Tyre Pressures

[terry]

Can anyone help with tyre pressures on my 4. Its a 1989, Spanish registered, left hand drive, 1100cc running on 135 by 13 tyres. I do not have an owners handbook and my Haynes manual does not give any information on pressures. What pressures should I use for everyday use?

Thanks Terry

 

[benchseat]

The owner’s manual for the GTL specifies front 20 psi (1.4 bar) front, 24.5 psi (1.7 bar) rear for everyday, or 22/1.5 and 26/1.8 for motorways.
I have to say that, to me at least, this sounds impossibly soggy and could possibly lead to problems of rim sealing if you are running on tubeless rims, which presumably you are with a 1989 vehicle (my owners’ manual dates from 1978). I always use 27 (front) / 30 (rear) which is the level that most modern cars seem to run on. This gives an adequately comfortable ride and improves fuel consumption, although I am aware that higher pressure will compromise roadholding to some extent.
The Haynes manual, as you say, does not specify anything apart from ‘refer to specific tyre manufacturer’s recommendations’. Which might be worth doing.

 

[jjad]

On our 1990 GTL (with 135R13 tyres), I pump them up to about 26psi all round, as advised by Derek of Renospeed.

Others on here use 28psi.

 

[malcolm]

I've standardised at 30psi for all my cars. That what they can lose a bit of air and still be at the right pressure.

Modern tyres tend to have softer sidewalls so tyre pressures should be higher than the original manual figure. 28 is probably about right.

 

[terry]

Thanks very much everyone for your help.

Terry

 

[AdamWilkes]

Just be aware of the tread wear pattern over a longer term; assuming wheel alignment and suspension are ok, excess wear in the middle of the tyre can indicate over-inflation and excess wear on both outer edges can indicate under-inflation. Crazy driving can also wear tyres out in unusual ways

 

[angel]

I inflate them to 23-24 psi front and 26-27 back. The only issue I had was inner tubes going flat randomly, due to the fact that modern tyres are not built for them and are rough inside. After going tubeless and still running the same pressures, no more problems.
R4s are lightweight and have narrow tyres, they need lower pressures than modern cars so that tyres get warmed up quickly and work as they should.