Hi Everyone.

I am looking for some expert advice here.

I have an 04 Coupe, alabaster. I just purchased this Crossfire a few months ago and am excited for spring...

I noticed that the car didn't have any security locking wheel bolts so i took the rear wheels off to figure out the exactly size, length needed to buy them etc.. The car has aftermarket Mandrus Millennium Black rims with chrome lip.

The previous owner went all out and put really wide rims and tires on the car. After taking off the rear wheel i noticed a slight rub spot on the inner wheel well roughly between the 10 and 11 o-clock position. Not extreme but still a concern. I had asked the previous owner if he had noticed and rubbing but he said that he didn't notice any but there is obviously evidence that there was some. It may had been from a single occurance or maybe not... Being Winter here and not having the ability to drive the car yet i have no way of testing and seeing if this will be a rear chronic rubbing issue or not. If it will be i would rather fix it now in winter then wait for summer when i should be driving instead of fixing lol...

Here are the wheel and tire specs:
Wheel: Mandrus Millenium 20X10J ET30 Thus a 20 inch rim diameter with 10 inch width with offset of 30mm.
Tire Size: 305/25/20 Thus 26 overall tire diameter (same as stock) and the width is roughly 12 inches wide

That being said i was wondering if anyone has any experience in knowing if i need to put a thin wheel spacer in order to get the rear wheels a little further away from the inner wheel well..

The other concern is if i were to put a thin wheel spacers would it end up pushing the wheel out too far as to causing the wheel to end up rubbing on the outside fender panel, knowing that the wheels and tires are already wide and further out as well even without spacers??

As for springs i believe that they are stock and that the car has not been lowered thus helping my situation here i believe..

I just want to do this right and have a good looking car and a safe ride...

Any advise would be greatly appreciated.

Thanks

S

 

305 on a 10 inch rim is too wide in my opinion.
Most I would go on a 10 inch wide rim is a 295, tires on wider rims over rim width range will cause excessive tire roll, wider rim size and narrower tire will be opposite and be alot sitiffer.
Since a 305 on a 10 inch rim would cause more tire roll, if it was on a 10.5 - 11.5 rim would have less tire roll

 

Hi Speedy,

Thanks for your input and insight, i certainly understand your logic on the tire roll but it still doesn't help me with the rubbing issue and if i could use a thin wheel spacer to rectify this.

If anyone is running wide tires and wheels and may have run into this wheel well rubbing i would certainly like your input as well.

Thanks

S

 

How's your inner tire wear on the rears? If noticeable, you might consider installing some adjustable rear cambers which will allow you to push the top of the tire out enough to clear the well without the need for spacers!

 

just as reading this ,,my thoughs were the same and i have a set of the rear links jim

https://www.crossfireforum.org/forum...inks-sale.html

 

Just my opinion but for racing you want a wheel that is the same as the section width of the tire (305 ~12") for spirited street driving, the same as the tread width (305~11"). Very low profiles are more sensitive to wheel size than taller tires and with too narow a rim you need to reduce pressure to keep all of the tire on the ground (too narrow a rim will make the center crown and wear the middle of the tread quickly).

If you really need 305's then I'd suggest two sets of wheels and tires: one for street driving and a second set for "other".

ps In general you can use a 3mm spacer and maintain the hub centric loading. More and the spacer will need to maintain the lip.

pps for maximum cornering about a degree negative camber doesn't hurt.

 

Hi,

Thanks for the input. I am not familiar with rear links.
There is no noticeable tire wear. Would these rear links just push out the top of the tire when the suspension is compressed? Or would it always be in a non vertical position with the top of the tire slightly pushed out? Excuse my ignorance on this topic. I will have to research it a little.

 

Tire & Wheel Plus Sizing

Plus sizing is one of the easiest ways to achieve enhanced performance and improve the appearance of your vehicle. In the example below, a 15x7 wheel with a 205/65R-15 tire is considered the O.E. (original equipment) size. Converting to a plus one size would mean increasing the wheel diameter by one inch (16x7.5) and selecting an appropriate tire to fit (225/55R-16). Likewise, moving to a plus two fitment would result in a 17x8 wheel and a 245/45R-17 tire. It is important to note that although the wheel diameter is increasing, the overall diameter of the tire remains consistent.

Two things happen to the tire to increase performance when moving into plus sizes. First, the tire becomes wider due to an increase in section width. This provides a larger footprint and more contact with the driving surface. Second, the aspect ratio is lower, resulting in a shorter sidewall. The combination of these changes offers better lateral stability and increased steering response.

