have a front flat - stop to fix it, have a bite to eat, and continue on. Power is back! 3 1/2 mins down the road and its gone again. Argh!

2hrs later I put the head unit back into PT mode and power returns for the final 11kms of my ride.

I'd investigate vibration dampening since this only happens on the road (not the home trainer) but there is no consistency other than if its going to drop, it drops within the first few minutes of a ride and doesn't return.

3 days and counting waiting to hear back from Saris email support. Hmmm.

flapsupcleanup

I wouldn't fiddle with the email support from Saris. Call them up. He may have questions for you to help him troubleshoot. They are super great.

gplama

I'm in AU, so I'll have to do some timezone calculations first

Today I opened up the hub again just to see how much movement there was with the battery holder. It doesn't sit 100% snug, and there was a little movement. I added some tape around it so its locked in tight when installed. See pics:






Its currently raining hard, and I've just cleaned the bike, so tomorrow I'll see how it holds up.

gplama

That wasn't it. Hub dropped at 3mins into my ride today. Grrrrrrrrr levels rising rapidly.

Parked the bike at work, 10mins later I turned on the hub and spun the wheel - its back!... and I think Saris are getting this hub back....

mountaincycle

I would call Saris first thing in the morning, they are very good with returns and repairs. 10+ days you'll have your wheel repaired and returned.. I have had good luck with Saris when I have had a problem w/my PT, cables or CPU (computer unit)
good luck, Mike