Static Charge Buildup When Riding - ZAP!

[odonnebj]

Has anyone ever experienced getting shocked by your bike? I kept hearing static shock discharge sounds coming from the rear of my bike every so often, and over the last 2 evenings I was actually shocked from my front left shifter 3 times. My friends heard it loud and clear. As such, we tried a little experiment throughout the rest of the ride. When coming to a stop at a light I would NOT unclip and then touch someone that was next to me... ZAP! We repeated this over and over for the rest of the ride without fail. If I unclipped though and touched my foot to the ground then there would be NO zap.

[benb]

It seems more likely to be the electric drivetrain having an intermittent short (ground?) somewhere.

It's really hard to understand how you could be getting static buildup on a bike.

[mstateglfr]

Nope, never happened to me and havent seen it happen.
One more reason to stay mechanical, I guess?

[gbcoupe]

I've had static build up on rollers. As I recall, it was isolated to the drums. No shocker.

[benb]

I missed the details that the bike is carbon and the shock is coming from the front shifter.

Carbon is an insulator the point carbon fiber airplanes have to have a metallic mesh embedded as a layer... that plus the fact you say it's coming from the shifter really does kind of point a smoking gun at the electronic drivetrain.

You'd think that would be a REAL easy thing to get covered under warranty, I'd certainly be going to the LBS.

SRAM electronic shifters essentially have an ARM computer in there... it probably has some diagnostic that can show a fault if the dealer has a way to read it.

[odonnebj]

That was one source of getting shocked. It was at the junction underneath the brake lever. I’m assuming I’m touching something on the shifter that discharges it, and it’s not the shifter getting “charged”.

Also, from time to time I do hear a static discharge sound coming from the rear. Perhaps rear derailleur?

I should also mention that even if I don’t hold the hoods and put my hands on top of the bars, that I can still shock someone.

[Mark McM]

It's your electric personality!


Aircraft also have a problem with static buildup, so they often employ static discharge wicks to dissipate static charge, in the form of wires trailing off the flight control surfaces:




So maybe you just need the same thing on your bicycle.

[benb]

Maybe it's a feature.. I'd start entering crits and learning how to shock other guys with your elbows in the corners.

[parris]

This is just a shot in the dark. Did you start wearing a fair amount of wool for your kit lately? That may be something to look at.

[reuben]

Originally Posted by Mark McM

It's your electric personality!


Aircraft also have a problem with static buildup, so they often employ static discharge wicks to dissipate static charge, in the form of wires trailing off the flight control surfaces:




So maybe you just need the same thing on your bicycle.

Electronic shifting is the gift that keeps on giving. Waiting for brake fluid to leak onto shoes and cause someone to slip and fall.

POTD, by the way. I don't think I ever had streamers on my bike, but I did have cards in the rear spokes.

[dustyrider]

Originally Posted by parris

This is just a shot in the dark. Did you start wearing a fair amount of wool for your kit lately? That may be something to look at.

This was my thinking, especially if you can generate the shock by touching other things besides the shifter.

[Peter P.]

One could argue that while the carbon is an insulator, it's also behaving like a capacitor dielectric, allowing a charge to build up.

In order for that static charge to build up, I would expect friction to be present somewhere. Is the OP wearing wool or wool blend garments?

[charliedid]

Originally Posted by parris

This is just a shot in the dark. Did you start wearing a fair amount of wool for your kit lately? That may be something to look at.

Interesting thought. Wool shorts and a microfibre saddle will make your balloon stick to the wall :-)

[fellowpicker]

I was commuting home from an evening class once and got caught in a fast moving thunderstorm. Anyone from Albuquerque knows what I'm talking about. Anyway, nowhere to seek shelter and I could feel the hairs on my neck starting to tingle. Next thing I know, the brightest flash along with the loudest clap of thunder occurred very nearby. I was riding on the tops and at that moment, a one inch spark jumped from both of my thumbs to the exposed portion of the bars. I just about soiled my shorts. The ultimate static discharge.

[MikeD]

Originally Posted by Peter P.

One could argue that while the carbon is an insulator, it's also behaving like a capacitor dielectric, allowing a charge to build up.

In order for that static charge to build up, I would expect friction to be present somewhere. Is the OP wearing wool or wool blend garments?

Carbon an insulator? No, carbon is an excellent conductor of electricity. Maybe encapsulated in the epoxy matrix it is.