DIY changing the offset on my wheel to fit the corrado

[corradog60stage4 0]

Stock BBS RS001 are 15 X 7 ET 25 with a 4X100 bolt pattern.

OEM outer is 1.0 and OEM inner is 5.5.

 

 

 

SAE to metric conversion

ET is measured in mm

1 inch = 25.4mm

 

Back to my RS001 wheels I have that I will convert them to 16 inch wheels. People are still very confused as how to calculate or have an idea of offset.

First positive offset can be reduced with the use of adapters and spacers but

 

what alot of people that do not know that you cannot use adapters or spacers to increase the offset of wheels. The only way is the mill the hub surface of the wheel. I had a few yahoos telling me that with ET 10 wheels I would need spacers to make the offset positive. This is wrong.

Going with spacers makes the wheel poke out which is undesirable for wide wheels.

 

What I like about my RS001 wheels is I can alter the offset anyway I please without the use of adapters or spacers.

 

OEM the RS001 comes with a 1 inch outer and a 5.5 inch inner thus giving you a 15 X 7 wide wheel with an ET of 25.

 

To keep the same ET of 25 but going wider you can put 1.5 outer and 6.0 inner or 2.0 outer and 6.5 inner. both combinations will give you ET 25 but the first will give a 8.0 wide wheels while the second a 9.0 wide wheels.

 

Leaving the 1.5 outer and 6.0 inner you can put just a wider outer 2.0 and leave the 6.0 inner to get an ET of 12.3. some may ask how you get ET 12.3? When you add width on the outer you will reduce the offset by the same amount. so you add 0.5 inch which is equivalent to 12.7mm gives you ET 25 - 12.7 = ET 12.3. You want a wider lips like 2.5 with the 6.0 inner the ET will be ET 25 - 25.4 = ET -0.4.

 

you can leave the outer alone and increase or decrease the width of the inner barrel as well. Let say you have the 1.5 outer and 6.0 inner ET 25 you want to increase the inner to 6.5 so the equation will be ET 25 + 12.7 = ET 37.7.

 

So I got two 1 inch , four 1.5 inch, four 2.0, two 2.5 inch outers, four 6.0 inner and two 6.5 inner to play with.

 

bbs instar

different width lips

 

different width inners

 

new lips and barrels sitting in the garage for years.

some rs bolts and nuts to hold the wheels temporarily together

2 inch lip

plaaced instar over barrel first.

lip goes over the instar

bolts and nuts

looks pretty shiney

16X 8.5 wide

6.0 inch inner barrel clears with 5-6mm before hitting the spring.

looks like going with a 2 inch outer is too wide and will give me rear wheel arch issues.

 

[VRChris 0]

Leaving the 1.5 outer and 6.0 inner you can put just a wider outer 2.0 and leave the 6.0 inner to get an ET of 12.3. some may ask how you get ET 12.3? When you add width on the outer you will reduce the offset by the same amount. so you add 0.5 inch which is equivalent to 12.7mm gives you ET 25 - 12.7 = ET 12.3. You want a wider lips like 2.5 with the 6.0 inner the ET will be ET 25 - 25.4 = ET -0.4.

 

you can leave the outer alone and increase or decrease the width of the inner barrel as well. Let say you have the 1.5 outer and 6.0 inner ET 25 you want to increase the inner to 6.5 so the equation will be ET 25 + 12.7 = ET 37.7.

 

Wow, that was a lesson!! :cuckoo:

But, completley wrong im affraid, if you add a certain amount to one side of a wheel it changes the offset (ET) by half that amount, eg, you add 0.5" (12.7mm) to the ouside of a wheel, the offset reduce's by 6.3mm, think about it, offset is the distance from the MIDDLE of the wheel to the mounting face, you add to the outside of a wheel that distance changes but the middle of the wheel moves also doesn't it!

[corradog60stage4 0]

Leaving the 1.5 outer and 6.0 inner you can put just a wider outer 2.0 and leave the 6.0 inner to get an ET of 12.3. some may ask how you get ET 12.3? When you add width on the outer you will reduce the offset by the same amount. so you add 0.5 inch which is equivalent to 12.7mm gives you ET 25 - 12.7 = ET 12.3. You want a wider lips like 2.5 with the 6.0 inner the ET will be ET 25 - 25.4 = ET -0.4.

 

you can leave the outer alone and increase or decrease the width of the inner barrel as well. Let say you have the 1.5 outer and 6.0 inner ET 25 you want to increase the inner to 6.5 so the equation will be ET 25 + 12.7 = ET 37.7.

 

Wow, that was a lesson!! :cuckoo:

But, completley wrong im affraid, if you add a certain amount to one side of a wheel it changes the offset (ET) by half that amount, eg, you add 0.5" (12.7mm) to the ouside of a wheel, the offset reduce's by 6.3mm, think about it, offset is the distance from the MIDDLE of the wheel to the mounting face, you add to the outside of a wheel that distance changes but the middle of the wheel moves also doesn't it!

Hey buddy you forgot to read this :cuckoo:

 

Stock BBS RS001 are 15 X 7 ET 25 with a 4X100 bolt pattern.

OEM outer is 1.0 and OEM inner is 5.5.

so if you read adding 0.5 + 1.0 to the outside = 1.5 and adding 0.5 + 5.5 to the inside = 6.0 the ET remains the same at 25 but the wheel becomes 15 X 8.

I wonder who's :cuckoo:

[VRChris 0]

LOl, what you quoted there is true, who's saying it isn't??

 

My point is what you've said here....

Leaving the 1.5 outer and 6.0 inner you can put just a wider outer 2.0 and leave the 6.0 inner to get an ET of 12.3. some may ask how you get ET 12.3? When you add width on the outer you will reduce the offset by the same amount. so you add 0.5 inch which is equivalent to 12.7mm gives you ET 25 - 12.7 = ET 12.3. You want a wider lips like 2.5 with the 6.0 inner the ET will be ET 25 - 25.4 = ET -0.4.

 

This is'nt true, when you add width to an outer it does'nt change the offset by the same amount.

A wheel made from your centre with a 6.0 inner and a 2.5 outer as you mentioned would be ET 12.3 btw. (your wheel with a 1.5 outer and 6.0 inner is still ET 25 as you say, you add 1" to the outside to give 2.5 outer and 6.0 inner, ET is the original 25mm minus half what you've added (25 - 12.7 = 12.3) , because you add 1" to the outside of the wheel, the midddle of the wheel moves by half an inch (12.7).

[zak 0]

where did you get all the barrells?

[corradog60stage4 0]

where did you get all the barrells?

 

i bought the outers and inner barrels new.

[corradog60stage4 0]