Wheel/tire sizes for the R

[Zach34]

So FFR's 818R supplement recommends the following for wheel/tire sizes:

Hoosier A7/R7:
Front 225/40/17
Rear 255/35/18

Toyo R888
Front 215/45/17 (This size requires the front lower arms be mounted for extra caster)
Rear 255/35/18

Yokohama Advan Radial Slicks
Front 210/610/17
Rear 240/640/18

From what I can tell, FFR's gray 818R show car does indeed have 18s on the rear. However, after some searching on the build threads, I see Chad and SixStarCars running 17s on the rear. Plus, Chad went to 235s on the front, and SixStar squeezed 245s on the front.

For a guy who has never bought slicks, what do I need to be thinking about before shelling out money for wheels? Any pros/cons to 18s in the rear vs 17s? I know Chad has talked about rubbing issues on the fenders. Do the 235s/245s really work?

[Zach34]

Dumb question? I just wonder why FFR recommends 18-inch rears but none of the guys who actually race seem to be going that route. Just cosmetics?

[Pearldrummer7]

For me it was money and clearance. I could get a 17x9 with a good offset. The advantage to going 18" was a 9.5" wheel but in the offsets available (within financial reason) I couldn't make the wheels fit. Might as well stick at 17" diameter at that point.

[Mitch Wright]

I have gone with 17X8 on the fronts and 18X9.5 rear. At this point since I have the wheels I am not going to second guess myself and I have a number of tire choices available for the 17 and 18" wheels.

[C.Plavan]

17" tires/wheels are generally cheaper/lighter. With any quality race wheel, you are not stuck to off the shelf offsets. I was able to get a 17x9 rim in whatever offset I pretty much wanted with a very reasonable price.

225 R7's will rub on the front. Sure, you can maximize the camber as a band aid like FFR wants us to do, but the magic camber number for me requires rubbing. FFR knows this, that's why they redesigned the front fenders to have more "Flare" like the rear flare.

[xxguitarist]

Just another option for you guys, we have 245/15 A7s front. They are lower offset than needed, but it was what was available. They rub slightly on the inside of the fender, but it's functional. Rears are currently 16s (245), will be 17s (295?).

[Zach34]

Dragging this thread back out to douse it with a little gasoline:

How important are forged wheels for racing? Is it worth the 4x-5x price premium?

It seems for almost every non-forged wheel out there, you can find someone claiming that they've seen 100 of them fail in person (exaggerating slightly, but that's what happens on the internet). I know several of us R builders are running cast wheels. Is the spun-barrel process advertised by Enkei and several others a significant improvement over cast?

[C.Plavan]

Dragging this thread back out to douse it with a little gasoline:

How important are forged wheels for racing? Is it worth the 4x-5x price premium?

It seems for almost every non-forged wheel out there, you can find someone claiming that they've seen 100 of them fail in person (exaggerating slightly, but that's what happens on the internet). I know several of us R builders are running cast wheels. Is the spun-barrel process advertised by Enkei and several others a significant improvement over cast?

Just grab some Team Dynamics 1.2's. Forged are not worth the extra cost for the 818. I just had a Corvette blow up a Forgestar wheel in front of me at the Western NASA Championships.
We have cast OZ racing wheels on all the NP01s. They bend when we abuse them, but are easily fixed by a good wheel shop. None have broke. The repair shop says it all comes down to the pot metal. The cheap Chinese pot metal in some wheels are the reason of the failures. Stay away from those cheap Chinese wheels for racing, and you will be fine.

[Hindsight]

Many people are racing with cast aluminum wheels. Enkei have proven to be strong, light, and reliable, especially the RPF1. There are cheaper wheels out there like Rotas. You will hear horror stories about them but plenty of people race on them now, and TONS of people race on Enkeis and don't break them.

I wouldn't buy a forged wheel for strength since it's really not needed vs a well-made cast wheel. I would buy a forged wheel for weight savings. As for whether it is worth the price premium, that's not something I can say because it depends on the value of the dollar to you and how important it is to have lighter wheels. The lighter your wheels and suspension (un-sprung weight), the better your car will perform and handle.

[RetroRacing]

We tried 235 hoosier slicks on the front with 35mm offset wheels. Doesn't work well if you want the ride height less than 3.5" and spring rates less than 650lbs. We are going to 15's in the front, with 245 slicks. That will give us what we need to lower the car to where we want it.
We have run some pretty cheap wheels with slicks without issue, while at the same time, breaking a panasport on the same car. We don't go for thin spoked wheels though, and we inspect often.

[Zach34]

Thanks guys, that's perfect.

Cutting through the marketing lingo is part of the challenge. I looked at Forgestar. I don't think any of their wheels are actually forged. They are cast and the barrels are roll formed, which is fine (OZ and Enkei do the same with some of their wheels and it sounds like those are winners), but it's confusing at a glance. They are just throwing the word "forged" into their roll-forming process since it sort of mimics actual forging.

That's good to hear about OZ and Enkei, those are two I've been looking at. So many of their wheels are 18"+, though. Any opinions on SSR?

I do have the new nose - hopefully that lets me get the car low without rubbing too much on 17s.

[Sgt.Gator]

I've used Enkei PF01 and RPF1 and not had any issues. I *think* all Enkei Racing wheels are made in Japan. I'm not sure about their Tuner wheels.

[Bob_n_Cincy]

I've used Enkei PF01 and RPF1 and not had any issues. I *think* all Enkei Racing wheels are made in Japan. I'm not sure about their Tuner wheels.

Enkei is a Japanese company, but is all over the world. There is a big plant near one of our autocross sights in Columbus, Indiana. Making wheels there for 30 years.

http://therepublicphotos.com/p133247428/h6A9A9007#h6a9a9007

[DanielsDM]

Here is a video that shows how flow formed wheels are made. The wheel "blank" is cast then the rim part is forged to the finished width.
http://949racing.com/wheeltech.aspx

Links not working right now. Here is the same video on YouTube.
https://www.youtube.com/watch?v=nG0cwYIbsNc

[Sgt.Gator]

Enkei is a Japanese company, but is all over the world. There is a big plant near one of our autocross sights in Columbus, Indiana. Making wheels there for 30 years.

http://therepublicphotos.com/p133247428/h6A9A9007#h6a9a9007

I had no idea! Thanks.