Should I go 18's

[squidz 10]

I just saw thunderkiss with his 18's coys and I like the look... SHould I go 18's or stay with my 17's?

Edited July 30, 2009 by squidz

[ForceFed70 14]

If you've already got 17's, I'd just stick with them. Doesn't seem worth it just for a slightly larger wheel.

[cphsonic 11]

Looks great with the 17s, why bother!

[69RestoRod 10]

Nope. They look good as is as still gives you some meat on the sidewall like a muscle car needs.

[Justafordguy 10]

That is a very nice coupe, I think it looks great as is.

[S code 69 13]

I don't like the looks of anything bigger than 15's on classic cars myself, the bigger the worse it looks.

 

I have 18's on my GT500 because that's what it came with, they look Ok on a newer car but I still don't like them. if I could get 16" wheels to fit over the brakes I'd swap them down to 16, I might give up a little handling but it would be worth it to get rid of the road noise from the thin sidewalls.

[Thunder Kiss 13]

Those wheels look tough on your car. :thumbup1:

Unless you can get out of them and into 18s for only a small outlay I wouldn't bother.

[opie_803 14]

i have 18's on mine and like them. i had a hard time deciding between 17's or 18's but glad i went 18. i also wanted something besides the bullit styled wheels that seem to be everywhere. they look good but i wanted something a little different.

 

your car does look good like it is.

 

good luck whatever you do.

Edited July 31, 2009 by opie_803

[gsxrken 21]

Looks are subjective of course, but wheel weight is not, and 18s are heavier, and that weight is further out from the center, which is even worse. You could add 30 feet to your 60MPH to 0 stops. From performance perspective, you only go as big as brake clearance requires- I had to go w/17s to clear my 13" brakes on the Mach1.

 

Another thing 18" tires are a lot more money than even 17s, which are usually quite a bit more than 15s. One of my other cars has 18s and it costs about 1200 to replace the Pilot Sports every two years or so.

[ForceFed70 14]

You could add 30 feet to your 60MPH to 0 stops.

 

30 feet is a huge increase. You have any reference info to back this up?

 

Let's be honest here, the weight of the wheel/tire package isn't going to have a big effect on your braking distance.

 

There are some disadvantages and disadvantages to a larger wheel. Stopping distance isn't one of them.

[gsxrken 21]

30 feet is a huge increase. You have any reference info to back this up?

There are some disadvantages and disadvantages to a larger wheel. Stopping distance isn't one of them.

 

You're correct to ask for some backup on this and let me clarify, if not backup a bit. If your brakes could lock up your wheels in either 15 or 18" dress, then your distances wouldn't change at all. But most factory brakes from the 60s are marginal at best and can barely lock up the stock pizza cutters these cars shipped with on a cold stop= forget about the fade on a second or third hot stop. I've seen some tests I'll try to dig up and post that showed cars unable to even lock up the tires on hard braking with the oversized rims. (Not vintage mustang but the point is similar).

 

Also let me qualify my statement a bit further. Bigger isn't automatically heavier- you could get a lighter 18 than a heavy 15 theoretically. But a more typical scenario might be the following: I just looked at tirerack at typical TT2- a 14" rim is 14 pounds, a 17" is 20, so lets say an 18 would be 22 pounds. 14" BF Goodrich is 24 pounds, 18" is 30 pounds, so an 18" rim/tire setup is 14 pounds more each. And remember this is a spinning weight, so more rotational inertia has to be overcome. It will acclerate slower for sure (physics) and maybe stop slower (depending on your brakes).

[cphsonic 11]

We track Stangers usually go for big because of less sidewall deflection in the corners. But then, thats on a fully built car, not one with stock brakes or underpinnings.

Rotational inertia is somewhat theoretical but is also widely discussed on our local track club forum. Always a fun subject it seems. ;) I once tried calculating the braking/accelleration inertia ("resistance" to changing speeds so to speak) coming from rotational energy in wheels & tires as compared to the pure kinetic inertia from the mass of the rest of the car, and though I dont recall the exact numbers I think we were in the 5% or so at 60 mph. Only difference I noticed when going from 17s to 18s was the better turn ins.

[grendi 16]

If you got stock brakes, get some high quality brake pads like the Poterfield R4-S (APD-34 / SHOE151).

your car will stop faster then with 14" wheels and "value" pads.

Edited August 4, 2009 by grendi

[zerfetzen 10]

From what I've read, increasing wheel size means decreasing performance, however it increases steering responsiveness which feels like increasing performance.

 

To take an extreme example, when you take a tight corner with virtually no sidewall, the car is more likely to break traction and slide. When you take a tight corner with sidewall, the sidewall on the outside of the turn gives (decreasing steering responsiveness a little...but that's just the "feel" of it). When it gives, it places more rubber on the road and gives you better cornering. I'm sure that's why NASCAR doesn't use Conestoga wagon wheels.

 

The same is true during a launch, which is part of the reason why drag racers have "wrinkle walls". No large wheels there.

 

Increasing wheel diameter is also usually associated with increasing weight, which decreases performance.

 

 

Most of that I got out a book called Chassis Engineering, and mostly near a section on the subject of the Circle of Traction.

 

I think the only reason to get larger wheels is because you personally like the look better, or because your brake rotors and calipers require it. I'd keep the wheel diameter as small as possible, given good brakes.

Edited August 5, 2009 by zerfetzen

[grendi 16]

just compare the tracks of nascar to formula D, DTM tracks or WRC courses.

 

last time i checked, i wasn't driving in circles all day long :tongue_smilie:

[Thunder Kiss 13]

Although I have noticed a slightly firmer ride going from steel 15" Magnum 500s to 18" alloys, it wasn't as bad as I thought. I have fairly soft Gabriel shocks in my car.

 

Handling and grip have increased dramatically - much less sidewall flex and tires that have gone from "all season" 400+ treadwear BFG's to modern 240 treadwear performance tires can't even be compared!

 

As for decreased performance due to more rotational mass - Maybe in theory, yes, but in the real world I can't feel it.

[cphsonic 11]

From what I've read, increasing wheel size means decreasing performance, however it increases steering responsiveness which feels like increasing performance.

 

Yep that's the balance you need figure out for your ride & skills. Cup cars run on those balloons mainly for historic reasons I guess, and now its just a part of the suspension. I've only tried one on an oval but it should be interesting to see how they perform under real twisties. DTM or WTCC cars run what works, they are probably the truest statement to where the balance is between small and large on the track.