anyone help me out?

[sLoWnStEaDy]

I am needy i know....

I am wondering if by chance If someone would happen to have a 5X4.5 bolt pattern rim with something like a 28X11.5X15 (325/50/15 would work) or a 27X10.5X15 (295/50/15 would work) layign aroudn that i could barrow for a weekend. I am not going to do any driving on it or anything like that, i just want it for mock-up so i can see what will be needed as far as modification to the RX7 to fit something like that. I dont know what i need for backspaing either so i guess i will try anything....

I can guarantee NO damage either to the wheel or tire and could buy you a case of beer or just throw a little cash at you...

[Drifte]

you can always throw cash at me man, any time.

[TbTalon94]

or a case of beer

[DustinsDuster]

youre too late, i sold my weld wheels which were both Chevy and Ford Mopar bolt pattern, 15x8, 4.5" back spacing with a 27x10.5 tire under it. if you are interested in them, i can talk to the guy who bought them. he said if they wouldnt fit his car he was just going to take them out to the swapmeet this year and sell them.

[sLoWnStEaDy]

youre too late, i sold my weld wheels which were both Chevy and Ford Mopar bolt pattern, 15x8, 4.5" back spacing with a 27x10.5 tire under it. if you are interested in them, i can talk to the guy who bought them. he said if they wouldnt fit his car he was just going to take them out to the swapmeet this year and sell them.

Not looking to buy anythign right now, just barrow for a weekend so I can figure out for sure what I need.

Is there a way to figure out what backspacing and such you need? I am going to run 15X10 in the rear HOPEFULY with a 325/50/15 tire but I am not sure how well that would work so i may have to go 295/50/15. I just dont want to drop the money and have it now work and be stuck with tires i cant use... I have been watching ebay just lookin for a cheap used set or something i can expirement with. There is a pair of slotted wheels with 10.5" slick on dragsource but the guy cant tell me the backspacing or bolt pattern so....

[DustinsDuster]

slotted wheels? you mean aluminum slot wheels? or slotted bolt pattern?

if you can tell me what car he had them on, i should be able to tell you the bolt pattern at least.

personally, i say if youre going to be doing some metal work to make them fit at all, why not just fully tub the thing out all the way? then you could be pretty sure you could fit a 325 under it...

[sLoWnStEaDy]

Well, a full tub would be awesome!! However not a chance that will happen. I am going to keep the independant rear suspension and everything. Only "metal work" i might have to do is cut away a little bit of the rear fenders. There are people running completely stock cars with 17X10.5 out back so i figure as long as I get the right offset i shouldnt have any problems.

to get a 17X10.5" rear with a 295 to clear the inside suspension and such, all you need is a +15mm offset and either wide rear fenders or you have to "roll" the fenders. So a 15X10 shouldnt be a problem at all however with the wider wheels i will just have to get the offset figureds out. probably go with something around +5mm or so. I would rather have the wheels stick out a little and have to flare it than have to deal with it rubbing the suspension... We'll see...

[sLoWnStEaDy]

OK, i found a rim i like (couple actualy) but they dont say the offset, just says "backspacing" I want to go with something like +5mm to make sure the tires clear the inside but most rims i see that i like just say 4" backspaing or something similar. What backspacing would give me close to +5mm offset ona 15X10 rim?

IIIRC offset the distance that the hub mounting surface is from the centerline of the rim. Therefore on a 10" wide rim with 4" of backspacing, I assume that means the hub mounting surface is 1" offset to the inside of the rim. Now that would mean they have an offset of -25mm?

Sorry, kinda late for me to be "thinking" probably WAY off with that statement...

[DustinsDuster]

offset and backspacing are two different ways of basically saying the same thing. a 5mm offset is saying that the center of the rim is offset 5mm to the outside of the car, moving the tire 5mm (about 1/4" into your car. backspacing is simply saying the amount of rim going back into your wheel well. if a 15x8 rim has a 4.5" backspacing, that means 3.5" of rim goes outward from the hub and 4.5" goes back into the wheel well.

one thing you should be sure to take into consideration,especially if youre running a slick, is not only width of the tire, but section width. section width is the absolute widest a tire will be. my 10.5" slick had a 11.9" section and only a 9.9" tread if i remember right. also remember a wide tire will bubble out a lot more if its put on a narrow rim. a 10.5" tire on an 8" wide rim will have a larger section width than 10.5" tire on a 10" rim.

if i were you, i would measure the depth of your wheel well at its most narrow point, then take a straight edge down from your wheel well lip and measure to your hub, figuring out how much space you have between your hub and well edge. after you know the section of the tire you will use, take that plus a 1/2" or so and subtract it from the distance from the hub to the wheel well lip, and you'll know the maximum amount of "front spacing" you can have. once you have that, you can figure out how much backspacing you can run (depending on how deep your wheel well is.

if anyone wants to chime in with anything on this, feel free. i am not a wheel and tire guru, just speaking from the personal expiriences i have had.

[sLoWnStEaDy]

THANKS!! to make sure i understand, a 15X8 rim with a 4.5" backspacing would be a +12mm offset because the hub mounting surface is offset .5 inches toward the outside edge of the rim... therefore a 15X10 with a 4" backspacing would be something like -50mm offset because the hub mounting surface is offset 2" toward the inside of the rim... (4" behind the mounting surface and 6" outward)

In case anyone is curious, i am going with Cragar SS or Weld ProStar or Weld draglites. 15X10 out back with a 295/325 and 15X6 up front with a 185ish. Kinda going for the 'old "fat and skinnies"

[DustinsDuster]

ugh, Cregars will look like garbage on an RX7. leave those for the old timers who had them on their car in highschool 50 years ago.

Pro Stars look cool, but they only have the one bolt pattern, so if you ever decided to sell, you couldnt sell them to a Chevy guy. Draglites look good, and usually have both the Chevy and Ford/Mopar bolt patterns, and look just about as good as Pro-stars in my opinion. Draglites would be a lot easier to sell if you ever change your mind about them. i told one friend that i wanted $350 for mine (rims and tires) and he had them sold less than 24 hours later...

again, just my opinion. i would probably go with Draglites.

[DustinsDuster]

and yeah, it sounds like you have the idea on measuring backspacing.