Question on bike crash

kjab

So I had a crash today and I can't work out what happened, can anyone shed any light / give a hypothesis.

Cycling on my daily commute to work. Sunny, road is flat & dry and no cars around, going steadily at 25-30kmh. Next thing is my bars have gone almost 90 degrees anti-clockwise (ie turning to the left) and I get flipped over the handlebars. Land on my shoulder, back and knees onto the road.

The main impact went onto the right shifter, but the stem is now pointing to the right. The headset is still tight. The front wheel isn't buckled by the inner tube has burst. Can't see an obvious tear in the tyre but centrally the tread is slightly worn.

So, did I inadvertently pull the bars too far over to the left (which I don't remember doing), or could the front inner have burst to cause a twist. I don't remember seeing any debris or anything on the road and I definitely didn't hit the kerb.I guess the tube could have popped when I went over. The top tube is cracked too so the bike is trashed

Any thoughts?

https://imgur.com/a/C0riE

Cheers!

veronese68

Sorry to hear that, hope you're ok.
Were you riding in a straight line? If so something in the road is most likely I would think. Could something have flipped up and got caught in your front wheel? Seems unlikely for the tube to just burst with no good reason. Had you just replaced the tyre or pumped it up? Could the brakes have been rubbing causing heat to build up?

joe2008

Sorry to hear that. As you mention the kerb you were probably not in the middle of the road, but is there a chance you caught a catseye badly?

I caught a old raised iron one with my back wheel on a deserted moorland road throwing me off my bike in a similar fashion a while ago.

To be honest, it's the one of the reasons I only use tubulars. At Christmas I hit some debris on a descent doing around 40mph, front wheel blew out, but because the tube was glued to the rim I had complete control of the bike and safely brought it to a stop.

svetty

Most likely you hit an object or pothole. Alternatively a stick or something kicked up and got caught in your front wheel - a plastic bag blown into it by the wind?

Is the stem still tight on the steerer - could it have swivelled? Could the steerer have sheared?

I doubt the inner tube would have spontaneously just burst - most likely this was either due to an impact or the crash.

savvasstavridis

Sorry to hear that.Hope you're ok!

Seems more likely to me that this happened from a burst tube. If you lose the air at once it is likely to steer to one direction. I suppose it is not a blocking of the front wheel.
This happens also if you drive into a parallel (to your direction) groove on the tarmac, but you would have spotted it.
By the time the tyre has no obvious damage, I suppose it was a faulty tube. As someone told before, did you change your tube recently? If the tube folds somewhere in the tyre it is likely to burst.

kjab

Cheers for the replies.

I was probably a couple of ft or so from the kerb on a two-lane one-way road. They don't have cats-eyes in australia either!

Was an oldish tyre and tube that I've been commuting on for the past few months so not sure how many km (I only do 40-70km a week commuting). Tyre pumped up a couple of weeks ago to 90. It also wasn't especially hot - it was 40 degrees when I rode home last week but below 30 this morning! No brake rub either

Ah well, maybe it was something in the road. Just don't remember seeing anything after I fell (apart from stars for 5 mins lol)

Cheers all!

cougie

Don't think it's a blow out. You normally hear those and it doesn't send the bars round either.

No chance you hooked the bars on something to the left ?

davesnothere