New Shoes...

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mattwithcats

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Bought two new tires this weekend...

For $100 out the door, two Hercules Tour 4.0 Plus, 205/60R15 91H...
http://www.herculestire.com/tire-gallery/passenger-and-light-truck/touring/tour-40-plus/

These are "H" rated, so the pressure on the door must be adjusted...
(the OEM's were "P" speed)
29 PSI recommended pressure on the door sticker, 35 PSI max on the OEM rubber...
Hence, 29 / 35 equal .83 inflation percentage...
These are 44 PSI max, so 44 times .83 equals 37 PSI adjusted...
 
Last edited:
Originally Posted By: mattwithcats
Bought two new tires this weekend...

For $100 out the door, two Hercules Tour 4.0 Plus, 205/60R15 91H...
http://www.herculestire.com/tire-gallery/passenger-and-light-truck/touring/tour-40-plus/

These are "H" rated, so the pressure on the door must be adjusted...
(the OEM's were "P" speed)
29 PSI recommended pressure on the door sticker, 35 PSI max on the OEM rubber...
Hence, 29 / 35 equal .83 inflation percentage...
These are 44 PSI max, so 44 times .83 equals 37 PSI adjusted...


Why did you come up with that?
And are the new tires up front and if so, how are the rear tires?
 
Read are year old General Altimax HP,
with 51 PSI max...

Pressure is adjusted for them too...

Sidewall is stiffer in "H" rated,
if I ran door sticker pressure,
the sidewall would flex too much,
generating excessive heat...
 
Hello, For a while now, say 25 years, I've noticed that my tires will wear on the sides if I don't keep 'em around 36-38psi.
My tires have been wearing evenly and I like the slight amount of bulge.

I also like the formula the OP used. I don't know if his parameterization is correct.
Using some result as a factor on another tire's MAX pressure figure is questionable.
But hey, if you get a number less than 40, how bad can it be? Kira
 
Originally Posted By: mattwithcats
Bought two new tires this weekend...

For $100 out the door, two Hercules Tour 4.0 Plus, 205/60R15 91H...
http://www.herculestire.com/tire-gallery/passenger-and-light-truck/touring/tour-40-plus/

These are "H" rated, so the pressure on the door must be adjusted...
(the OEM's were "P" speed)
29 PSI recommended pressure on the door sticker, 35 PSI max on the OEM rubber...
Hence, 29 / 35 equal .83 inflation percentage...
These are 44 PSI max, so 44 times .83 equals 37 PSI adjusted...


Sorry. That's entirely wrong.

Long version: Barry's Tire Tech - Load Tables

Short version: Speed rating does not affect the pressure specification on the vehicle tire placard (the sticker on the doorframe), nor does the maximum pressure listed on the sidewall of the tire. Use the same pressure as before.
 
Last edited:
Originally Posted By: mattwithcats
These are "H" rated, so the pressure on the door must be adjusted...

Huh?

Quote:
(the OEM's were "P" speed)

Never heard of "P" speed rated tires before.
 
I feel the pressure that's stated on the door jamb of a car or truck, are for the tires that came with the vehicle when new. If your replacement tires have different pressure ratings, I would go with whats on the new tires not the door jamb. Otherwise there wouldn't be any pressure requirement statement on replacement tires.,,
 
Originally Posted By: Quattro Pete
Originally Posted By: mattwithcats
These are "H" rated, so the pressure on the door must be adjusted...

Huh?

Quote:
(the OEM's were "P" speed)

Never heard of "P" speed rated tires before.


Never knew there a P rating either!

L 75 mph 120 km/h Off-Road & Light Truck Tires
M 81 mph 130 km/h Temporary Spare Tires
N 87 mph 140km/h
P 93 mph 150 km/h
Q 99 mph 160 km/h Studless & Studdable Winter Tires
R 106 mph 170 km/h H.D. Light Truck Tires
S 112 mph 180 km/h Family Sedans & Vans
T 118 mph 190 km/h Family Sedans & Vans
U 124 mph 200 km/h
H 130 mph 210 km/h Sport Sedans & Coupes
V 149 mph 240 km/h Sport Sedans, Coupes & Sports Cars
 
Last edited:
Originally Posted By: CapriRacer
Originally Posted By: mattwithcats
Bought two new tires this weekend...

