From the tire calculator I'm using 245/30/20 gets you the closes to stock specs. I've noticed most people are running 35 series, I figure it's to give you alittle more rubber to help protect your wheel, but my calculator shows a 4.0% difference meaning if I'm going 60mph I'm really going 62mph. Is this a big difference?

 

Are you considering using 35 series tires on the front and rear? If so, the OD of your wheels will be uneven. Try this wheel & tire calculator. Hope this helps.

 

Thanks for the link. I came up with the same results. I was just wondering why I've haven't found anyone running 30 series. All are running 35's.

 

Why not go 255 / 35 / 20 ? You'll have your cake and eat it too.

Your speedometer "error" will be close to where you want it to be and you'll have the extra sidewall you want. Unless I'm missing something????

Try running this size on this tire calculator. www.1010tires.com/TireSizeCalculator.asp

 

So your saying 255's will work. I thought they would be to wide in the front for a s type.
I really didn't want to run 30 series but I didn't want my speedo off either. I haven't seen
A post where someone is running 255's everyone is running 245/35/20's.

 

I was wondering when someone would mention what car you were talking about. A good tip is to put your MY, model and engine size (for s-types) so you don't end up with misinformation like above.

 

They would have to be 255/30/20 not 35's to be close to stock. I haven't seen anyone running 255's on a S type. Do you know if they would be to wide in the front? Everyone running 20"s seem to be running 245/35/20 which I assume is to help with potholes but the 35's has a 3.85% difference from stock. I getting ready to buy tires this weekend and need to know whats best for my STR.

 

May have to go with the 245/30/20. I just realize my wheels have a offset of +34 20x8.5. Isn't the stock offset +45? Can't wait to put these on.

 

Whoa!!! That's exactly what I was missing. I had no clue we were discussing an S type. I guess that's a classic case of apples and oranges. I was using an XJ8 original spec. Sorry about the confusion. Good luck with your tire choice. I don't have any intelligent input.

PS you may get better input if you post your question in the S Type Section even though it's a tire and wheel question.

 

don't worry about it quiet, happens all the time.

 

Before I had my 22" on my s-type I also had 20's but was using 245/35/20, reason for me was that 30 series was to low profile and looked like it had a gap in between and just didnt lokk right, but thats my taste. When I had my 22", I had on 255/30/22 and looked perfect on them.