Thanks for the details of the offsets. I think I'd target a similar setup of 9"F and 10.5"R. As for the comment on mold release just run the car through some twisty roads to get the tires hot and then let them sit overnight. Then is game on at the race track.

 

Do you know your offsets?

 

Those look really, really good. The car looks so much better with 19" wheels than it does with the 20" wheels IMO.

Uncle Jed
2016 GT4 GT Silver
2013 BMW 535i
2008 BMW M3 Coupe

 

Currently the 8.5 vs 9 in 19's up front is only a real issue if you want to run Hoosiers. R7's come in sizes of 235 and then 265. If you want to run 265's you need the 9 inch wheel up front. 8.5 is fine for the 235's but you go with less rubber, potentially decreasing front grip in a car that already tend to understeer out the box.

For non Hoosiers the 8.5 is fine as 265 Cup 2's have been reported to not work and rub and other tires that will work (Cup 2's and RE71R's ) come in sizes (245/255) that are fine for 8.5 wheel.

In the rear 11's in 20 works well as you don't have clearance issues with the toe link, but if you go to 19's it becomes an issue. In 19's 11 works and a number of folks run them, although you might experience slight rubbing on outside. Some folks, myself included, go with 10.5 in the rear, simply to get a bit more clearance and since you can run the 295 tires on either - it makes no material difference.

In short, if you go custom go 9F and 10.5 or 11R. It gives you the best options to run the wider 265 hoho's and any of the street tire setups.
If you go off the shelf go with the OZ set that comes in 8.5F and 10R. It runs the street tire options and the smaller hoho setup.

The wheel options are well documented in the Track Wiki.

https://rennlist.com/forums/gt4/9323...etup-wiki.html

And, while I wat typing this I got the call from Forgeline that my new shoes have shipped...

(19*9ET50;19*10.5ET46)

 

forgeline run 11
i have updated them
they will make 10.5
it was et 50 then 45. we just requested 43

also
we got re71 266 to fit front.

 

well said
if u are buying custom
9/10.5
feel free to b different.
I also got 10" to fit front. but trust me. that's not what u want

 

Had a good time at the DE this weekend. It was on the Shenandoah track at Summit Point, WV. The track is about 2.3 miles long and has 16 corners, so lots of opportunities to test for under- or over-steer.

And, I'm happy to report, no under-steer with these wheels and tires; or, more correctly, no excessive under-steer -- as long as I did my part, the car turned in and tracked out very nicely. And, the RE-71Rs are significantly longer-lasting than the Dunlops that came on my car. I should be able to get at least two weekends out of a set of the Bridgestones, whereas the Dunlops didn't last one weekend.

In one of the sessions, a red 991 GT3 pulled out right behind me. When I couldn't pull away from him in that first, warm-up lap, I let him pass and then started chasing him. I expected him to start walking away from me due to his greater horsepower and PDK trans, but he never got more than 100 yards ahead of me for the entire 25 minute session. And that includes whenever we came up on traffic. Since we were the two fastest cars out there, with plenty of skilled drivers on the track, I'm inclined to believe the car was handling just fine.

So far, I'm pretty thrilled with the car. A friend of mine with a full-blown 987.1 race car (stripped, caged, Hoosiers, race suspension, etc.) was there this weekend. With my old Cayman R on NT01s, he could just barely pull away from me. With the GT4, despite being on street tires (okay, just barely street legal, but still...), I was able to lose him completely in less than half a lap. Afterward, he said he tried his damnedest to keep up with me, but fell behind even in the corners, which is where I would have expected the Hoosiers to make up the difference.

 

Thanks for the update. Great report--these sound like a very viable DE alternative tire. Any direct comparison data? Did you run Summit Point on your stock 20" tires prior?

The sizing is almost perfect--only 0.1" smaller overall diameter both front and rear, while maintaining the same 0.2" OD front-rear difference as stock. The only question is whether the taller sidewalls allow for more rollover...

 

50 front, 47 rear

 

really cool
to hear that bill. now there a viable much less costly alternative!

 

Car looks great!

 

A couple of interesting notes about the RE-71Rs:

1. The tires are surprisingly "talkative". I've run R888s and NT01s before, but they were pretty silent before sliding (haven't tried Hoosiers). These tires let you know when you're getting close to the limit. As Skip Barber likes to say, these were very happy tires.
2. Sidewall rollover was not a problem. Tire wear never got close to the little triangles molded into the sidewall (about 3/16" away, front and rear) -- it looks like I could actually run slightly less camber than I currently have. I won't know for sure until I can swap the street wheels/tires back on and can inspect the whole tread widths.
3. The tires were far, far quieter on the ride home than R888s or NT01s, actually not much worse than the ride up when they were virtually new.

BTW, the GT3 I mentioned above was running on nearly-new Trofeo Rs, if that gives a reference point.

Thanks!

 

They look good. You happen to know how much weight this wheel/tire combo saves over OEM wheels?

 

Don't have any same-track direct-comparison data yet. I ran on Summit Point Main with the stock Dunlops and Shenandoah with the Bridgestones. My next event will be on S.P. Main, so I'll get a direct comparison there, but that probably won't be until August.

I'm planning to weigh the wheels & tires when I swap back to the stock wheels. Wanted to do it last night, but didn't have a chance. I'll get it done before the weekend, and will post the results.

 

Looks great, always great to see a rare DBM!