running on different rim sizes

you'd want the larger rim in front for FWD.

running on different rim sizes

anybody tried running 15's or 16's on the front and 17's on back? any feedback about ride comfort and performance would be appreciated

i know but it doesn't look good just want it for looks

actually you would want the smaller wheel on the drive side and the larger wheel on the roll side , also for performance and ,handling. look at how any gt car is setup , you will see this. denso sard supra , has 19" in front and 18" in back. hence its rear wheel drive. on a front wheel drive . i understand that the smaller on the front might induce understeer , but i think if you run the same profile tire on both front and rear , this should remedy this.

and tes , others have thought about it , im one of em .

I dont know anything about GT car. But I think they put 19 front 18 rear is because they want to put a bigger brake at the front.
I THINK Bigger diameter rims don't do anything good at performance side, wider rims does. Just my 2 cents.

As for phal99, it works fine if you put different size rims at the front and rear. It looks good, but not good for performance as others say.

Many FWD Honda stock cars run 16f/15r in Japan. TopFuel runs 17/15 on their EK.

But if it's just for looks it dosen't matter what you do.

on fwd , bigger brakes is why they do this but , for handling and acceleration purposes , the smaller , but wider wheel goes on the front . i know what im talkin about here.

find me one FWD car that is set up with larger rims on back besides cars at the drag strip running 13/14 slicks up front. On circuit cars, the goal is to reduce understeer on FF platforms, that is done using tires with a wider contact patch and less sidewall up front vs. the rear. Hence the larger rim (usually 16 w/ 225 mm tires) go up front and the smaller (let say 15 with 195mm) in the rear. A setup like this will always give you better rotation through the apex.
And you claim the only reason they do this on FWD is to clear large brakes.. then wouldn't it make sense to strap some 17/18's on the back by your reasoning? Or at least even up the F&R size?

off the top of my head here are some professionally setup cars I can remember running larger rims in front vs rear:
Top Fuel EG6 - 17/15
Circuit Spec ITR -16/15
Trial Celica 19/17

the only FF cars I remember running with smaller rim in front are the ricer from down the street rolling hard with steelies up front and huge pepboys rims in the rear.

Okay now that makes sense. Wouldn't it be better to just run same size wheels are around then?

run 20s in the rear and 14s in front so you look like a hotwheels toy. lol

no but seriously, i get why those fwd pros use bigger rims up front. 15x7 rims are pretty rare. most are 15x6.5. on the other hand, 17x7 is common and some are even 17x8. bigger diameter rims are often also wider and provide more traction. and if you're running engines with as much torque as those pros do, you would need that extra traction to get the power down to the road without too much wheelspin. if you put small, lightweight rims in front it'd be hard to get the car off the line quick.

on the other hand, if you're running a stock or even lightly modded engine on a fwd, you would want smaller lighter rims up front so that the engine is bearing less unsprung weight. you wouldn't need the extra traction because even just 14x6 with good tyres can give you enough traction to get a quick jump off the line.

in terms of looks, i personally prefer all four rims to be of the same size. call me conventional but that's just the way i like it. but i guess if you do want bigger rims in the rear and smaller rims up front, i don't think it'd look that bad. you might have problems looking for people or shops who are willing to sell just 2 out of a set of 4 rims though.

bigger wheels = less sidewall on the tires. During hard cornering the tires would want to flex and the sidewalls roll inwards toward the contact patch causing really sloppy handling. Also you may notice the maxium tire width avaliable for 15's are 205, 225 could be found on R compound competition tires (Advans, Hoosiers, etc) but those are really expensive. With 16's and 17's you can easily find 225mm or wider.

I understand that but the issue I was addressing is "bigger rims in the rear = best for FWD." I'm saying f that was true, wouldn't you want to go even bigger for the rear or at use the same size as the fronts if you need to clear the brakes? 17" wheels would clear all larger brembos with aluminum hat rotors, and many companies in Japan make 4piston caliper brake upgrades that will clear 15's and 16's.


BUT my personal perference is to run 15's all around with 205/50/15 tires. Many people don't go with a staggered setup, i've personally only seen it done by performance shops and racing teams who has the money to spend on different size rims/tires to find the optimum rim/tire size combination.

you would want the smaller but wider wheel on the front smaller for acceleration , and wider to control understeer ,i see you mentioned top fuel cars , hence the rim on the front may be smaller but the tire is larger for hooking up . the same applies if your puttin down almost 400+ horses to the front wheels at the track , trying to hang curves , then yes , you want the taller rim in the front to help wheelspin to be kept at a minimum and yes to keep understeer down .but simply to our corollas which are also long and also have a tendency to oversteer half way thru an apex and will never see 400+hp at the front there is no need for the front larger rim. it simply is a draw back for acceleration , and the tire patch width can accompany the front in traction. so speaking on the handling of our corolla's the smaller tire shorter but wider rim would indefinitly go in the front.

now , i dont know about you guys but my allignment is setup for the track , my rear camber is a little more negative from stock and also has a slight toe out


exp.

^ front of vehicle
[------] front wheels


\------/ rear wheels over exadgerration for illustration.


^ top of vehicle

/-----\ rear negative camber , once again over exagerated for illustration.

[-----] front camber.

so you see this setup will help with any understeer problems at the track , and also keeps predictability. now can you see where the front wheels will be shorter but wider ?

In the top view, I thought you would want to make the wheel like this in FF car.
\-----/ front

|-----| rear

Coz when you step on gas, the torque of the front wheel will pull the wheels inward to become like
|-----| front

|-----| rear

You will only want to make this in a FR car
|-----| front

\-----/ rear

[----] front

\----/ rear

top veiw : for a rear wheel drive car this will make it dangerously oversteer and most likely spin out every time when accelerating out of a corner. this is a strictly drag setup.

if a FR or MR car has oversteer problems , you would want the back like this:

[----] front

/----\ rear.

vice versa for the understeer problem on a FF only .
EXP.
[----] front

\----/ rear

for a FR or MR with understeer problems you would want this:

\----/ front

[----] rear

this will make the front end more responsive to input , and also more control in deep corners.

hopefully you dont have tourque steer that bad on your FF. you want to keep the front wheels as strait as poss. unless your taking a lot of deep tight corners , then this is what you would want:

\---/ front

[---] rear

Ic ic, thanks for clear things up!

understand that these are toe adjustments , and not camber. just want to make sure.