• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Tire pressure question

Share this page

Brosky

Brosky

Great Pumpkin
Offline
Now that I've switched over to Goodyear Assurance 205/70/15 tires, I was wondering what the recommended air pressures would be for those tires. No real help from Goodyear or Sears, but I never expected any. I started at 26 front and back and the ride seems fine up front, but the back seems a little shaky over a bump compared to the old Redline Michelens (rocks) which bounced the front end over any little bumps.

By bouncing, I mean almost a shimmey or shaking affect. Not serious, just barely noticeable. I do have all new rack bushings, shocks and link kits in front, but rear is all original. Or at least it will be for the remainder of the summer. No major wear back there or leaks in the levers either.
 
Paul,
That pressure, 26 lbs, seems really low to me. I run 34 lbs in my radials. Isn't the tire pressure embossed on the sidewall somewhere?


Bill
 
Bill, the pressure listed on the sidewall is the <u>maximum</u> allowable inflation pressure.
I would think that 26 front and 28 rear would be about right for those tires on a 6.
Of course, the proper way to figure it out would be to run the same stretch of road at various pressures, and take tire temps, wouldn't it.
Jeff
 
I don't know, Paul, running tires in that mid-twenties range makes for mushy handling for me. That plus it gives uneven tire wear. I ate up a set of Pirelli P4000 tires because I kept them at about 27lbs of pressure. Too, that particular tire was not that great a tire. I got unbelieveable grip on a hot dry surface with them. Wet was another story. They were scary on wet pavement. All 7000 miles. I now have Michelin Hydroedge 205/70R15 tires and with their really square sidewalls, they don't like low air pressure. My footprint at 34 is perfectly flat. They handle very well on hot dry, brake beautifully and grip like crazy on wet roads. For my car, these are the perfect tire. A bit pricey but I feel I will get my money's worth out of them. I just changed the Michelins on my Tahoe with 110,000 miles on them and lots of tread left. I am a big fan of Michelin. I even like the French, especially their fries.



Bill
 
32 rear - 30 front is my preference but to each his own for his/her own ride comfort and ability. 26 seems a bit low to me though.

Harry,
CT
 
[ QUOTE ]
I ate up a set of Pirelli P4000 tires because I kept them at about 27lbs of pressure. Too, that particular tire was not that great a tire. I got unbelieveable grip on a hot dry surface with them. Wet was another story. They were scary on wet pavement.

[/ QUOTE ]

I had the same result with Pirelli's 35+ years ago. Sounds like nothing has changed.
 
[ QUOTE ]
[ QUOTE ]
I ate up a set of Pirelli P4000 tires because I kept them at about 27lbs of pressure. Too, that particular tire was not that great a tire. I got unbelieveable grip on a hot dry surface with them. Wet was another story. They were scary on wet pavement.

[/ QUOTE ]

I had the same result with Pirelli's 35+ years ago. Sounds like nothing has changed.

[/ QUOTE ]


Pirelli = Italian, my new fuel pump = Italian.
Oh Geez, now I am in trouble....


Taiwan and India are looking better and better.


Bill
 
Bill, the problem I had with the Pirelli's was on wet pavement. I loved the dry pavement traction and did not mind the short tread life because I have never had a performance tire that lasted very long. The only tires that seem to last is these M. Redlines that ride and perform like iron. The only reason they are still on the car is I have not got around to deciding what I want to do about them.

I never liked black walls on my TR4 and used to run very narrow white walls or white letters. I ran the same on my GT6.

But that was all just my prefrence. The kind and finish of the wheels also has a big influence on the look of the tire. As far as performance, sure I want it all but I don't drive like I once did and my tires do not have to either.
 
I agree, Tom. The Pirellis stuck like glue on hot, dry pavement and they fill the wheelwell nicely. They were suicide on wet, as you said. I personally have Panasports with the Michelin Hydroedge tires and they also fill the well nicely. The ride is adequate. These are not performance tires, as such. They are designed to go on bigger, heavier vehicles like sport utilities. But then again, performance on a TR6 means good handling, good traction and good braking. Trust me, the tires can take a lot more than my little car can dish out.


