rsilvers129

I noticed that 285 is the only width that Tire Rack suggests. But if I were to go to 275, there is a massive amount of options and at much lower prices. Besides the obvious 1 MPH speedometer error at highway speeds, which is not enough to worry about, is there something wrong with using 275 width tires?

https://www.tirerack.com/tires/TireS...45&diameter=20

https://www.tirerack.com/tires/TireS...45&diameter=20

There are also some 295 45 R20s that may fit.

Normally Tire Rack lists alternative sizes, but is not doing it with these for some reason.

BigKutta

There should be no issues. I use wider tires on my MB because they look nicer. Just make sure tirerack confirms that they will be a perfect fit.

OneOfOne

they flat out told me that the tires I ended up buying using their pricing wouldnt work. town fair tire recommended them. so theres that. probably a liability concern but I am happy I bought what I did.

itiongo

If the difference was $1k+, then I might consider it. Me, saving $200-300 on tires, I'll pay the extra money to make sure by expensive Q7 is able to perform the way it was meant to. My model would be: if you can afford an expensive car, you can afford expensive tires.

rsilvers129

The best tires are not made in 285/45R20.

If you want the best tires, they are 10mm less wide, and about $400 less per set.

So no, I am not excited about spending $400 more on worse tires just so that they can be 10mm wider. and 0.2 inch taller.

itiongo

Yep. Correct. Saving $400 is quite a big difference. There are really a lot of good options for 20".

rsilvers129

In the 285 size that Audi recommends, and the only size that Tire Rack shows as compatible, there is only one normal all season, and two run-flats, for 20 inch. CROSSCONTACT LX SPORT. Tire Rack's rating of that is terrible - only 3.9/10 of people would recommend it.

So for someone who doesn't want run-flats, they can either spend around $1300 on that poorly rated tire, or $1000 for a much better rated tire in a non-recommended size which is about 0.2 inches shorter and 10mm less wide. And once you accept that 275 size as ok, there are a lot of choices - with even $500 sets available.

I wish I had 19 inch.

palmxp3

Industry recommendation is to keep within +/- 3% and every vehicle's speedometer is calibrated to indicate faster than actual speeds, sometimes as much as 5-10%. I suggest going slightly taller in the overall diameter if there are no factory sizes.

For instance, your speedometer may show 80mph, but actual speeds are probably closer to 76mph. Going down to a 275/45/20 will lead to actual speeds of 75mph. When your odometer shows 50k miles, you will have traveled only 46,875 miles.

Here's a great site comparing different tire sizes: https://tiresize.com/calculator/

I may go to a 275/50/20, which is available in the highly rated Michelin Premier LTX. Using the same formula, this should result in actual speeds of 77.8mph when indicating 80mph on the speedometer. The higher profile tire will probably reduce initial turn in speed with the trade off being better ride comfort. Looks wise is subjective and some like a lower profile tire. I prefer a big CUV/SUV with something a little meatier.

BigKutta

So you're saying that you'd put $75 tires on your Q, if it was available?

I dont think OP is trying to save a few bucks...only trying to widen his options/

rsilvers129

Europe has a speedo standard that says they are not allowed to indicate slower than you are going. US doesn't have that, but in practice, car companies don't want to indicate slower than you are going. That being said, I think they all try to be dead on. I have a Suzuki motorcycle that indicates 66 mph when I am going 60, according to a GPS. But all of my four cars are exactly matching a GPS. Like exactly.