Confirm my backspace please

[usa-69z]

Guys , can you confirm that i have ordered the right backspace for my 69 camaro. 18 x 10 with 5.75 b/s & 18 x 8 with 4.75 b/s.
i know 9.5 with 5.5 is the norm on rear but squeezin' a bit more in the rear.
Am i right ???


thanx ,

Gav

[Swain]

Sounds about right, be careful with tires

[Steve Chryssos]

The answer is maybe. I've got 18x10's on my 68, so I get asked this question a lot! A 9.5" wheel is a relative no brainer on a 1st gen Camaro, while a 10" wheel requires quite a bit of planning, some tweaking and usually more money in the form of custom backspaced wheels. But the temptation of "stuffing" your wheelwells can be undeniable. Here are some tips for everyone who can't resist:

1) Measure twice, cut once: The old adage can be applied here--especially since measurements will more than likely vary from side to side.
2) Backspace measurements are absolute: Manufacturer quoted backspace measurements include the bead. While wheel width measurements exclude the bead, back spacing is measured from the mounting pad to the rear edge of the wheel including the bead. So a 10" wheel is really 11" wide, but 5.75" backspacing is exactly that: 5.75"
3) Compensate with thin spacers: People think I'm nuts for suggesting this, but you can perfectly nail your backspacing with the help of thin spacers. I recommend Baer's billet wheel spacers. (i.e. Baer part number 2000008 .250" spacer) They're sold for specific bolt circles. And they're solid 6061 billet aluminum so they won't crack like junk cast universal spacers. Say your measurements suggest 5.5" backspacing. Order your wheels deeper at 5.75" back and then shim them out with spacers. Any local machine shop can turn them down to the exact thickness required per side. You might need .150" on one side and .250" on the other side. All said and done, your wheels will fit evenly on both sides with little or no rubbing--just like the pros. You will need to make sure that your wheel studs are long enough. Make sure or die.
4) Rubbing: You're pushing wheel width to the limit. Despite your best efforts, one or both tires may rub. It's better to bias clearance towards the wheel arch lips rather than the inner wheel house. The lips will cut a tire down sooner than later. Sidewall rubbing against the inner wheelhouse is usually no big deal. Or if you want perfection, be prepared to roll those lips.

Hope that helps
/Steve

[DriverzInc]

The answer is maybe. I've got 18x10's on my 68, so I get asked this question a lot! A 9.5" wheel is a relative no brainer on a 1st gen Camaro, while a 10" wheel requires quite a bit of planning, some tweaking and usually more money in the form of custom backspaced wheels. But the temptation of "stuffing" your wheelwells can be undeniable. Here are some tips for everyone who can't resist:

1) Measure twice, cut once: The old adage can be applied here--especially since measurements will more than likely vary from side to side.
2) Backspace measurements are absolute: Manufacturer quoted backspace measurements include the bead. While wheel width measurements exclude the bead, back spacing is measured from the mounting pad to the rear edge of the wheel including the bead. So a 10" wheel is really 11" wide, but 5.75" backspacing is exactly that: 5.75"
3) Compensate with thin spacers: People think I'm nuts for suggesting this, but you can perfectly nail your backspacing with the help of thin spacers. I recommend Baer's billet wheel spacers. (i.e. Baer part number 2000008 .250" spacer) They're sold for specific bolt circles. And they're solid 6061 billet aluminum so they won't crack like junk cast universal spacers. Say your measurements suggest 5.5" backspacing. Order your wheels deeper at 5.75" back and then shim them out with spacers. Any local machine shop can turn them down to the exact thickness required per side. You might need .150" on one side and .250" on the other side. All said and done, your wheels will fit evenly on both sides with little or no rubbing--just like the pros. You will need to make sure that your wheel studs are long enough. Make sure or die.
4) Rubbing: You're pushing wheel width to the limit. Despite your best efforts, one or both tires may rub. It's better to bias clearance towards the wheel arch lips rather than the inner wheel house. The lips will cut a tire down sooner than later. Sidewall rubbing against the inner wheelhouse is usually no big deal. Or if you want perfection, be prepared to roll those lips.

Hope that helps
/Steve

Could not have said it better myself. What size tire are you going to run, 275/40/18? Tire size will make all the difference too....

[usa-69z]

Awsum info Steve ,you have nailed pretty much everything there. I thank you.
I have just ordered some billet 3 piece rims (yesterday) and started to get a bit anxious on wether i did get the right combo. Just in case i had to make a qwik call to change things.
Im running the tried and tested 17 x 9.5 with 275 rears now, But im wanting bigger. ..i will stik with the 275 tyre though.
Im gunna try the g-force Kd goodrich tyres this time too.

Gav:cheers:

[usa-69z]

Could not have said it better myself. What size tire are you going to run, 275/40/18? Tire size will make all the difference too....

Jon , 'off topic' do you have the 'speed tech kit' on shelf ? a-arms and coilovers etc. (69 cam) Ill be in cal first week of june and want to buy parts off shelf.(in stock)

Cheers, Gav

[buickfunnycar.com]

Awsum info Steve ,you have nailed pretty much everything there. I thank you.
I have just ordered some billet 3 piece rims (yesterday) and started to get a bit anxious on wether i did get the right combo. Just in case i had to make a qwik call to change things.
Im running the tried and tested 17 x 9.5 with 275 rears now, But im wanting bigger. ..i will stik with the 275 tyre though.
Im gunna try the g-force Kd goodrich tyres this time too.

Gav:cheers:

A 245/45 or 245/40 front with a 275/40 rear should be just about perfect on those wheels Gav...:yes:

[usa-69z]

A 245/45 or 245/40 front with a 275/40 rear should be just about perfect on those wheels Gav...:yes:

yer all champions !!:thumbsup:

[Steve Chryssos]

...Im running the tried and tested 17 x 9.5 with 275 rears now, But im wanting bigger. ..i will stik with the 275 tyre though.
Im gunna try the g-force Kd goodrich tyres this time too.

Gav:cheers:

Well that's great news because you can use your existing combination to really get in there and measure clearances all the way around. With that info in hand, you might squeeze a 285 :unibrow:

[usa-69z]

Well that's great news because you can use your existing combination to really get in there and measure clearances all the way around. With that info in hand, you might squeeze a 285 :unibrow:

Gee Steve , i may be pushing my luck with that... ive seen a 285 with a 9.5 rim but neva a 10incha with 285 sqeezed in:willy:

[Steve Chryssos]

I'm a bad influence. On a 67/68, a 285 absolutely, positively fits if you follow all of the custom backspacing tips and roll the wheel lips. 69's are easier since there is even more room. 285mm converts to 11.22" inches. I just measured a 69here at the shop and came up with just over 12" of clearance at the tightest point. That is at roughly 11 o'clock when facing the wheel. In my case, the lips have been rolled and painted with black 3M body Schutz paint.

[Rybar]

How low your car sits and the stiffness of your rear suspension will make a difference if you can fit them in without rubbing.

I think the sizes you ordered will be fine with a 275-40-18 rear tire.