General Cycling Discussion - A Physics Question

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View Full Version : A Physics Question

Prosody
12-21-03, 09:08 PM
I ask this question out of pure curiosity. In a strong crosswind, 25 to 30 mph, is a bicycle more stable at slower speeds or at faster speeds, and why?

Mtn Mike
12-21-03, 09:54 PM
I would say that a cyclist is more affected by a strong crosswind while traveling at higher speeds because the total wind resistance would be greater. You have 1) a perpendicular wind force vector, and 2) a parallel force vector both from moving forward, and from the effective forward force of the crosswind. Of course it's been a while since I've taken physics, so I might be talking out my a\$\$. :eek: But personal experience on the bike supports this, I think.

cycletourist
12-21-03, 10:19 PM
Of course in practice the biggest problem with strong crosswinds is what happens when an 18-wheeler passes and temporarily blocks the crosswind.

12-21-03, 11:39 PM
Your bicycle will be more stable at higher speeds due to a more effective gyroscopic effect of your wheels. But of course, if your riding disc wheels....forget it!....you're get blown off the road regardless of speed!

skiahh
12-22-03, 12:30 AM
Fixer's right. You can look at airplanes, too. The faster you go, the less "crab" - or angle into the wind - you need for a given crosswind component.

Dave Stohler
12-22-03, 11:04 AM
Well, I have an advanced degree (MS, mechanical engineering), but since nobody likes my posts, I can't answer your question. Sorry.

12-22-03, 11:45 AM
Gust and straight blowing makes a difference also.10mph straight blowing and then a 20 mph gust is different from a straight blowing wind.

Jonny B
12-22-03, 04:18 PM
The direction the wind is blowing would probably make a difference. If it's slightly from in front I think it'd be harder to ride, slightly from the rear would be easier (as far as front-to-back wind resistance goes anyway. Stability is another matter of which I have little knowledge).

Allister
12-22-03, 05:21 PM
Your bicycle will be more stable at higher speeds due to a more effective gyroscopic effect of your wheels. But of course, if your riding disc wheels....forget it!....you're get blown off the road regardless of speed!

Even then you can compensate to a degree by leaning into it if it's a constant wind. It's when the it's gusting that it's really dangerous. But yeah, the faster you go the more stable you'll be.

AndrewP
12-23-03, 09:24 AM
I dont think you will have any stability at 0 mph, so I would vote for more stability at high speed.

jedi_rider
12-23-03, 09:56 AM
My quick assessment: At certain high speeds, you've got wind directly in front of you and to the side. This clash of the winds may create turbulence causing instability in your steering.

Conclusion: You probably have more control at slower speeds.

Of course, I'm not sure at what speed you have to go, but if you can effectively go fast enough to create an airfoil around you sufficient enough to keep the crosswind from effecting you, then you'd be OK. I'd imagine that you'd have to be going very fast ---> faster than 50mph probably.

Disclaimer: There are those that think I'm full of of it, so take this with a large grain of salt.

lsits
12-23-03, 10:33 AM
Well, there's the actual wind direction and then there's the aparent wind direction. Say the wind is from the northeast and you're traveling north. The faster you travel the more the wind will seem to be coming from the north-northeast. I vote for more stability at higher speeds.

cycletourist
12-23-03, 10:39 AM
If it is cold outside, I vote for staying home when the wind is blowing. I am most stable when sitting on my couch :-)

12-23-03, 10:58 AM
I vote it doesnt matter because you cant stop the wind,you can only ride in it and beat it.

don d.
12-23-03, 11:41 AM
why this question was posed...

miamijim
12-29-03, 08:54 AM
Dave stolers nobody lkes your posts because most of them are like your previous post...and most of them are vague at best if not in-correct at many times.

Your more stable at faster speeds

F=MV2...the more force you have to counteract the force of the wind the more stable you'll..

I'm not an engineer but I've been riding for awhile now so what the heck do I know....

deliriou5
12-29-03, 03:19 PM
even if you're more STABLE at higher speeds (that is, the bike is less likely to get in an accident in the first place), i would choose to ride at the slower speed, because of the better reaction time, increased stopping distance, and reduced momentum in the EVENT of an accident.