Thread: Donut tires
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Old 01-17-2011, 06:43 PM   #9 (permalink)
rmay635703
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Quote:
Originally Posted by Frank Lee View Post
What gain? I'm totally not buying it.
Quote:
Originally Posted by Ryan May
So for the rear of your car just keeping lots of air in the tires will do almost exactly what donut spares do, if you downsize remember that your car has to be light enough on the backside for the tire or you won't really gain anything and might loose. I would actually weigh the back half and see what they are at if you want to test skinny small tires on the back and make sure you aren't getting too far into the weight rating on little tires.
I don't really buy the gain in the video either, obviously if your odometer is messed up by the tires you can see all sorts of amazing gains.

Donut spares on my C-car yielded a max range of 50 miles, of coarse I was running 72v but it was a relatively impressive number I'm told. I could coast on flat smooth pavement upwards of 2 miles.

Is the potential gain really worth messing up your speedo and driving on hard rubber tires though?

The only way the donut spares will gain you is if the tires are WAY overrated for the weight you put on them, if your paticular car is even 1/3 of the weight rating of the donut spares expect
NO GAIN and very poor wear and life.

Quote:
Originally Posted by euromodder View Post
My temporary spare is only 135 wide.

Don't use temporary spares permanently, they're not designed for it.

They'll easily take more than the 50mph / 50 miles labels on them, but they result in serious problems regarding handling and braking.
Especially in the wet, they quickly get skittish .
I agree with most of that, but like any tire they can last a long time if they are used at a light enough weight. On my C-car some of the donut spares lasted over 10 years, although admittedly I could never break 55mph on flat ground. The donuts are rated at the speed and mileage at their weight limit, many are rated at over 2000lbs EACH, obviously if you run MUCH MUCH less weight than that they can be driven faster (they usually need balancing though) (the rating is based on max weight and speed that causes overheating and failure)

I found them to be VERY sturdy built tires, even fully deflated they looked like they had air in them and even with severe weather checking they lasted and lasted until I finally got a slow leak in 1st one than another. Between me and the previous owners we had over 8k on the tires, some have over 10k now. Which is fairly impressive for a tempory spare that I can buy for $5 with a rim at the junkyard. Most are 3 ply all around like old balloon tires solid nylon core from sidewall to the tread, all one material, very strong, very stiff, very bumpy.

Cheers
Ryan
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