SweetRide45

iTrader: (2)

I'm thinking of going w/ Boyd Coddington Smoothie II's. What I've come up with is this:

Front: 17x8 - 245/45/17 - 4.5" b/s
Rear: 17x10 - 275/45/17 - 5.75" b/s

Anything I should change? I want to stay stock height to keep my speedometer right, etc. I also don't want it to protrude out of the fender lip. I'm looking for both wheels to stick out equally from the wells. Kandied's car looks ideal. I know he's running different size rims, but his stance looks just about right and it's what I'm looking for.

How does this sound?

SweetRide45

iTrader: (2)

Nobody knows?

nolanr0413

do a search to be sure or pm kandied or crazyhawaiian. they both run tens in the back . But the front sounds right.

Kandied91z

iTrader: (7)

fronts good with b/s and tires....

the rear though you should probably be running a 285 since that's the right width for a 10" wheel.

crazy is running a 9.5 in the rear with that b/s i'm running. to put it this way i'm running 6.75 rear so to have the wheels in line up front i'm running a 4.75 front.

that's all i can share about my setup. slight hammering in the back and removal of rear bumpstops though but it sits absolutely perfect. then again crazy's doesn't look to bad either. you should be fine either way.

johnyIROC

That is perfect... exact same setup as I have...


I went with Boyd Magneatos:

17X8 245/40/17 4.5BS
17X10 275/45/17 5.75BS

No clearance issues whatsoever and they look great!

Kandied91z

iTrader: (7)

after doing the calc your right...a 275 width would be better suited for the 17. 285 is perfect for the 18.

the only that bothers me with the backspacing is the rear would be .25 out more then the front though but i' sure it wouldn't be that noticeable.

SweetRide45

iTrader: (2)

So possibly the 5.5 out back would be better for the rear, as it would stay inline w/ the front? Maybe 5.5 is a more standard backspacing as opposed to 5.75.

johnyIROC: Did you need a custom made rim w/ those backspacing? How long did it take you to get them? Just a polished finish? I found the Smoothies at a local shop for around $230 for the 8's and like $250 for the 10's...not bad at all. Do you know if the smoothies clear a 12" rotor setup? How about 13"? I heard those rims are rounded in the back, and it would scrape.

Kandied: I'd rather not be rolling fender lips, etc...so, the 275 tire w/ 5.5 would fit perfect, right? Fronts, should be no problem...

Thanks a lot guys

Nazzz28

4.5" BS on the 17x8 front is fine, and a 5.5" BS would be right for a 9.5" rear wheel. Since you are going with a 10" width I think you would need a 6" BS on the rear to make it stick out the same amount. I don't know if you would need to hammer the inner well in the rear for clearance though.

I have 17x8 fronts with 4.5" BS and 17x9.5 rears with 5.5" BS and they fit perfect. I am also running a 285/40/17 in the rear because my car originally had 235/60/15 tires which have a 26" diameter. If your car had a 25.6" diameter tires than you would want to use a 275/40/17 in the rear. Either of these tires should look and work fine on that width wheel.

Kandied - Do you have a 4th gen rear end? That just seems like a lot of BS for a 10" wide wheel.

Kandied91z

iTrader: (7)

nope....stock rear. it does seem like alot of backspace but it's what's needed to have the wheels right where i wanted them. you can't tell they are any wider then stock in the rear unless you see the car from behind.

MrDude_1

if it was me, id go with 9.5" wide in the front.....

SweetRide45

iTrader: (2)

I don't want to shave the tie rod ends, or have problems w/ the aftermarket sway bars...I think 8 in the front is max for that...so, if I go w/ 17x10 out back, 5.75 should do it, right? I don't want to modify or bang out the wells at all. I just want a bolt on, and I'm done.

Kandied91z

iTrader: (7)

doing so you'll have the rear wheels different tracking then the front. as far as 9.5's there alright i suppose and they can be made to work with certain instances which we all know. i for one am so glad i went back to 8" up front though and it's not just because of the suspension.......8/10 is perfect.

SweetRide45

iTrader: (2)

Kandied: So your saying this combo would be the best bet:

17X8 245/40/17 4.5 B/S
17X10 275/45/17 5.5 B/S

I called the rim joint by me, and they said they have the Smoothies in 0-22mm backspacing. Sound right to you? What would I need? He looked in the book, and at least picked the correct tire sizes (shown above)...backspacing I'm not too sure about though...

Kandied91z

iTrader: (7)

well if he has boyd then it can be made in any offset......

i don't know what to tell you as your wanting something different then what i have. with your backspacing numbers the rear is a 1" difference.

i'm running 4.75/6.75 and it works for me. does anyone know what the stock front backspacing is?

