Thanks for the picture. Looks like 18's won't even clear the calipers on the SQ5. As spijun said earlier, the Audi recommended sizes are 235/55 R19 and 255/45 R20.

 

though I know its the Internet forum 'lore' so far. Again, someone can simply look physically at a SQ5 minispare as a starting point on wheel size. The last gen. S6's, W12's and S8's could use 18's with 385mm rotors just barely (balancing weights included), and these are 380mm and similar caliper designs. I own one and have run 18's, and have the 18" factory spare in the trunk that has also been on a front wheel for one blowout. The Q5 factory wheel offsets are also more aggressive than most other car body Audis with bigger wheels so there is more general clearance near the barrel to spoke area where calipers can sometimes snag, and that area specifically is one where the newer Audi high volume caliper design also slimmed things down a lot.

More generally, if you go back to when this general caliper design was phased in (succeeded the old HP2's from first gen 2.7T S4's and A6's, and the 4.2's in A6's and 8's), it was done both to get rid of the old iron caliper weight and to reduce wheel clearance requirements from older clunky caliper design. Side clearance also used to be a problem with old 2.7T's and also necessitated some pretty awkward wheel designs to clear the spokes.

I have yet to see a post where anyone has field verified it. The picture could be called either way, since from 20 to 18 would reduce radius an inch, which is just about the debatable part of the picture angle. No doubt it's close, as it is w/ my A8 w/ the 18s.

 

You're completely right and I'm an idiot - 20 to 18 is 1" not 2"! There's about 1.5" clearance in that picture on a 20" rim, so an 18" rim should still have 0.5" clearance which should be enough to account for any small differences caused by the balance weights and incorrect measurements due to camera angles.

But to address laakness last post, 19" wheels are fine because I have yet to see balance weights exceed 0.5" deep

 

Yes, some 19's will fit according to my SA but then the offset comes into play more with caliper clearance. I went 20 because I din't want it to be close or have to ship them back all over a few dollars in price.

The offset in the wheels I bought is 30mm.

 

The offset point is relevant in addition to the diameter. Folks with old 2.7T S4's and A6's learned this the hard way with the older HP2 brake designs that either needed more aggressive offsets or kind of funky (and not so attractive) spoke designs.

But, Q5's have among the most aggressive factory offsets of any Audi sold--in a given wheel width that is since the numbers have to be considered together. They tie with the S5 if I have it right, and are just slightly less aggressive than the RS5. All the A class sedans are generally less aggressive, and many of the S's too. Basically it takes fender flaring a la the typical RS vehicles (plus at least the older A6 based allroads). Alternatively, what you find in the typical SUV fender look like a Q5, especially if built from an underlying car platform with a slightly less aggressive stance like the basic A5/B8 A4.

The specific design of the front brake calipers found on the Q5's and SQ5's also minimizes the side clearance issue. If you look at the outer caliper corners you will see how the corner gently eases off. That and how the caliper now mounts into the hub bolt-on bracket are how they revv'ed the design basically to fit more brake diameter into similar sized wheels than an Audi generation or two back. A contra design still sold if you look at it BTW are the typical Brembo eight or six piston fixed caliper set ups a la the RS5 (and R8). Beefy caliper, very angular on the outer corner. Pads drop in from above track style and are held by pins instead of by removing the caliper shell like you find on the volume Audi set ups now. That also makes the caliper "taller" though relative to the rotor. Thus even down at 365mm compared to the SQ5 at 380mm, no surprise to me that something like the RS5 would take at least a 19" AND an aggressive offset wheel.

 

That is excellent information!

 

New to this forum but read a ton of info on the winter tire question for SQ5.
I just bought my SQ5 and it came with the stock S 20" wheels with summer performance tires. I live in Fort Collins, Colorado. We get intermittent snow and the roads clear fairly quickly.

The summer tires are scary on any snow at all beyond a dusting. Trying to stop quickly beyond 5 mph is like driving on skiis and cornering is terrible. So definitely get winter tires before driving the car off the lot if you could get snow where you live.

I considered just buying tires and remounting those between the summer and winter months. However I would then have to bring the car in twice a year to have this done. I've heard some people say that this isn't good to mount and re-mount twice a year, but my wheel guy at Audi didn't seem to have a problem with this. By the time I got the car (late January), they didn't have any in the size that would fit my wheels stock wheels, so this wasn't an option.

I ended up getting a complete wheel/tire set up and going with the Hartmann HR8 (anthracite, or darker, style) in the 19 inch. They have silver or anthracite, I chose anthracite because they're darker, look a little cooler with the monsoon gray color I got, and I think will look less dirty in the dirty winter road conditions. I wrapped them with Pirelli Scorpions. I've only driven this set up a couple times in the snow, but so far they seem great. I was planning on getting the Blizzak LM -60s, but they were also out this late in the season. My wheel guy at Audi dealer thinks they'll be great.

So far this set up looks amazing on the SQ5 and does well in the snow. I'll update later if I have any further thoughts.

 

Plus, it is a chance to clean stuff up, give brake wear a good look see, etc.

If you are a DIY on the swapover, consider buying the screw in extension stud you insert after removing the first lug bolt toward the top. ECS and others sell it. There are plastic ones (and the A8 comes w/ one), but given the weight metal is much sturdier and avoids possibility of shearing it off. They are several inches long, and it helps on both dismount to avoid a sudden drop of the wheel onto the brakes, and on aligning on getting back on. At 29" outer diameters, these wheels are quite heavy and bulky compared to many.

 

Call Hartmann wheel. They are the experts. I tried to go the eBay way but the 20 inches wheels I ordered would not clear the brake caliper. I went with a 20 inch wheel with the factory 20 inch spec winter tire. It is late in year so idk what you will find. I had to go with a silver RS4 style wheel. Not my first choice but I was limited.

 

Uh oh, am I in trouble?

I called Tirerack, told them I had a Q5 2.0 and they recommended 17" wheels and shipped 'em out. Is that too small a wheel for the Q5?

Bob