[RocktimusPryme]

So I’m still kicking around wheel ideas. I’ve started to get more active locally a test n tunes and what not. So I’ve been looking at more race oriented wheels. I really dig the Race Star Dark Stars. They are semi affordable. But more importantly, all black. Hard to find shots of them on classic cars but, it’s a five spoke rim. Hard to go wrong.

Anyway, I saw a low of shots of them with a reverse stagger, 17” either skinny, or 17x7 up front with a fat tire tall sidewall 15 in the back. Anyone have any experience with this? I really like the look. And you have more tire options with the front 17. But again, it’s mostly shown on more modern cars.

[amcmike]

What's the question exactly?

If you're into straight line, it's a great combination, as long as you're okay with the look. The taller sidewall on the rear will help straight line traction (with negative effects on handling relative to having 17s all around). The shorter sidewalls on the front will help stability and control. Of course, the bigger rim does effect rotational mass, however would probably be immeasurable impact to 1/4mile times.

[RocktimusPryme]

I guess, I was soliciting opinions on the general look. And was hoping someone had their car on this setup and could provide pictures. The look a crazy common on newer mustangs and camaros, but hard to find on a classic car. Even the Dark Stars themselves I think I only saw pictures on maybe 2 vintage vehicles.

I had shied away from them because most cars today have the spokes of the wheel all the way on the outside of the wheel, lots of backspacing. Classic cars look better with more of a "deep mag" look with the close to a zero offset, ie on an 8 inch wide wheel 4 inches of backspacing. A lot of the Race Star catalog is similar, with a half mile of offset. BUT, their 15x8 and 15x8 look like they do have the classic deep well look. So I am beginning to strongly consider those.

I know "opinion" forums are usually a waste of time, the OP has already made up their mind and is just looking for confirmation bias. But in this case, its sorta a new idea. Ive only recently noticed cars with this setup and its hard to find comparisons on anything but a 2016 Camaro.

[JSPONT]

That all started because the new cars have big brakes and that's the smallest front rim they can fit. A friend of mines Z06 has 17 up front, he paid 5k to pull smaller brakes on the back so he could put a 15 inch rim with a tall tire to get traction. Over 1000 hp car. I love the look on the " newer cars" no so much on out old classics. just my .02

[RocktimusPryme]

Originally Posted by JSPONT

That all started because the new cars have big brakes and that's the smallest front rim they can fit. A friend of mines Z06 has 17 up front, he paid 5k to pull smaller brakes on the back so he could put a 15 inch rim with a tall tire to get traction. Over 1000 hp car. I love the look on the " newer cars" no so much on out old classics. just my .02

That makes sense, and I wonder if it would indeed look better with a big brake rotor in the front, I have a generic Right Stuff basic disc kit in the front, might be an excuse to go to a bigger rotor Ive never been completely happy with the performance of those brakes anyway.

[Steve C.]

Old dated material but it might be of interest.......

"Wheels: How big is too big?

The general rule is to only use as big a wheel as you need to clear brakes and suspension components. The weight of an average car for road racing usually requires brakes that are too big to fit inside 15-inch wheels, so larger ones are used.
So the question becomes what is the best size wheel to use ? It's natural for us to think that bigger is better, and it's true that the general public prefers the look of larger wheels, but don't let that trick you. Oversized wheels will slow you down. It all comes down to moment of inertia. The excess weight of a larger wheel is an important issue, but the diameter of it is a much more important factor. The effect of a 10-pound weight at the end of a 12-inch string is much less than a 10-pound weight at the end of a 36-inch string. The larger-diameter wheels are not only heavier, but are much harder to control the rate of rotation like the weight at the end of the string.
Now let's look at overall tire diameter and the effects of sidewall flex. Let's say you've decided on a tire diameter and are looking at what combination of wheel diameter and sidewall height to run. The taller the sidewall, the more flex it can have. This is a good and a bad thing, but mostly a bad thing. When the sidewall id tall, it can deflect quite a bit, throwing away any sense of your suspension alignment settings. Too short of a sidewall a sidewall can be oversensitive to surface conditions, and gives you far less warning before traction is lost. The trick is to find the right balance.
The sweet spot for most of our muscle cars and track cars is 17- or 18-inch wheels. this isn't just our opinion, but that of many industry insiders. The 12- or 13-inch rotors usually chosen by the road racing crowd fit in these wheels just fine, and don't need the additional clearance given by a 19-inch or larger wheel. Consistent with that, BFGoodrich doesn't even make their sticky road race R1 tires for any wheel larger than 18 inches in diameter.
So why does NASCAR still use 15-inch wheels ? The rules mandate these 15-inch wheels and have for many years; knowledgeable fans speculate that this rule won't change. It can be argued, however, that oval track cars use this tall sidewall as a part of their tunable suspension. Since their quickness is defined by how they can plant power out of the turns, tire pressure can be used to improve that.
That brings us to ask why new Corvettes and Vipers use such large wheels. The simple answer to that is because they look cool. There is no advantage to these larger wheels except their looks. The laws of physics would suggest that using a smaller wheel while still clearing the brakes would make the car faster.

