Wipeout Part 2 - Car got me!

[GFamily]

. . . the incident today involved me travelling at probably somewhere close to 30mph on a slight descent.

I was pumping the brakes, but the surface was just so wet I couldn't stop in time.

Lesson to be learned perhaps?

 

[Arch]

Lesson to be learned perhaps?

I was thinking that...

While the driver was clearly at fault for taking a chance, travelling at nearly 30, in the wet, on a bike seems a bit too fast. We just don't have the braking power of four fat tyres....

Especially given the way drivers seem unable to appreciate the potential speed of a cyclist.

Still, hopefully there's no serious damage done.

 

[lejogger]

I was thinking that...

While the driver was clearly at fault for taking a chance, travelling at nearly 30, in the wet, on a bike seems a bit too fast. We just don't have the braking power of four fat tyres....

Especially given the way drivers seem unable to appreciate the potential speed of a cyclist.

Still, hopefully there's no serious damage done.

Yes, you are perhaps both right to an extent. While I am legitimately entitled to be travelling up to and including 30mph in a 30mph zone, for as long as motorists see a bike and automatically think 'slow... must get out in front', travelling that fast in those conditions is probably an unnecessary risk.

Commuting to work is all about arriving safely, not risking all to arrive quicker than yesterday.

As a human being though I'll freely admit that I get a thrill from travelling as fast as it's safe to do, and while other road user's inability to gauge the speed of a travelling object should not prevent me from cycling as I'd like (within the law), doing so frequently may put me at risk.

Quite often, I feel that a high average speed and the ability to keep up with traffic actually makes me safer. I don't get overtaken as often because in 30mph zones during rush hour traffic rarely reaches 30mph so on the flat I generally keep up. Drivers seem to be more patient when I'm travelling fast because they don't feel as held up when stuck behind me.

 

[GFamily]

Yes, you are perhaps both right to an extent. While I am legitimately entitled to be travelling up to and including 30mph in a 30mph zone,

Personally, I'd say you are only 'entitled' to travel up to the speed where you can safely stop in the space ahead of you. You may choose to ride faster; but it's at your own risk.


As you found out.

 

[lejogger]

Personally, I'd say you are only 'entitled' to travel up to the speed where you can safely stop in the space ahead of you. You may choose to ride faster; but it's at your own risk.


As you found out.

I try to always travel up to the speed where I can safely stop in the space ahead of me. Whether that's 5 mph or 50 mph, if another road user makes a mistake and impedes into that space when they have no right to do so I can't be held to blame for it. I didn't crash at a T junction or roundabout or traffic light where I should have been expected to stop. I had a long empty road ahead of me. If the situation were that I was travelling at 15 mph but the driver pulled out half the distance away from where he did, you wouldn't be accusing me of careless riding, but the circumstances are exactly the same.

 

[GFamily]

If the situation were that I was travelling at 15 mph but the driver pulled out half the distance away from where he did, you wouldn't be accusing me of careless riding, but the circumstances are exactly the same.

Not really.

When you brake you rely on the friction of your brakes to convert your kinetic energy into heat energy.
Kinetic energy is proportional to the square of your speed, so had you been travelling at 15mph rather than 30mph you would have been able to stop in 1/4 the distance. So, yes, I would not have accused you of careless riding in those circumstances.

I get a thrill from travelling as fast as it's safe to do, and while other road user's inability to gauge the speed of a travelling object should not prevent me from cycling as I'd like (within the law), doing so frequently may put me at risk.

As you found out, it wasn't really safe at the speed you assumed was safe.

 

[Rolling Thunder]

We just don't have the braking power of four fat tyres....

I feel I should post that increasing the surface area in contact with the road does not increase the breaking power (unless your tires are sticky like in F1 or something)


I suspect that a bicycle would stop in a shorter distance from 30mph than a car, even in the wet.

 

[lejogger]

Not really.

When you brake you rely on the friction of your brakes to convert your kinetic energy into heat energy.
Kinetic energy is proportional to the square of your speed, so had you been travelling at 15mph rather than 30mph you would have been able to stop in 1/4 the distance. So, yes, I would not have accused you of careless riding in those circumstances.

