Why do aftermarket rims = lowering the car

[AJT]

I always wondered, my 02 doesn't have a noticeable wheel gap with factory rims. Everyone that gets aftermarket rims seems to have the "4 wheel drive look" unless they lower.

Is that because it is just more noticeable, or optical illusion??

I would like to get some HRE's,but I don't want to lower my car. I run Pilot sport cups 345/18" now.

Sorry for Another wheel question...

 

[ViperJohn]

The 4 x 4 looks is more obvious with the 19 inch and 20 inch wheel packages. If you stick with 18's, the ride height won't change.

 

[dyeguy]

19" and 20" tires are usually alot lower profile so they don't fill up as much of the wheel well. The second number in the tire size indicates the tire's profile height. It is a percentage ratio of the tires width (ie the 30 in 275/30/19) A 275/35/19 would be taller than the 275/30/19 and fill up more of the gap. I went with a 335/30/20 tire on the rear of my car which fills up the gap even more than the stock tire did so it actually looks like it has been lowered. I hope that makes sense.

 

[ViperJames]

I am not sure that I agree the 19 and 20 inch packages make the 4x4 more obvious......the diameter is bigger yes, but the stock tires are pretty low profile to start, so if you go to a 20 inch rim/tire, you are taking up more of the space, even if the tire is a TINY bit lower profile the over all result should be similar.......

 

[vipertime3]

Simply compare the O.D. (Outer diameter) of the stock wheels/tires vs. any aftermarket wheels you might be interested in. If you plus up the wheel diameter and go with a lower profile tire, you can maintain (roughly) the same O.D. There are lots of aftermarket packages/combinations for the Viper that increase overall O.D. and some that reduce it. If you've reduced O.D. then you'll have a larger gap between the fender and the tire. Remeber half of the delta goest to changing ride height, and half goes to the fender-to-tire gap.

Examples: (sorry for the formatting)

Sidewall O.D. Radius O.D. Delta Radius Delta Fender Gap Ride Height Req'd Lowering
Stock Front 275 0.35 18 3.7894 25.5787 12.7894 0.0000 0.0000 3.0000 27.5000

Rear 335 0.3 18 3.9567 25.9134 12.9567 0.0000 0.0000 3.0000 28.6250

Sidewall O.D. Radius O.D. Delta Radius Delta Fender Gap Ride Height Req'd Lowering
19s Front 275 0.3 19 3.2480 25.4961 12.7480 -0.0827 -0.0413 3.0413 27.4587 -0.0413

Rear 345 0.3 19 4.0748 27.1496 13.5748 1.2362 0.6181 2.2146 29.2431 0.6181

Sidewall O.D. Radius O.D. Delta Radius Delta Fender Gap Ride Height Req'd Lowering
20s Front 275 0.3 20 3.2480 26.4961 13.2480 0.9173 0.4587 2.5413 27.9587 0.4587

Rear 345 0.25 20 3.3957 26.7913 13.3957 0.8780 0.4390 2.5610 29.0640 0.4390

Sidewall O.D. Radius O.D. Delta Radius Delta Fender Gap Ride Height Req'd Lowering
19s Front 285 0.3 19 3.3661 25.7323 12.8661 0.1535 0.0768 2.9232 27.5768 0.0768

Rear 355 0.25 19 3.4941 25.9882 12.9941 0.0748 0.0374 2.9626 28.6624 0.0374

 

[AJT]

Thanks

I'd like to keep 18" tires, just didn't want to spend all that $ on some HREs & then have to spend a bunch more to make it look "right"

I've got 295 cups on the front & 345 cups on the rear.

 

[ruckdr]

Just use the tire diameter calculator.
http://www.miata.net/garage/tirecalc.html

It the overall diameter is the same for 17,18,19,10,21,22,23,.... inch rims, then the gap will be the same.

Here is another calculator:
http://www.rx7.org/Robinette/tire_diameter.htm

Later,

 

[Austin]

Andy, what wheels are you looking at in the HRE line?

 

[AJT]

Hey Austin,

547R FULL Chrome & new Pilot Cups. I believe R refers to the lip.

I think they would look great on my car. I'm just trying to swallow the cost. I sure don't want to pay another 4K to lower after that.

 

[95Viper]

Remember too...different vendors and different tires made by the same vendors have different outside diameter even with the same 335/30/18 or whatever applicable measurement.

The only way to know for sure is lookup the OD specs on each tire and compare.

 

[AJT]

Remember too...different vendors and different tires made by the same vendors have different outside diameter even with the same 335/30/18 or whatever applicable measurement.

The only way to know for sure is lookup the OD specs on each tire and compare.

If I use the same size & type tires = 18" Mich. Pilot Sport Cups, then it should like the same...

I was just wondering with the rim so much more open than stock HRE 547r, whether the optical illusion made it look worse?

Thanks
Andy