ok guys - we're all going to have our opinions about wheel size;
bottom line = identify your objective when considering a custom wheel/tire setup:
- am i gonna track the car?
- am I gonna just go to shows and keep it clean all the time?
- do i drive it daily and want it to look good and perform well on the steet?

knowing where you stand with your car and what your objective is should help you identify what style/color/ preference of wheels and tires you should go with....
just my .02

 

You are absolutely correct...so by freeing up rotational weight at the flywheel I can allow for the addtional weight at the wheels. However it does not equate to 250lbs dead(static) weight. If your wheels are 8-9lbs lighter(cummatively or each wheel?) than stock, you do have an edge over stock. The wheels are able to turn with less resistance. The average drivetrain loss is 15-20%. By reducing weight at any point in the drivetrain, you reduce that loss percentage. By adding weight you increase it....obviously. So by me adding the wheels, I reduced the flywheel weight thus allowing less resistance.....and allowing the driveshaft to turn more freely and quicker giving more stored engery to the wheels. The flywheel weight was reduced by 14.5lbs. That a huge difference in resistance. You are correct that 20's are mainly for show.....however it's a give and take realtionship when it comes to performance. Show and go/Performance can be achieved and they can coexist. This was relized when designing this car. Some just take it further. Add some weight here.......reduece there. As long as there's a balance go for it. There has to be some creature comforts and attractiveness in a car to spark interests. Those come with a hit to performance if not, the whole car would be a straight-up race car.

For the origianl post: If you go with 20's be prepared for the addtional weight unless you go with a lightweight wheel or make adjustments for the increased rotational weight. If you're not concerned with the weight and it's all SHOW...have fun with it.....BUT you can have both.....if you want to spend the money.

 

BTW: RodH-

Good discussion....this is what forums are all about.

 

Go for 20x9 et+35 and 20x10 et+37 wheels the best tire size to go with is 275/30r20 front and 285/30r20 rear so3 pole positions. i saw this on a girls car and it looked awesome...she even beat me in the handling dept. she tells me the car was stock.except for the tires and wheels.but if thats the case that tire and wheel set-up sure did make the diffrence...

 

will some of you people with 20's on their cars post soe pics please.

 

NOZ4U,
1 pound of unsprung weight (ie: wheel) is equivalent to 4lbs of static weight. So, for example, if each new wheel you were putting on the car weighted 10lbs each, more than stock it would be like adding 160lbs to the car (40x4=160). Dont forget the 20" tires will weight more than the 18" so that is even more weight.

When I worked at Fikse Wheels, our German Distributor put a test together for Auto Motor und Sport ( a very famous German car magazine, equivalent to our Road&Track). Using a Porsche 993RS they did acceleration times (0-62, 0-100) and braking distances. First they did the test with the stock Porsche/Speedline wheels with OEM tires, they they did the test with our lightweight Fikse wheels with a lightweight Michellin tire and there was a signifigant difference.

If you want looks, 20" are ok (overkill IMHO), but if you want performance you should stick with 17" or 18".

 

I got 19's all around, but if I had to do it again, I'd consider18's up front and 19's in the back. That will give you equal sidewall height between the fronts and rears. With the 19's up front, the profile looks scary thin, IMO.

Spending the $ on forged wheels is recommended though.

 

I really dont see why people say it depends on what you want: all show no go or for perform. If you go with 20's and if your gonna run a TT, SC or lots of goodies and go NA them 20's are gonna SHOW AND GOOOO. My opinion is go with whatever you like and if performance is what your seeking and since 20's are all show then if you go 17, 18, 19 without mods then I guess you will be Mr. no show no go lol. It just seems like most people are like oh my if you go with 20's you aint gonna run which is well ha.

 

I really dont see why people say it depends on what you want: all show no go or for perform. If you go with 20's and if your gonna run a TT, SC or lots of goodies and go NA them 20's are gonna SHOW AND GOOOO. My opinion is go with whatever you like and if performance is what your seeking and since 20's are all show then if you go 17, 18, 19 without mods then I guess you will be Mr. no show no go lol. It just seems like most people are like oh my if you go with 20's you aint gonna run which is well

 

Get 19"s... you will bend the 20"s for sure. Even 19"s are pushing it. Make sure you buy forged, and dont compromise.

