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GREAT SCOTT! :twisted:

I thought the top speed was clamped to 81 mph. We'll have to see what the new electric DeLorean can do.

http://delorean.com/2011/10/electric-delorean/
 
Me too, 132 was the max even if I did not insist. The car can probably go faster if the gear ratio was a little longer or if it had more than one gear. But there again, would you feel entirely safe at 150 or so ?
 
Having been "forced" to drive at pretty much my car's limit in the HOV lane in rush-hour traffic a few times, I've had absolutely no issue with the iMiEV's stability or handling - recall, I'm also running 60psi in my tires.
 
60psi, are you noticing any benefit, i do not have the exact stock value in mind but 60 seems a lot more than stock? If so, are you measuring an increase wear in the center of the tire ?

Thanks
 
Llecentaur said:
60psi, are you noticing any benefit, i do not have the exact stock value in mind but 60 seems a lot more than stock? If so, are you measuring an increase wear in the center of the tire ? Thanks
60psi = 413.7kPa, whereas the Mitsubishi-recommended pressure is 36psi = 250kPa

The benefits I subjectively notice are improved handling (I live up a twisty windy road) and a significant energy consumption decrease. I have been running 60psi in my Gen1 Honda Insight for 8 years - when I replaced its special LRR Potenza RE92 tires at 70,000 miles (112654km) there was still plenty of tread left (it is a light car) and it was very even treadwear - I replaced the tires simply due to their age and not treadwear. Depending upon the type of tire - (for example, the old bias-ply tires) overinflation could result in excessive center tread wear.

The negative is, of course, a harder ride which is especially noticeable when one hits a pothole. :cry: Whether it has any relationship to the tire pressures I don't know, but when going around a corner even moderately fast on a bumpy road the iMiEV ASC kicks in very unexpectedly.

Disclaimer: I run 60psi and am comfortable with this, but I am not recommending for anyone to exceed the manufacturer's specifications. Note that maximum pressure listed on the sidewall of our tires is 50psi (345kPa)
 
Joe,

I don't see how such high pressures could possibly improve handling - Higher pressures reduce the sidewall flex which also reduces contact patch and that reduces the friction with the road surface - Less friction there means the tire loses traction sooner than if you were using the recommended pressure. I suppose you could be getting a percent or two greater range due to the decreased rolling resistance, but I'd bet any improvement is too small to measure

If extreme tire pressures were better for handling, all racecars would be doing this . . . . but they're not. They all run pressures much lower than the manufacturers maximum. (NASCAR cars leave the pits with cold pressures in the low teens) The long established method for determining the best pressures for handling is to chalk all the tread from sidewall to sidewall and then keep adding pressure gradually until the tire no longer rolls the edge of the tread when cornering hard - In other words, the lowest pressure which keeps you from rolling over on the sidewall is the best pressure for handling. If you're a driver who corners hard, then you'll need two or three more pounds than someone who doesn't drive as hard as you do

Good on you for not recommending anyone else try pressures higher than the maximum recommended by the tire manufacturer - Running pressures so high that the sidewalls cannot flex in a pothole is certainly one way to ruin a tire by damaging the tread plies. They do publish a max pressure and mold it into the tire sidewall for a reason

That said, my experience is that almost all vehicle manufacturers recommend pressures on the low side of optimum (I'd imagine this is so you'll be happy with the cushy ride) so I always run my tires harder than the vehicle manufacturer recommends. Great handling is why I bought my Miata and I've found that 32 to 34 PSI works best for handling when I drive it hard . . . . as in occasionally sliding all 4 tires in a corner hard :D Mazda recommends a ridiculously low 26 PSI

With my iMiEV, I use 45 PSI while Mitsu recommends 36. Personally, I would never go higher than the max rating molded into the tire - There's nothing to be gained and it could result in a damaged tire

Don
 
Don, I defer to your experience in the handling department - perhaps the liveliness I feel in my iMiEV is simply due to the minimal contact patch :roll: , yet I consider the iMiEV very stable at speed. However, when it comes to mileage gain, I believe there were a number of tests which showed a significant improvement at higher tire pressures. For example, I briefly looked at EcoModder and they repeated the Mythbusters results as being a 7.6% reduction in fuel consumption in going from 35psi to 60psi:

http://ecomodder.com/forum/showthread.php/mythbusters-tests-tyre-tire-pressure-17151.html

Translate that 7.6% into a range increase and that gives us close to five more miles of range for the iMiEV.

My Gen1 Honda Insight lifetime of over 77mpg isn't only due to featherfooting. :geek:

Nevertheless, as you pointed out, we don't want anyone to treat this as a recommendation to exceed the manufacturer's tire pressures, which are posted on the driver's - side door.
 
emissionimpossible said:
I don't know how to post pics, but I'll give it a try...My bumper sticker:
427891_10151246608595289_360124799_n.jpg
Thank you for posting. Very creative, I thought! :cool:

To post the picture, you highlight the link and click on "Img" in the edit menu.
 
JoeS said:
Don, I defer to your experience in the handling department - perhaps the liveliness I feel in my iMiEV is simply due to the minimal contact patch :roll: , yet I consider the iMiEV very stable at speed. However, when it comes to mileage gain, I believe there were a number of tests which showed a significant improvement at higher tire pressures. For example, I briefly looked at EcoModder and they repeated the Mythbusters results as being a 7.6% reduction in fuel consumption in going from 35psi to 60psi:

http://ecomodder.com/forum/showthread.php/mythbusters-tests-tyre-tire-pressure-17151.html
Your link was to a test with a car using 'normal' tires - I would expect the benefits of overinflating LRR tires to be much less. Even so, the benefit of 60 PSI vs 40 PSI was only 1.4% and I'll bet the difference between your 60 and my 45 with our LRR tires is well less than 1% . . . . way too little to be able to measure and next to no gain achieved by going beyond what the tire manufacturer considers safe

Don
 
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