How come I don't see much vendors advertising 21" wheels
 

Its either 20" or 22".

IMO 21" is perfect for the panny, not to small looking that it gets dwarfed by the car's size and not too big that it dwarfs the brakes and looks like its running on rubber bands.hilarious just my .02

Due to the ideal tire size for 21" having been discontinued.

I had 21" on my 7 series. It was very hard to find tires for it.
I guess size popularity never cought on.

It's very expensive to make a mold for a wheel, especially for one that only applies to one car and cannot be made to fit others. There has to be enough demand to warrant the capital expenditure to produce.

At the moment there are NO 21" tires made that fit our cars. I have a set of HRE's just waiting for the P Zero Nero GT's to come out in the right sizes!

Tires.

man which is why I haven't really bought wheels yet....sucks love the size look on the panny wih 21",

So do I, I hope the tires come out sometime soon.

Its looking more and more that I go with 20"s and do a slightly thicker tire combo. Even looking at turbo IIs looked a little dwarfed by the panny's size.

22s you will be happier with the look especially lowered

And 22s more common. Imagine taking a road trip one weekend and out in the sticks tire is toast. And earls tire shop doesn't have 21 and most shops won't stock Em. At least 22 is easier to find something to get me home

Im getting to the point where i might have to look at 22's as well... not liking the rubber tires tho but tires are cheaper.

Ride is fine. The big boys seem to always put 22s on

I just dread the 580/680/880 and some of 101 here in Cali hilarious thats like 1 bad uneven surface freeway construction from dented 22's.

Not a huge difference between 21 and 22 profiles. If the hole is that bad nothing will save ya