The Quest to fit 10 Inch Wide Rims on the front.!

well, huge rims have come down to the point were anyone can afford them...and I'm sticking it out to see if I can get some 10" wide rims on the front (since it's doing the steering and the biggest track problem our cars have is front oversteer eventually) so gents, anyone with 10" rims or attempted to fit them and kept the mock up pix POST THEM UP!

Specifically I've found some rims in 19x10 that come in offsets from +20 to +48 so it's now a case of working out what I can and can't do with regards to brake's hitting rims and how close to the shock body I can get

Legally I need an offset of ~30-48 (total vehicle track is not allowed to exceed 1" more than stock) but again depends on brakes + shocks.


http://www.aspecwheels.net/index.php...roduct_id=1142

Far North Racing - Stealth - Tires and Wheels

You cannot eliminate understeer (that's the proper term for "front oversteer") using tire widths, unless you are willing to run wider front tires than your rear tires.

Understeer is a natural feature of an AWD with a front weight bias and a near 50/50 torque split. It can be reduced, but never eliminated. Think of the car as a FWD than can put power down.

DG

I figure it should atleast help, I know there is no miracle cure :)

caliper clearance is NOT a function of offset; it's a function of spoke design. i wish i'd understood this better when i was shopping for mine...so i'll repeat myself for the sake of clarity:

CALIPER CLEARANCE IS A FUNCTION OF SPOKE DESIGN, NOT HUB OFFSET.

how do i know this? because a 24mm offset wheel and a 35mm offset wheel WITH THE EXACT SAME SPOKE DESIGN will clear the same calipers with identical clearance. this is why 3/s owners can tell you offhand what offset on what width will work with the stock perches--but finding compatible spoke designs is a hodge-podge of luck.

what you really need to do is figure out what's the largest amount of wheel you can place inboard with any given suspension/coilover setup, and go with that. i'm confidant that you could probably run 285's on 10" rims up front--provided you had coilovers & spokes which cleared the calipers. not a lot of 3/s owners are running 10" up front. one of the things i heard when i was shopping is that the fnorks in 9.5" size have a different spoke design than in 10". keep that in mind; just because "size 1" fits the brakes doesn't mean "size 2" will also fit the brakes.

my suggestion? get a caliper outline & use it to size/judge the rims you want to use. most BBK mfgs have these available for download on their website; someone on here may have one for the 1g/2g tt brakes. in all liklihood though, you'll probably end up with a forged 1-piece wheel; as the nature of this application demands a more "open" spoke design to accommodate the large brake calipers.

p.s.

my guess is you might be able to swing 35mm offset 18x10's on the front, but pay close attention to what suspension you use & the spoke design you decide upon. function > form in this case. if, by some miracle, you can fit more inboard than that, you can always shave the hub surface a little bit. or you can try to run 40/45mm's and pray to god you don't need 1" spacers.

p.p.s.

according to: http://www.1010tires.com/wheeloffsetcalculator.asp

going from 8.5" 45mm offset to 10" 32mm offset; you'll be +6mm inboard and +32mm outboard. so around 1 1/4" extra outboard. 45mm makes it +19/+19. i don't know if there's a full inch available to go INBOARD (i certainly don't think so with the stock perch) so just an fyi. but 1/2" spacers will turn +45mm offset wheels into +32mm wheels (and provide a bit extra caliper clearance as well). like i said though, my GT-C's are 24mm offset and need spacers to clear the calipers. they stick out quite a bit.

you "might" try rolling the front fender out--to help "disguise" the width.

Yep I use that site all the time...I'm still keen for pictures of what other people are running to get an idea, and from what I've seen of my current strut clearance I should be able to clear a 38mm 10" rim...I'm just kinda keen to see how bad people are finding their rims when they have go to a 10" size..i3igpete has 10" rims for example so I'm hoping to get some info/pix from him.

fwiw my 38mm offset 8.5" rims can fit a 17mm socket easily between the tyre sidewall and the current coilovers...I can also EASILY move the top of the shock inboard by an inch and adjust the lower mounting to keep the camber right which should give another 5mm or so.