 

Couldn't have said it better myself

 

another

 

The fact is, even if you TT or SC the car, you are still loosing performance compared to a car with the same mods and smaller/lighter wheels. You havent taken into consideration that the engine mods do nothing for the braking or handling of the car and it is proven, heavier wheels/tires, decrease braking and handling ability.

This is about choices. If you want 20"s, put them on. People on this board are just letting you know what the drawbacks to running 20"'s are. There are definately no performance advantages to running 20"s....

 

It depends on what you're defining as performance. If you only counting lateral acceleration as performance than yes it will affect it. However "performance" is more than that. A 20in wheel will give you a wider contact path hence more rubber on the road. A larger diamter wheel will allow you to run a larger tire without going outside the constraints of the original tire diameter. You could certainly run a 300 tire with a 17in wheel but WOW! Not going to work well with our car. Now if you run a 300 with a 20 or larger (granted rolling the fenders) than your only combatant is weight.

If weight is the only issue........forged 20in wheels. They make em. Why not have a larger contact path on the ground? The weight on my wheels(even though its unsprung weight) was very negligable compared to the stock 17in wheels.

 

A 20" tire does not give you more contact patch than a smaller diameter tire. Contact patch is equivalent to the width of a tire. If you have a 275/40-18, 275/35-19 and a 275/30-20 all of the contact patch's are going to be either the same or within a couple tenths of an inch of eachother (for all practical purposes, the same). The ony thing different with at 20" tire vs 19, 18, or 17 is the sidewall height. You can run the same width tire on the car no mater what the wheel size is, the wheel well of the car is a fixed size, going to a 20" wheel does not magically allow you to run a wider tire.

 

Here is a pic of mine. 20x9 and 20x10 with eibach springs.

 

Ahhhh... A common misnomer my friend. A 20" tire DOES give you more contact patch than the same width 17" tire. Why, you ask? Well, the reason behind it is this.... The contact patchis the same width, but it actually is longer front to back. I am 100% positive of this, and it has been discussed many many times. I promise you it is true.

 

Ranger, sorry your wrong, if the overall diameter of the tire is the same then how does the contact patch get bigger on a 20" vs a 19" or 18".

Taken off the Tire rack website, info on Bridgestone S03

SIZE OVERALL DIAMETER SECTION WIDTH
275/40-18 26.7" 10.2"
275/35-19 26.6" 10.2"
275/30-20 26.5" 10.2

In this case the 18" tire technically has a bigger contact patch because it is .2" of an inch bigger in overall diameter, but for all intents and purposes, they are the same.

I didnt list a 17" tire because Bridgestone doesnt have a 275/45-17 but it should be about the same progression, 26.8" OD and 10.2" section width, so technically it would have a larger contact patch than a 20" tire.

The Bottom line is 20" tires are purely for looks, not performance. When was the last time you saw a 20" wheel on a racecar? The largest you will ever see will be a 19" on the old SuperTouring cars. The reasons they had 19" tires were to clear the 15" brakes they were using and to have as short a sidewall as possible to increase the spring rate on the suspension. The only reason they were able to get away with 19" was the low weight of the cars, the low horsepower the engines made and the lack of downforce the cars made. All other current GT cars use 18" wheels/tires as the best compromise between brake clearance, weight and performance, not to mention the horsepower they are making and the downforce they are generating could not be supported by a tire with such a short sidewall.

 

but dude 99.9% on here will never be in gt race etc. Maybe im wrong but I see 99.9% here doing street and going to the 1/4 track and run. I see the point about a car with the same setup but different wheels would perform different and maybe not depending on the driver. Its just different strokes for different folks. For me since most of my time is spent daily driving I would take some fat *** 20's with a TT or SC anyday and still fly like a bat out of hell and for the what tenth or a few tenth of sec guys (which is a lot i guess when it comes down to it at the track) just buy 2 sets of wheels to squeel

 

Like I said before, its down to personal choice. Just dont confuse 20" wheels with performance, some people seem to think bigger is better but that is not always true. One thing is for certain you will need to get a big brake kit front and rear for the car. It just plain looks silly having 20" wheels with the stock brakes.......