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Sun Jan 02, 2011 8:04 am

Does anyone know what the offset was on the factory 4 lug wheels on a 70 model standard bug? I have looked for a stamp, but I think the wheels have been painted a few hundred times, so no marks are visible.??

Sun Jan 02, 2011 8:22 am

In 1970 - 4Jx15 rims with a 40mm offset was original, or at least that's what the Bentley says. I'm not sure if VW bothered to stamp the offset at that point. It'd be ET40 if they did.

-Andy

Sun Jan 02, 2011 9:20 am

glutamodo wrote: In 1970 - 4Jx15 rims with a 40mm offset was original, or at least that's what the Bentley says. I'm not sure if VW bothered to stamp the offset at that point. It'd be ET40 if they did.

-Andy
I have some and they are stamped with the size (4Jx15), VW logo, and month/year of manufacture, but not the offset.

Sun Jan 02, 2011 3:25 pm

so if the stocks are ET 40 , and i go with a wheel that is ET 25 will it move the wheel outward or inward?

Sun Jan 02, 2011 3:44 pm

pintokiller79 wrote: so if the stocks are ET 40 , and i go with a wheel that is ET 25 will it move the wheel outward or inward?
The tire will move outward.

Mon Jan 03, 2011 11:23 am

Keep in mind that offset and backspace are two different measurements.

Offset is how far from dead center on the rim the bolt surface is from the rim's edges. There is zero, negative and positive offsets.

Backspace is how far the inside rim edge is from the bolt surface.

I just bought some 15 x 4.5" new chrome rims for my '74 Beetle with front disc brakes. I asked the vendor several times if these would interfere with my calipers and was told, "No, they won't interfere".

I was also told the backspace was the same as OEM VW 15" x 4.5" rims...IT WASN'T :evil: . The backspace was 1/8" deeper causing the wheels to hit the calipers.

I think I may be able to grind a little (<.030") off the calipers to get them to fit. There is enough "meat" to accomodate this "fix".

BTW: I also asked if they were made in China and was emphatically told they weren't. When they arrived, their boxes had "Made in China" printed clearly on them!!!

Mon Jan 03, 2011 1:09 pm

Pink MG wrote:
Offset is how far from dead center on the rim the bolt surface is from the rim's edges. There is zero, negative and positive offsets.

Almost

Offset is from the centerline to the hub mounting surface

On the stock offset question, I've never heard nor seen 4" et40 stock rims

All mine have been ET34 for 4" and et41 for 4.5"
type3s had et46

Mon Jan 03, 2011 5:15 pm

I just bought some 15 x 4.5" new chrome rims for my '74 Beetle with front disc brakes. I asked the vendor several times if these would interfere with my calipers and was told, "No, they won't interfere".

I was going to buy the same wheels, 4.5's in the front, and 5.5's in the back. I also have disc brakes in the front with drop spindles. I thought there wouldn't be an issue since my stock wheels clear the calipers, and the chrome ones are supposed to be a stock wheel??? I had also considered the Sprint Stars, but I get mixed reviews if they will clear the calipers too?? It is a lot more difficult than I thought to find front wheels that will fit!

Mon Jan 03, 2011 6:47 pm

This is what the US/Canada 1970-79 Type 1 Bentley says:

"Karmann Ghias have 4½Jx15 wheels. As of March, 1972, this rim size has also been used on other models covered by this Manual. Offset is the difference between the center of the rim width and the mounting face that bolts to the brake drum or brake disc hub. Karmann Ghia wheels have a 46-mm offset. 1974 Super Beetle wheels have a 41-mm offset, and the wheels for other late models have a 34-mm offset. The 4Jx15 wheels used on cars other than the Karmann Ghia prior to March 1972 have a 40-mm offset The 1973 Sports Bug has 5½Jx15 wheels with a 26-mm offset. The 1974 model has the same rim size with a 34-mm offset. Wheels for the 1974 Super Beetles and Sports Bugs cannot be installed on earlier cars that have strut front suspension."

Tue Jan 04, 2011 9:01 am

Joel...I left out "center of" the rims edges...cerebral atrophy mate! Thanks for catching that :oops:

Tue Jan 04, 2011 11:06 am

looks like some stock chrome ghia wheels would be the best bet for clearing the calipers since ghias had factory discs right? or do they just make a universal "stock" chrome 4x130 wheel and let you deal with the fitment issues? thanks for the offset/back spacing clearification too, that is valuable info!