Wilwood 12.19" rotors will fit within some 15-inch wheels.

Also this old material related....

Using a 5.0 Mustang for testing.
Baseline- 14.7303 average and 88.98 mph average.
With lighter wheels- 14.6973 average and 89.17 average.
Finish line advantage over baseline- 4.4 ft.

I believe the lighter wheel combination was 8 lbs per wheel, but not 100 percent sure. But there is a lot more to the total effect than wheel weight alone... wheel moment of inertia and wheel-mass reduction. On average you can safely assume that with a typical live axle, a 10-pound-weight savings at the wheels will be about equal to 30 pounds off the axle.

From a David Vizard's article


.


.

[RocktimusPryme]

That was a good read, even with a 17x7 I gotta think a racestar is going to be lighter than a Rally II with 235/60s. 15 ot 17 Im going to go with a slightly slimmer tire in the front, because I currently have some minor rubbing issues.

It seems like from a performance standpoint its the best of both worlds, a little better handling setup on the front with the taller sidewall in the back. Its all about do you like the look at that point, which Im honestly not sure on. There are not many examples on classic cars to compare to. I think Im sold on the Dark Star in general, its just a question of if I want to be the guinea pig on the style portion of it. I do like the idea of maybe being able to go to a C5 front brake. While I have been more proactive in getting to the track its still a street car first. So handling/braking is still valuable, that's why Im not looking at a full on skinny up front.

[Steve C.]

17x9.5 up front and a 15x10 out back

https://cimg2.ibsrv.net/gimg/ls1tech...f40c34462f.jpg


https://cimg3.ibsrv.net/gimg/ls1tech...18738a618e.jpg

https://cimg1.ibsrv.net/gimg/ls1tech...c2d2763440.jpg



.

[RocktimusPryme]

Yeah, there are a lot of 2000 and up cars. That looks great btw. No way im fitting a 9.5 in the front. But a 17x7 will fit. or a 15x7. Im still undecided on if I want to be the first gen Guinea pig.

[RocktimusPryme]

So I did find one on a classic car. This picture kinda sells me. I think Im fine with that look. Im at least going to give it a shot. Im sure some here will hate it, but some people here hate anything that isnt a 14" redline.

[amcmike]

Worst case you buy new front rims and tires and sell the old ones if you don't like it.

I gotta admit, it's looks better than I would have expected before seeing pics. I might have even considered it myself if I were setting mine up for straight-line fun (mine is more pro-touring). It seems to work best if the rims are darker in color, and you don't have the rear tire too much taller (overall O.D.) than the front.

The nice thing too, is most of your braking is with the front. So being able to put on the bigger discs will help all the more with getting is hauled down in the 1/4.

[amcmike]

Originally Posted by RocktimusPryme

That was a good read, even with a 17x7 I gotta think a racestar is going to be lighter than a Rally II with 235/60s. 15 ot 17 Im going to go with a slightly slimmer tire in the front, because I currently have some minor rubbing issues.

It seems like from a performance standpoint its the best of both worlds, a little better handling setup on the front with the taller sidewall in the back. Its all about do you like the look at that point, which Im honestly not sure on. There are not many examples on classic cars to compare to. I think Im sold on the Dark Star in general, its just a question of if I want to be the guinea pig on the style portion of it. I do like the idea of maybe being able to go to a C5 front brake. While I have been more proactive in getting to the track its still a street car first. So handling/braking is still valuable, that's why Im not looking at a full on skinny up front.

