Front wheel Issue

[GaryFM]

Hi all,

I had an issue on my ride tonight that I am concerned about.

Bike Alliance TCR, R500 Front wheel, Polar magnet and sensor on LHS. rider 83kg.

I have a left hand hairpin corner close to home that I like to try to go as fast as my ability will allow. Trying to hold a tight line tonight, on a damp road, the front wheel slid sideways and the bike leant right over. I am not sure if it was immediately or before the bike slid but I heard a loudish noise from the front wheel. (Clank, clank,clank)

Due to total luck the bike hit a dry patch and stood up and I road another 15k home without an issue (other than heart in mouth). I couldn’t get it to make the noise again but didn’t push it too hard.

I checked the wheel and spokes when I got home and can’t find anything wrong.

Any ideas why the clank clank clank? If it was the Magnet hitting the sensor does this mean the wheel twisted that much when the weight was applied at a weird angle eg when it was lent over. Do wheels warp 3-4mm if sideways pressure is applied?

Could I have another issue eg bearings or ?

I have a spare wheel and will replace it for tomorrow’s ride and have the LBS check it at next service. I don’t really know what happened but are more curious than concerned. Thoughts?

Thanks in advance-Gary

[sogood]

I think just as you were about to hit the deck, your jaw joint made those clank clank noise.

The other possibility is pedal strike.

[twizzle]

If it was the Magnet hitting the sensor does this mean the wheel twisted that much when the weight was applied at a weird angle eg when it was lent over. Do wheels warp 3-4mm if sideways pressure is applied?

Check the inside of the fork for rub marks from the tyre.

[drubie]

In the shed, rotate the wheel so the magnet is lined up with the sensor. Put your thumb on the wheel and push hard. If you can deflect the wheel far enough with your thumb that the magnet can touch the sensor, you've found your answer.

[Phill_B_34]

Valve stem crashing/slapping side to side in the rim hole with the much higher lateral loads (via higher lean angle from slip) that the wheel is not usually subjected to.....?????

[rustychisel]

In the shed, rotate the wheel so the magnet is lined up with the sensor. Put your thumb on the wheel and push hard. If you can deflect the wheel far enough with your thumb that the magnet can touch the sensor, you've found your answer.

+ 1. probably found your answer. Yes, you can deflect a wheel that far.

[MichaelB]

Solid waste release/retention valve clenching & un-clenching.

Buy a lotto ticket, and don't worry about it until you hear about it.

[trailgumby]

Probably wheel flex. Are there any rub marks on the magnet or sensor?

BTW, that was a lucky escape. Wet weather is not a time I'd be choosing to push any limits, especially on the road. I'm glad it ended OK.

[human909]

Any ideas why the clank clank clank? If it was the Magnet hitting the sensor does this mean the wheel twisted that much when the weight was applied at a weird angle eg when it was lent over. Do wheels warp 3-4mm if sideways pressure is applied?

Wheels can easily ward 3-4mm! 3-4mm is not very much at all!

Extrapolating these results suggests you only need 20kg lateral force to warp a wheel 4mm. Not much at all for a slip and stick event.

[GaryFM]

Hi all,

I've had some time to look closely at the wheel and still cant see anything obviously wrong or any marks. I did apply some lateral force to the wheel and am surprised how much flex you can get if you apply quite a bit of lateral force.

Thanks all for the advise, I'll put this one down to luck and learn from the experience.

Gary