For $100 out the door, two Hercules Tour 4.0 Plus, 205/60R15 91H...
http://www.herculestire.com/tire-gallery/passenger-and-light-truck/touring/tour-40-plus/

These are "H" rated, so the pressure on the door must be adjusted...
(the OEM's were "P" speed)
29 PSI recommended pressure on the door sticker, 35 PSI max on the OEM rubber...
Hence, 29 / 35 equal .83 inflation percentage...
These are 44 PSI max, so 44 times .83 equals 37 PSI adjusted...


Sorry. That's entirely wrong.

Long version: Barry's Tire Tech - Load Tables

Short version: Speed rating does not affect the pressure specification on the vehicle tire placard (the sticker on the doorframe), nor does the maximum pressure listed on the sidewall of the tire. Use the same pressure as before.
This ^. BTW from which Chinese province do those tires emanate?
 
Findlay, Ohio...

Hercules is a subsidiary of Cooper Tires...

https://en.m.wikipedia.org/wiki/Cooper_Tire_%26_Rubber_Company
 
Last edited:
Originally Posted By: mattwithcats
(the OEM's were "P" speed)

Is this for your Smart? If so, according to TR, the OE tires were "T" speed rated.

BTW, how did you manage to mount 205/60R15 tires on it anyway?
smile.gif
 
Like stated before, speed rating has nothing to do with the correct tire pressure that should be used per door placard. The replacement tires you put on have a higher load index by 3 ranges over stock. If you are trying to re-invent your car by guessing at the correct pressure, you would actually need less pressure, not more by going to a higher LOAD rated tire. Just set them at 30psi and forget about it.
 
OE ratings are for OE tires. I like to adjust them as they wear. Usually a few psi higher in front than the rear. On my winter tires the pressure is about 10 psi over what the door placard says.
 
Originally Posted By: BigCahuna
I feel the pressure that's stated on the door jamb of a car or truck, are for the tires that came with the vehicle when new. If your replacement tires have different pressure ratings, I would go with whats on the new tires not the door jamb. Otherwise there wouldn't be any pressure requirement statement on replacement tires.,,


There AREN'T any pressure requirement statements on replacement tires. In fact, if you contact any tire manufacturer, they'll recommend that you use the vehicle manufacturer recommends.

http://www.michelinman.com/US/en/safe-driving/tire-safety/tire-pressure.html

Item number 4: "Compare the measured psi to the psi found on the sticker inside the driver’s door of your vehicle or in owner’s manual. DO NOT compare to the psi on your tire’s sidewall."

They state specifically to NOT inflate to what's on the sidewall of the tire. That is the pressure at which the tire can carry its rated load. It, in no way, is a recommended inflation by the tire manufacturer.
 
Originally Posted By: CapriRacer
Originally Posted By: mattwithcats
Bought two new tires this weekend...

For $100 out the door, two Hercules Tour 4.0 Plus, 205/60R15 91H...
http://www.herculestire.com/tire-gallery/passenger-and-light-truck/touring/tour-40-plus/

These are "H" rated, so the pressure on the door must be adjusted...
(the OEM's were "P" speed)
29 PSI recommended pressure on the door sticker, 35 PSI max on the OEM rubber...
Hence, 29 / 35 equal .83 inflation percentage...
These are 44 PSI max, so 44 times .83 equals 37 PSI adjusted...


Sorry. That's entirely wrong.

Long version: Barry's Tire Tech - Load Tables

Short version: Speed rating does not affect the pressure specification on the vehicle tire placard (the sticker on the doorframe), nor does the maximum pressure listed on the sidewall of the tire. Use the same pressure as before.


Matt - Please go read through the links that CapriRacer provided.

You're misreading Tire Rack's information, you're confused about speed ratings, load, pressures, and now, you're choosing to argue with and try to correct the board's resident tire engineer and expert on this...
 
Originally Posted By: Hokiefyd
There AREN'T any pressure requirement statements on replacement tires. In fact, if you contact any tire manufacturer, they'll recommend that you use the vehicle manufacturer recommends.

http://www.michelinman.com/US/en/safe-driving/tire-safety/tire-pressure.html

Item number 4: "Compare the measured psi to the psi found on the sticker inside the driver’s door of your vehicle or in owner’s manual. DO NOT compare to the psi on your tire’s sidewall."

Agreed.

Quote:
They state specifically to NOT inflate to what's on the sidewall of the tire. That is the pressure at which the tire can carry its rated load.

Not necessarily. Often times what's noted on the tire is the max cold inflation pressure and is not the same as the pressure at which the tire is rated for max load.

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=21
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=196
 
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