Goodyear Tripletreads

[bernzx]

I just had GY TripleTreads 195/60x15 installed and they are a vast improvement over the GY Integrities. The dealer set the tire pressure at 35psi and I thought I would ask for advise before I raised the tire pressure. Any suggestion would be apperciated. Also the rev per mile on the stock tire are 850.2 vs. 859.15 for the new and 70mph is now approx 69.26mph. Is there any way to make a correction to the speedometer?
Bernzx
2005 Super White Prius
Vancouver,WA

[tumbleweed]

I just checked the tire rack site and they list the OEM Integrities size 185/65-15 at 855 rev/mile and the TripleTread size 195/60-15 at 863 rev/mile. Did you get your numbers from the Goodyear dealer? If so I wonder why the difference. Anyway the difference is still only about 1% so if your consumption screen says 50 mpg it would actually be 49.5. But frankly I doubt it's that accurate anyway. You could check the speedometer with a digital watch using the speedometer check things on the highway. But when you are going an indicated 60 mph, for example, that means somewhere between 59.5 and 60.5 anyway.

Tire pressures, well I know from my own experience that higher pressure means improved mileage. I keep mine at 42 psi all around, I can't tell the difference when the back ones are 2 lbs less but lots of people like them that way so that's OK too. I think tests have indicated that higher pressure means the tires can run a little faster without hydroplaning. But those same higher pressures (40 to 44 lbs say) may also mean a slight increase in stopping distance and a slight decrease in maximum cornering power simply because the contact patch is a little smaller.