Buying Saab Diesel

[Norfolk Jim]

Out for a drive on Saturday and all seemed fine - apart from a Brake Light Lamp Failure message. Quick tap on lamp and mental note to check bulb when home (quickly forgotten so still to do) and Mrs NJ seems happy enough.

Ride was very comfortable which made me wonder a little with sport chassis - check tyres and all were 32 so pumped up to 36 and wonder if I did right thing?? Quite a lot firmer ride now; doesn't bother me but Mrs NJ will notice......................hmmmmmmm - quandary as tyres seemed to be wearing evenly (all Michelin Primacy3 with loads of tread) oldest are back which were fitted in April according to bills and that was only 4k ago? Slightly temped to let them down to 32 again and watch them??? Car handles fine though.

[mikeloadsasaabs]

I'm surprised the car feels right with 32psi Jim. The day we collected our Aero estate, on the same wheels and therefore tyre sizes as yours, we went on to collect our son plus his belongs from uni. By the time we left Swansea it was pretty well loaded, with three passengers (us) on board. I distinctly remember how badly it drove across country, wallowing around and feeling generally unstable, and how it was difficult to keep it from wandering on the motorway. The next day, I checked the tyres and, like yours, they were only 32psi. Having raised them to 36, all was well again. To my mind, it's a safety issue and I wouldn't run them that low unless I was just popping to the shops every day. TBH, you'll probably not notice the extra firmness after a while.

[ScarbSaab]

Agree with mikeloadsasaabs, the handling firmed up when I increased mine to 36psi without significant decrease in ride quality. When I had Vredestein Sessantas on the Aero I did briefly try their recommended pressure of 46psi, but you felt every pebble! As the car had been doing some heavily laden runs, I did have the 17" summer tyres at 40psi, but the 16" winters now on are at 36psi (not that I am able to use them ).

[Audax]

It really depends on the suspension fitted to the car and the tyres in use and their load rating. It could just be that the tyres on Jim's car have a higher load rating and stiffer sidewalls which mean with extra air in they are too rigid, it even varies between different tyres from different ranges but the same manufacturers with the same ratings on them.

[mikeloadsasaabs]

It really depends on the suspension fitted to the car and the tyres in use and their load rating. It could just be that the tyres on Jim's car have a higher load rating and stiffer sidewalls which mean with extra air in they are too rigid, it even varies between different tyres from different ranges but the same manufacturers with the same ratings on them.

You're probably right Audax, perhaps it's a case of trial and error, although I stand by it being a potential safety issue. I haven't found a lot of difference between makes. I bought just a pair of Michelin Primacy 3s (for the rear) last summer, and they are reputed to have a good ride. Perhaps this is down to less rigid sidewalls? Can't say I have ever noticed much difference between brands!

[Steve440]

My last Aero had a complete set of Pirelli's on it and that always used to feel stiff on anything above low 30's.

The Aero I have now has a mixture of Michelin, Avon and Semperit ( yes I know I will sort that out once they are worn out) and I have not noticed any difference in ride quality between 32 and 36.

The car when purchased had obviously been run with low tyre pressures due to the ware pattern. With them now at the correct pressure the only difference I have detected is maybe more road noise on some surfaces.

Anybody been in a BMW Mini with run flats on it? SWMBO has one and I would rather walk than go for more than a few miles in that, road noise is terrible an if she drives over a 10p I could tell you if it was heads or tails.

Steve

[sgould]

I found out recently that "extra load" tyres have stiffer treads, not stiffer sidewalls.

[Norfolk Jim]

Well mine are all Michelin Primacy 3 and loads of tread on them. They are 94W XL.

The handling seems no different and even at 32 it feels solid with no wander or creep but when shoved up to 36 it really feels hard.

Oddly though the wear is even across the whole tread at 32.

I'll see what happens over next month.

Thanks for input guys

[jmblack]

The Aero I have now has a mixture of Michelin, Avon and Semperit ( yes I know I will sort that out once they are worn out) and I have not noticed any difference in ride quality between 32 and 36.

I had semperits on a Renault once and was surprised how well they performed and wore...

[sgould]

Somewhat counterintuitive,  we found that the ride comfort improved on the 9-3 Vector when the tyre pressures were increased to the max recommended value.  But that was in the early days before the Hirsch springs were fitted, when the ride on the original 215/50 17 tyres was really harsh.  Just less harsh on the higher pressures.

[Audax]

I found out recently that "extra load" tyres have stiffer treads, not stiffer sidewalls.

I'm not convinced that is always true, the difference between tyres and how stiff the sidewall is can be quite different on how easy they are to fit, some slide easily onto a rim, others cause lots of swearing and grumbling.

[mikeloadsasaabs]

Somewhat counterintuitive,  we found that the ride comfort improved on the 9-3 Vector when the tyre pressures were increased to the max recommended value.  But that was in the early days before the Hirsch springs were fitted, when the ride on the original 215/50 17 tyres was really harsh.  Just less harsh on the higher pressures.

I found a similar thing on my old 9-5, but after the Eibach suspension was fitted. The ride was actually better on the 225/45 17s than the 215/55 16s. Perhaps the suspension is tuned/optimised for the 17s?

[Norfolk Jim]

As the song say's 'Things can only get better..................................' having seen it now off the ground I am dead chuffed to say "I've got Hirsch suspension - wahoo" and that's why it's a little firmer so my next quest is to see if indeed I have Hirsch power upgrade as it does go rather well!!!!!!! Will know soon.............................and shame dealer that sold car to me didn't know!!!!! ££££'s in - wondered why it sat quite low

[wrighar]

As the song say's 'Things can only get better..................................' having seen it now off the ground I am dead chuffed to say "I've got Hirsch suspension - wahoo" and that's why it's a little firmer so my next quest is to see if indeed I have Hirsch power upgrade as it does go rather well!!!!!!! Will know soon.............................and shame dealer that sold car to me didn't know!!!!! ££££'s in - wondered why it sat quite low

Try putting your Vin no. in here and see if your entitled to a badge (only hirsch performance tuned Vin's can get them).

http://extranet.hirsch-performance.ch/badge/

if it say yes....

[sgould]

Some people are just lucky....