TA 'B. F. Goodrich' - tyre pressure??

[BMK]

What tyre pressure should I run in the TA radials B. F. Goodrich.

On 15"x8" and 15" x 10".



Currently at 26psi should I drop to 22psi.

Cheers

Bernie



Bernie Knight
Mt. Gambier South Australia

[REDSC400]

Hi Bernie:
I have Goodrich Eruo's (like the TA but much higher speed rating I think?? now no longer available sadly) on my Cobra.

I am currently running 21 Lbs air in the front and 22 Lbs air in the rear for normal street use (Cruising).

When I was at a higher air pressure, I found the ride quality too "hard" and too much feedback was transmitted to the steering wheel and arse.

The softer tire pressue has provided a nice ride quality.

Now, if you are using your car for other than general cruising, your tire pressure may need to be higher. I have read some old road test reports in which tire pressures (low) were the culprit in squirrely and squirmy handling on original Cobras.

I would be be very interested in the feedback from others as I am new to the Cobra.

Cheers.

[jayscobras]

LOWER PRESSURES ARE FINE FOR STREET DRIVING.

BOTH PETE TORK AND I RUN THOSE TIRES IN STREET CLASS AND WE BOTH RUN THE SAME PRESSURES ON THE TRACK.

26PSI ON THE FRONT AND 28 ON THE BACK. THAT IS ASSSUMING YO HAVE 295-50 ON THE REAR OR 275'S.

AT THE STRIP I DROP TO 22 AND DON'T KNOW WHAT PETE DOES. HIS CAR IS TOP END POWER AND HE DOESN'T SPIN MUCH OFF OF THE LINE.

JAY

[BMK]

Hi Jay

now over the jet lag.

Thanks for the feedback..

I have been looking for another shirt for you and will send it to you when I get your return address. Hav't received the envelope yet.



Art, thanks for the road feedback. The wheels came in straight from the tyre fitter and they are at the higher pressure of 28psi.

I will use your pressure as a start figure as I am using the car for general cruising at the moment.

I had the tyre pressure, suspension settings, firing order etc. for my first Cobra written on the wall of the garage and and sincve sold the Cobra and house.

As suggested will start at your two and report back.

The ' QA1 ' coil overs have a number of adjustments and this will be a trial and error situation as most of these setups are used by drag racers as they are a popular choice.

Once I get some in car feedback on the tyre pressure I will start to play here.

Thanks again guys. Much appreciated.

Bernie

Bernie Knight
Mt. Gambier South Australia.

[Bob In Ct]

Superformance recommends 18 PSI for street driving.

Bob

[BB427]

I run 24 lbs in front and 22 in rear with a big block

Brent

[REDSC400]

Originally posted by Bob In Ct


Superformance recommends 18 PSI for street driving.

Bob

Bob:
Is that what you are running? I remember you saying you had 305-50-15s in the rear and 285's up front?

Are those what you are running now and at 18 PSI?

[BMK]

Thanks again

I may also go as low as the 18psi and see what I think.

Have gone 21psi front and 22psi back. Drove over to a race exhaust place in Warrnambool Victoria, about 400 km round trip and it did feel better.



Less jumpy on the rough undulating bitumen and it felt more responsive through the steering (read novice driver).

Will keep experimenting.

Thanks all

Bernie

Bernie Knight
Mt. Gambier South Australia

[REDSC400]

Bernie:

Yah, experimentation is the key here. The thing we have to watch is the concavity or convexity of the tread due to low or high PSI pressure. This could cause long life wear problems however, not too many of us seem to care about tire tread life (LOL).

What tire brand are you running and are your shocks/coil overs adjustable in any way? This also is a factor in ride.

I am running 265-50-15 in the front and 305-50-15 in the rear on Halibrand pin drives.

Even though I say the drive quality is "soft" that still has to be couched with the fact that if I drive over a leaf laying on the road I still know it. I mean the ride is firm for sure just not jarring.

If you find a real large parking lot that is vacant (and near some air pump) you may be able to do some informal skid pad work and quickly get dialed in for cornering pressures. That is a good way to find out when the rear breaks and what the car's characteristics are when you take your foot off the gas when cornering fast. (caution with that BTW).

Also, what engine do you have? A big block or small block?

At times, I wish I had a "virtual" Cobra to drive where I can reconfigure it with different brands of tires, rear drive ratio gears, cam, carbs, trannies, shock settings, springs, gas payloads, etc.

Those are a lot of variables which I would LOVE to play around with.

Cheers Bern.

[BMK]

Thanks there Art,

I am running the 'QA 1' coil over shockers and a spring set up off the shelf. They are an aluminium full adjustable.

I have a 9" rear end set up with four bars.

The guys at McDonald Bros Racing primarily build race cars and drag cars, but have not had a lot of experience with Cobras.

Whilst we are happy with the shocker set up. The tyre pressures was the first stop. From there I will start playing with shocker adjustments they are currently set on 4 with an adition 15 adjustments.

Additionally I can then wind up the springs. So theres plenty of experiment and 'R+D' ahead.

I have 15' rims the alloy halibrand style.

8" front with 235/60 and 10" back with 295/50 B F Goodrich T/a radial.

Once I get the tyre pressures right I can then experiment with settings.



Hell I am enjoying driving the car around. Its still in white Gel coat but all complete. I have a little interior aluminium work to do to complete the car then I will paint it in early 2004.




I have my photos on a disc now but will take my laptop to one of our posting experts to put some pictures on.

Talk soon. Again thanks for your help.

Bernie



Bernie Knight
Mt. Gambier South Australia

[Bob In Ct]

Hey Art:
I'm running 245/60-15 in front and 275/60-15 in back. I run 18PSI all around. There is a lot of air (volume) in those tires, 18PSI is plenty.

I grew-up in farm country, most tractors have about 5PSI in the back tires. When you have a lot of square inches of surface you don't need a lot of pressure. I run 100PSI in my little bitty bike tires.

Bob

[REDSC400]

Hi Bob:
Yah, you are right. Plus the fact that you are running 60s means you have even alot more air volumn. So your 275-60-15 are in the 28" tall range and the 245-60-15 are in the 26.6" range? They must fill up the wheel wells nice, eh? You told me once you had 305's in the back at one time right?

Are those Goodrich T/A's you are running now?, (I think thats what I saw on your car in Lyme Rock) or Dunlops or Yoko's?

Do you know about those McCreary tires? In searching the web, that company seems to have two major divisions, one primarily devoted to aircraft tires and the other a specialty tire division. The Road Star appears to be an auto racing tire but I have not seen it in any catalog nor can I find it on the web (I have not tried too much however). I wonder if they are Tube tires. Alot of the Hoosiers are tube tires, and frankly, I do not want to get into that tube stuff again if I can help it.

[Bob In Ct]

Hey Art:
The car came with 305/50s on the back. I put on the 60s. They're T/As. I'd love to get a Kevlar belted tire.

Bob

[BMK]

Hi guys



Thanks for the feedback and discussion. I will go to 18psi on the front and back and see what happens with ride and wear.

The boys at McDonald's Bros, Racing have some ideas for the QA1 settings also, so should end up with a good set up.

Thanks again. Will give you some feedback later

Bernie

Bernie Knight
Mt. Gambier South Australia.