[DTM_]

Just want some preferences on cold tyre pressures from those who have fitted non-RFTs.

I have had the Michelin PSSs on the E92 for a year now (265 & 235 X 19s) but only travelled 4000 Ks and no highway driving at all yet. I have been using 32 PSI all round in cold tyres, and this is both comfortable and responsive for steering, braking etc.

I have read the other threads and comments to follow the manufacturer tyre stickers but using RFT pressures seems excessive - my car indicates up to 3.4 BAR with 4 people highway driving - this is 49 PSI!

I ask the above because we just had to replace the rears on the X1 (P7 RFTs) - we followed the tyre pressure guide with mostly 4 passengers & luggage on board, of 2.9 BAR (ie 42 PSI) - we only managed to get 20,000 Ks out of those tyres though - the tyre fitter said no more then 34 PSI is required but have about 2 PSI more in the fronts (P7 RFTs as well).

[SE7EN335]

Originally Posted by DTM_330D

Just want some preferences on cold tyre pressures from those who have fitted non-RFTs.

I have had the Michelin PSSs on the E92 for a year now (265 & 235 X 19s) but only travelled 4000 Ks and no highway driving at all yet. I have been using 32 PSI all round in cold tyres, and this is both comfortable and responsive for steering, braking etc.

I have read the other threads and comments to follow the manufacturer tyre stickers but using RFT pressures seems excessive - my car indicates up to 3.4 BAR with 4 people highway driving - this is 49 PSI!

I ask the above because we just had to replace the rears on the X1 (P7 RFTs) - we followed the tyre pressure guide with mostly 4 passengers & luggage on board, of 2.9 BAR (ie 42 PSI) - we only managed to get 20,000 Ks out of those tyres though - the tyre fitter said no more then 34 PSI is required but have about 2 PSI more in the fronts (P7 RFTs as well).

32 psi is way too low. 38 psi all around, and if you need a bit more traction, lower the rears to 35-36 psi minimum.

[Ken Oath]

Can you provide the exact tyre information as printed on the sidewall?

From the information it is possible to obtain if the tyre is P-metric and the TRA load inflation table will give the load carrying capacity. As the tyre you have fitted appear to be a plus 1 it can then be determined the correct inflation pressure.

[EB89]

I run 42 PSI all round.

Don't know why, rear it in here a while ago that 40 was good. So 42 deflates to 40 by the next time I fill them

[DTM_]

Originally Posted by Ken Oath

Can you provide the exact tyre information as printed on the sidewall?

From the information it is possible to obtain if the tyre is P-metric and the TRA load inflation table will give the load carrying capacity. As the tyre you have fitted appear to be a plus 1 it can then be determined the correct inflation pressure.

Thanks Ken - the car is fitted with 19" rims from the factory as per the tyre sticker - sizes 255/30/19 & 225/35/19 - if you refer to "plus 1" as fitting the next tyre size width up, yes that is what I did. And they are 93Y and 91Y as per originals.

The tyres do not have the 'P' prefix on the size. Looking at the data string reads H203 DOT 6U18 002X 3615 (month & year), numerous E2 numbers 0210561 0213411 S2WR2.

[Ken Oath]

As per ETRTO the TIP (Tyre Information Placard) the OEM tyre size, maximum load and inflation:

Front 225/35 R19 XL 88Y - 560kg (1235lbs) 2.9bar, 42psi, 290kpa
Rear 255/30 R19 XL 91Y - 615kg (1356lbs) 3.4bar, 49psi, 340kpa

Load Index 88 = 560kg (1235lbs) per tyre 2.5bar not XL
Load Index 91 = 615kg (1356lbs) per tyre 2.5bar not XL
Load Index 93 = 650kg (1433lbs) per tyre 2.5bar not XL

Y speed rating = >300km/h


For the new tyres maximum load and inflation:

H203 DOT 6U18 002X 3615
Tyre manufactured by Michelin, France, 36th week of 2015

E2 numbers 0210561 0213411 S2WR2
European Noise approval numbers

Front 235/35 R19 XL 91Y - 615kg (1356lbs) 2.9bar, 42psi, 290kpa
Rear 265/30 R19 XL 93Y - 650kg (1433lbs) 2.9bar, 42psi, 290kpa

Importantly this is based on XL (Reinforced) tyres. These values should not be used for Standard tyres without XL markings.

