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I got your guys ideas on wheels. I have stock non offset trailing arms. I went with 18x8.5, 0 offset 4.5" bs with BFG sport comp 245/40r18 in front (fits great). I went with 18x9.5, 0 offset and 5.25" bs with same tire, but size 275/40r18. The shop called and said the wheels in the back will not fit alone with no tires mounted. They said it was going to hit the ebrake cable and once the suspension was lowered the spring bolts would hit the wheels? The wheel supplier says that it will fit, what gives? Anyone running this size wheel on a stock C3.
Last edited by King Lear; Jan 21, 2016 at 03:55 PM.
You can relocate the e-brake ..... As to spring bolt. Can you run a shorter bolt? there has also been discussions on the forum about mono springs of different lengths like one inch shorter to accommodate wider tires and wheels
You went with a rear wheel 1.5" wider and than went with an offset that pushes the wheel closer to the e bracket by 1.25". Exactly what brand and part number wheel are you using?
BTW, to the OP: I thought that the spring ends weren't an issue when using 18's, that the spring ends actually fall within the wheel's I.D. Are you using really long spring bolts?
You need to look and see how the wheel sets in the pocket before making anymore decisions....
If it sits too far inboard.....it will hit things as you say and look funny on the outside.
I am not sure what backspace my wheels are and have a lot of people ask.....I should measure one.
I am at 18x9 with a 275/40/18.
Maybe somebody else can chime in with their backspace?
I got your guys ideas on wheels. I have stock non offset trailing arms. I went with 18x8.5, 0 offset 4.5" bs with BFG sport comp 245/40r18 in front (fits great). I went with 18x9.5, 0 offset and 5.25" bs with same tire, but size 275/40r18. The shop called and said the wheels in the back will not fit alone with no tires mounted. They said it was going to hit the ebrake cable and once the suspension was lowered the spring bolts would hit the wheels? The wheel supplier says that it will fit, what gives? Anyone running this size wheel on a stock C3.
I have 245/45/18s on Coys C5 18" x 8 in front with a 4" backspace, those fit exactly the same space the stock rims were in. To me, 4" looks better than 4.5". I'm using hubcentric rings in front rather than the lugcentric form these wheels come with.
I have 275/40/18s on Coys C5 18x9.5 in the rear with nearly 5.5" backspace and I've installed hubcentric spacers that we milled down to .22". The parking cable mounts were relocated atop the trailing arms, fairly simple welding operation. And the spacers were really only needed to keep the rubber from hitting the inside surface of the wheel well, only on the left side for some reason. I am using long reach lug nuts with these spacers.
Also, I'm using 8" bolts on the rear spring and have enough room to clear the rim by more than 1/4" at rest.
It was well worth all the effort and expense to get this level of tracking improvement over street tires. I almost always look for best bang for the buck compromise, but on tires I went all in for the best extreme performance summer tires, Bridgestone Potenza RE-11s.
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Originally Posted by Silvertone
I have 245/45/18s on Coys C5 18" x 8 in front with a 4" backspace, those fit exactly the same space the stock rims were in. To me, 4" looks better than 4.5". I'm using hubcentric rings in front rather than the lugcentric form these wheels come with.
I have 275/40/18s on Coys C5 18x9.5 in the rear with nearly 5.5" backspace and I've installed hubcentric spacers that we milled down to .22". The parking cable mounts were relocated atop the trailing arms, fairly simple welding operation. And the spacers were really only needed to keep the rubber from hitting the inside surface of the wheel well, only on the left side for some reason. I am using long reach lug nuts with these spacers.
Also, I'm using 8" bolts on the rear spring and have enough room to clear the rim by more than 1/4" at rest.
It was well worth all the effort and expense to get this level of tracking improvement over street tires. I almost always look for best bang for the buck compromise, but on tires I went all in for the best extreme performance summer tires, Bridgestone Potenza RE-11s.
Got pretty much the same only Toyo T1R tires, 285/40/18 on the back and 255/45/17 on the front, rides like it's on rails now. I have Coys C5 18x9.5 w/ 5 in BS and Coy 17 x 8" with 4 in. BS. I did however not have to use spacers or anything, just relocate the e brake to the top of the trailing arm.
Last edited by MotorHead; Jan 21, 2016 at 05:17 PM.
