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Scorpwanna
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Joined: April 19, 2012
Posts: 794
Location: Arkansas
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 Posted: Sun Sep 14, 2014 7:14 pm Post subject: How do I measure a rim? |
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I need some new rims and I'd like to match them to the size I already have. Anyone tell me how to exactly measure it for the right size?
Some rims on this site say backspace 4 which I don't understand.
Eyeball measured through one of the holes in the rim the depth and it was about 5 inches.
http://www.mamotorworks.com/vw/subcategory/stock-style-4-lug-wheels
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1971 Super Beetle Sedan Stock
Manufacture Date: December 12 1970
Left Factory on: December 17 1970 (Emden Germany)
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Original Color: L 12 D Shantung Yellow
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theKbStockpiler
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Joined: July 07, 2012
Posts: 2316
Location: Rust Belt
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| Posted: Sun Sep 14, 2014 8:22 pm Post subject: |
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I have et 41 (offset of 41mm) on a 72 super and I have about .100" clearance to the strut spring seat. Mathmatically a et41 should have a backspacing of 3.9" but the lip is not included so mine actually measure 4.5 inches of backspace. So the lip will add an extra 5/8th of an inch.Offset means the hub is not exactly in the center of the rim but is jogged to the outside creating a positive offset. Backspacing includes the offset and is the distance from the inside of the rim where it meets with the hub to where the bead of the tire sits. I think I emailed every one on the exact backspacing of their stock style rims and no one got back to me.If you can contact the vendor ,also ask if they will garanty the runout to be under an acceptable amount.
You should use your old rim as a guide.  Edit: Some rims have the et stamped on the rim near where the bolt holes are.Check your old ones.
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Her74buggy
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Joined: September 29, 2013
Posts: 367
Location: Houston
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| Posted: Sun Sep 14, 2014 10:46 pm Post subject: |
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I bought the white wheels on that link because they were the only et 45, the rest are et 25. I wanted the et 45 because my 4.5 wides are et 41 so by going to the 5.5 wide I needed some more offset to keep the tires under the fender. Note the backspace on those are 4 15/16 or really 5 inches. They fit ok on the 74 super as I had a good tuck and clearance from the struts but the Chinese quality stamping caused the rim to drag on the brakes and that's not in the measurement. Remember, they look like stock but they aren't made like stock.
As far as measuring it's easy if you take a wheel off. You may even find the stamp on the wheel with ET##. I put a straight edge on the edge (yardstick, 2x4, whatever) then measured. Back edge to where your lugs touch the drum is your backspace.
Remember, total width is not edge to edge but where the tire bead locks.
Last edited by Her74buggy on Sun Sep 14, 2014 11:00 pm; edited 1 time in total |
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Brian
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Joined: May 28, 2012
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Scorpwanna
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Joined: April 19, 2012
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Location: Arkansas
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| Posted: Mon Sep 15, 2014 12:28 pm Post subject: |
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Her74buggy the rim you got from them is it pretty good quality?
_________________
1971 Super Beetle Sedan Stock
Manufacture Date: December 12 1970
Left Factory on: December 17 1970 (Emden Germany)
Received: Washington, USA
Original Color: L 12 D Shantung Yellow
SOLEX 34-PICT 3 Carb
I've got a Bentley |
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ashman40
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Joined: February 16, 2007
Posts: 15987
Location: North Florida, USA
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| Posted: Mon Sep 15, 2014 9:48 pm Post subject: |
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Brian posted a good pic but it doesn't show backspacing.
The one thing I disagree with in this pic is the wheel width. Wheel width is always from the inside of the lip not the outside.
What you should notice is that the backspace measurement includes the inner lip width. The offset does not. Since there is no standard for how thick the lip can be, there's no way to easily/accurately convert offset to backspace, or the other way round.
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AshMan40
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'67 Beetle #1 {project car that never made it to the road  }
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Brian
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| Posted: Mon Sep 15, 2014 11:00 pm Post subject: |
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| ashman40 wrote: |
| Since there is no standard for how thick the lip can be, there's no way to easily/accurately convert offset to backspace, or the other way round. |
I've noticed on most of my VW wheels the excess lip accounts for about half an inch.
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Last edited by Brian on Mon Sep 15, 2014 11:23 pm; edited 1 time in total |
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ashman40
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Location: North Florida, USA
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| Posted: Mon Sep 15, 2014 11:08 pm Post subject: |
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| Brian wrote: |
| I've noticed on mose of my VW wheels the excess lip accounts for about half an inch. |
AGREED! That's the value I use for estimating.
You also need to convert everything to inches or mm. Offset is normally given in mm. Backspace in inches.
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AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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Her74buggy
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Joined: September 29, 2013
Posts: 367
Location: Houston
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| Posted: Tue Sep 16, 2014 7:12 am Post subject: |
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| Scorpwanna wrote: |
| Her74buggy the rim you got from them is it pretty good quality? |
I got them on sale for $200 for all four including shipping ($45 each) and for the money I think the quality is good. They are sturdy and the welds look fine. As far as the fitment I have the disc conversion and the concave by the lugs is a bit more shallow than stock and that was why I had the rubbing of the wheel to caliper. Considering the et45 is hard to find in stock design wheels there are few choices out there. |
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Scorpwanna
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Location: Arkansas
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| Posted: Thu Sep 18, 2014 10:40 pm Post subject: |
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Since I had painted the rims it's hard to see exactly. I want to say the wheels have a 40x15 on them..
_________________
1971 Super Beetle Sedan Stock
Manufacture Date: December 12 1970
Left Factory on: December 17 1970 (Emden Germany)
Received: Washington, USA
Original Color: L 12 D Shantung Yellow
SOLEX 34-PICT 3 Carb
I've got a Bentley |
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Scorpwanna
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Joined: April 19, 2012
Posts: 794
Location: Arkansas
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| Posted: Sun Sep 21, 2014 7:00 pm Post subject: |
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Took some close ups of the rims that I could read some information on. If a rim were a 4 by 15 would it say 4.0x15 or 40x15. If 4.5x15 I'm thinking that's what I have. I used a tape measure and measured the depth of the rim edge to edge using tape to make a level enough surface. It measures approx. 5inches deep, so if I take away the lip maybe it's a 4.5 maybe it's a 4? About how deep are those lips anyway? Rims are confusing to me.
_________________
1971 Super Beetle Sedan Stock
Manufacture Date: December 12 1970
Left Factory on: December 17 1970 (Emden Germany)
Received: Washington, USA
Original Color: L 12 D Shantung Yellow
SOLEX 34-PICT 3 Carb
I've got a Bentley |
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ashman40
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Joined: February 16, 2007
Posts: 15987
Location: North Florida, USA
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| Posted: Sun Sep 21, 2014 9:13 pm Post subject: |
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That looks to me like "4Jx15".
That would mean a 4" wide wheel (between lips).
"J" represents the profile/shape of the lip. J is common/normal.
15 is the diameter (15").
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AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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