Rear Wheel Offset Specs

[Nickrap9]

Whats up guys? I'm currently in the hunt for some new wheels for my 03 Black Vert. I've narrowed it down to Godspeed's Black Chrome 18x9 (F) and 18x10 (R). The rear wheels offer two offset options (+22mm or +40mm). I currently have 17x9 Cobra Anniversary wheels with 275/40's all around (stock offset +26mm). I'm trying to figure out which new wheel offset would be best applicable and/or if mods are needed. Any input would be greatly appreciated.

ps. my new tires are Nitto 275/35/18 (F) 295/35/18 (R)

Thanks,

Nick

 

[KLLR SNK]

I would go 22mm up front and 40mm out back.

 

[SpectorV]

front spacing = width - back spacing

it seems 3.5-3.75 inches out back works good (mine are 3.75)

at 3.75 you may have to roll the fender lips though

every 1 inch = 25.4mm

offset is just how far off the center line the mount location is you can figure out the rest of the numbers from that alone

10" wheel with 40mm center line

its 40mm in front of center line or 1.6 inches

5 - 1.6 = 3.42 inches~ not to far off should clear any tire issues fine out back on an IRS car

 

[Nickrap9]

Re:

KLLR - thanks for the input. Thats what I was thinking too.

SpectorV - I really appreciate the break down. Gotta love math! it's the universal language. So the stock offset @ 26mm on a 9'' wheel would be 4.5 - 1.02 = 3.48 inches in front the midline of the wheel? This would make 5.52 inches of wheel from the hub to the inner edge of the wheel.When you say 3.5-3.75 inches out back (6.25 from hub to inner wheel), I'm assuming this is equivalent to the clearance needed between the inner edge of the wheel and the suspension (IRS)? Using the 40mm offset would have 3.42 in front and 6.58 behind midline of the wheel. Using a 22mm offset would put 4.14 in front and 5.86 from hub to inner wheel. You said at 3.75 offset, one might have to roll the fenders? I see at wheel at 3.5 offset having more of the wheel inset (6.5) toward the suspension? In addition, on deep dish wheels (like yours), the lower the offset the more inset the wheel would be (bigger lip)?

Awesome Redfire Vert! What are your wheel and tire specs?


thanks again

 

[SpectorV]

So the stock offset @ 26mm on a 9'' wheel would be 4.5 - 1.02 = 3.48 inches in front the midline of the wheel?

Thats 3.48 inches from the mounting surface not the midline (3.48 is = midline of the wheel 4.5 inches subtracing the offset)

This would make 5.52 inches of wheel from the hub to the inner edge of the wheel.

yup thats how much is behind the mounting surface, how much of the rim is inward. My tire rubs a bit on my inner fender thanks to my JLT air filter slightly pushing it outward a tiny bit FYI Ive fixed it since but just something to check.

When you say 3.5-3.75 inches out back (6.25 from hub to inner wheel), I'm assuming this is equivalent to the clearance needed between the inner edge of the wheel and the suspension (IRS)?

I am only talking about the outward clearance to clear the fender lip so you may not need to roll them. As far as the inside clearing the IRS bottom bolts you should be find with a 10 wide rim around 3.5 or more front spacing with a normal tire (nothing to fat or above a 295). Might be wise to grab the button head bolts or short head bolts to install to be safe. Ive never had a problem with my 295s at 3.75 inches front spacing on my 10 wide rims.

Using the 40mm offset would have 3.42 in front and 6.58 behind midline of the wheel. Using a 22mm offset would put 4.14 in front and 5.86 from hub to inner wheel.

Sounds right, but midline sounds wrong to me, but I get what you mean. Its from the mounting surface of the rim.

You said at 3.75 offset, one might have to roll the fenders? I see at wheel at 3.5 offset having more of the wheel inset (6.5) toward the suspension?

Yup by pulling more of the rim inward you will clear the fender lip more, but that opens up issues with clearing the IRS, if you are around 3.5 inches front spaced you should be ok and not have to roll the fenders, every car varies.... mine at 3.75 clears both sides NEARLY... one side 100% fine the other... has .1 inches that dont clear lol.... I had to roll the fender and the very edge where the rear fender meets the bumper cant be rolled and it still rubs here slightly on big bumps.

In addition, on deep dish wheels (like yours), the lower the offset the more inset the wheel would be (bigger lip)?

Thats the reason I wanted it setup with as much front spacing as possible so the lip could be bigger, some wheel makers just add more or less material to the mounting location of the rim. For my rims the center section was welded into the hoop at what ever location I desired (can scoot it inward or outward in the hoop) so thats why I wanted it as far out (as much front spacing) as possible as the further I pushed the more lip I see.

Awesome Redfire Vert! What are your wheel and tire specs?

Thanks! front 18x9 2.89 Front spaced (2.25 in lip) and rear are 18x10 with 3.75 front spacing and a 3.75" lip (nearly 4 inches just a bit shy)

Look into Gorilla Lugs for your setup, every one is a locking lug and they are easy to use and smaller than the OEM lugs as well.