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Hydroplaning Ladies & Gentlemen, Welcome To CSA's Believe It Or Not!

True story:

While driving my 1971 Volkswagen Super Beetle (Clementine orange), driver and one passenger, ski rack on back (with skis), I made a discovery.

We were someplace in the Rockies in Colorado in the early 70’s, cruising along at probably 55 mph, heading toward a ski resort. The winter sun was shining and had dried the highway off except for a strip of melting slush a couple feet wide down the centerline. The first discovery was by accident, but we repeated the experiment several times to confirm what we were observing.

When the Super Beetle’s left tires were steered into the slush, there was a momentary “pull” and the speedometer went from 55 to zero (on the pin). I could drive normally like this at a sustained 55 mph . When I steered to the right back onto dry pavement, there was another momentary “pull” and a tire sound that was just like that of an airplane touching down … “Raaarch!”. The speedometer shot from zero to 55 mph. As stated, I repeated this several times to understand what was going on.

The bug’s speedometer cable literally goes through the left front wheel spindle and actually secures to the wheel bearing’s grease cap, visible under the hubcap. The speedometer actually indicates the “speed” the left front wheel is traveling.

When the car drove onto the slush it hydroplaned on the left side only. Since the engine is in back, the car’s front-end is relatively light and I believe just the front tire hydroplaned. The wheel must have literally stopped turning for some reason. My theory has something to do with the gushing slush and the fender deflecting back at the tire as you could hear that going on during the “zero” at 55 mph" trials. What do you think?

P.S. My friend is 6’ 3" and the Super Beetle was the most comfortable car for our annual 2,700 mile ski trip of many cars and vans of that era that we used. With only two onboard, those seats went way back and the passenger’s seat reclined.


Well, since the speedo went to zero the wheel must have stopped rotating, but I can’t explain why unless the brake was dragging. Even with limited traction on the slush you’d think the wheel would still turn at some speed above zero. Guess not.

I agree with McP. I also found the information on the speed sensor location interesting I’ll try to keep this in mind for future use. Thanks.

I say no energy transfer between road and tire due to loss of friction, The wheel is driven by the car but needs the friction of the road to make this direction of movement rotational in additional to forward.

For me when I get in one of these Bugs today I am impressed by how close the passenger and driver sit, it’s is better in the SB but almost shoulder to shoulder.

I Would Not Have Believed It Without Actually Seeing It.

It’s just one more reason to slow down in all but ideal conditions and not drive “too fast for conditions”.