Why the heck are so many using ride-killing 20" wheels??

[MovingZen]

Well, so far you guys have given me zero reasons (other than looks) for 20" wheels. Show me some proof that 'handling' is actually better with 20" wheels. Show me proof where lap times are reduced and then I will buy into the handling improvement of 20" wheels.

Nobody has to prove anything to you. You quoted American Muscle saying that larger wheels "may" cause ride and handling issues. That's not proof of your point. My car came with 20" wheels stock. If you don't like how it looks, you don't like how it looks but if you're just going to claim handling issues based on AM, go drive one and see for yourself. I've had taller tires fold on me, go try that on for size and then come back and tell me how important ride quality is to you. Bigger brakes and less sidewall flex are more important to me than torque storage off the line. I'd rather pedal my acceleration than worry about sliding off into the trees at 130 mph. I didn't buy a Cadillac.

 

[blk02edge]

Majority of the most current track oriented cars/race cars are on 19" wheels FWIW. Going 1" more is negligible on a street car.

 

[Mojo88]

Majority of the most current track oriented cars/race cars are on 19" wheels FWIW. Going 1" more is negligible on a street car.

Thanks for that info. Very interesting.

 

[rotor_powerd]

F it, it's going to end up on 15 x 10s / 17 x 4.5s anyway. Unless you don't like to party. It's gonna be a good day, your gonna send it.

The only proper size wheels for these cars. Even on a 100% street car. Unless you wear skinny jeans. Lol

 

[ur bittn]

 

[03 DSG Snake]

LOL at consulting American Muscle for expertise on anything.

I've had no issues with handling on 20s, love the looks as well. For street and occasional track they work just fine. Sizes should be up to personal taste.

 

[GT Premi]

How old is that American Muscle article? I didn't know any current Mustang came with 16" wheels.

 

[Mojo88]

LOL at consulting American Muscle for expertise on anything.

I've had no issues with handling on 20s, love the looks as well. For street and occasional track they work just fine. Sizes should be up to personal taste....

Look, I totally agree about "personal taste" and all that. It should be your choice, and that's wonderful.

But why would you LOL at American Muscle? Justin and Steph have a lot of terrific and informative videos on YouTube.

 

[Mojo88]

Nobody has to prove anything to you...........

Well, when folks make a claim saying "my car handles better", then that demands some proof. If I said to you that I put new cams in and my car is faster, then you'd say "what did the dyno show" or you might ask "how much did your 1/8 or 1/4 mile ET's improve".

Beautiful GT500, btw.

 

[BOOGIE MAN]

The only way that bigger wheels "ruin" handling is by adding unsprung weight compared to smaller wheels. However, bigger wheels allow for bigger brakes, so balance that out however you like.


The C5 vette in your avatar came with 17 and 18s...
The C6 vette in your avatar (and the C7 for that matter) came with 18 and 19s...

Smaller sidewall = better handling (turning)
Larger sidewall = better traction on holeshots but more sidewall flex while turning, therefore "worse" handling

So if you wanted to put smaller wheels on a newer Mustang because of your argument that smaller wheels = better handling, and then you put small sidewall tires on it, the overall wheel would not "fit" the car and would look out of place.

 

[BigPoppa]

My s550 with the factory 20" wheels rides better than my s197 did with 18" factory wheels. Handles way better too.

 

[mc01svt]

OP is living 30yrs in the past. Gone are the days of 14/15in wheels, pathetic single pot brakes and bias-ply tires.

Most of all high performance cars come with ginormous 4 and 6 piston brakes that will not clear small wheels. Not to mention near race spec rubber with stiff sidewalls and low profiles. In fact some of the older 17in wheels are heavier than the newer 20s so unsprung weight is a none issue.

i can name about 15 cars with over 600hp that come stock with 20s. You are stupid if you think they engineers are handicapping the cars by putting larger rolling stock on them.

 

[DHG1078]

Well, so far you guys have given me zero reasons (other than looks) for 20" wheels. Show me some proof that 'handling' is actually better with 20" wheels. Show me proof where lap times are reduced and then I will buy into the handling improvement of 20" wheels.