[/size][/font][/color]As you found out, it wasn't really safe at the speed you assumed was safe.

Ok.. point taken (if your figures are correct - I'm not going to check), but what I was attempting to highlight is that whilst you should be preparing for the worst, you can't always allow for every eventuality. A car can pull out on you at any time, and at any distance from where you are. I was fortunate that I had enough time to react yesterday so I avoided a more serious incident. I wasn't tailgating or riding in an unsafe manner. I just got pulled out in front of, so regardless of the speed I was travelling at the time, there wasn't anything I could do.

There are always going to be what-ifs... what if I was travelling slower? I probably would have stopped in time. But what if I was travelling slower and the car pulled out when I was a lot closer to it? You can't predict the unpredictable, and you can't spend your life travelling at 8mph 'just in case'.

 

[Red Light]

Re. the bike. Check underneath the down tube for any creases and that the forks have not been bent. Wheels can usually survive a head on hit quite well but the forks and frame may not fare so well.

 

[vernon]

I feel I should post that increasing the surface area in contact with the road does not increase the breaking power (unless your tires are sticky like in F1 or something)


I suspect that a bicycle would stop in a shorter distance from 30mph than a car, even in the wet.

I think that you'd be surprised.

The limiting factor is not so much the tyre/road interface but the brake pad/braking surface interface. Bicycle brakes are nowhere near as powerful as servo assisted car brakes.

 

[vernon]

Ok.. point taken (if your figures are correct - I'm not going to check), but what I was attempting to highlight is that whilst you should be preparing for the worst, you can't always allow for every eventuality. A car can pull out on you at any time, and at any distance from where you are. I was fortunate that I had enough time to react yesterday so I avoided a more serious incident. I wasn't tailgating or riding in an unsafe manner. I just got pulled out in front of, so regardless of the speed I was travelling at the time, there wasn't anything I could do.

There are always going to be what-ifs... what if I was travelling slower? I probably would have stopped in time. But what if I was travelling slower and the car pulled out when I was a lot closer to it? You can't predict the unpredictable, and you can't spend your life travelling at 8mph 'just in case'.

The thing is you didn't have enough time to react. If you had, you would not have made contact with the car. The sight of any car at a junction is enough for me to exercise caution. The SMIDSY phenomenon isn't always down to driver error but sometimes down to car design with the window pillars forming blind spots. There's also a peculiar set of circumstances that render approaching vehicles 'invisible' if they fall within a specific region of the visual field. It was covered comprehensively in Bike magazine and was unchallenged by the normally vociferous motorcycle community who face the same risks as cyclists as far as SMIDSY goes.

 

[BentMikey]

I think that you'd be surprised.

The limiting factor is not so much the tyre/road interface but the brake pad/braking surface interface. Bicycle brakes are nowhere near as powerful as servo assisted car brakes.

It's possible, with poor brakes. With good brakes, the limiters are usually either the CofG/front wheel contact patch angle in the dry, or the road tyre interface in the wet. Cars win on both of those.

 

[lejogger]

I think that you'd be surprised.

The limiting factor is not so much the tyre/road interface but the brake pad/braking surface interface. Bicycle brakes are nowhere near as powerful as servo assisted car brakes.

I'm running a cyclo cross bike for commuting atm with mechanical disc brakes. The wheels stopped... the brakes weren't the problem. It was the lack of grip on the road from the tyre.

Im wearing Schwalbe Marathon 700x25 so it's not like I was on slicks either.

 

[lejogger]

The thing is you didn't have enough time to react. If you had, you would not have made contact with the car. The sight of any car at a junction is enough for me to exercise caution. The SMIDSY phenomenon isn't always down to driver error but sometimes down to car design with the window pillars forming blind spots. There's also a peculiar set of circumstances that render approaching vehicles 'invisible' if they fall within a specific region of the visual field. It was covered comprehensively in Bike magazine and was unchallenged by the normally vociferous motorcycle community who face the same risks as cyclists as far as SMIDSY goes.

Fine as a general point. But on this occasion the driver was approaching from the left at a side on 90 degree angle, so all he had to do was look out the window!

 

[Dan B]

And of course: a car with ABS can steer and brake at the same time. A cyclist, not so much.