MGB & GT Forum

Please advise which tyre manufacturer or manufacturers issue specifications for their tyres when fitted to a 52 year old car ?

Angels dancing on pins.

MG manual says 21/24 or whatever. Then they say add 5 or 6 psi for fully loaded or high speeds. so 27/30. I reckon I can run anywhere between 21/30 and be following MGs recommendation.

The maker of my tire has a number stamped on it - probably in excess of 50 psi (I remember reading it and thinking, "that's crazy" so it is a big number) If I am below that I am complying with their recommendation.

I emailed them and they did not respond.

I have done my due diligence for some insurance company and I would love to see one case of an insurance claim denial due to tire pressure. They'd be out of business pretty lickety split I think.

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Did you really thing they would ?

To have responded with a recommendation would have potentially put them in the frame for being sued when somebody had a blowout and was looking for someone to blame !

1971 MGB roadster, 185/70-14 Michelin Defender, 27psi cold front, 32psi cold rear, air not nitrogen.

I just completed a 30 mile freeway tire tread digital probe pyrometer temperature check on a 94*F afternoon, and all four tires had equal tread temperature outside, center, and inside. Handling is neutral.

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Be safe out there.
Kenny

Just to add fuel to the fire - tyre pressures for the MG RV8 running modern low profile tyres - 22 front 24 rear..... set by Rover in the mid 90s.

The only justification for running 27 / 30 would be if you drove everywhere at 100mph - then you would be in a different sort of trouble with the law

"The only justification for running 27 / 30 would be if you drove everywhere at 100mph ......"

Is this justification? The original tire pressure door sticker on my 1971 MGB roadster.

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Be safe out there.
Kenny

Well you're not running 165/14s so forget any insurance claims - LOL...

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The goal - Reliable summer driver interspersed with mechanical tinkering...
Motto - "Driving fifty in the twisties..."
On Mods - It's your damn car - Do what you want. Haters gonna hate...
On SUVs - Drive your B like a soccer mom is texting her friends about how she wants to kill you...
Red Betty - http://www.mgexp.com/registry/GHN5UH418165
Bart - http://www.mgexp.com/registry/GHD4U146898G

Originally those manufacturer guidelines were even lower. I remember Michelin plates near pumpstations in the 70's quoting 1,5/1,7 bar as regular.
By then I had already selected 1,6/1,8 bar for city driving and 1,7/1,9 bar on holidays. In those years I dared to drive in excess of 100mph

PS These old 1,9/2,2 bar figures are very close to my present 2,0/2,2 bar for my brandnew Michelins in the175/70R14 variety

Think this says it all for handling & safety.....http://www.v8register.net/subpages/news291210tyrepressures.htm

1971 GT. 30psi front 32psi rear.

Tyres wear evenly, handling is pretty neutral tending towards understeer. Ride is firm but not uncomfortable and a lot better than many cars I've driven.

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not sure what you are saying there , but the sticker is in line with 21/24 cold normal pressure + 6 all round for max speed and +2 on the rear for max load.

So you would only use these pressure with the mother in law in the back seat / boot at 100 mph+

Nope - just gives 2 more personal preferences

The optimal tires pressure will vary depending on the tire. It take a bit of time & experimenting to find the correct pressure for the tire & type of driving.

I am currently riding on Toyo RA-1 tires. For normal street driving, 26psi all around works great. For track days, I bump it up to 30psi front & rear.

I agree with those that say the recommendations on the door jamb or in the glove box are not relevant. Go with the tire manufacturers suggestions as a starting point.

Experiment; between cold and hot, tyre pressure should rise about 4 psi; any more and cold pressure too low; any less and cold pressure too high; works on a motor cycle and I have done it on 71 MGB GT.

Wow...

Seems like all I have to do is change tire pressures and all problems are solved..or created!!

Spring rates? Shock rates? What do you think...sway bars front and rear...or...panhard rod in the rear and sway bars for IRS only...as Vic Derrington says!

Amazing discussion...I must say.