Its not that easy to say. What improves handling isn't necessarily wheel diameter, but rather lower mass, especially rotating mass, short and stiff sidewall tires, and sticky compound tires. Smaller wheels and tires can theoretically have a lower mass, but not all wheels are engineered the same. A cheap set of 17's can weigh more than an expensive set of 19/20's. Having said that, even on a light weight set of 20's the majority of the mass is further from the center of the wheel than on a 17/18 which hurts performance. But again, we're talking in general terms and a poorly engineered 17 can be worse than a great set of 20's.

Then comes brakes. Bigger cars today weigh more. They need bigger brakes to compensate. Bigger brakes mean bigger wheels. We have to add a little bit of rotating mass to get better/adequate brakes on the car.

No one has gone out and done a comparison and bought a shit ton of wheels/tires of different sizes that fit one car and run laps. If you track your car a ton, you go for the smallest and lightest set you can find that fit your brakes. If you have never been on a track, find the wheels you like best and run them.

 

[Torch10th]

The biggest reason you see large wheels on factory cars these days is simply because they have become popular. Looks are subjective, but most people tend to like larger wheels.

There are some benefits to larger wheels, just as there are negatives. The larger diameter wheel does allow for larger brake rotors which have aloud manufacturers to make strides in stopping distance and specifically repeatability in hard braking that they couldn't accomplish just 10 years ago. The braking performance between a New Edge Mustang and even a non PP 2015 is insane.

The larger wheel also allows you to run a larger tire without adding sidewall. THe norm is a 28" combo these days which does a couple things for you. Combined with 5,6...now 10 speed transmissions, it's allowing gears to go deeper, with less spread which aides in acceleration while then also being able to get those RPM's down at cruise. A larger diameter tire carries a larger contact patch for better traction and also increases moment of inertia which slows torque application...again aiding traction in a street situation.

The draw back is that without expensive lightweight construction you add a significant amount of unsprung weight, especially on cars like the New Edge and SN95 which have suspensions that aren't designed around a smaller, lighter wheel and tire package.

 

[Zemedici]

Well, when folks make a claim saying "my car handles better", then that demands some proof. If I said to you that I put new cams in and my car is faster, then you'd say "what did the dyno show" or you might ask "how much did your 1/8 or 1/4 mile ET's improve".

Beautiful GT500, btw.

not particularly, most people would say 'sweet...' and go on about their day....it matters not to me what someone else does with their car and their money.

 

[DHG1078]

A larger diameter tire carries a larger contact patch for better traction

I was with you except for this. Any increase in contact patch area due to an increase in diameter is going to be minuscule. Probably wouldn't be able to see any increase in traction, even with good test equipment. Putting a wider tire is much better for increasing contact patch compared to increasing the diameter.

 

[08mojo]

I still refuse to believe 20" wheels kill the ride quality on these cars. I'd like to hear tire sizes of the cars the OP has driven. Really short, stiff sidewalls are what kill the ride quality--regardless of rim diameter. A 20 series sidewall is always going to have worse ride quality over a 35 series sidewall--whether it's a 18", 19" or 20" wheel.

 

[Torch10th]

I was with you except for this. Any increase in contact patch area due to an increase in diameter is going to be minuscule. Probably wouldn't be able to see any increase in traction, even with good test equipment. Putting a wider tire is much better for increasing contact patch compared to increasing the diameter.

If this was the case, you wouldn't see 33's, 35's what-have you on off-road vehicles. You wouldn't see large 33-35" tires on big slicks, because there are disadvantages to these types of tires. They take more power to turn because of that increase in moment of inertia. Why only increase width of the tire footprint when you can also increase length.

You obviously have to look at loading of the tire as well as inflation, but contact patch rules and if you're tying to go fast, having as much of it as you can is generally helpful. Since we're primarily talking about street cars here, adding tire height is the best way to do that as what you give up in rolling resistance is made up for in traction without having to run tires severely low on pressure.