 

here is more info. from tire tech

http://www.tirerack.com/tires/tirete....jsp?techid=25


Plus Size Wheels and Tires



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Large diameter wheels and wide, low profile tires go together and show up everywhere from America's new car showrooms to its roads, tracks and trails. So whether the vehicle came from the assembly line or was upgraded after it was delivered, Plus Sizing (also called "Inch-Up" sizing in other parts of the world) probably played a role in its tire size choice. Plus Sizing allows tires and wheels to make a fashion statement while providing a functional improvement.
Plus Sizing dates back to the 1970s when Plus One and Plus Two fitments were the available choices. Drivers could upgrade their cars from relatively narrow 13-, 14- or 15-inch wheels and tires up to wider 14-, 15- or 16-inch combinations. While Plus One and Plus Two are still popular today, the starting point now typically begins with 15- or 16-inch wheel diameters and grows from there.
Plus Sizing supports the premise that it's important to maintain the same overall tire diameter whenever changing tires and wheel sizes to ensure sufficient ground clearance, appropriate driveline gearing and accurate speedometer readings. Large changes in overall tire diameter can alter the accuracy of the speedometer as well as the effectiveness of anti-lock braking system (ABS), traction control and vehicle stability system.
Plus Size Wheel and Tire Examples
Rollover Plus Size Tab to Compare

• O.E. Size
• Plus One Size
• Plus Two Size
• Plus Three Size

O.E. Size
16" x 7" WHEEL 205/55R16


View All Examples

Plus Sizing wheels and tires is one of the easiest ways to improve the image of a vehicle. The visual appeal is obvious since alloy wheels are more attractive than tire sidewalls, and bigger wheels combined with shorter tire sidewalls produce a powerful image.
Using tires with shorter sidewalls also quickens steering response and increases cornering stability. Combining them with larger diameter wheels makes it possible to properly maintain the overall wheel and tire diameter, keeping odometer and speedometer changes negligible.
Plus Sizing's biggest risks stem from accidental encounters with potholes, curbs and debris on the road. Low profile tire sidewalls can be pinched more easily between the road and the rim because shorter sidewalls cannot accommodate impact as well as taller sidewalls. Once a vehicle has been Plus Sized, the driver has to try to go around obstacles, rather than run over them.
Additionally, wide tires tend to float on loose surfaces and cannot process water as quickly as narrow tires. This reduces snow traction and hydroplaning resistance when driving on water-soaked highways.
And finally, the maximum Plus Size applications for pickup trucks and sport utility vehicles result in wheel and tire combinations that are significantly heavier than the vehicle's Original Equipment (O.E.) tires and wheels. This increase in weight can lead to longer stopping distances, as well as increased suspension and brake wear.
Here's How We Do It!
We select O.E. equivalent tire diameters and load capacities by matching wider, lower profile tires with wider, larger diameter wheels. This maintains the accuracy of the vehicle's speed dependent systems, while reducing braking distances, improving responsiveness and increasing stability.
A Plus Sizing rule of thumb is to increase tire width by 10 millimeters and decrease sidewall height by 5 to 10 percent for each 1-inch increase in wheel diameter.
You will often find only +/- a few tenths of an inch difference in the overall diameter of the tires, as shown. This results in a negligible +/- four tenths of a mph speedometer variance.

 

Hi AMX,

thanks for all your tire and wheel info. Very useful.

Hi Padgett,

Just to clarify with the 3mm spacers. 3mm spacers should just be flat 3mm shims basically, hub centric with the axle lip, with the 5 hole for the bolts. After putting these 3mm spacers on there should still be enough lip left on the axle to rest your rim onto, not sure how much there would be left over. I will have to take the wheel off again and measure the hub lip to figure that out. If i get a few minutes i will have to take a few photos and post them etc..

 

Within certain limits that is. True a larger size increases the contact patch but is also decreases the loading on a tire and may put you on the backside of the traction curve.

People do not realize this but for a given tire, traction is a curve, increasing as the load increases, then peaking (and can be quite narrow) and then not quite dropping off a cliff but close. Now for a given tire the curve may shift a bit as you change the compound and the tread pattern/depth - why the Goodyear truck at major autocrosses would shave tires to 1/2 depth and serios racers change tires often.

Back in the day we would get these curves for race tires so could select the best for a particular car/track/weather & why careful track of the tire temperatures during practise was kept. (I recall one time being asked to try some street 165x13s (required for the class I was running) and coming in after a few laps with globs of tread sticking to the pavement. Went back to Michelin XASs)

Most of my racing was done with Corvettes and the right tires could make a big difference. With very sticky slicks on my 2900 lb small block a 12.65 (today it would be about 325/40/15) was about right for the rear. For rain I dropped to the equivalent of a 235x60 rain tire and had to be able to do a quick change if needed, the 12.65s were terrible if damp, you just could not load them.

