I know this has been talked about but just wanted to say WOW what an improvement! Put 234/45-18 Potenza on the front and 345/35-19 Potenza on the back. Better ride, grip and noise. Used stock BBS rims.
Derry
Derry
Very happy with Bridgestone tires
- Thread starter Derry
- Start date
2112
Blue/white 06'
H
HHGT
Guest
Been using them for a while and could not agree more. :thumbsup:thumbsup Also the road noise is gone away
Have not measured any speedo difference yet but the dia. change is about a quarter of an inch in the rear only. Given normal wear allowed I cannot believe it will be much. I will check though.
PL510*Jeff
Well-known member
not really. The rev's per mile are within 10 per Bridgestone tech page.
If you want it to be perfect, there's adjustments that can be made with SCT tunner or by Ford tech to stock ecu.
I did not use the 265 only because they are .5 inches smaller in diameter and I wanted to stay as close to stock heights as I could especially in the front, Buffalo Ny has some nasty road holes in spots.
FENZO
GT Owner
Probably a more experienced GT person could explain better... but, when I installed the FRPP pulley/tune on my '05 the pro-cal tool said my "revolutions per mile" was set at 712. I checked the # just to be sure. The Goodyear rears (315/40-19) rev/mi is 697 and the Bridgestone rears (345/35-19) rev/mi is 707. IF it is common for the stock setting to be at 712, you are in fact closer to actual with the Bridgestones without changing a thing.
Calculator: http://www.gtsparkplugs.com/TireCalculator.html
Calculator: http://www.gtsparkplugs.com/TireCalculator.html
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Fubar
Totally ****** Up
My vBox agrees with this statement. The bridgestones are extremely close to actual speed. Within +/- 2mph at 100mph
tpraceman
THEE GT OWNER
Derry, I am just happy to see you post old boy. Glad your still driving the GT.
Did you have any problems getting the lug nuts off?:rofl
Did you have any problems getting the lug nuts off?:rofl
centerpunch
ex-GT owner x2
Exact tire sizes vary by manufacturer and model. That online calculator is a good approximation, but the actual sizes are different.
According to the specs at TireRack:
Goodyear 315-40-19: 722 r/mile
Bridgestone 345-35-19: 728 r/mile
FENZO
GT Owner
That is a good point, the calculator uses the theoretical rev/mi from the eqn:
rev/mi = 63360[in/mi]/((((Width[mm])(AR/100)(2))/25.4[mm/in])+Dia[in])*pi) - which is basically mile/circumference.
It is interesting that the pro-cal instructions specified the use of the calculated value vs. actuals. The calculated value does not take into consideration the actual tire size or the reduction in overall diameter from the contact patch, which explains the higher actuals. I would have thought that the difference in the speedo/odo would be negligible, but I paced the GT against our '08 BMW (accurate??) and I was reading about 5mph lower. That probably explains why I got a 10 mph over speeding ticket when I knew I was only about 5 over on the speedo. I thought the LEO was full of sh!t:bored, maybe not.:biggrin
centerpunch
ex-GT owner x2
A GPS navigator, even a cheapo one, is a pretty accurate way to measure steady-state speed and check your car's speedometer.
Of course, a VBOX is even better. (It calculates the speed using a different method).
Of course, a VBOX is even better. (It calculates the speed using a different method).
I just leave my 9500ix in the speed readout mode, which works pretty well too. Looks like the 4th screen layout below all the time unless radar hits you then it switches over to the bar graph. It uses the detectors built in gps, I would guess it is fairly accurate.