If you want to contrast that versus a racing application, the NASCAR guys are a good point of reference. These guys run a pretty narrow tire by racing standards, so they have to gain contact patch elsewhere. They don't run large tire diameters either, so the way the accomplish greater contact patch is to reduce tire pressure. Again, they give up rolling resistance here, but any losses made there are overlooked by the greater grip level of the larger contact patch.

To really see the difference you'd have to plug your specific tire, size, pressure etc. into a footprint calculator. There's a reason though that OEM's are doing this. With a taller tire, small stiff sidewall and air pressures that are coming out of the factory near 40psi, you can maximize contact patch while reducing rolling resistance.

 

[DHG1078]

If this was the case, you wouldn't see 33's, 35's what-have you on off-road vehicles. You wouldn't see large 33-35" tires on big slicks, because there are disadvantages to these types of tires. They take more power to turn because of that increase in moment of inertia. Why only increase width of the tire footprint when you can also increase length.

You obviously have to look at loading of the tire as well as inflation, but contact patch rules and if you're tying to go fast, having as much of it as you can is generally helpful. Since we're primarily talking about street cars here, adding tire height is the best way to do that as what you give up in rolling resistance is made up for in traction without having to run tires severely low on pressure.

If you want to contrast that versus a racing application, the NASCAR guys are a good point of reference. These guys run a pretty narrow tire by racing standards, so they have to gain contact patch elsewhere. They don't run large tire diameters either, so the way the accomplish greater contact patch is to reduce tire pressure. Again, they give up rolling resistance here, but any losses made there are overlooked by the greater grip level of the larger contact patch.

To really see the difference you'd have to plug your specific tire, size, pressure etc. into a footprint calculator. There's a reason though that OEM's are doing this. With a taller tire, small stiff sidewall and air pressures that are coming out of the factory near 40psi, you can maximize contact patch while reducing rolling resistance.

You don't run a large diameter tire off road for contact patch. A larger diameter makes it easier to roll over obstacles. Deflating the tire pressure absolutely helps increase contact patch area, and reduce sidewall stiffness.

Increasing the diameter itself, assuming the same tire, sidewall strength, etc. does not increase contact patch area. Your tire comes from the factory about as round as it gets. The cars weight deforms the tires in each direction. Increasing the diameter does not change how much the tires deform, changing other variables like pressure, compound, etc. does.

 

[DHG1078]

If this was the case, you wouldn't see 33's, 35's what-have you on off-road vehicles. You wouldn't see large 33-35" tires on big slicks, because there are disadvantages to these types of tires. They take more power to turn because of that increase in moment of inertia. Why only increase width of the tire footprint when you can also increase length.

You obviously have to look at loading of the tire as well as inflation, but contact patch rules and if you're tying to go fast, having as much of it as you can is generally helpful. Since we're primarily talking about street cars here, adding tire height is the best way to do that as what you give up in rolling resistance is made up for in traction without having to run tires severely low on pressure.

If you want to contrast that versus a racing application, the NASCAR guys are a good point of reference. These guys run a pretty narrow tire by racing standards, so they have to gain contact patch elsewhere. They don't run large tire diameters either, so the way the accomplish greater contact patch is to reduce tire pressure. Again, they give up rolling resistance here, but any losses made there are overlooked by the greater grip level of the larger contact patch.

To really see the difference you'd have to plug your specific tire, size, pressure etc. into a footprint calculator. There's a reason though that OEM's are doing this. With a taller tire, small stiff sidewall and air pressures that are coming out of the factory near 40psi, you can maximize contact patch while reducing rolling resistance.

oh and off road guys are concerned about increasing tire diameter, not so much the wheel diameter. The bigger the difference, the more tire they have to protect the wheel from hitting obstacles, increasing contact patch through adjusting tire pressure, and making it easier to roll over obstacles by keeping the center of the wheel as high off the ground as possible. Wheel size is the secondary objective constrained by tire selection and brake size.