It sure would be lighter. I'd go with a 215/50R17. Believe it or not, that will actually handle better than it does with the 235s on 15s it has now (even though you're giving up about 1/2" of tread).

[RocktimusPryme]

Originally Posted by amcmike

It sure would be lighter. I'd go with a 215/50R17. Believe it or not, that will actually handle better than it does with the 235s on 15s it has now (even though you're giving up about 1/2" of tread).

That’s actually exactly what I have in my summit box lol.

I’m now waffling over what size rear. My 245/60 is about an inch five or take a quarter from my lower shock mounts. So with a wider wheel and wider tire it will be close. I wanted to go 15x10 but I think it will either hit that shock or stick out obnoxiously outside. A look I just don’t care for. So probably going to be 15x8

I’m trying to figure out if I can safely run the 275/50 over the 255/60. I don’t want the extra height of the 60 series. I only have 3.08s and if my math is right, the difference in those heights is basically one full gear step. Ie, taking my 3.08 down to a 2.93. I cant be giving up any gearing lol!

Ive stared at it alot, Im pretty sure the 15x8 with 4"BS with a 275/50 will fit in the back.

[4dblnkldude]

Nahhh

[amcmike]

Originally Posted by RocktimusPryme

That’s actually exactly what I have in my summit box lol.

I’m now waffling over what size rear. My 245/60 is about an inch five or take a quarter from my lower shock mounts. So with a wider wheel and wider tire it will be close. I wanted to go 15x10 but I think it will either hit that shock or stick out obnoxiously outside. A look I just don’t care for. So probably going to be 15x8

I’m trying to figure out if I can safely run the 275/50 over the 255/60. I don’t want the extra height of the 60 series. I only have 3.08s and if my math is right, the difference in those heights is basically one full gear step. Ie, taking my 3.08 down to a 2.93. I cant be giving up any gearing lol!

Ive stared at it alot, Im pretty sure the 15x8 with 4"BS with a 275/50 will fit in the back.

If anything you need more BS than that, unless your rearend is narrower than stock. Usually you want +6 to +8 offset rims. Their stuff is either 0 or negative. So on the back, the best you can do is 15x8 and 255.


None of the 17x7s have the right offset either. Looks like you'll have to step up to the 17x8s, which you could still run with the 215s.

[RocktimusPryme]

I have a nova rear end (8.5). So it is narrower than stock.

Also I have a disc kit on the front that moves the wheels out 3/8ths. Why wouldn’t the 17x7 work? Isn’t 17x7 the same backspacing as a rally II?

FWIW I called them and they said they would make the offset what I wanted for a reasonable price.

[amcmike]

Originally Posted by RocktimusPryme

I have a nova rear end (8.5). So it is narrower than stock.

Also I have a disc kit on the front that moves the wheels out 3/8ths. Why wouldn’t the 17x7 work? Isn’t 17x7 the same backspacing as a rally II?

FWIW I called them and they said they would make the offset what I wanted for a reasonable price.

When I looked at their online catalog, I didn't see a combination of wheel offset and bolt pattern that would work in 17x7. But looking in Summit, they do show it with a 4.25" b.s., which is perfect. So it does look like you're good to go there.

As for the back, I have the 8.5 Nova rear too. I'm also running discs in the back (which pushes it back out a little). Are you running discs (or plan to) on the rear? My combo is 17x9.5 with 5.5" backspacing and 275/40s. It's tight, but works. That would be equivalent to 15x8 and 4.75" backspacing for reference.

Hopefully that helps.

[1965gp]

I like it- gives the car a ‘tough’ look. I remember in high school we thought a car was fast if it had different wheels on the back!

If I did it I would buy 17’s for the rear in addition to the 15”s so you could go back and forth.

[RocktimusPryme]

I have discs in the rear too. As I understand it the diameter of a 17 allows you to clear the shock mount with a wider rim. With a 15 there is no chance I’m getting an extra inch and a half of backspacing.

And yeah I had thought that maybe in the future finances allow extra rims to swap out, not even so much for the 17 as for a street tire to take the miles off the drag radials.


Of course when i was back there looking measuring tire clearance I saw that my axle tubes were leaking. So I got that going for me.

[Lee]

Larger front diameter than rear makes MORE sense to me, on RWD cars with powerful motors.

Go for it!