Xxr 521 wheels

[DButler]

I found some wheels i like. I seen these wheels on a 68 camaro at a show with stock suspension. The fronts are 18x8.5 with a 1.75 lip and a 25mm offset the rears are 18x10 with a 3.5 lip and a 25mm offset...the wheels are 5x120....i know in the back i will need to do some wheel tub work and probably need a small spacer since rearend is it stock length. I know i will need hubcentric spacers since the wheels are 73.1. I think stock camaro is 70.4 but i not sure so if someone could help on that. Also i am not sure how to figure backspacing since they are the et 25 mm...i dont really understand how these measurements are. I want to be sure front wont hit....do you think ill need spacers.... i am thinking a 255/35/18 or 265/35/18 on front and275/35/18 or 285/35/18 on rear.....can someone help with this. I am mainly worried about front i dont want.it to rub...i think i will need a small spacer plus i am have c4/c5 hybrid brakes on front and c5 brakes on rear....i have seen people run 8.5 on front....any help is greatly appreciated...i would like to order monday so if someone could help out. Thanks

[SR71]

an 8.5" wheel is 8.5" measured between the bead seats. it is generally accepted that an 8.5" wheel is 9.5" overall width. so, 1/2 of 9.5" is 4.75". this is the center of the wheel and the starting point for figuring offset. since you have a +25mm off set(and 25mm is ~ 1"), you are moving the wheel pad ~ 1" from the center to the outside. you will have roughly a 5.75" backspacing.

looks like you are going to need ~ .75" spacer front and ~ 1.75" rear.

[srh3trinity]

Read up on the 5x120 vs. 5x4.75 debate while you are at it unless by spacers, you mean bolt on adapters that correct for this.

[DButler]

The guy said be was using a 3/16ths spacer on rear with stock style rear...the rear wheels is 10" so the 25mm means it is 25 mm from the center line toward front of rim so a 10 wheel would be 6.50 backspace since it is really an 11" wheel? How do you come to conclusion i will need a .75 spacer on front? Just wondering how you figures that....and what about my tire sizes what do you think?

[DButler]

It says i can get the 18x8.5 fronts with a +25mm or a +35 mm and says i can get back with a +25 or +12mm which is the best way to go so i can use less spacer....even with these differences it says front has 1.75 lip and rear has 3.5 lip wouldnt the lip be different if offset is different?....also what is the hub bore size of stock camaro? Im gonna ise 35 series tire what do yall yhink

[SR71]

with a +25mm, the rear would need about .75" spacer. my brain was still asleep this morning. the rear space for a 10" rear seems to work best around 5.75".

I'm no fitment guru, but the front wheel is typically an 8" with a 4.75" back. if I was going 8.5", I would want to add an extra 1/4" on each side of the wheel. 5" is about all of the back that you can stand on the front/

a tru-turn kit changes the front entirely though..

[SR71]

a 3/16" spacer on the rear is going to be darn near perfect with the +12mm offset.

[DButler]

This is for the 67 it is stock style the 69 has tru turn...would a 25mm or 35mm be better for front?so still need a .75 spacer on front? Do you know what hub bore is on camaro? I at rod run where are you?

[howehot]

I have this wheel on my Monte Carlo with a Schwartz Performance chassis. Can't help with the fitment on a Camaro but my help with some general info on fitment.

Jeff set up the track to fit the wheel. He has used XXR' s on several builds and had knowledge of the backspacing I would need. Front required no spacer and the 5x120 bolted on fine to the Wilwood hubs.
Rears I had widened to12" by Weldcraft and had the hub machined out to 2.175 to clear the axle reatainer on the full float 9" leaving enough material to allow the center cap to still be used. I believe the hub was 1.75" as delivered. I used a 1" spacer on the Moser hat. I have 13" Wilwood brakes and plenty of clearance with the 18" wheel.

If you have room for the wheel/tire combo, with proper spacing they will bolt up.

https://static1.pt-content.com/images/pt/2012/07/c0af60e6-1.jpg

[DButler]

I am going to make room in back...there was a 68 with them so i know i can make them work lol for the money this is a nice wheel. Are you running the 8.5 in the front?

[SR71]

myself, I would put 1/2" studs in the rear and run the correct spacer with the 12mm offset. I would then use the 35mm offset in the front to make more room for a hubcentric adapter with the correct pattern and thickness.

if you are willing to go to the trouble of making them fit, I would go ahead and get a front wheel, put some long studs in the front hubs and stack washers on the lugs to get the fitment that I wanted. then measure the thickness of the washer stacks and have the adapters made in the appropriate thickness and pattern.

a 245 would be very happy on that 8.5" wheel.

I was in that mess at the grand friday night. I'm just kicking back and taking it easy tonight.

[DButler]

245/40 or 35

[howehot]

I am going to make room in back...there was a 68 with them so i know i can make them work lol for the money this is a nice wheel. Are you running the 8.5 in the front?

Yes. 8.5 fronts.

[SR71]

depends on which rear you go with. you always want the front to be a little shorter than the rear. I would consider going with a 40 series front and rear if available. imo, a 26" rear is just a little too short on a first gen. my 69 pulls it off only because I tuck so much tire.

[DButler]

I am looking to place order tomorrow for tires and rims. The front I am going with either 245/40/r18 or 235.40/r18....back probably 275/40/r18...They only have +25mm rims in stock so i am gonna go that route and make them fit. What do you think about my sizes sizes I have selected?

[SR71]

I think the listed sizes will work out great.

[DButler]

Ordered wheels today now just got to.order tires...im excited to get these on.

[DButler]

The guys at mtns was running 265/35 up front...will a 245/40 be narrower than this....section width is overall width aired up correct....i just want to make sire front wont rub with 8.5 so i know exact tire is important....by the way i recieved wheels and i like them alot

[SR71]

yes the 245 will be narrower. the published section width is the overall outside width when installed and aired up on the listed measuring rim width.

in my experience, .5" change in rim width will normally change the section width .25".

[Hugger67RSSS]

David, post up some pictures and what exactly you ended up using as far as spacers. Curious to see how they look on a 67. Thanks!

[blown67]

any updates [pics] also considering these wheels for my 67 camaro