SweetRide45

iTrader: (2)

Wouldn't I need a bigger offset in the back to accomadate a larger wheel? If I do them at both 4.5 backspacing, wouldn't the rear stick out?

Kandied91z

iTrader: (7)

lol...yeah.

Nazzz28

I think what Kandied has been saying is that in his case he got wheels with more backspacing so he could tuck them. However, since he got a 18x8 front with 4.75" BS he needed a 18x10 with 6.75" of backspacing on the rear to make the outside track of the wheels equal. According to this you would need a 17x10 with 6.5" BS to have the rears stick out exactly the same as the front. However, if you use this BS you will need to massage the inner rear well to eliminate rubbing issues. In my case I went with a 17x8 front with 4.5" BS and a 17x9.5" rear with 5.5" BS. I chose these sizes for three reasons.

1st - The 17x8 front, even when lowered, will not rub.
2nd - By only running 5.5" of BS I would not need to do any hammering in the rear well. 5.75" of BS should be fine and should not rub.
3rd - Even though the back wheels stick out 0.5" more than the fronts, with my BS, you don't really notice it. I could of went with a 4" BS on the front, but I am looking into getting baer front brakes in the future and know that this will push the front out 0.25".


In your case I think that a 5.75" BS would be your best bet if you don't want to massage the rear well. A 5.5" BS on a 17x10 would result in the rear wheel sticking out 0.5" further than mine, so you would want the bigger BS to pull the wheel back in.

About the wheels that the shop said they have. I am assuming that the 22mm is the offset of the wheel from the center line, so a 17x10 with a 22mm offset would give a 5.85" BS. I don't know if this is right so correct me if I am wrong.

Kandied91z

iTrader: (7)

yeah a .5 isn't much however a 1" is. you should be fine either way. i really didn't have to do much modifying, less then 3 min to do both sides. it was mostly because of the suspension and not wanting to interfere with the fender too.

SweetRide45

iTrader: (2)

Can anyone verify that 22mm offset or whatever the place told me is 5.85" b/s? Their website lists it as:
17x10 5-120.65 38GMP
17x10 5-120.65 6P
17x10 5-120.65 38P

17x8 5-120.65 0GMP
17x8 5-120.65 41GMP
17x8 5-120.65 41P
17x8 5-120.65 0P

Now, the 5-120.65 is the bolt pattern, so, that's right. The letters at the end are the finish..P-Polished, GMP, I don't know. Now, the numbers before the letter, it says it's the backspace in millimeters...but I'm not sure which ones would work. Doesn't seem like those are the ones, but can someone inform me? The guy looked up the car, and said 275's and 245's would work...but I assume it WOULD work, but if it looks right, that's another story...

Nazzz28

Backspace / Offset
Available in 1/8-inch Increments

size min max
in mm in mm

17x7 4.5 13 5.25 32
17x8 4.5 0 6.25 44


17x10 4.5 -25 8.25 70


18x7 4.5 13 5.25 32
18x8 4.5 0 6.25 44
18x9 4.5 -13 7.25 57
18x10 4.5 -25 8.25 70
20x8.5 4.5 -6 6.75 51
20x10 4.5 -25 8.25 70

I just got these numbers off of this site http://shop.sportruck.com/ for the Boyd Smoothie II wheels.

Now if you are looking at the 17x10 inch wheels with a 22mm offset they will have a 5.85" BS. To calculate this you start at the wheel centerline, in this case 5" because the overall width is 10".
Then you subtract the offset if it is negative and add it if positive.

5" + (22mm/25.4mm) = 5.85" BS

To verify this calculation look at the 17x10 listed above. It has an offset of -25mm.

5" - (25mm/25.4mm) = ~4.0" of BS + 0.5" for lip = 4.5" final BS

However, in the chart above it seems like they add an additional 0.5" to the backspacing either for the lip of the wheel or tire used. So according to the chart above the 22mm offset wheel you are looking at may have an actual BS of 6.35".

I would personally call Boyds and find out what you need, because their wheels are available with BS in 1/8" increments.

I hope that this helps. It seems like some manufacturers add different amounts for the lip so using the offset isn't always the best way to calculate BS.

SweetRide45

iTrader: (2)

Thanks for your help!! I tried calling Boyd, and got a fax machine
Now I found out Spohn didn't even start building my order that I put at the beginning of last month! 2 more weeks on that one as well (so they say)... Things just keep taking away for my goal of getting done for the summer. Oh yeah, and I didn't order my brakes from Thunder yet, b/c I don't know for sure if the 12" or 13" setups w/ clear the Smoothie II's

SweetRide45

iTrader: (2)

Had to post this dummy reply to send it back up top...damn error screens

Kandied91z

iTrader: (7)

welcome to building a car and why mine has taken years....always plan ahead. that's why i'm already on modifications for next winter.