DB9 Tires and Sizes
 

It's time to replace the tires on my '07 DB9. I'm able to get Conti ExtremeContact Sports for ~$800 plus M&B, but only for the DB9 Sport Pack sizes of 285/35/R19 (R) and 245/40-19 (F). My existing tires are the regular, non Sport Pack sizes of 275/35-19 and 235/40-19. Although it has the Sport Pack wheels, my car doesn't have the Sport Pack itself.

I can't imagine there would be any issue w/ fitment, but I may be wrong. Any ideas?

Sheriff - I believe you have the ExtremeContact Sports on your DB9 - what size and do you still like them?

Thanks

If you look in the owner's manual. page 13.6. you will see that sport pack wheels and standard wheels are exactly the same width. 8.5 front and 9.5 rear. so the tires will fit.

No problems with fitment. I've been running the larger size Continentals for many years.

I have 245/35/20 fronts and 285/30/20 rear. I believe the 245's will fit just fine for you on the front.

I love my new Conti's. The only thing is when its cold---ie.....not driven for a week and its 34-40 outside, I get a bit of tire shake until they warm up. Not bad, but I hit the interstate 1 mile from the house and only do 35mph till then. So expected. When I had them in warmth, they were perfect. Quiet, and gripped great.

I went up one size tire on my stock 19" rims with no problem. A local corvette owner bought them a d then sold them. Too good a deal to pass up!

What does going from 19" to 20" do to the speedometer?

This is a really handy site: https://tiresize.com/calculator/

A few minutes plugging in tire sizes will tell you all you ever wanted to know!

Its not the wheel size that changes the speedo but the tyre size. In most cases, going up on the wheel diameter and down on the tyre profile keeps the rolling circumference almost the same.

It depends on the tire aspect ratio, what tires are you running?
For instance, factory is 26.58 (675.1mm) with 275/35-19's and I'm running 325/345 rear's with 25 aspect ratio tires on 20's, this puts me with 1% minus/plus stock diameter.
If you change to a smaller overall diameter the wheels will spin more per revolution and the speedometer will say your going faster than you really are, If you increase the diameter the speedo will say your going slower than you actually are.