Firestone Firehawk SZ50 EP RFT - What air pressure are you running ???

Hrdtop00 · 10-07-2002, 09:09 PM

What air pressure should I be running in the Firehawks for maximum wear? I had a four wheel alignment done this morning and the owner told me that I shouldn't run any less than 40 lbs. He put 45 lbs in them! So, I stopped by a local tire dealer and asked the same question. They said 40-45 lbs. Well, I've been running 30-32 lbs. cold!

kgb14 · 11-03-2002, 11:55 PM

I just got new Firestone tires for my 2001 at the local chevy dealer Friday. They put 31 pounds in. Seems like they should know the right pressure to put in, right?

Not too long ago I had a new set of tires put on my '95 Camero. They put 40 pounds in at Sears. I lowered the pressure to what the door sticker calls for - 30 lbs.

84Wolf · 11-06-2002, 02:33 PM

The maximum inflation pressure written on the sidewall of the SZ50 EP RFTs is 44psi. The '01 Corvette factory service manual states that 40lbs of pressure should not be exceeded for the Goodyear EMTs even when mounting the tire to the wheel! It states that if the bead won't seat with 40lbs of pressure or less, then the bead needs to be lubricated again. I would imagine that the Firestones are similar. I just had a set of SZ50 EP RFTs installed on my '01 Coupe yesterday and am currently running 30psi cold. My DIC displays 33psi hot. The outside temperature here in Raleigh today is in the mid to high 50's and the roads were damp from rain yesterday and last night.

I ran 28psi cold in the Goodyear EMTs during the summer, and 30psi in the winter. I was able to get 30k miles on the original tires.

[Modified by 84Wolf, 12:01 PM 11/6/2002]

NYN8IVE · 11-07-2002, 03:03 PM

Quote:

The maximum inflation pressure written on the sidewall of the SZ50 EP RFTs is 44psi. The '01 Corvette factory service manual states that 40lbs of pressure should not be exceeded for the Goodyear EMTs even when mounting the tire to the wheel! It states that if the bead won't seat with 40lbs of pressure or less, then the bead needs to be lubricated again. I would imagine that the Firestones are similar. I just had a set of SZ50 EP RFTs installed on my '01 Coupe yesterday and am currently running 30psi cold. My DIC displays 33psi hot. The outside temperature here in Raleigh today is in the mid to high 50's and the roads were damp from rain yesterday and last night.

I ran 28psi cold in the Goodyear EMTs during the summer, and 30psi in the winter. I was able to get 30k miles on the original tires.

[Modified by 84Wolf, 12:01 PM 11/6/2002]

I just ordered the same tires and also have '01 Coupe, what's your opinion so far as compared to Goodyears?

84Wolf · 11-07-2002, 09:44 PM

-NYN8IVE-

I'm sure my "seat of the pants" comparison is a bit off due to the fact that I'm currently running on the new SZ50 EP RFTs Vs. used Goodyear EMTs but I'm very pleased with the Firestones. The ride quality is superior - much quieter and less harsh, even with the Z51 suspension. The grip in the wet is better than I remember with the Goodyears when new. I haven't pushed the dry handling of the new tires yet, but almost every forum member who has made the switch reports that the dry grip is better than the Goodyear EMTs. As for the look of the tires, I like the raised rib "rim protector" in the sidewall, as well as the more aggressive tread design. Another C5 was parked next to me today at lunch, and the more rounded shoulder profile of the Firestones didn't really make the tire look narrower from behind when compared with the other C5's Goodyears. So far, I would recommend getting the SZ50 EP RFTs to anyone who wanted to keep runflat capability on their C5.

kgb14 · 11-08-2002, 12:30 AM

I like the Firestones ALOT more! My Runflats were SOOOOO noisy! Having a conversation on the highway was a challenge. The new Firestones, after a hundred miles or so are a great improvement. The tires don't follow the grooves in some of the roads like the Goodyears did, seem to handle better and have felt better in the rain. Also, my dealer recommended setting my alignment to "zero" because the old right front tire had been wearing heavy on the inside edge. So far I am very pleased.
:yesnod:

NYN8IVE · 11-10-2002, 12:07 PM

Thanks for the feedback, I had them installed yesterday morning and my initial impression echoes everyones here that they are:
Much Quieter :D
Ride Better, infact it feels like my previous car - Jaguar XJS. :D
Wet Traction is better, its been raining in SoCal this weekend. :D
By the way it took about 90 minutes to install and no problems with sensors. :D
The shop that installed them said that they inflated to 38lbs and the Max is 44.
Isn't there a source that can tell us definitively? :confused:

84Wolf · 11-12-2002, 07:23 PM

I'd wouldn't exceed 32psi cold on either the Firestone or Goodyear runflats. I think some of the tire shops are over-inflating the tires because they are not used to runflats. Remember that the runflats have stiffer sidewalls that will support the weight of the vehicle with zero air pressure. These tires don't require the same air pressure to operate as regular tires. Just compare the maximum pressure rating of these tires to the regular tires on your other vehicles and you'll see that even the maximum inflation pressures are less.

I ran 28psi cold in the Summer, and 30psi cold in the Winter in my Goodyear EMTs and got 30k miles of use. The front tires wore fairly even and the back tires wore slightly more in the center. I probably could have run less pressure in the back tires and the wear would have been more even.

NYN8IVE · 11-15-2002, 05:36 PM

I just got off the phone with Firestone Corporate and they told me to use the Vehicle Manufacturers recommended pressure of 30 lbs. The installer had them at 38lbs and with recent hot weather here they have climbed to 42 and triggered Sensor High Pressure alert. I'm gonna try 32lbs and see. :confused:

Kenny94945 · 11-21-2002, 11:37 AM

Hi co-members,
I am on the last legs of my RFT Firestones.
If I may share my thoughts.
I got 20K milegae which is standard for my driving.
As I noticed the wear pattern halfway through there life I altered the air pressure...noting how how like the car to respond.

I am now at nine pounds difference between the front and rear.
Rears at 25 psi cold. Fronts at 34 psi cold.

For me the fronts have excess center tread. The rears as the heated up the centers started to wear and therefore I continued to lower the pressure.

Also note the tire moniter system activates at low pressure of 25 pi. Simple reset w/ dash buttons.

Gearhead Jim · 11-24-2002, 10:12 PM

FWIW, the Bragg-Smith sets their Goodyear EMT's at 36 front/34 rear, COLD for track use. I keep my BFG KD's 32 front/30 rear COLD for street driving, wear seems pretty even and handling is good.