I am running a BBK that sticks out LESS far than stock brakes so I should be doing well there too.

i wouldn't think you'd have to adjust camber at all if it was set right to begin with. flat level is flat level. putting an extra inch inboard or outboard shouldn't require camber adjustment if it was flat level to begin with.

now if you've got some rake in there, then yes, you might need to adjust. personally, i wouldn't try and mess with suspension/alignment. i'd go with rolled fenders/bolted on flares before i did that. seriously, if mine was a track car, i wouldn't care if i had FG fenders pop-riveted on there--if it meant that the car passed inspection.

p.s.

come to think of it, 42/45mm rims might not be bad...if you're getting the same sizes on all four. provided the spokes clear the calipers, all you'd need to do is maybe run spacers up front. the rears would probably fit without any issues. again though, the calipers can be a BITCH to fit over. tt brakes won't fit mine at all. i guarantee 355's would fit without so much as a scrape.

the camber is not exactly what I mean...the camber does not change...the angle that the shock is at does....you know how you can adjust the strut top? making sense?

but yeah i recon it'd fit...I just want more info as to what I'm up for..

second problem is I don't really have access to the wheels...getting a brake template is no issue....I want a wheel template! :p

Better offset calculator

Custom rims, wheel tire packages for your ride - RIMSnTIRES.com

&

http://www.kouki.co.uk/utilities/vis...ize-calculator

Why do you need 10" rims on the front? why not just go with 9"? will be much easier to find. Also when looking for wheels try Element Custom Wheels Tires, Wheel Tire Packages,Cheap Rims,Car Wheels and tell it what car you have and it will give you a list of all wheels that fit. Of all the sites I visited it had the most. And for the wheels I want it said they are "guaranteed to fit your car" which is more than any other site said. Once you have found the wheels you want get them cheaper from other sites like aspec.

those are some good links. i just picked one without tire-size calculations, because it's fairly easy to determine what works as far as tires go.

one thing i DID learn from that link though (thx, btw) is that the stock tire combos have 1" upsize on the rims to the tires. 8" wide rims use 9" wide tires. 8.5" rims use 9.5" tires. (approximately on all of these). which actually makes the 10" rim 11" tire (285) a very, very good upsize match for our cars.

imho, i think 10" all around is a very good size, and i've been using it since 2007. only thing i "might" change would be to go with slightly more offset--if i could figure out a way to do it. but i'm already 4-7mm more inboard on these than stock. i think i could do it though...now that i have coilovers.

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I figure it should at least help

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It won't.

Understeer/oversteer is a measure of the balance of the grip on the car. A car that understeers loses grip on the front first. A car that oversteers loses grip on the rear first.

By fitting wider tires, you (in theory) raise the limits of the car, meaning that the point where the car loses grip will be higher up than it was before. But the ratio of when it loses grip will be unchanged.

In order to change the understeer/oversteer balance via changing tire widths, you will have to run wider tires on the front than on the rear. Because the understeer in the car is largely built in (due to AWD and weight distribution) to make any real difference in understeer/oversteer balance through tire widths will require the fronts to be very much wider than the rears - like 285s on the front and 235s on the rear.

I tried something like that on my race car, early on (235s on the front, 205s on the rear, in a BFG R1 race compound) and it worked in some situations, but it also limited the maximum amount of grip in the rear and there were times when I needed more absolute grip out of the rears, so I abandoned the experiment.

90% of the understeer complaints I see are driver induced and cannot be fixed via mechanical means. Go ahead and fit super-wide tires on the front if you wish, but be aware that it will not cure your understeer issue.

DG

Thicker sway bar in the rear?

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Originally Posted by inperfectdarkness

one thing i DID learn from that link though (thx, btw) is that the stock tire combos have 1" upsize on the rims to the tires. 8" wide rims use 9" wide tires. 8.5" rims use 9.5" tires. (approximately on all of these).

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That's because wheels are measured from the inside lip to the other inside lip while tyres are measure from the outer sidewall to the other outer sidewall.

http://i299.photobucket.com/albums/m...asurements.jpg

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Thicker sway bar in the rear?

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Doesn't work - well, doesn't work as expected.

The thicker rear sway bar attempts to reduce grip on the rear by increasing the amount of rear weight transfer. Normally, that increases oversteer.

But AWD cars have a differential connecting the front and rear wheels. When you apply power, the differential "senses" (that's a gross oversimplification of a complex action but we can treat it this way) that the rear has less grip and routes the power forward - where it induces understeer.

However, that rear sway bar is still there, doing it's best to unstick the rear. So in instances where the differential isn't playing games, it induces oversteer.

What you wind up with is a car that, in the main, understeers, but every once and a while snap-oversteers with very little warning - and the more rear spring/bar you put in it, the worse it gets.

