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Discussion Starter · #1 ·
After much searching and calculating, I finally found my rims. Keep in mind my suspension setup is not like most of yours. The wheels I found are the Boss 304's and are 18x9 (front and back). They have 245/40ZR18's all the way around (Nexen N3000). The rims have a 5.5" backspacing (14+mm offset). They absolutly fit perfect and look great. Very excited about them. One tire has a hole in the sidewall but I am buying 2 new Nexen N3000 tires and installing them on the front as there has been little wear on the tires that are on them as you can see here:

Here is the front of the wheels:

I installed one to verify clearances full lock to full lock and had about 2" from the frame both ways and about 1.5" to the fender lip. Here is how they look up front:

The car is setting on the ground and I made sure the suspension was compressed back to normal:

I did not clean them, just tried to see if they would fit:


My setup as of now is as follows:
2" drop spindles (Mcgauhys)
10.5" rotors with metric caliper disc brake kit
stock A-arms and centerlink
605 ps (16:1 ratio)
narrowed 8.8 Ford explorer rear end with disc brakes (56.5" WMS to WMS)
leaf spring pocket kit

I have 60" from WMS to WMS up front.

Thanks goes to Laszlo for the spreadsheet, very handy tool.
Josh
 

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Looks good Josh! :)

Are your steering arms hitting the stops, or does the 605 box limit your steering some. I'm surprised the tires are so far from the frame at full lock. Is it 2" at the back of the tire too???

When we discussed this I think you said those wheels were 5" backspacing, not 5.5". ;)

By my calculations the insides of your front tires are 49.3" across, and the outside is 68.5". I thought 68"+ outside would work with a 2" drop. Looks like your fender is still above the tire.
 

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Discussion Starter · #6 ·
Looks good Josh! :)

Are your steering arms hitting the stops, or does the 605 box limit your steering some. I'm surprised the tires are so far from the frame at full lock. Is it 2" at the back of the tire too???

When we discussed this I think you said those wheels were 5" backspacing, not 5.5". ;)

By my calculations the insides of your front tires are 49.3" across, and the outside is 68.5". I thought 68"+ outside would work with a 2" drop. Looks like your fender is still above the tire.
The set we talked about I didn't buy. I called a guy about these and he didn't want to budge on the price. Within the next hour he called back:).
Here is the link to the specs:
http://www.bossmotorsports.com/wheels_detail_specs.cfm?id=112
I was looking at a wheel with a 6.1" BS but they scared me a little and wasn't what I wanted (I wanted the Boss 304's). The fender is almost in line with the top of the tire. According to your spread sheet, the inside is 49.8" and the outside is 69". Boss's specs state the backspacing for the rims are 5.5" but I had to adjust it to 5.55" on the spread sheet to get the 14+mm (.55) offset.
In a side note, the new tires are very close to the tire diameter that was previously on the car (the old S-10 rims). The difference is the backspacing and the width.
As for the distance from the frame at the back of the tire, I will measure it tonight. My first guess was a couple of inches. Probably more like 1.5". I was just excited they didn't hit.
As for the 605 and the steering geometry/parts, I basically used Ackerman's Angle formula. Interesting info, found here:
http://www.carbibles.com/steering_bible.html
Since I can turn my steering wheel basically 3 turns from lock to lock and I know my ratio is 16:1, I can calculate the deflection. If I assume it can at least turn 360* one direction, I divide the number of turns in half =1.5 x 360* =540*. Divide 540*/16 (ratio) and I end up with 33.75* deflection.
Of course that only works if you know about what degree you can turn one way:).
Now i sort of also cheated by laying out it out in AutoCAD. It gave me a max angle of deflection before I hit the frame. I set it at 34 degrees to be on the safe side.
So in reality (since I have inches between the tire and the frame) my deflection angle may be less than 33.75, which keeps me safe. I did grind down my stops a little when I installed the drop spindles but not alot. Just by drawing it up, I have closer to a 25* deflection. This makes for a little tougher time making tight turns.
i may work on it a little to get it to turn a little better. If I get it turning tighter I may have to section the frame a little. I really need to do more inspecting to determine what is actually causing the lack of deflection angle but I can survive with what I have. Probably a little more info than what you were wanting but it is still all floating in my head right now.
Josh
 

