Velox has the VX6-R wheel which John Ryan is using I believe, it is around 15.5lbs and +42.

http://s24.photobucket.com/user/jdrd...520aw.jpg.html

.1 is within noise. That is the point that frustrates me most about what people are told and believe. There are soooo many things that play in that you cant bolt on lighter wheels, maybe not go faster and then say the wheels arent worth time. that is all im saying.

I'm only a "part-timer" in the sport, but have been around for a long time. My guess is they want to allow appearance mods (+ 1" diameter), not performance mods (+ 1" width).

because 18x7 is so sexy.

If we get tall and skinny enough, it would look appropriate on a Model T.

The reason stated (and is legitimate) is to help people with "wrong" sized wheels. 14, 16 and 19 inch wheels have poor choice for street tires currently.

The appearance thing is secondary to evening the playing field to a car that may have a certain package that bumps the car to 16" wheels for example (from a 15 obviously in this example).

Not an issue for our car really. Cars like the Performance Pack V6 mustang being able to use 18x8.5 instead of 19x9.5 is HUGE though

I updated my build page with my experience on concrete for the second time, and first time with the car prepped. It was insanely compliant. I was scared of being bad at it but I set some really quick times on practice day. Cant wait for tomorrow to rock the class for points.

The latest SCCA rulebook update 5/1/2013 doesn't list RTR in Appendix A. Did I miss something or will the nearly stock cars compete in C Stock the rest of the year?

http://scca.cdn.racersites.com/prod/...ated%205-1.pdf

RTR is a supplemental class for SCCA Nationals and National Tour events.
as such, your local region may or may not offer it.

The only difference between C Stock and RTR is the R compound tires are not
allowed in RTR. RTR tires must have a tire wear rating of 140 or higher.

I would suggest you register in CS and just go have some fun. (unless your local
region implements RTR or has a street tire PAX class).

Road tire may not show up as it was a temporary class. It will be gone in 2014, replaced by Street (C Street for us). It only matters if you have other stock rear wheel drive street tire cars to run against.

I saw you mentioned that you are new to it so if class is unimportant for you. Just run whatever class has other people (RTR, C Stock or STX). You likely wont beat anyone with any experience in those classes for a while so the last 6 months of this season, run whatever gives you competition to compare yourself too.

I run RTR with a RTR prepped car and often match or beat semiprepped STX cars so dont let classes tie you until you're ready to prepare for a particular class. Read my original post in this thread for RTR prep as it is the most affordable class (95% Full prep around $2000) if you enjoy it enough to prepare to compete, but don't worry about that until you have enough seat time to gauge if this is worth dedicating the time/effort/money for you.

Is anyone running a Rival or Z2 in 215/45 in RTR?

Yes, it's narrower. I think this may not be a terrible idea because:

*It has a smaller diameter than a 225/45, therefore more gearing advantage. I know my 225/45 snow tires reduce the car's acceleration

*It is a "square" setup. According to Hollis' Street Tire FAQ, a street tire should be the same width as the wheel. A 235 is pretty crammed on there.

*Less squirm and numbness (I assume) than a 235/40

*Lighter weight than a 225 or 235. On my miata, I could really feel the difference in a heavy wheel or a heavy tire.

The key to your noticing the acceleration difference with your snow tires is the fact that snow tires are typically heavy and have a higher rolling resistance more-so than the diameter.

I am running the 215/45 Z2, but I would prefer to have the 235/40 Z2 or the 225/45 Rival/RS3. I got the 215s knowing they were the lightest tire since I am still running stock wheels.

They were good enough for us to get a 2nd & 4th in RTR at Dover tour, and we'll see how they do at the DC ProSolo this weekend. I think the other two RTR FRS/BRZs running this weekend have the 235/40 Z2s

Chances are unless you are a top driver, 215, 225, and 235 are all going to be very similar in times. The only tire which comes in 235/40/17 is the ZII right now. I have heard from some who have tried different sizes the 235/40 ZII is the better tire due to both grip and gearing.

I have 225/45/17 BFG Rivals on the stock rims, I think the acceleration is slightly worse than the stock sized tires, but I gain a couple MPH in 2nd gear.