The 3S has a rear-torque-bias centre diff so the problem should be a little less prevalent, and indeed, the 3S will rotate a little with throttle before the understeer takes over. But any car that can sent large amounts of power forward will understeer.

I set up AWD race cars with just the slightest bit of spring/bar oversteer bias, so you can get the rear dancing on rapid transitions and lift throttle, and I prefer to do it with spring rather than bar (after a series of aftermarket rear bars, I eventually went back to a OEM rear bar) The 3S, with it's rear-torque-bias centre diff, probably needs even less rear spring.

The other issue here is that the 3S has McStruts on the front, so it has horrible (which is to say, very little) camber gain in roll. The way you normally combat this is to run a lot of front bar, and I expect that a good way to reduce understeer on a 3S is to thicken up the front bar a lot.

However, once you get to the point where you are lifting the inside front clear of the ground - normally the hot ticket on a car like an M3 or Mustang - that differential issue rears up. Lifting the inside front under power is going to cause all three diffs to go insane.

So on a 3S... well, the main issue with a 3S is "doctor, it hurts when I do this" so the solution is to "don't do that" and get a car with less Weird Harolds (like a C5 Corvette) for track use. But if you are bound and determined to use the 3S, the answer is probably more front bar, as the lack of camber gain in the front is the single largest problem. Quaife front diff, Quaife centre diff (assuming that doesn't remove the rear torque bias feature, which is pretty important) and leave the rear viscous.

Street car, larger front bar and be done with it.

DG

Quote:

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Originally Posted by DG

It won't.

Understeer/oversteer is a measure of the balance of the grip on the car. A car that understeers loses grip on the front first. A car that oversteers loses grip on the rear first.

By fitting wider tires, you (in theory) raise the limits of the car, meaning that the point where the car loses grip will be higher up than it was before. But the ratio of when it loses grip will be unchanged.

In order to change the understeer/oversteer balance via changing tire widths, you will have to run wider tires on the front than on the rear. Because the understeer in the car is largely built in (due to AWD and weight distribution) to make any real difference in understeer/oversteer balance through tire widths will require the fronts to be very much wider than the rears - like 285s on the front and 235s on the rear.

I tried something like that on my race car, early on (235s on the front, 205s on the rear, in a BFG R1 race compound) and it worked in some situations, but it also limited the maximum amount of grip in the rear and there were times when I needed more absolute grip out of the rears, so I abandoned the experiment.

90% of the understeer complaints I see are driver induced and cannot be fixed via mechanical means. Go ahead and fit super-wide tires on the front if you wish, but be aware that it will not cure your understeer issue.

DG

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sorry, I'm obviously not being clear...by "I figure it will help" I don't mean with the balance, I mean with the overall performance of the car.

i have 9.5 wide rims and they sit flush with stock front fenders w +42 offset.

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Originally Posted by mb7050

i have 9.5 wide rims and they sit flush with stock front fenders w +42 offset.

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on stock perches????

Can I see pictures? this is awesome :)

Quote:

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Originally Posted by mb7050

i have 9.5 wide rims and they sit flush with stock front fenders w +42 offset.

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What car? your spyder or SL?

i don't think it would matter if it was fwd, awd, spyder, or coupe. rims should fit the same; it's just caliper clearance that differs.

Good point, plus I was confusing MB7050 with another member that has a spyder and a 99 SL.

Quote:

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Originally Posted by DG

Doesn't work - well, doesn't work as expected.

The thicker rear sway bar attempts to reduce grip on the rear by increasing the amount of rear weight transfer. Normally, that increases oversteer.

But AWD cars have a differential connecting the front and rear wheels. When you apply power, the differential "senses" (that's a gross oversimplification of a complex action but we can treat it this way) that the rear has less grip and routes the power forward - where it induces understeer.

However, that rear sway bar is still there, doing it's best to unstick the rear. So in instances where the differential isn't playing games, it induces oversteer.

What you wind up with is a car that, in the main, understeers, but every once and a while snap-oversteers with very little warning - and the more rear spring/bar you put in it, the worse it gets.

The 3S has a rear-torque-bias centre diff so the problem should be a little less prevalent, and indeed, the 3S will rotate a little with throttle before the understeer takes over. But any car that can sent large amounts of power forward will understeer.

