Measuring for Backspace Front Wheels

[SRT_DSTRHOLC]

I understand how to measure for correct BS on rear wheels, but how do you do so on the front since the wheels turn in and may interfere with frame etc. Any guidance would be great.

Plan if possible is to run 18x8.5 with 5.7 BS 245/50-18 tire on front. Thanks

 

[zhandfull]

I understand how to measure for correct BS on rear wheels, but how do you do so on the front since the wheels turn in and may interfere with frame etc. Any guidance would be great.

Plan if possible is to run 18x8.5 with 5.7 BS 245/50-18 tire on front. Thanks

Best way is to use a wheel with a know backspace. With that said your in the right ballpark. I run a 18"X9" with a 6.3" back space on front and it's about perfect. Keep in mind smaller diameter wheels or dropped spindles change everything as the outer tie rod can start hitting the rim or tire with that much backspacing.

 

[72BBSwinger]

Might be more bs than needed but will work fine and have plenty of fender clearance.

 

[SRT_DSTRHOLC]

Thanks guys. Is there a way to measure for what would work? To know forsure?

 

[Idaho]

You can buy tools that bolt on and simulate a wheel and tire. Around $125 IIRC.
Other than that it's what zhandfull said, use a wheel. Borrow if you can. Talk to the local tire shop to get a loaner.

 

[Keith Mopar]

Since wheels are so expensive and nobody wanted to return them without a restocking charge and for me to pay shipping both ways I bought a Percy's wheel right. Worked like a dream.
I have 17's on the front of my car 225 45r17 rims are 17X8 with 5.5 inch's of back space, steering in full lock puts the tire quit close to my sway bar, but clears all suspension components. This is on a 65 Cuda with wilwood disc's.

 

[72bluNblu]

An 18x8.5" with 5.7" of backspace should fit just fine, especially with a 245 on it. Measuring backspace for the front gets complicated because of the turing radius, as zhandful mentioned the best way to do it is to see what others are running. Which is why I keep a spreadsheet of all the wheel/tire combo's I see on here, especially the ones that are running 17's and 18's and wider tires. 18's clear the tie rod unless you have drop spindles, and an 8.5" rim with 5.7" of backspace should clear the fender just fine.

Your tire selection isn't going to work though unless that's a typo. A 245/50/18 would be 27.6" tall, and there's no way you'll get those on the front, they'll hit the corner of the fender and then some. Even in the back that'd be pretty close to the limit. Not to mention you won't find that size for a car tire, they'd all be for light truck/SUV use.

For the front, 26" is about as tall as you want the tire to be. In a 245 the closest you'll get is a 245/40/18, which is about 25.6" tall (same height as the 275/40/17's on my Challenger). The other way to go would be to get a 255/40/18, which would be exactly 26" tall.

 

[SRT_DSTRHOLC]

An 18x8.5" with 5.7" of backspace should fit just fine, especially with a 245 on it. Measuring backspace for the front gets complicated because of the turing radius, as zhandful mentioned the best way to do it is to see what others are running. Which is why I keep a spreadsheet of all the wheel/tire combo's I see on here, especially the ones that are running 17's and 18's and wider tires. 18's clear the tie rod unless you have drop spindles, and an 8.5" rim with 5.7" of backspace should clear the fender just fine.

Your tire selection isn't going to work though unless that's a typo. A 245/50/18 would be 27.6" tall, and there's no way you'll get those on the front, they'll hit the corner of the fender and then some. Even in the back that'd be pretty close to the limit. Not to mention you won't find that size for a car tire, they'd all be for light truck/SUV use.

For the front, 26" is about as tall as you want the tire to be. In a 245 the closest you'll get is a 245/40/18, which is about 25.6" tall (same height as the 275/40/17's on my Challenger). The other way to go would be to get a 255/40/18, which would be exactly 26" tall.

Sorry! Yes 245/40 is the tire I want. I appreciate all the help guys!