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Discussion Starter · #7 ·
Also sorry about the angle of the pics, there is a heat pump in the way and I couldn't get a good shot.
Josh
 

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They look great:tu Glad they worked out for you, time to get out and drive it:D
 

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Discussion Starter · #10 ·
They look great:tu Glad they worked out for you, time to get out and drive it:D
I spent all my slush fund buying rims and since one tire has a hole in the sidewall, I have to buy 2 new tires and will have to wait on it being on the road. Hopefully will driving it to Somernites cruise with my new rims. Gonna be cold with no heater.

Thanks for the complements guys. I was very excited about them, just ask my wife. told her it was like Christmas.
Josh
 

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According to your spread sheet, the inside is 49.8" and the outside is 69". Boss's specs state the backspacing for the rims are 5.5" but I had to adjust it to 5.55" on the spread sheet to get the 14+mm (.55) offset.
Josh
Hmmm, the spreadsheet whould work like this....

Take the 60" MSW and subtact .55" from each side to get the tire centerlines (track width). Then add the tire width, which is 9.6" for a 245 tire to get the outside width. 60-.55-.55+9.6 = 68.5". Not sure why you're getting 69".

To get the inside width, you subtract the tire width...

60-.55-.55-9.6 = 49.3"

I do think that limiting steering angle a little is a viable option to prevent tire rubbing, as long as you don't go too far. I believe my C4 steering limits the angle somewhat. The C4 Corvette has almost exactly the same turning radius as a tri-5, but it has a shorter wheelbase too at about 96".
 

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Discussion Starter · #13 ·
Hmmm, the spreadsheet whould work like this....

Take the 60" MSW and subtact .55" from each side to get the tire centerlines (track width). Then add the tire width, which is 9.6" for a 245 tire to get the outside width. 60-.55-.55+9.6 = 68.5". Not sure why you're getting 69".

To get the inside width, you subtract the tire width...

60-.55-.55-9.6 = 49.3"

I do think that limiting steering angle a little is a viable option to prevent tire rubbing, as long as you don't go too far. I believe my C4 steering limits the angle somewhat. The C4 Corvette has almost exactly the same turning radius as a tri-5, but it has a shorter wheelbase too at about 96".
I know why, because I must had been playing with the WMS and changed it from 60" to 60.5". Playing a little too much. After changing it back, my numbers match the above. I may measure everything just to keep on my records plus the spread sheet.
I've been able to get around easily with the current deflection angle on the car but I can tell a difference and have taken the neccessary steps to avoid tight turns.
Sometimes it's just a puzzle. I at least was able to get a "range" of what would possible work. I honestly did not believe the 9" wide rims would work but they look real good with all that tire under there. I'm going to have almost 2" clearance to the frame in the back and over 3" to the quarter. I would habe liked a little less backspacing for the rear (or a wider wheel) but these will have to do. I'll post up my measurements when I get them this weekend.

Thanks again for the comments. Car looks great with them. Sort of a smooth retro look.
Josh
 

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Discussion Starter · #14 ·
Laszlo, clearance from the back of the tire to the frame was 2.5" full lock. The stops do not allow it to go any closer. I at least know I can take more off the stops to get a better turning radius. I have to order lug nuts today to get all of them mounted on the car then I'll grab some more pics.
Josh
 

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Discussion Starter · #15 ·
Got one side of the car done. I have to pull the wheel back off to cut the studs but the wheels sure do make the car look good. Ordered a tire for the one that was damaged. I haven't takin pics yet, want to take some outside of the garage...lol. I really like my wheels.
Josh
 
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