It was a dark and stormy night . . .

Ok, more details:

• Former front tires, Sumitomo T4s, 51 psi max sidewall
• Front tires replace by rear Sumitomo T4s with 5/32" remaining
  • Part of this test was to NOT rotate tires so the front would wear out first
  • It worked as I have a year or so remaining on the now, front Sumitomo T4s
• Replaced with Yokohamas, 51 psi max sidewall (51 psi Sumitomo T4s no longer available)
  • Firestone mounted and deflated to door jam pressure, 32-35 psi
  • Yokohamas are on the rear wheels per Firestone recommendation
  • 37F, last night, got barely 50 MPG on 32-35 psi, over 5+ miles @50 mph
    
  • 37F, this morning, got 63 MPG on 45-48 psi, over same 5+ miles @50 mph
    • because of cold and time, did not fully inflate tires
• looking at having a lug-nut welded onto scissor jack and an electric drill
  • compact, see 'trailer stabilizing systems'
    
  • electric drill handles both scissors and wheel lug nuts
    • both cars have 1 kW, inverter
    • have not selected the electric drill, yet

I agree that the scissors jack 'crank' is the weak part of the design. It has too much slop and not enough leverage. But with a welded lug-nut on the worm-screw and a strong electric drill, it should be no problem. I may need a U-joint to the socket. FYI, I've got a nice, electric hammer drill used to build the wheel-chair ramp for the wife. Worse comes to worse, use the lug wrench to crank it up and down but a long-handled ratchet would work too.

Overall, I'm happy with this approach. The two new tires were half the cost of four. It also lets me roll-in a new brand of tires and not risk a whole lot if they don't work out.

Bob Wilson

ps. I'm more interested in high pressure tires over low-rolling resistance at lower pressure. Now if we're talking 45 vs 51 psi, well that is perhaps negotiable. But I really am a fan of hard tires for low rolling resistance . . . the physics are inescapable.