I set up AWD race cars with just the slightest bit of spring/bar oversteer bias, so you can get the rear dancing on rapid transitions and lift throttle, and I prefer to do it with spring rather than bar (after a series of aftermarket rear bars, I eventually went back to a OEM rear bar) The 3S, with it's rear-torque-bias centre diff, probably needs even less rear spring.

The other issue here is that the 3S has McStruts on the front, so it has horrible (which is to say, very little) camber gain in roll. The way you normally combat this is to run a lot of front bar, and I expect that a good way to reduce understeer on a 3S is to thicken up the front bar a lot.

However, once you get to the point where you are lifting the inside front clear of the ground - normally the hot ticket on a car like an M3 or Mustang - that differential issue rears up. Lifting the inside front under power is going to cause all three diffs to go insane.

So on a 3S... well, the main issue with a 3S is "doctor, it hurts when I do this" so the solution is to "don't do that" and get a car with less Weird Harolds (like a C5 Corvette) for track use. But if you are bound and determined to use the 3S, the answer is probably more front bar, as the lack of camber gain in the front is the single largest problem. Quaife front diff, Quaife centre diff (assuming that doesn't remove the rear torque bias feature, which is pretty important) and leave the rear viscous.

Street car, larger front bar and be done with it.

DG

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Doesn't a larger bar on the front typically increase understeer? My understanding is very basic. from what I have read in magazines etc.

Soooo IPD...where's your piccies!!! :p

i have custom made camber plates and shite tein coilovers
http://img202.imageshack.us/img202/8288/69966666.jpg

-1.5 camber up front

looks fantastic...any chance of some pix from the insides showing your shock clearance etc?

there is about 3-5mm clearance. I´ll take pic sometime

awesome :) so you had to have custom camber plates to bring the top of the shock all the way in?

not all the way but some

i had to make custom plates because shitty tein plates cracked

mb7050, what rims are those?

enkei rp03 but beware these wheels can´t stand real driving :(

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Originally Posted by mb7050

enkei rp03 but beware these wheels can´t stand real driving :(

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what do you mean? They break, bend?

bend real easily

you've bent one?

yap 2 both rears they can be fixed but they bend easily

Wow lucky I didn't buy them. My current wheels cracked due to not handling the abuse I give them and I desperately wanted a set of RP03. Just bought some XXR that should be a stronger design.

Quote:

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Originally Posted by MR2

Soooo IPD...where's your piccies!!! :p

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you do realize i'm still in the f**king sandbox, right?

what the hell is the sandbox?

it's somewhere in the vicinity of this:

http://http://static.funnyjunk.com/p...zero_ocean.jpg

ok I played around with how far the strut will allow me to move it back...this is essentially adjust two places.

The idea is to pull the strut to plate inboard (Picture 1) to it's maximum adjustment, see how in the first picture I've still got around 1cm of adjustment before I need to get a custom plate? well to stuff around with it I pulled it further in (maximum adjustment) and ended up with around 5mm of additional clearance..
before I move on I'd also like to look at adjusting the plate to allow for more castor as well..seeing as there appears to be a fair amount of room on all sides of the spring.

before adjustment:
http://3000gt.com.au/car/Misc/teins/...eforeplate.JPG
showing how you could modify the plate:
http://3000gt.com.au/car/Misc/teins/...replatered.jpg
showing how much space there is around the spring even at maximum adjustment
http://3000gt.com.au/car/Misc/teins/...tclearance.JPG


to maintain your camber you then need to push the hub knuckle back out...this is what actually forces the lip of the Rim away from the shock/spring as opposed to just giving bucketloads of camber

before adjustment:
http://3000gt.com.au/car/Misc/teins/...t/knuckle1.JPG
After Adjustment:
http://3000gt.com.au/car/Misc/teins/...t/knuckle2.JPG
showing how you could egg it a little more (red is stock, yellow egging it a bit more)
http://3000gt.com.au/car/Misc/teins/...t/knuckle3.jpg

SOO, the end result with toying around with all this is I now have ~36mm of clearance between the tyre/rim and the spring...funny as the 19x10+42's should only need an additional 26mm...so I could fit a +46 mm offset 19x10 rim...assuming the spokes cleared! :p which means that MY CAR WOULD BE LEGAL IN AUSTRALIA YAY!

now I just need to find someone willing to sell the XXR's in +46 offset as opposed to the +42 that's everywhere...I may end up settling for a +42 though, and just flairing the guards slighly (will stick out 12mm more than the current rims do.)