Guess now "late breaking" into a corner is common, back then it was still a fine line between loading the front tires under breaking then transitioning into cornering. Stop braking too early & lose the load and the turn was liable to go ito sudden dramatic understeer. Felt a lot like driving on ice.

So for a track day I can almost see a sticky 305 but not for everyday driving unless done slowly. The stock 255 seems fine for all around use and a 500 wear rating & mine seem to do OK a heavy rain at 50 but feel a little loose at 70. I'd have to wonder about even a 285 in those conditions. Of course if you live in Arizona or Nevada...

Just my opinon, YMMV.

 

A easy to check the bolt (thread into the hub) push the bolt through a bolt hole and check inside you should have 5/8 sticking through.
also factory wheels used BALL lug bolt
aftermarket uses TAPER lug bolt

THE TAPER CANNOT BE USED IN THE BALL TYPE RIN.
AND THE BALL CAN NOT BE USED IN THE TAPER TYPE RIM

 

I took the rear wheel off again to take a few pics of the tire rub marks and take a few measurements.

Looks like the car has a rear negative camber of roughly 1.1 degrees.

I measured the lip on the rear axle hub, it protrudes out 0.340 inches. But after looking at the inner wheel it appears that there is quite a large taper inwards to ease mounting the wheel onto the hub. The taper is 0.150 inches inwards thus without any spacers the wheels only has 0.190 inches lip support between the rim and the hub.
Looking at these measurements it is obvious that there is no way to put thin wheel spacers such as 3 or 5mm as there would be no support left for the wheel.

So i guess there would only be a few solutions to the rubbing issue.

One being as suggested to go with 285 or 295 tires as opposed to the 305 currently on the wheels
and the other being what was also suggested being put adjustable rear cambers.

I have a question about the camber links. If i would put these adjustable links, change the main center link to an adjustable one, would i need to do anything to the other link that is on the upper front side of the axle? If the main middle link is now slightly extended and the other front one is left the same would this create some toe in on the rear wheels?

I've attached some photos of this.

Input on this would be great.

thanks

S

 

As the OEM setup is factory set to be as straight as possible without being adjustable, making the camber adjustable only changes the in-out stance of the tire. So nothing else will change. Toe stays the same. It appears that the rub isn't constant but may be happening on heavy road bumps. You could go to adjustable Konis to stiffen the rebound and possibly stop the rub, but at the expense of a stiffer ride.

 

as I said I have a set of mikeR's rear adj links ( missing 4 inserts) but i didn't tell you I have a set of KW springs and shocks, the fronts are new (springs and shocks) never installed,, the rear was on for about 6 to 7 months, ,I drag race and the kw's are not for me. the pic below is what you would get
again front springs & shocks NEW never installed
rear were on my car for 6 to 7 months I will take 500.00 + shipping for them that is 1/4 of the cost for new k w's jim

 

I have identical marks in my rear wells too. Have had since new. When the suspension bottoms out, or nearly, even the OEM tires/wheels hit.

 

Thanks for all the input guys

As for the rear camber links would there only be 1 link per side to change ? The long curved bar only?

As for the adjustable shocks, you are saying that by adjusting it to be stiffer I assume that when the shock collapses it would thus collapse slower with more restriction in order for it to not allow the wheel to come up as fast? Is this correct?

Also is there such a thing on this car like a suspension bottoming rubber stop? If there is one could I put a bigger one in order to restrict the range of motion upward and have it bottom prior to getting the wheel hitting the wheel well?

Thanks

S

 

Your camber posted is within stock specifications. It's simple really. The tires only rub on massive bumps. During normal driving no interference. If it bothers you, one logical choice, narrower tires. The geometry of the suspension has the top of the rear tires moving inwards under compression. Since the camber is within factory specifications don't bother with the adjustable camber arms unless you want to keep the wider tires and adjust the camber so the tires fit without rubbing. I'm lowered as far as possible and rub in the same place with a 275 tire. Heck, I'm lowered to the point that I rub the stock rubber and tires on huge dips. But I'm also aligned with a bunch or rear camber. What do you want and what's important to you?

Les

 

I will let you know on Wed. after paying the Bills If you still have them I make take you up on the offer..Are they ajustable as in wanting to drop it an inch?

 

You are second in line as i have a buyer and like you he is checking his finances he will let me know next friday, and i can let u know at that time. and yes they are adjustable see the adjusters purple at the top or the picture. jim