Ride Comfort - Tyre size and pressure

[Neville G]

After buying my 2012 (2013 model) S60, I was disappointed with hard ride when compared to my previous car, a Jaguar S-Type (the V6TD engine gave up on it !).
The S60 is fitted with 235x45x17 tyres and the pressure is 34psi., but the S-Type uses 235x50x17 's and the standard pressures for those is 31F and 32R.
The S60's at 34psi. seemed high when compared to the heavier S-Type, so I dropped them down to 30psi all round, which improved the ride quality over small sharp bumps considerably.
As I still have the S-Type and the wheels will fit the S60 (with modified bolts - flat faced instead of 60deg. taper), I have now put those onto the S60 and the ride comfort has been transformed.
If you want a more comfortable ride, I can highly recommend Changing to 50's instead of 45's and dropping the pressures down to 30psi.

[Clan]

Originally Posted by Neville G

After buying my 2012 (2013 model) S60, I was disappointed with hard ride when compared to my previous car, a Jaguar S-Type (the V6TD engine gave up on it !).
The S60 is fitted with 235x45x17 tyres and the pressure is 34psi., but the S-Type uses 235x50x17 's and the standard pressures for those is 31F and 32R.
The S60's at 34psi. seemed high when compared to the heavier S-Type, so I dropped them down to 30psi all round, which improved the ride quality over small sharp bumps considerably.
As I still have the S-Type and the wheels will fit the S60 (with modified bolts - flat faced instead of 60deg. taper), I have now put those onto the S60 and the ride comfort has been transformed.
If you want a more comfortable ride, I can highly recommend Changing to 50's instead of 45's and dropping the pressures down to 30psi.

Your tyres are best set to eco settings 38PSI otherwise you WILL find the edges rapidly wearing off, 30 psi is dangerously low for 45% section tyres and the fuel consumption will be noticeably worse. It is guaranteed when you hit a pot hole at speed at 30 psi your wheels and tyres will be ruined with a bill of over £1500 each wheel . 45% tyres are virtually racing tyres and must not flex.
you might be better off swapping your wheels for 7 x 17 which accept 215/50/17 in the volvo accessory catalogue . your speedo will be a bit inaccurate with the Jag wheels on. volvo has software and/or different steering lock stops for different wheel and tyre combinations. Explained in the accessory book below.

https://accessories.volvocars.com/en-us

[GMcL]

30psi is way too soft. As mentioned the shoulders will wear very quickly.

I typically run my S60 diesel 37psi front 35psi rear and use the Eco setting for long distance high speed runs.

The tyre pressure above is used on 235/40x18 summer tyres and 215/55x16 winter tyres.

The 16" wheels give a much more comfortable ride being higher profile and softer winter compound rubber. The R-design I have gives a less forgiving ride but still soft compared with the two Focus cars I have/had which run on 235/35x19.
I test drove a V90 which had clown car 21" wheels which felt at odds with the rest of the car.

[Kev0607]

Originally Posted by Neville G

After buying my 2012 (2013 model) S60, I was disappointed with hard ride when compared to my previous car, a Jaguar S-Type (the V6TD engine gave up on it !).
The S60 is fitted with 235x45x17 tyres and the pressure is 34psi., but the S-Type uses 235x50x17 's and the standard pressures for those is 31F and 32R.
The S60's at 34psi. seemed high when compared to the heavier S-Type, so I dropped them down to 30psi all round, which improved the ride quality over small sharp bumps considerably.
As I still have the S-Type and the wheels will fit the S60 (with modified bolts - flat faced instead of 60deg. taper), I have now put those onto the S60 and the ride comfort has been transformed.
If you want a more comfortable ride, I can highly recommend Changing to 50's instead of 45's and dropping the pressures down to 30psi.

Just go with what says in the owner's manual or on the pillar inside the driver's door. It'll tell you pressure to use for economy and the correct pressure to use if there's no weight in the car.

38psi is most fuel efficient, but its way too hard for my liking.

[Neville G]

Thank you all for your comments, but I am quite happy to sacrifice a bit of loss of economy and uneven tyre wear, which in my experience won't happen anyway, for comfort. Please remember that 30psi. is only 1.0psi. less than these tyres were designed to be run at on a considerably heavier Jaguar S-Type.
I am well aware that if the pressure is too low it can cause the outer edges to wear more quickly and, by the same token,running them too high will cause the middle of the tread to wear out quicker. Also remember that the contact patch area will be affected at the same time. Low pressure INCREASES the contact patch area and high pressure REDUCES it, which also means MORE or LESS grip. "OFF ROAD" drivers and riders lower their tyre pressures to get MORE grip on loose and slippery surfaces. I therefore agree that a higher pressure will, in theory, give better MPG, but at the expense of grip. The best way to get better MPG is to adjust your driving style and be more gentle with your right foot !!!

CLAN. Sorry, but your comments are frankly ridiculous ! 50% aspect ratio tyres would have to be much, much softer than 1.0psi. low to cause wheel rim damage and since when have 45% ones been anywhere near to "Racing" specification. Furthermore, I have no idea where you dreamed up £1500 to replace a wheel and tyre. Get real man !!

[Clan]

Originally Posted by Neville G

Thank you all for your comments, but I am quite happy to sacrifice a bit of loss of economy and uneven tyre wear, which in my experience won't happen anyway, for comfort. Please remember that 30psi. is only 1.0psi. less than these tyres were designed to be run at on a considerably heavier Jaguar S-Type.
I am well aware that if the pressure is too low it can cause the outer edges to wear more quickly and, by the same token,running them too high will cause the middle of the tread to wear out quicker. Also remember that the contact patch area will be affected at the same time. Low pressure INCREASES the contact patch area and high pressure REDUCES it, which also means MORE or LESS grip. "OFF ROAD" drivers and riders lower their tyre pressures to get MORE grip on loose and slippery surfaces. I therefore agree that a higher pressure will, in theory, give better MPG, but at the expense of grip. The best way to get better MPG is to adjust your driving style and be more gentle with your right foot !!!

CLAN. Sorry, but your comments are frankly ridiculous ! 50% aspect ratio tyres would have to be much, much softer than 1.0psi. low to cause wheel rim damage and since when have 45% ones been anywhere near to "Racing" specification. Furthermore, I have no idea where you dreamed up £1500 to replace a wheel and tyre. Get real man !!

I have been working professionally on volvos for 47 years and seen it all many times before I suggest you take my advice . rather than insult my intelligence.