SQ5: alternate tire sizes?
 

For my SQ5, I currently have 255/40R21. The selection for new tires is very limited and substantially expensive. Have Pirellis now.
What choice could I have? Is it not acceptable to install a 255/40R20?

Need some advice.

Your wheels are 21", you can't magically install 20" tires on them.

So no, you can't install 255/40R20 on 21" wheels.

You could certainly go to tire rack and buy new tires and wheels that are smaller.

Audi needs a new pair of shoes!
 

so was advised I could substitute a 265/40R21 on my SQ5 for a 255/40R21 and have more choices in models of tires. Would there be any detriment in appearance, maintenance,ride or durability in making this change?

Any one have an expert opinion?

The 265 tire is .3" taller and .4" wider than the OEM tire. I don't see an issue with looks or driveiblity, but I would take a good look at the clearance you have over the top inside shoulder of the tire. On my Q5 (2010 3.2) the control arm is very close to the tire.

Alternative size tires
 

Thank you. Greatly appreciate your response.

I have the same tires on my 16 SQ5- There is no All- season option for this exact tire/rim size. Just Summer/Performance which is what my Pirelli's are or winter. Audi dealer in CHI has been looking for an All-Season option, but there just isn't any out there- for this same exact size. Really odd.

Other option of course is to go to 20" wheels then more of a choice.

I'm not so sure there is an advantage of 21" vs. 20". They came with my 16 SQ5 I just bought a few months ago so no choice. 20" probably rides better than 21" though. Very odd that there are only Summer Performance and Winter tire options for this vehicle and wheel size.
Audi dealership couldn't fine any either. Nobody has been able to find an All- season tire from any manufacturer that fits a 21" for a 16 SQ5 here in the US.

Will 275/35/21 also work with no additional modification ie spacers?