Warning:Rear Wheel Lock Up

[gsrunner]

Rear wheel lock up

Hi all,

This is my first post - not what I would have liked as a first but I thought this thread was my most appropriate starting point. I know it is not the usual place to start and I apologise for that but given the subject matter it seemed to fit best here.

I bought a 1200GSA last month and it had its first service last week. Up to then, it was sweet as a nut and I was really enjoying it. Great bike. One slight complaint in that the BMW supplied battery charger never went above 2/3 charge. I reported this to the dealership who tested the battery but could find nothing wrong. Maybe it's the charger?

My first ride out after the service and I was travelling approx 55mph in a dead straight line on a straight road with loads of space and perfectly clear visibility. Suddenly the revs start dying away. Then, the rear wheel locked and I skidded for approx 20m leaving a thick trail of rubber behind me. I know I should have dipped the clutch but I didn't. Perhaps it all happened too quick, I can't really be sure now. I have been riding various bikes for 15 years and have plenty of experience. Anyway, whatever was locking the wheel must have unlocked at that point because it threw me across the carriageway - lucky there was no oncoming traffic - while the bike skidded off into the nearside verge. Luckily an ambulance was coming down the road anyway and was with me in 5 minutes. I was patched up and sent to hospital. Lucky I wasn't going too fast as I got away with 7 stitches in my right forearm (note to self, never wear a mesh jacket again) and bruising to knee, hip, ribs and shoulder. Police were on the scene rapidly, including an Accident Investigator specialising in motorcycles. They reviewed the skidmark and concluded that it was vehicle defect and are happy to provide me with a report to that effect.

My bike is now at the main dealers awaiting inspection by an independent inspector. My worry is that it was a brand new bike just having had it's first service when it suffered a catastrophic failure that could quite easily have killed me.

I will keep you informed to progress, but I will say this has severely dented my faith in the bike and brand. I bought a GSA as I believed I was getting the best. I am now not sure what to think. My worry now is how to prove that this is what happened, as so far the main dealer apparently cannot find any evidence of skidding on the rear tyre! No worries there because there is a load of rubber left on the A15 which the Police will verify came from my bike. Anybody out there have any ideas?

I would also like to say thanks to all the people who stopped.

Thanks and hi to everybody,

Jim

 

[Paul S]

Jim

Nasty experience and glad that you were able to walk away from it.

Not sure from your description what caused the rear wheel to lock but the fact that it "unlocked again" would suggest either an engine or gearbox problem rather than electrical.

Let us know what the outcome is once the bike has been properly examined.

 

[wildbeeste]

I think we would all be interested to know why this would happen. It cannot be the battery. There is nothing electrical that could cause a lock up.
Very scary stuff

Jim waving a police report of the accident under the BMW dealers nose should prompt some action. I would imagine they would be onto Germany PDQ to find out if any similar reports.

 

[Deleted account 210609001]

I suppose an electrical fault could cut the ignition temporarily, but then even if the fault corrected itself the engine wouldn't start if the wheel was locked.

Glad you're basically OK although more than a little shaken, I would imagine.

 

[birdseye]

Jim waving a police report of the accident under the BMW dealers nose should prompt some action. I would imagine they would be onto Germany PDQ to find out if any similar reports.

Come on - these are the guys who put every second accident down to excess speed. I remember one saying ( very useful at the time) my daughter accident was down to a blow out whereas in reality she didnt pay attention . hit a stationary car and then the kerb causing a blow out.

Dont know what caused his accident - wish him the best. But automatically blaming the bike is nonsense.

 

[Slowdown]

Mmm - thinking about this raises the following:-

The alternator output of the GS is 600 watts, I think the GSA is more - if none of this is available to the bike, where does it go? If the battery went open circuit, I'm fairly sure the bike would run. If the battery went short circuit there'd be one hell of a mess under the seat, wouldn't there?

I think I'll try hitting the kill switch at 30mph tomorrow, just to see if a dead engine provides enough engine braking to lock the back wheel.

 

[Wierd Bob]

I'm at a loss as to why the rear would lock up like that.
I have hit the kill switch (or turned off the ignition) at slow speeds a couple of times to either switch off or switch back on the ABS (yes yes I know its neither big nor clever and I should have stopped first) and the rear never locked.
I know the GS (and GSA) are geared very low so the engine breaking is quite strong but if it was that strong you could never be able to bump start the bike (which I've done - well helped someone else on my bike do ) . Admittedly one of the times the rear tyre was muddy and it was pissing rain, so grip levels were low, the rear locked while trying to bump start but this is at 5 - 7 mph (or as fast as we unfit duffers could push it). The rear tyre remember would have been trying to turn a static engine so locking the rear then is understandable.
Its a very scary thought to think it could lock like that and I would have to count on my very small amount of wits to clutch in!

Cheers

Bob