Borrani Rims
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- Posts: 3
- Joined: Sat Jan 03, 2004 7:59 pm
- Location: Miami , Florida
Borrani Rims
Has or does anyone know if Borrani RW 4075 will fit on a 330 GT 2+2 in place of RW 3812 ?
I don't know if they fit, but I can tell you how these wheels are different:
RW3812: Size = 7 x 15; Offset = -25 mm; Backspace = 63mm; Fits 330 GT
RW4075: Size = 7-1/2 x 15; Offset = -9 mm; Backspace = 100 mm; Fits 250 GT, 365 GT and BB512
All of this information is taken from Borrani brochures.
Hope this helps,
Ruedi
RW3812: Size = 7 x 15; Offset = -25 mm; Backspace = 63mm; Fits 330 GT
RW4075: Size = 7-1/2 x 15; Offset = -9 mm; Backspace = 100 mm; Fits 250 GT, 365 GT and BB512
All of this information is taken from Borrani brochures.
Hope this helps,
Ruedi
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- Posts: 3
- Joined: Sat Jan 03, 2004 7:59 pm
- Location: Miami , Florida
Kind of hard to explain without a drawing, but I'll try anyway:
Offset is measured from the center of the rim (middle of the wheel) to the surface where the splined hub attaches to the wheel hub.
Backspace is measured from the vertical surface of the rim flange (facing the center of the car) to the surface where the splined hub attaches to the wheel hub.
So, both measurements take into account the combination of the wire wheel AND the splined hub.
Offset is measured from the center of the rim (middle of the wheel) to the surface where the splined hub attaches to the wheel hub.
Backspace is measured from the vertical surface of the rim flange (facing the center of the car) to the surface where the splined hub attaches to the wheel hub.
So, both measurements take into account the combination of the wire wheel AND the splined hub.
skymaster7,
I found a good diagram & explanation of offset & backspace at:
http://207.158.236.129/Offset.htm
Ruedi, thanks for starting the ball rolling with your explanation.....
Will
I found a good diagram & explanation of offset & backspace at:
http://207.158.236.129/Offset.htm
Ruedi, thanks for starting the ball rolling with your explanation.....
Will
Not a bad description of the concepts. However, a few things are worth pointing out:
1. In the context of the Borrani measurements, the "Bolt-up Face" is the surface where the splined hub meets the axle. This is what I meant with my earlier remark "measurements take into account the combination of the wire wheel AND the splined hub." The problem this creates is that offset and backspace numbers are quite useless if one tries to measure a wheel by itself and doesn't know how much the splined hub adds to backspace and offset.
2. The Borrani brochures have many errors and inconsistencies. One of them is that Borrani drawings show backspace being measured differently for "Record" and "Standard" wheels: According to the drawings, backspace for "Standard" wheels is measured from the rim to the wheel hub, while "Record" wheels are measured from the rim to the "Bolt-up Face" of the splined hub. I cannot believe that different measurements were applied but that one of the drawings is wrong. I haven't found anybody yet who knows or can confirm which one is right and which one is wrong.
3. The drawings on the web site show backspace being measured from the lip. This is incorrect. Backspace is usually measured from the innermost (as related to the car) surface of the rim, at the nominal diameter of the wheel. This has to be somewhere below the lip on the rim, otherwise the tire falls off.
4. Wheel width is usually measured at the inside shoulders of the rim, not at the outside as shown in the drawings on the web site.
Will: FYI, I responded to your private message with my e-mail address. I have some information for you.
Cheers,
Ruedi
1. In the context of the Borrani measurements, the "Bolt-up Face" is the surface where the splined hub meets the axle. This is what I meant with my earlier remark "measurements take into account the combination of the wire wheel AND the splined hub." The problem this creates is that offset and backspace numbers are quite useless if one tries to measure a wheel by itself and doesn't know how much the splined hub adds to backspace and offset.
2. The Borrani brochures have many errors and inconsistencies. One of them is that Borrani drawings show backspace being measured differently for "Record" and "Standard" wheels: According to the drawings, backspace for "Standard" wheels is measured from the rim to the wheel hub, while "Record" wheels are measured from the rim to the "Bolt-up Face" of the splined hub. I cannot believe that different measurements were applied but that one of the drawings is wrong. I haven't found anybody yet who knows or can confirm which one is right and which one is wrong.
3. The drawings on the web site show backspace being measured from the lip. This is incorrect. Backspace is usually measured from the innermost (as related to the car) surface of the rim, at the nominal diameter of the wheel. This has to be somewhere below the lip on the rim, otherwise the tire falls off.
4. Wheel width is usually measured at the inside shoulders of the rim, not at the outside as shown in the drawings on the web site.
Will: FYI, I responded to your private message with my e-mail address. I have some information for you.
Cheers,
Ruedi