"The 33"-Road Bike Racing - Powertap losing the signal

I thought I'd check with some other powertap users on this one, since Saris is closed until Monday and I have exhausted my own ability to troubleshoot.

My head unit keeps losing the signal. The transmission icon is lit up but the power and other readings become dashed lines - sometimes for a second or two and sometimes for longer. Yesterday's ride was missing about 3 miles for what's normally a 25 mile ride, so it's really off.

First thing I did was tinker with the shark fin placement. That seemed to have no effect. Next thing I did was replace the battery in the head unit. (I replaced the hub batteries about a month ago). That didn't work.

Today I noticed the power reading was also really buggy - for example, I was going up a hill and it was reading at least 60 watts lower than it should be for my effort. Other times I was on a flat section and it wasn't reading any power or cadence, just showing zeros.

There are two things that happened just before this started. I dropped the head unit. It only fell about 1.5 feet, but it hit pavement. I also was fixing a flat back tire and knocked the shark fin completely out of position.

I'm guessing I either messed up the head unit when I dropped it or knocked a wire loose when I moved the shark fin.

Has anyone else ever had this happen?

I do not own a PT. In my experience with wireless speed/cadence if you are having dropouts and buggy readings it might be due to a weak battery. Perhaps check that if the problem persists.

Batteries are brand new. That's not the problem.

Like I said, no PT here, so I'm all out of ideas.

As am I. It's going to be odd training on "perceived effort" until I get this sorted out.

As am I. It's going to be odd training on "perceived effort" until I get this sorted out.

I hate you, I want a PT!

I'll bet that a firmware update will fix it instantly. A friend of mine had these exact same problems this week. Same firmware version as he had before, but just flashing it fixed it.

It's REALLY easy to flash it:
http://www.saris.com/t-firmware.aspx

Once you do that, mount it, spin the wheel, stop it, then zero the torque. You might then want to run through all your settings and make sure it's set up properly. I believe most of it stays (odo, circumference, etc.) but I can't remember for sure.

Post back how it goes!

Yeah, just went through 2 weeks of headaches with my "new" PT SL 2.4 wireless. Only to finally find out on my 3rd telephone call to Saris that I had the wrong firmware (5.33).

Could be firmware, that's worked for me before. Could be batteries even if you just put "new" ones in.

I thought I'd check with some other powertap users on this one, since Saris is closed until Monday and I have exhausted my own ability to troubleshoot.

My head unit keeps losing the signal. The transmission icon is lit up but the power and other readings become dashed lines - sometimes for a second or two and sometimes for longer. Yesterday's ride was missing about 3 miles for what's normally a 25 mile ride, so it's really off.

First thing I did was tinker with the shark fin placement. That seemed to have no effect. Next thing I did was replace the battery in the head unit. (I replaced the hub batteries about a month ago). That didn't work.

Today I noticed the power reading was also really buggy - for example, I was going up a hill and it was reading at least 60 watts lower than it should be for my effort. Other times I was on a flat section and it wasn't reading any power or cadence, just showing zeros.

There are two things that happened just before this started. I dropped the head unit. It only fell about 1.5 feet, but it hit pavement. I also was fixing a flat back tire and knocked the shark fin completely out of position.

I'm guessing I either messed up the head unit when I dropped it or knocked a wire loose when I moved the shark fin.

Has anyone else ever had this happen?

You do zero the torque at the biginning of each ride, right?

Another likely suspect is the contact between the head unit and the mount.

TF

You do zero the torque at the biginning of each ride, right?

Another likely suspect is the contact between the head unit and the mount.

TF


Um...no. Instructions didn't say to zero it at the start of each ride - only when the power isn't returning to zero when coasting. "Frequently" is the term the manual used.

How do you clean the contact area? I used a toothpick and got a speck or two of lint out.

I also just updated the firmware. I'm heading out soon and am crossing my fingers that something I just did will solve the problem.

Um...no. Instructions didn't say to zero it at the start of each ride - only when the power isn't returning to zero when coasting. "Frequently" is the term the manual used.

How do you clean the contact area? I used a toothpick and got a speck or two of lint out.

I also just updated the firmware. I'm heading out soon and am crossing my fingers that something I just did will solve the problem.

I certainly hope that you zero after the firmware upload.

Ink erasure followed by spray contact cleaner.

TF

Okay, all of that (including zero-ing of the torque after firmware update) didn't work. I'm going to try TF's recommendations for cleaning the contact area next and cross my fingers.

It really likes to mess with me. The signal seems to drop more frequently when I'm trying to do an interval than when I'm in the recovery period.

Okay, all of that (including zero-ing of the torque after firmware update) didn't work. I'm going to try TF's recommendations for cleaning the contact area next and cross my fingers.

It really likes to mess with me. The signal seems to drop more frequently when I'm trying to do an interval than when I'm in the recovery period.

Do you have access to another one? Swap wheels, swap cpu and see what works. - TF

EDIT: Ignore this post and read waterrocket's. - TF

If you have any PT-riding friends, you might swap wheels with them. It's starting to sound like your wiring harness.

EDIT: TurboTurtle blast you posting that before I got to this thread!

I was afraid it may be something in the wiring. It started over the weekend, between the first and second days of my very first stage race.

I was travelling with a teammate, and in addition to the two events I described in my OP, the bike was getting packed and unpacked fairly often from the back of a pick-up truck. She was handling the bikes gently, but who knows what may have happened in all of that chaos.

I'll see if I can swap stuff out with someone else's powertap and maybe pinpoint the problem.

It has always been wiring harness problems for me. If you're using zip ties on the wires, stop. Tape only. Tape only. Tape only.

It takes next to no force to pinch the wire and destroy the harness.