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Look more "closely". The "ring" is a bit "darker" than the sleeve in the snapshot. A quality shock is NOT "thin walled"! This is a very "tried and true" install that's done by many builders!Here's a link to an Afco kit for their "smooth bodied" shocks!I believe the sleeve for the DRM is different and a single "diametered" product with no recess as in the Afco sleeve.

http://www.speedwaymotors.com/RS/SR/Product/10620125SB7_R.jpg

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There is "NO COMMENT" regarding "BOWING" as you call it of the A-arms. The upper shock mount requires a "minor" spread to accomodate the hat/spring and I stress "minor"!The spread required for the QA1 is "less"!

You could help your cause "somewhat" by using 12.5" wheels and I believe that it's maybe the recommended "max" by some tire manufacturers. Yours would be an interesting start because you seem to "know" where you want to go. Now you just need to confirm "two" things. The clearance you have presently from tire side wall to suspension and inner chassis parts(wheelhouse etc.)

The second and maybe "most important"! Is the rear suspension "centered and square" in chassis! Many (most would be a stretch)aren't. There are many that report and document as much as a 3/4" offset to the right. Your desired combination would require the correction of this. It really should be anyway.

After you establish these numbers it becomes easier? Maybe not! You need to do these measurements both sides and maybe with tire pressure decreased maybe a little from recommended.

It might be interesting if Brian could contribute his inner clearances with his 335's on 12" wheels and what the "back spacing" and offset of his wheel is. With his clearances does he have any "inner" rub under "any" circumstances?

Hey Coaster!

I added the offset formula to the C4 tech FAQS and I'll be sure to be back! It's time for "work" here on the "right coast"!

I posted a comment on the C4 Technical FAQS and summary that should eliminate some confusion when doing wheel comparisons for fitment. I posted only one example of the "flawed math" with the "correct formula" in the same reply. You can use the formula as is for back spacing and front spacing calculations and I'll edit the post with a formula for offset from back spacing later.

I haven't been to this forum for quite some time and I was PM'd some questions from another forum regarding wheel fitment and they used the information from here I guess for reference.

The more important "dimension" when contemplating wheel "fitment" is generally regarded to be "back spacing". That determines the clearance to critical suspension and chassis components. I doubt that someone could have gotten into a "fitment" situaton using the "front spacing" information posted there.

It appears that the "wheel offset/front spacing/rear spacing" needs some attention. The math is flawed. The correct math for front or rear "spacing" is done from "TOTAL" wheel width and not "advertised width" bead to bead. I've seen these figures posted on other forums "as fact" and never actually knew from where they came. Someone PM'd me the thread and I thought I'd check it out.

The easiest way to "correctly" establish "front spacing" is to first calculate "rear spacing". Front spacing is the "simple result" of subtracting the "rear spacing" from the "TOTAL" wheel width.

The math when "advertised offset" is known:

(offset)/25.4 = X + (total wheel width)/2 = "back spacing"

"front spacing" = (total wheel width) - (back spacing)

It is generally accepted fact "total wheel width" is "advertised width" + 1"(1/2" each bead flange"!

A simple example: C4 9.5/56mm

56/25.4(2.205) + 10.5/2(5.25) = 7.45 (BS)

10.5 - 7.45 = 3.05 "front spacing"

The math from "advertised back spacing":

(back spacing)- (total wheel width)/2 = offset

The same C4 9.5/7.45:

7.45 - (10.5/2)5.25= 2.2 X 25.4 = 55.88 (offset)

round up 56mm




This math is using "generally accepted" allowances for 1/2" bead flanges. There are "minimal" differences wheel to wheel! I didn't do the math for all wheels but it appears that all were calculated in the same fashion so I anticipate the same eroneous information.

I'm quite comfortable with my numbers and my math.

And just what was "so pathetic" about my comments on the CF regarding your rear. I believe I summed up the replacement of the bearings and seals for the "short axles" quite efficiently for you. I kept it "very simple" for you. It's been explained to you here similarly.

Short axle bearings and "clutch packs" usually give "fits" the "first" go.


I actually "wandered" over here just to check some information that I was told was here in some sort of tech file regarding wheels and stumbled on this thread. I haven't been here for quite some time. Maybe I should hang around a little more!