UKSaabs

A friend is offering me another 9-5.
It has 17" alloys and low profile tyres.
What for?
I like comfort, do low profiles have that?
They cost more!
What's the point?
The car has everything I want, but low profile tyres? I just don't see the point!

I'll give you £50 for em' then...

Nice one Jim lad!
But it doesn't answer the question, who needs low profiles on our roads?
Anyway, I'm going watching touring cars on telly now. (yeh, I know, they need 'em)

In theory, you'll get slightly sharper steering, a little more grip (because they are wider, not because of the low profile) and, to some, an improvement in the looks. The ride will worsen. It depends where and how you like to drive.

You should be able to sell your wheels and replace them with 16 inchers at a profit, but beware of resale afterwards.

ALL 9-5s have low profile tyres, it's just a matter of how low depends on the size of the wheel. In order to keep the gearing pretty much the same with different size wheels it is necessary to reduce the profile of the tyre when the big lump of metal in the middle gets bigger. The difference in ride between 225/45/17s and 215/50/16s is not that great actually.

If the question means "why are they better?", then it's a bit like saying why have better brakes, or better handling, or a faster car...

215/55x16 actually. Should be an extra half inch of rubber to keep the radius the same. I haven't driven a 9-5 on 17s and the same suspension as mine (I've only tried them on iwantanaero's rather 'firm' car) so I don't know if you'd notice the difference in ride comfort, but I suspect it would make some difference.[/b]

They look nicer!

Personally if I were out for comfort I'd choose 16's, I put some 17's on my 9000 and took them straight off, made it a bit skittish bumpy on the lanes.

2p.

They are also safer in a blow out- less tyre to shred up, the tyre walls don't blow so badly as they are stronger, and the effective rolling diameter of the affected wheel is not reduced by so much.

Personally I think that it's a bit of an old wives tale that low profile tyres=poor comfort.

It may have been true on older designs of cars as the suspension wasn't designed with them in mind. So retro fitting something lower profile than what the car was originally designed for, can worsen the ride.

A tyre introduces a huge variable into the set-up of the car (different compounds, different sidewall ratings, different inflation levels), it is after all, essentially an undamped spring. So if car designers can eliminate or reduce that variable from the suspension set-up and build the comfort and ride quality into the springs, dampers and geometry they will. Hence they can get the grip and steering precision that a low profile tyre offers with the ride quality defined by the suspension.

This is why cars are rolling off the production lines these days with 17s fitted as standard and 18s or 19s offered as extras. The new Jaguar XF will come with 17s as standard and no doubt still have Jag's legendary "magic carpet" ride quality.

9-5's came off the production line with 17s as standard on the Aeros (and Vectors I think ), so why don't you give it a test drive before assuming that the comfort will be worse. You may be pleasantly surprised.