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Originally Posted by El Rayo
CapriRacer, would you warn against cutting deeper threads (say 3 mm or 1/16") in a worn down (2 mm remaining) tire? ....
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Yes. In passenger car tires, there is only a little bit of rubber on top of the belts. Reducing it tends to produce cracks, which allows moisture and other contaminants into the belt, which causes corrosion, which leads to the belt coming off - ala the Firestone tires.
Quote:
Originally Posted by El Rayo
.......Cutting custom threads is customary among racers, but I don't know if they start from special, non-treaded cores. In my case the tires in question are 6.00 x 16 diagonal treaded and retreaded (I think that's the correct term) tires for my 1938 Chevrolet pickup, the pattern being simple zig-zag that's easy to cut deeper........
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Truck tires get a little more tread and are a little safer to regroove - particularly if they are designed to have this. Your retreaded tire no doubt have been retreaded with this in mind.
Quote:
Originally Posted by El Rayo
......Driving my 2000 Th!nk City EV I've found that a sudden deceleration (emergency stop, but not locking the wheels) from 80 kph/50 mph to zero followed by a relatively fast acceleration to 80 kph takes as much energy as driving 5 km/3 miles at 80 kph constant speed on level road.......
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I think what you are saying is that each time you accelerate or brake, you get the equivalent of 2½ km or 1½ miles of fuel (including how much distance you travel it takes to do that). This doesn't sound like a lot. When I drive to work, I drive 10 miles and accelerate (and stop) 5 times = 15 miles.
If I improve the weight of the tires by 50% (which is pretty much absurd), I am only improving the mass of the car around 1½%.
Quote:
Originally Posted by El Rayo
........As each wheel acts as a flywheel I would think that there is something to gain in the weight of the wheels. No rim supplier nor any tire supplier have been able or willing to give the weight of their product......
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I think you'll find that Tire Rack has the weight of every tire they sell!
Quote:
Originally Posted by El Rayo
...........My 155/70R13 Continental EcoContact summer tires are fitted to original aluminium rims and my 155/70R13 Continental WinterContact tires are fitted to original steel rims. Would you believe that the winter wheels are lighter than the summer wheels? Can the winter tires be that much lighter than the summer tires? Taking one of each apart to weigh them separately is out of the question as the work would cost as much as a new set of tires.
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I think you'll find that alloy wheels are not as light as you may think. Properly designed, a steel wheel should weigh exactly the same amount as an alloy whel. The principal is called "strength density" and for most metals, it is the same. (Carbon fiber is really good compared to most metals) The trick is to make sure the metal is being used effectively and not just occupying space - which happens a lot (and not just in wheels!)