[DTM_]

Originally Posted by Ken Oath

As per ETRTO the TIP (Tyre Information Placard) the OEM tyre size, maximum load and inflation:

Front 225/35 R19 XL 88Y - 560kg (1235lbs) 2.9bar, 42psi, 290kpa
Rear 255/30 R19 XL 91Y - 615kg (1356lbs) 3.4bar, 49psi, 340kpa

Load Index 88 = 560kg (1235lbs) per tyre 2.5bar not XL
Load Index 91 = 615kg (1356lbs) per tyre 2.5bar not XL
Load Index 93 = 650kg (1433lbs) per tyre 2.5bar not XL

Y speed rating = >300km/h


For the new tyres maximum load and inflation:

H203 DOT 6U18 002X 3615
Tyre manufactured by Michelin, France, 36th week of 2015

E2 numbers 0210561 0213411 S2WR2
European Noise approval numbers

Front 235/35 R19 XL 91Y - 615kg (1356lbs) 2.9bar, 42psi, 290kpa
Rear 265/30 R19 XL 93Y - 650kg (1433lbs) 2.9bar, 42psi, 290kpa

Importantly this is based on XL (Reinforced) tyres. These values should not be used for Standard tyres without XL markings.

A lot of info, thanks Ken. Very much appreciated.

The tyres do have the Extra Load description after the size - so 42 PSI F&R is the recommended correct pressure.

[///ASN]

Originally Posted by DTM_330D

.....we only managed to get 20,000 Ks out of those tyres though......

The power of torque in Diesel.

[Ken Oath]

Originally Posted by DTM_330D

A lot of info, thanks Ken. Very much appreciated.

The tyres do have the Extra Load description after the size - so 42 PSI F&R is the recommended correct pressure.

The inflation values given are the minimum for the maximum weight for speeds upto 160km/h. So on the TIP the value for four people and luggage is now replaced by 290kpa (42psi.) If you intend to go above 160km/h then the inflation pressure is increased but the load cannot exceed the maximum.
For XL tyres don't exceed 350kpa.

The inflation values can be decreased below 290kpa if the mass is not the maximum. You could use the TIP as a guide to decrease the inflation.

[DTM_]

Originally Posted by Ken Oath

The inflation values given are the minimum for the maximum weight for speeds upto 160km/h. So on the TIP the value for four people and luggage is now replaced by 290kpa (42psi.) If you intend to go above 160km/h then the inflation pressure is increased but the load cannot exceed the maximum.
For XL tyres don't exceed 350kpa.

The inflation values can be decreased below 290kpa if the mass is not the maximum. You could use the TIP as a guide to decrease the inflation.

Thanks very much for explaining all this Ken.

[satz]

I've been trying 38psi all round (cold). I have non-RFT at front and RFT at rear. (Mine are 18" wheels).

[Desertraptor]

Had a tyre pressure warning today. Stopped and checked and all were fine. Pulled in to servo to check and all were over 40
Dropped them back to 38.

[Grohouse]

Personally, I run mine at 34 rear and 32 front because of how crap the roads here are in Adelaide... M-Sport suspension and bumpy South Rd is a recipe for a successful migraine.

[Desertraptor]

Brighton Rd isn't any better. For that matter most of our main roads are crap

[e36mmm]

For me 37f/38r
If i have passengers and stuffed boot 38f/41r

[satz]

38 psi cold all around on my non-RFT 19s. Passengers or not

Now that I've fitted lowering/stiffer suspension maybe I need to play around with tyre pressures, although it's riding pretty well. Very firm but not jarring (my fillings are still in my teeth).


cheers

p.s. Just saw my old message above when I used to have 18in wheels!

[DTM_]

Originally Posted by Desertraptor

Brighton Rd isn't any better. For that matter most of our main roads are crap

I know what you mean and about South Road mentioned above - I drive on those roads from time to time, and will be later this week when I travel to SA again. Very similar to some of the roads I drive on here. FWITs worth, I am running 34psi all round atm and it is OK.

[DTM_]

Originally Posted by satz

38 psi cold all around on my non-RFT 19s. Passengers or not

Now that I've fitted lowering/stiffer suspension maybe I need to play around with tyre pressures, although it's riding pretty well. Very firm but not jarring (my fillings are still in my teeth).


cheers

p.s. Just saw my old message above when I used to have 18in wheels!

Hey Satz - have you posted any before and after pics of your car with the new suspension?

[satz]

DTM, no proper pics yet. Too lazy/busy to wash the car before taking some pics. And you know the recent weather in CBR has been unreliable...

Will do soon though!

Originally Posted by DTM_330D

Hey Satz - have you posted any before and after pics of your car with the new suspension?

[nash_86]

I run 36 psi all around. Loving my new Michelin Pilot Sport 4S's.

[DTM_]

Originally Posted by nash_86

I run 36 psi all around. Loving my new Michelin Pilot Sport 4S's.

Great Rubber!