Bent Wheel Rim Puzzle

[wildbears]

Which rim is more likely to get bent?

The bike has identical rims and tires, front and back.

Weight on and tire pressure in are the same for each wheel.

Speed is constant.

You hit a 1 foot in diameter symmetrical pothole at a speed that allows each wheel to drop 2 inches into the hole..

Which rim is more likely to get bent?

[955i]

Well, I can narrow it down to a 50/50 choice easily enough! But, my experience is that it is the front wheel that gets bent. All the force goes right into the wheel. Any upward bounce or force is overwhelmed by the mass and momentum of the bike and rider. When the rear wheel hits the same bump, it has more independent up and down movement and does not have the entire mass of the bike to contend with. (On the other hand, of course, rear wheels have shorter spokes and more of them for a reason.)

[802Mike]

Read his problem again, wheels and weight are the same.

[955i]

I read it correctly. The wheels and weight can be theoretically the same in my example. I just think the front takes more of a hit because the impact has nowhere to go except into the mass of the bike and rider. The rear is carrying the same mass, but it is able to deflect the impact upward more easily.

There's been some interesting studies done on bicycle road tires how they actually behave in real world conditions. It's amazing how important it is to be able to absorb the shock of bumps, even as small of bumps as what we would consider to be merely road "chatter."

[802Mike]

The rear, because that's what happened to me once.
Maybe because power is being applied to it.

[Loggiebone]

More suspension travel to absorb the impact in front so my guess is rear

[Loggiebone]

Joe really likes the rear!

[wildbears]

Think about angle of impact....

[justjoe]

I do that all the time. I usually like my victims to be sitting in a chair with easy access to slip in behind them. That way, when I clamp the rag of love over their face, I don't have to support their weight...

Oh wait for a second, what are we talking about?

[wildbears]

The bend accurrs when the wheel hits the trailing edge of the pothole.

The angle of impact for the bike is steeper for the front wheel than the back due to the relative positions of the wheels.

Think in terms of pulling a kid's wagon up and over a curb. It's easier to get the the back wheels over once the front wheels are higher.

[955i]

It is said better here than in my answer above. But, this is what I meant.
Thanks for the puzzle, Wildbears. This was fun.

[wildbears]

I almost did a partial quote of your answer. Good thinking.

[Pete_Tallahassee]

When I think back it's been the front wheel that I have mostly dented.

[Loggiebone]

On my R/RS...I managed to trash both. Badly dented the front and broke the rear. Gotta love ATL streets!😜