Tue Jan 04, 2011 12:45 pm

I'm not an expert on VW wheel specifications. Maybe there is a thread in the section for Wheels?

One thing for sure is that VW OEM fits better than the aftermarket stuff every time.

I am going to grind my calipers...too late to return the new wheels, I already mounted brand hew Nankang 145/80R15's on them :cry: I been at this hobby for almost 5 decades and should have known better :oops: ...but I took the vendor's word for it this time.

The Chinese made CRAP in this hobby is getting old really fast.

Tue Jan 04, 2011 12:50 pm

Offset and backspace are the same. Just slightly different measuring points.
They only thing i am unsure about backspace is if the rims bead holder which is usually .5" is accounted for in the measurmnt

Goodluck
charley

Tue Jan 04, 2011 6:54 pm

Pink MG, I feel your pain on the cheap Chinese crap! I have no clue who to buy my wheels from, and after you being lied to, I don't know who to trust, or who has a QUALITY product. I am new to the on road scene, rail buggy wheels were much easier, and tires were easy too, until you cut and grooved them. :P NE ways, back on track here, I wonder if buying actual Ghia calipers, and rotors would give you the clearance? I myself have the Empi front set up, and the stock wheels are pretty close to the little "nubs" that stick out where the caliper piston is housed.

Tue Jan 04, 2011 8:48 pm

Some handy stock wheel links:

4 Lug:
http://web.archive.org/web/20041226061648/www.oxfordshirevwoc.co.uk/whsteel4.htm

5 Lug:
http://web.archive.org/web/20041226061648/www.oxfordshirevwoc.co.uk/whsteel5.htm

Wed Jan 05, 2011 8:41 am

Charley:
Offset and Backspace are not the same measurement. The edge of the rim, not the bead is where the measurement is taken for Backspace. Lay a straight edge across the backside of the rim and measure down to the hub (bolt) surface = Backspace. See that neat graphic Joel posted for Offset measurement.

Pintokiller79:
The part of my calipers that hit are also little nubs that appear to be casting related. The calipers are OEM Ghia calipers.

Wed Jan 05, 2011 10:56 am

thanks for all the info on backspacing, and offset guys, i think i got a good grasp on it! I appreciate it!

Wed Jan 05, 2011 11:04 am

ok, wasn't 100% sure,

but a 15x6 -12et is the same as 3.00" backspace or very close depending on rims edge design.
so i still don't see how it is different besides reference point and units? what am i missing?

Charley

Wed Jan 05, 2011 12:22 pm

Not necessarily defending any bad info from vendors, but mixing disc brakes and dropped spindles from different manufacturers will throw off any customer service rep. It's really heard to be able to be 100% accurate with so many variables. If your beam is adjustable depending on the height may cause issues. Their statement regarding offset of the aftermarket wheel in comparison to a stock original wheel could be correct, but if the shape of the wheel is a little different [as in your case], you may get rubbing issues when using a non-stock [for your car] item such as the dropped spindles and disc brakes. I can almost guarantee that if your car was in it's stock configuration you wouldn't be having this problem. Easiest way to be successful the first time is to find someone with the wheel/tire/suspension combo and find out what they did. Baring that, you'll need to measure and test fit before mounting tires.

Personally I put a set of early Riverias on my '69 and had issues. If my suspension were stock, they would have fit fine, but with my 2" cut/adjustable Puma beam, CB disc brakes and CB dropped spindles, I had significant rubbing problems. My fix was to use two 3/8" spacers on each side. This new offset the wheels were enough so the balljoints wouldn't rub.

-jeffrey

Wed Jan 05, 2011 12:58 pm

That's why I didn't mention the vendor...as jhicken knew, my car has too many variables. Although the calipers are OEM, the spindles are dropped on an OEM standard ball joint beam.

I checked the ball joint clearance after discovering the caliper rub and there is no issues there. Hopefully, about .030" off the caliper and eliminating the two casting "bumps" with my trusty angle grinder will solve the problem.

The chrome wheels are indeed slightly different than OEM though. I have a couple of gnarly OEM VW 15" x 4.5" wheels and tried them...no rub. It's the center (slots) that rubs, so the Offset and Backspace are not an issue. It seems to be the way the slots are stamped. Those measurements would possibly cause ball joint interference if they were not close to OEM.