Tyre pressure : 235/65R16

[Tufty_B]

Can the Syncro peeps advise of what tyre pressure they are running for their 16" wheels, to give me an idea for the 235/65R16's that I have.

[CJH]

Mike

I can't advise, but out of interest, can you post the max load and max pressure moulded into the sidewalls of those tyres (and if you've got a handbook for your syncro, the max axle load for each axle)? I posted in another thread about a formula for getting a good starting point for tyre pressures, and I'd be interested to know how close it gets to the values that people are going to suggest to you.

Chris

[lloydy]

i went by the max tyre pressure on the side wall. fronts about 5psi less than the rear

[Tufty_B]

Mike

I can't advise, but out of interest, can you post the max load and max pressure moulded into the sidewalls of those tyres (and if you've got a handbook for your syncro, the max axle load for each axle)? I posted in another thread about a formula for getting a good starting point for tyre pressures, and I'd be interested to know how close it gets to the values that people are going to suggest to you.

Chris

OK, I've just got back home so I'll have a look tomorrow and check that thread out.
Thanks

[Tufty_B]

CJH,
I have used the spreadsheet with the following data:

• Axis load (f/r): 1300/1380kg (from the wiki)
  Tyre Spec (max load/pressure): 825kp/240kPa

and this gives a result of:

• 100% (f/r) 26/28 psi
  90% (f/r) 29.6/31.9 psi

So am I correct in assuming that these are the recommended pressures at cold and the the further calculations show the pressure at specific temps (i.e. 112/190 F)?

The current pressures were 32.5 psi f/r, so I've left as is.
The tyres are quite new so there is no appreciable difference in wear across the width.

What pressure are others running on their 16"

[CJH]

Hi Mike

Yes, I think that's what it means. Please don't mistake me for some sort of expert on tyres though . That's just a spreadsheet that was posted in a forum for one of my other vehicles. The basis for its calculations seems sensible though, and whenever I've compared its results to manufacturers' specs it's been quite close. I'm not sure what the 90% value is all about - "Percentage of optimal grip surface" - maybe for a slick you'd use 100%, and 90% represents a typical tread pattern?

The syncro maximum axle loads are evidently a bit different from a 2WD - my handbook quotes 1100kg/1300kg (F/R) for a 'normal' payload, and 1200kg/1400kg for a 'higher' payload. Using the higher payload figures with your tyres would give 90% figures of 26.7/32.3 PSI - the rear value being pretty close to what you're already running. It's getting quite close to the tyre's maximum pressure of 34.8 PSI, but I guess that's quite acceptable.

The best advice will be what people with experience of your particular combination can offer.

Chris

[syncropaddy]

2.5 bar front / 3.0 bar rear. It will make little difference to the handling if you are a few psi up or down as T3 don't handle!

[CJH]

2.5 bar front / 3.0 bar rear. It will make little difference to the handling if you are a few psi up or down as T3 don't handle!

2.5 bar is 36 psi, which is just over the max psi for Mike's tyres (240kPa = 34.8psi). 3.0 bar is 43.5 psi, which is way over. I don't think those pressures are suitable for Mike's tyres.

[Tufty_B]

2.5 bar front / 3.0 bar rear. It will make little difference to the handling if you are a few psi up or down as T3 don't handle!

I've noticed that corners are to be respected and that stopping isn't particularly quick either
I'll check the tyre temp after a run with an infra red thermometer after Xmas and see if that indicates whether the temp is consistent across the tyre width to try and determine an appropriate pressure. Though in the past I've tended to keep on eye on tyre wear on previous cars to confirm the correct pressure but this only becomes apparent over a high mileage and swapping the wheels around to even out tyre wear on the syncro will make this a little trickier.

[Ralf85]

I'm using recommended tyres for my van and pressures recommended too ie 39psi on the front and 48 on the rear.

[Tufty_B]

I'm using recommended tyres for my van and pressures recommended too ie 39psi on the front and 48 on the rear.

Can you let me know the tyre size and make because that seems to be quite a high pressure.

[syncropaddy]

Most cars and vans run in the low to mid 30's PSI so if your tyres dont allow that then get shot of them and buy proper ones!

[syncropaddy]

Most cars and vans run in the low to mid 30's PSI so if your tyres dont allow that then get shot of them and buy proper ones!

I'm using recommended tyres for my van and pressures recommended too ie 39psi on the front and 48 on the rear.

Can you let me know the tyre size and make because that seems to be quite a high pressure.

No it isnt. Those are average values for van tyres