Bill
 
I am running Continental Super Contacts. 195/65R15. They do still fill the wheel wells with the lowered suspension. I use 30psi up front and 32 psi in the rear. Tire pressures can vary quite a bit depending upon how much other suspension work has been done, the types of roads you drive on and the style of driving that you do.

/ubbthreads/images/graemlins/cheers.gif /ubbthreads/images/graemlins/driving.gif
 
I have been considering three basic choices.
1) just staying with the Red Lines and original wheels in spite of the harsh ride and low performance.
2) Panasport +1's and a better tire.
3) Chrome wires and a suitable tire.

I know the Panasports would look nice and be better all around. The biggest problem is that I just love the look of wires.

I know - buy two more TR6's! /ubbthreads/images/graemlins/grin.gif
 
[ QUOTE ]

I know - buy two more TR6's! /ubbthreads/images/graemlins/grin.gif

[/ QUOTE ]

Are you still married and are you planning on staying that way?


Bill
 
[ QUOTE ]
Bill, therein lies the problem! /ubbthreads/images/graemlins/yesnod.gif

[/ QUOTE ]


My wife just inherited a bunch of property from the proverbial "rich old bachelor uncle" and I found that it will only go in her name. After 31 years, being single is looking better and better. What does this have to do with tire pressure?


Bill
 
I'm running 26 front and 28 rear on my Yokohama Avid T4's. Seem all right so far. But I must admit I'm lucky if I do 75 miles a week. It only comes out on sunny days when I'm not working. /ubbthreads/images/graemlins/cheers.gif
 
Mine is driven like Jerry's and maybe to an occasional club trip up to Maine or New Hampshire. I may bring it up to 34 on all corners and play with it from there.

I do miss the look of the redlines, but I figure that it will pass after a while of looking at these nice shiny black wide tires.

Why does the front end, which is obviously heavier with the engine, call for less air pressure than the lighter rear end? This confuses me, but then it doesn't take a whole lot to do that.
 
[ QUOTE ]
Of course, the proper way to figure it out would be to run the same stretch of road at various pressures, and take tire temps, wouldn't it. Jeff

[/ QUOTE ]

You hit the nail on the head, Jeff! /ubbthreads/images/graemlins/iagree.gif

Asking anyone what pressure they use on their car and hoping it will work on yours is really sort of hopeless.

The tires are different, the suspension is different, the load in the car and it's distribution are different. Even the driving conditions and driving style are likely quite different.

Best anyone can give you are some very general guidlines, which is actually all the original owners manual did (and that manual is woefully out-of-date with modern tire technology, so don't go by it or any label attached to the car either!)

You simply have to experiment with the pressures and find what works best for you. Even then it will be a compromise depending upon whether or not you have a passenger in the car, the specific road conditions and air temperatures, how much fuel is in the gas tank, etc.

Measuring tire temps and checking corner weights would be the most "scientific" way of adjusting, but seat-of-the-pants testing and is a lot more practical for most of us.

If the rear of the car is squirrely, raise the rear tire pressure a few pounds and see if it's more or less squirrely. Adjust accordingly. Do the same with the front.

Once you find a setup that seems to handle as well as possible for your usual driving conditions and technique, with your tires, chassis, car weight and weight distribution, etc... write it down. But, be prepared to change if different/new tires are ever installed or the suspension setup is rebuilt or changed in any significant way, or even if weights or it's distribution in the car are ever changed.

/ubbthreads/images/graemlins/cheers.gif
 
[ QUOTE ]
Why does the front end, which is obviously heavier with the engine, call for less air pressure than the lighter rear end? This confuses me, but then it doesn't take a whole lot to do that.

[/ QUOTE ]
In general, radial tires have more grip when they have more pressure. If you are trying to balance the handling so that both ends slip at the same time, the front & rear pressures need to be adjusted accordingly. If the back end tends to come around while the front end sticks, higher rear pressures will help balance the handling. Note: non radial tires as often used on race tracks don't work this way.
D
 
I usually have the rear tires inflated to the max indicated on the sidewall and the fronts about 4 pounds lower for the reason Dave states. About the last thing you need on a TR3 or TR4 is the front end getting a better grip (IMO).
 
I thought tire pressure was based on the make and model of car that you have, not the tire. My TR6 recommends 22psi front and 24psi rear. I have run these pressures for 9 years with good tire wear and performance.
 
Back
Top