Wheels: Working out offset

[Morgs]

Guys

Simple question (Call me daft, but I've never had to know before)

How do you work out what offset a set of rims are?

[Nemi]

there is usually a sticked on the inside of the rim.

[Morgs]

I should clarify, there is no sticker and I've searched for information on the rims in question (speedlines, can't find any info at all !!)

[bogrider]

This may or may not help.
http://img227.imageshack.us/img227/4213/offsets25kz.jpg (http://imageshack.us)

[MrMayhem]

good post

[McKVNT]

Ahh - thats exactly what I needed as well!

[Mofo]

goog... :eek:

http://images.google.com.au/images?svnum=10&hl=en&lr=&q=wheel+offset

[Robbo]

good post,great valuable info guys cheers :)

[mys1]

Yep, thats exactlly how you measure offset :)

Tyson

[IMACUL8]

Hey Guys

This offset calculator is great also:

http://www.1010tires.com/WheelOffsetCalculator.asp

Dan

[cy3org]

Good info, but im still a little confused. For example:

On my corona i have a set of aftermarket 180/65/R14 rims/tyres. I tried changing them with the rims i have on another car, a Magna. They were 225/50/R16. Both sets were 5 stud, and although the 16s did fit into the wheel arch and could have sat there not touching anything, they simply did not fit onto the studs (the holes were wider apart).

Now I am in the market for a set of bigger rims for the Corona. What do I need to look for to ensure they'll fit in every way?

[DCIEVE]

need pitch circle dia on the bolts to be correct as a start
then correct no. bolts

if your struggling with that part maybe leave the offsets for now :p

[[ant]]

haha yes as DCIEVE says your PCD (pitch circle diameter) is wrong.

when you have wheels and they say 4x114.3 or 5x120 this is the number of studs (4 or 5 etc) and then the other number is the PCD. This will determine if the wheels will fit on the studs.

[gazza750]

PCD, or Pitch Circle Diameter, is the diameter of an imaginary circle drawn through the fixing holes of a chainring. Since it's not possible to measure this directly, you can instead measure the distance between the centres of consecutive fixing holes and convert to PCD using this table:
Distance between fixing holes PCD
34.1mm 58mm
43.6mm 74mm
50.6mm 86mm
55.3mm 94mm
64.7mm 110mm
71.7mm 122mm
76.5mm 130mm
79.4mm 135mm
84.7mm 144mm

for more info http://www.needforspeed.co.uk/htmlpages/TechWheels.htm

[Joe]

That was a very good post

That wasn't, as aren't the rest of your 2 and 3 word replies...trying to increase post count to access FS section issit?

[mitchy]

PCD, or Pitch Circle Diameter, is the diameter of an imaginary circle drawn through the fixing holes of a chainring. Since it's not possible to measure this directly, you can instead measure the distance between the centres of consecutive fixing holes and convert to PCD using this table:
Distance between fixing holes PCD
34.1mm 58mm
43.6mm 74mm
50.6mm 86mm
55.3mm 94mm
64.7mm 110mm
71.7mm 122mm
76.5mm 130mm
79.4mm 135mm
84.7mm 144mm

for more info http://www.needforspeed.co.uk/htmlpages/TechWheels.htm


i assume that is for 5 stud? the distance between stud centres will be different for 4/5 stud, even if both are 114.3PCD or whatever PCD you are using.

not to mention distance between studs for 114.3PCD is missing from that list, and probably the most common PCD for imports. :)

67.2mm for 5 stud

[ARETHT3]

i like

[Milhouse]

you like what ?

[mitchy]

men

[Joe]

Troll. Banned.

[Simon]

whats the go regarding offset + spacers??

ie i wish to fit 18x8.5+42 when my car uses standard 17x7+55

in theory i should loose 6mm internal and gain 32mm external.

now if i fitted a spacer of around 5mm what would happen to my offset and internal/external widths???

[shifted]

How do spacers work exactly? Do you put them on behind the rim and they just push your wheel out further?

[R3N]

spaces push it outward

[lachlanrb20s13]

fyi, bogriders diagram is straight up wrong in atleast 4 ways






whats the go regarding offset + spacers??

ie i wish to fit 18x8.5+42 when my car uses standard 17x7+55

in theory i should loose 6mm internal and gain 32mm external.

now if i fitted a spacer of around 5mm what would happen to my offset and internal/external widths???

yep ur inner lip will move in 6mm, and outer lip will site 32mm further out


with a 5mm spacer, you will have a theoretical offset of 18x8.5 +37...so from your current specs.. the new wheels + spacer would sit 1mm further in, and the sit 37mm further out

[mitchy]

http://www.1010tires.com/WheelOffsetCalculator.asp

[Simon]

fyi, bogriders diagram is straight up wrong in atleast 4 ways







yep ur inner lip will move in 6mm, and outer lip will site 32mm further out


with a 5mm spacer, you will have a theoretical offset of 18x8.5 +37...so from your current specs.. the new wheels + spacer would sit 1mm further in, and the sit 37mm further out


thats what i thought, it can be confusing trying to work it out.
needed clarity on that!

i know the rims will rit with a full guard roll and the natural camber at my ride height.

mitchy: yeah been trolling that website lol

[Mr Scorpio]

How do spacers work exactly? Do you put them on behind the rim and they just push your wheel out further?

In terms of effecting your offset the size of the spacer will lower your offset by its width. ie 5mm spacer will lower the offset by 5mm. So if you have a rim that is 18x9 +30 and ran a 5mm spacer it will effectively make it an 18x9 +25.