Winter Tyres and pressures

[belsbus]

Hi,

Have had some winter tyres fitted about a month ago, when I checked the pressures they were all around 31 PSi (done by the fitter who was one of those guys who turns up with a van and does it for you....nice!

Any way, I checked them today and they were a bit low 27 to 29 . Is 31 correct?? I know that the advice is different pressures for front and back but is that when you have different size tyres?? Mine are all the same size and I have a tin top that has had a push up roof put on it.

Any ideas??

Thanks
Bel

[francophile1947]

What size tyres are they?
I would expect pressures of about 35psi, but with non-standard tyres, it's more a question of seeing what feels best when driving.

[belsbus]

Hi John,

Thanks for replying. They are Cooper weather master 215/65 R15

I must admit they look a bit low at 31!

Shall I give them a bit of a pump up??

Thanks

Bel

[francophile1947]

I would I run mine at 40psi, but they are larger tyres than yours.

[scanner]

I run 215/65-16s at about 36psi.
31 is a bit low for any car these days, most run @ 32-36 minimum and a Bongo is on the heavy side anyway.

[mikexgough]

40 psi on my 17's...

[belsbus]

OK, looks like a bit of pumping is required!

Thanks

Bel

[Ron Miel]

OK, looks like a bit of pumping is required!

Thanks

Bel

Don't overdo it. John's right - a bit of testing at different pressures is the best way to decide. With 15s, you shouldn't need to go too high all round, if my experience is any guide.

When we first got our Bongo, with 215/70/R15* Japanese Dunlop RV502 "occasional off road" reinforced tyres already fitted all round, and a heavy new camper conversion, I found it quite skittish if I followed the high pressure all-round recommendations then very common on the forum. So, I did a lot of careful road testing and concluded that steering, road holding, traction, ride comfort, and (as since proved) likely tyre life was probably best at 28 psi front/36 psi rear.

Have run at those pressures ever since, including with Vredestein Quatrac 2, M+S, tyres fitted two years ago. Never a moment's misgiving at those pressures, quiet and comfortable ride, no uneven tyre wear, no punctures, and tyres lasting very well. The tyres do not look soft but only (slightly) "loaded", which of course they are, and are designed to appear, thus giving good traction/braking. They do not run hot, summer or winter and at all speeds up to the limit.

Can't speak for low profiles, 195s on the front, or cheaper tyres same size as mine, but suspect that some of the low profiles in particular may produce such an altered Bongo set up, that higher pressures might well then be better.

Suspension suffers, as does your bottom, if you run tyres harder than is really necessary

*(That, slightly bigger tyre than on most Bongos, is the Mazda-prescribed fit for the rear wheels on our 2WD SG5W AFT, cold weather spec Bongo. Have never really worked out why but it's probably a function of the heavier cold weather ones, with dual batteries, etc. post 1999 "new shape". Already changed to that fit all-round, in Japan, I've left it that way, as it also gives a greater choice of fully matched tyre brand all round, in the UK market.)

[skater]

OK, looks like a bit of pumping is required!

Thanks

Bel

Don't overdo it. John's right - a bit of testing at different pressures is the best way to decide. With 15s, you shouldn't need to go too high all round, if my experience is any guide.
So, I did a lot of careful road testing and concluded that steering, road holding, traction, ride comfort, and (as since proved) likely tyre life was probably best at 28 psi front/36 psi rear.


Suspension suffers, as does your bottom, if you run tyres harder than is really necessary

Have carefully edited the above to support what I'm going to say , luckily this never happens in mainstream media.

For my wife's Freelander , on 195/80/15 all round, Landrover revised their tyre pressures down to 26 psi and 30 if fully loaded.

My Bongo is a bit heavier but not too dissimilar so there could be some relevance.

Freelander tyres have slight bulge but don't look flat. 195/80/15 is a size on my Bongo's door plate.

Tyres are supposed to have a ( slight ) cushioning effect.

Having a bit of softness in the tyre helps grip by making a slide more progressive whereas a ( really ) hard tyre could breakaway
more suddenly.

Having said all that, there are so many variations depending on rim size , tyre size, tyre make, vehicle mass , driving style etc
that you do have to experiment a bit within the suggestions on the forum.

Most important is to check regularly. If you find one or all have gone down to low 20s you'll be asking for trouble.

My tyres are now 5yrs old and are not holding their air very well anymore.

What shall I get next decisions, decisions.

Edit: Landy tyres actually on 28psi and some Googling suggests 30 for normal loads might be better.
We've just got it so have to start learning like when we got the Bongo.

My Bongo on 34 all round, usually not much in the back.

End of my rambling.

[Ron Miel]

Or to put that another way, if tyres look the same when the vehicle's either empty or fully loaded, they could be at too high a pressure.

Or, from another viewpoint: HGVs tend to run all tyres at very high pressures, whatever the vehicle's loading, and that can be at the risk of other road users. Have you ever seen a lightly loaded articulated truck jacknifing in what should have been perfectly manageable straight line braking (I don't mean emergency stopping) - it's not a pretty sight!