Got pretty much the same only Toyo T1R tires, 285/40/18 on the back and 255/45/17 on the front, rides like it's on rails now. I have Coys C5 18x9.5 w/ 5 in BS and Coy 17 x 8" with 4 in. BS. I did however not have to use spacers or anything, just relocate the e brake to the top of the trailing arm.
These cars are for driving, I just can't see keeping the old 15" setup. Must have sold my rallys too low, they went very quickly to a guy with an El Camino.
When I did my first test fit, it didn't appear that I would have to move the brake cable mounts, but was in the process of replacing the trailing arms so I wound up moving the mounts anyway.
8" bolts may be a little tight in 17" rims, but should be OK in 18" rims.
10" bolts won't fit inside much of anything. I took mine off.
If you need to shorten the bolts a little and have a fiberglass rear spring, you can remove the block above the spring and buy yourself a solid 3/4" that way without changing ride height.
I thought I read 5.25 requires relocating the ebrake cable, I put c5 zo6 wheels on my 79 and measure the backspacing to order the 2.75" spacers to allow the 18x9 rear wheels to fit with 5in BS... I dont ever recall seeing wheel offset measurement before transverse engine front wheel drive was invented.
Here are the photos showing the brake line issue and the rear spring bolt. The 275 tire is 10.9" section tread width so its gonna hit too. The last pic is the front 245/40/18 front it is only 25.6" tall but it fits the rear fine as far as clearance on the 18x8.5 wheel. I'm going to have to lower the front. VBP said the 460lb coils would be stock height my front end looks like a 4x4 with the 15" rims and 27.5" BFG Radial TAs.
So here is the math I figured in my head that will make these wheels and tires work with no mod to the brake or anything else. See if I'm missing something?
.75” bs difference between 4.5 and 5.25 minus 1” wheel difference between 8.5” and 9.5” = .25
.23” offset difference between -6mm and 0mm
10.9” section width for the 275 tire
9.8” section width for the 245 tire
1.1” difference in section width divided by 2 since ½ the width will be in front of wheel and ½ in back toward frame = .55”
So if you add all the differences up a 1.03” spacer would give me all I need to clear with no mods other then longer wheel studs.
Here are the photos showing the brake line issue and the rear spring bolt. The 275 tire is 10.9" section tread width so its gonna hit too. The last pic is the front 245/40/18 front it is only 25.6" tall but it fits the rear fine as far as clearance on the 18x8.5 wheel. I'm going to have to lower the front. VBP said the 460lb coils would be stock height my front end looks like a 4x4 with the 15" rims and 27.5" BFG Radial TAs.
So here is the math I figured in my head that will make these wheels and tires work with no mod to the brake or anything else. See if I'm missing something?
.75” bs difference between 4.5 and 5.25 minus 1” wheel difference between 8.5” and 9.5” = .25
.23” offset difference between -6mm and 0mm
10.9” section width for the 275 tire
9.8” section width for the 245 tire
1.1” difference in section width divided by 2 since ½ the width will be in front of wheel and ½ in back toward frame = .55”
So if you add all the differences up a 1.03” spacer would give me all I need to clear with no mods other then longer wheel studs.
C5 Zo6 17x8 245/50/17 front 18x9 275/45/18 rear, I measured for 4 in backspace for the front and 5 for the rear. I am using stock trailing arms and a mono spring in the rear.
C5 Zo6 17x8 245/50/17 front 18x9 275/45/18 rear, I measured for 4 in backspace for the front and 5 for the rear. I am using stock trailing arms and a mono spring in the rear.
Did u use a spacer?, relocate ebrake cable? what length are the leaf spring bolts? Just curious why mine is such a cluster f and everyone else seems to just bolt it on and go!
Did u use a spacer?, relocate ebrake cable? what length are the leaf spring bolts? Just curious why mine is such a cluster f and everyone else seems to just bolt it on and go!
Yes I used 3" and 2.75" do to the C5 off set of the wheels. I had to use the spacer to get the back spacing right where it needed to be a 4" front and 5" for the rear. I did not move the ebrake cable, my spring bolts are 6" if I remember correctly (yes it looks like a 4x4). You state you ordered 5.25" bs and I believe that is where your problem is, everyone else seems to use 5 in bs and everything stock or 5.25 and move the bracket.
...unless I'm comparing wheels of the same width.
18's wnt fit?
