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MG MGB Technical - Another tire question

I didn't see this mentioned in the archives. The tire pressure guide on the glovebox door says to have the tires, 165/ 14, inflated to 27 PSI front and 32 PSI rear. I am running 185/ 70 14. Should the pressure still be 27 front and 32 rear, or is it personal preference. (I usually add a couple more PSI on my other vehicles)
John (again)

John, I'm running the same tires and I run 32 psi all around.

Tommy Ducote

I used to run 28/32 on 165 and 175, but I've found on wider tires 30/30 works well for general driving.
Steve Simmons

the size of tyre does not relate to the pressure. If you look in the archives again you will see that diffrent folks have diffrent pressures to suit their driving. My advice is to playaround and find a balance.
Cecil Kimber


Wide tyres run lower slip angles but also handle power and cornering grip better than narrow tyres. All things being equal you should with a wide tyre have less power oversteer and the pressures can be balanced more evenly, but it is personal preference.


I have running 185/70 14 tires for years and have always followed the 3 psi difference (fronts 3 psi lower than rears) between front & rear. This difference has always been recommended as a starting point and has an affect on the understeer/oversteer properties of the car. My car's handling is quite neutral with the 3 psi difference and I have seen no need to change it in everyday driving.

Currently I run 29 in front and 32 in the rear.
Richard Smith 1

Richard is right on the money!
The differences in pressure affect understeer/oversteer.

Push vs. loose for us Nascar types.
I run with 30psi in front and 36 psi in the rear for autox.
Kumho Ecsta V700 tires. [185/55R14's]
Safety Fast
Dwight McCullough

BEFORE I was running 185/70 tires I was running 165's.

One of the things I noticed with the smaller tires is that if you increase the pressure beyond the recommendations in the handbook, the car would get what I call the 'basketball effect'. Felt like the two front tires were bouncing like basketballs.

This effect seems to be much mitigated with the 185/70 tires and I don't feel it at all now. For an extreme example of this effect, find a midget or a Sprite with original size tires, jack the pressures to 32 and take it for a drive. The effect (particularly on the less than pristine road surfaces that one finds in the southern U.S.) will hit you in the face.

Bottom line is that you must find the best pressures for your area that balances ride with handling. I recommend a 3 psi difference between the front and back to start. Vary the pressures in the tires while maintaining the 3 psi difference until you get the ride and handling compromise that works for you. THEN mess around with the difference between the front and back to achieve the understeer/oversteer that suits your driving style.
Richard Smith

This thread was discussed between 01/04/2005 and 05/04/2005

MG MGB Technical index

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