Having been on here and also asking locally, and having had my suspension checked as ok, it seems my hard ride is down to tyres & wheels. I have alloy wheels and the tyre size is 225/45 R17. I presume the 17 is the wheel size? - although in measuring the best I can accuracy wise the wheel seems to be approx 18" from one side of the rim to the other. I am not particularly bothered about them being stylish/fast cornering/boy racer stuff etc (old man taking old wife for nice sedate drives) - so what would anybody recommend I fit for maximum comfort and low noise? Do I have to change the wheels or is there deeper thicker tyres available that will fit the wheels I have? Could anybody also give me an idea of what sort of difference I could expect in bumpiness/noise reduction - 25%? 50%? etc. Obviously I don't want to go to all the expense if it only makes a small marginal difference.

 

You would be able to put a little bit of a bigger tire on the 17 but not much before it starts rubbing and you wouldn't see a whole lot of difference.

To get the most comfort out of you ride your best bet would be to drop down to 16inch rim and put 225/55-16 on. The will give you the most air between you and the road and give you a softer ride.

The noise is going to be dependent of the tire itself since both have a width of 225.

The more air between you and the road will dampen the bumps. An exact percentage I cant say. But when your down to the tires to enhance your ride your results are going to be limited.

 

Royston, out of curiosity, what pressure are you running in your tires? If you are keeping the tires up near the max inflation pressure, that will transfer more road noise to the interior of the car and give a harsher ride. Even dropping the pressure by 3 psi (but keeping it above 32 psi) can make a difference in the ride. Also, what is the load rating of the tires (should be stamped on the side of the tire through the use of a letter-normally a B or a C). The higher the load rating, the stiffer the sidewall is, therefore more road noise/harsher ride is transferred to the interior of the car.

Like was mentioned, you can step down to a 16" rim (can't go any smaller than that) to get a bit more rubber between you and the road. But, I think for the cost, you are not going to see much improvement. Most of the gain that you will see will be from going with a softer sidewall tire than reducing the rim size.

 

Everything mentioned so far is pretty dead on. The 16" wheel would be more cushioned. With a 16" you could run 225/60R16. The ride would be very nice assuming you get a nice quality tire too. The wheels would add significant cost id switching sizes.

Just a quick tire size explanation to you know what to look for: 225/45R17
The first number (225) is the width of the tire in milimeters
The second number (45) is the ration of height to width
The third number (17) is the rim size of course.

The larger the second number, the more cushion you have. Of course there is a trade off. The higher the second number the more you give up in high speed performance. Just in case you might be concerned with that.

I'm a tire guy. That's how I make my living. When I was shopping for my current, and first, Jaguar 16" rims were a must. They are the smoothest ride and the prices are usually lower as well as readily available at any tire shop that you may have to stop at in an emergency.

The quality of the tire you choose wil have a lot to do with how much noise it makes. And as a general rule, the softer the sidewall, the cheaper the tire. A high quality tire should be pretty firm. You can press down on a nice Pirelli or Michelin with significant force before it collapses. A lower end tire you would be able to collapse with one arm.

If you decide to stick with the 17" wheels, I believe you could put a 235/45R17 on there just fine. It is still a 45 profile (middle number) but because the first number is larger the height of sidewall ends up being taller.

Hope some of this helps. And with all that being said, a Jaguar on 19" wheels still rides like dream. If your suspension parts are as they should be, a set of nice tires will make any size wheel ride nice and smooth on a Jag.

 

Thanks for the helpful reply. The wheels I have look very nice and obviously the cost of changing to 16's would be expensive. Given this and what I am trying to achieve - would there be enough noticeable difference in the two options you gave above to make it worthwhile swapping? Also can you recommend a specific tyre manufacturer depending on which of the above two I go for? Please take into account that I only go to the local shops and the odd jaunt down the motorway at 70mph, and will only probably do about 3000 miles a year as I'm retired. (pardon the pun )

PS. The noise factor is far less important than the bumpy backside factor.

 

You would get about an 1" to 1/3" more sidewall height with the 16" tire depending on if you compare to a 225/45R17 or a 235/45R17. I think a picky person could notice a difference. The 16" would be a more floaty smooth if that makes sense. With the amount of driving you plan to do I would think the 17" would be fine. The modern Jaguars do not come with 16" wheels and they still all ride very nice and smooth.

Michelin, Pirelli, Yokohama, and BFG all make excellent tires in either size. Mine came with Yokohama 580's on it. They rode nice, smooth and quiet but one of the tires separated very shortly after I bought it. I decided that I would just put a new set on instead of replacing just the one. For me it was between the Michelin Primacy MXV4 and the Pirelli P7. I went with the Pirelli P7 because I could put them on for half of what the Michelin would cost me. So far, I love them. They are very quiet and smooth and I don't worry about them no matter how fast I drive.