Rim's Offset

[GupZ]

Hi guys..i just got a noob question about the meaning of the offset of a rim.
We always see some description about a wheel such as 18 x 8.0J OFFSET +55, what is the meaning of the 8.0J and the offset +55? i got some pictures here and they should be in different offset size and that 8.0J thingy.
I could pretty sure that those rims are in 18 inches, but is the S13 in 10.0J and the DC5 in 8.0J (Approx) and why should we care about the offset size?
if i want to fit brembo into my car, what offset or what J should i get?
Thx :p

http://i186.photobucket.com/albums/x166/Gupz4148/sampleworkxd9180sx.jpg

http://i186.photobucket.com/albums/x166/Gupz4148/sampleworkxd9hondadc5.jpg

[trism]

the offest is how far the centre mount is from the centre of the wheel.
so +55 means its 55mm towards the outside of the wheel from the centre line of the wheel.

the other part, 8.0j is how wide the wheel is in inches

[GupZ]

the offest is how far the centre mount is from the centre of the wheel.
so +55 means its 55mm towards the outside of the wheel from the centre line of the wheel.

the other part, 8.0j is how wide the wheel is in inches

so is it mean that the S13 is with 10.0J and the DC5 is with 8.0J (approx) according to the photo? does that affect of installing a brembo?

I still dun understand the meaning of Offset, is it a standard size of each car?
that means if the original spec is in +55, i would need to buy any rims with offset +55?

[thebob]

Usually for bigger brakes you require a lower offset.

For instants 45+ on 15 inch wheel will clear OEM caliper. But when you add endless caliper you need a 35+ or lower to clear caliper without using a spacer. Lower the offset the more dish, the further the wheel sticks out.

[trism]

no thats not right!!

the bigger the brake, the more offset you need.

the lower the offset, the deeper the lip.

[thebob]

Ok from first had experience 39+ wasnt enough i needed 35+.

[Spicey]

- or negative offset wheels

http://www.japanesenostalgiccar.com/forum/pics/rims/sakura.jpg

+ or positive offset wheels

http://www.carrims.us/alloy-wheel-424.jpg

So most FWD cars come with +35 or +40 rims and by lowering the offset to +10, +20 or even a 0 offset will put more dish on the rim and poke it out of the gaurd more. (its not recommended to put a 0 or +10 offset on your FWD unless it is pretty modified, I only used them as examples)

[GupZ]

so is that mean the photo (s13) that i have provided has a +10 or +25 (approx) offset? and DC5 with +55offset?

so with diff offset, could i still use my oem typr or i needa buy a new set of it?

[DLO01]

no thats not right!!

the bigger the brake, the more offset you need.

the lower the offset, the deeper the lip.

TheBob is correct, generally.

It really comes down to the ALL of the following: Wheel offset, size of wheel and the design of wheel.

Generally speaking, same wheel, same size, you'll need a lower offset to bring the spokes out further to clear the calipers.

http://i13.photobucket.com/albums/a265/DLO01/Temp/WheelOffset.jpg

[thebob]

Depending on the size of the brake. MOST brake upgrade kits require a lower offseted wheel. Spoon calipers for EG, EK and DC require 38 or less i think. But as Deano said, depending on the style of wheel. Its a try and buy type thing.

[trism]

TheBob is correct, generally.

It really comes down to the ALL of the following: Wheel offset, size of wheel and the design of wheel.

Generally speaking, same wheel, same size, you'll need a lower offset to bring the spokes out further to clear the calipers.

http://i13.photobucket.com/albums/a265/DLO01/Temp/WheelOffset.jpg

ok, so looking at that pic. the dotted line is the centre line of the wheel.

the further the mounting hub of the wheel (the red line) is towards the front (outside) of the wheel, the larger the offset. thats positive offset.

if it goes back to the inside of the centre line, thats negative offset.

did we clear that up?

now, so in order to fit bigger calipers you often need to push the spokes further outwards, and so you fit a larger caliper....

[DLO01]

You should not look at it as the Red line that moves (the hub does not move). Rather it is the 'Wheel Centerline' that moves according to what offset the wheel is.

So in order to move the spokes 'outward' to clear a larger caliper the 'Wheel Centerline' will move toward the Red line, and therefore a lower value offset.

[trism]

no, the centre line doesnt change position. its the centre line. it stays at the centre.

its the hub that moves. it its on the centre line, its 0 offset. the further it move out, the larger the positive number becomes. so a 9" wide wheel with +20offset has a deeper dish than one with +50 offset. 30mm more dish infact.

[DLO01]

so a 9" wide wheel with +20offset has a deeper dish than one with +50 offset. 30mm more dish infact.

^^^ That is correct. A lower offset and you have more room for larger calipers. Thats the guys original query.


no, the centre line doesnt change position. its the centre line. it stays at the centre.

its the hub that moves. it its on the centre line, its 0 offset. the further it move out, the larger the positive number becomes.

^^^ Thats incorrect. How can the hub move, its a fixed part of the car? A lower offset moves the centerline of the wheel outward. Thats why lower offsets stick out of the gaurds and why lower offsets rub on gaurds.

[trism]

:/

i still dont agree.

not the hub of the car, the part of the wheel that bolts to the hub of the car. it moves in relation to the centre of the wheel.

http://www.raceandroad.com/images/ns-offsetexplained.jpg

http://www.discounttiredirect.com/images/wheel.offset.gif

the dish is on the outside of the wheel, not the inside.

the more dish (less offset) you have on teh "front" or outside of the wheel, the less room there is on the inside of the wheel, or the part where the brakes are.

http://www.japanesenostalgiccar.com/forum/pics/rims/sakura.jpg

these have negative offset. there is lots of dish, and not alot of room on the inside for brakes. it also pushes the outer edge of the wheel out, and will stick out of the guards


the less dish (more offset) you have, the more room for brakes
http://www.carrims.us/alloy-wheel-424.jpg

and it pushes the inner edge of the wheel in, and will scrub on the springs.

http://www.tirefactory.com/img/offset.gif

like so

[DLO01]

Last post. Those are just photo explaining offset distances.

Your hub on your car does not move. The Face on the wheel bolts up to this hub face. You have to picture this WILL stay still.

Therefore if you have a higher offset +50 the wheel will sit in more toward the car, therfore the centerline sits in more, further away from the hub.

If you have a lower offset +40 the wheels will sit out more toward the gaurd, therefore the centerline sits out more closer to the hub.

[DLO01]

Ultra last post. I am just being nice. :p

You've got it the wrong way.

Look at that last photo, or whatever photo.

Take the +30 offset and the 0 offset.

See how the +30 offset the spoke bend in toward the brakes? This will hit calipers. The 0 offset spokes are straight? This will clear. And the -30 definatly will clear.

[trism]

*nod*

i understand now :)

was always informed that if your calipers didnt clear the spokes, then you need higher offset.

misinformation is a killer :)

[DLO01]

All good. We learn something new everyday. I know offsets can be confusing. Its definatly a big misconception going round, always has been. :thumbsup:

But yeh as I said, to clear big brakes. It really comes down to the ALL of the following: Wheel offset, size of wheel and the design of wheel.

[trism]

yeah, wheel design i spose.

thats prob where i got the more offset needed argument.

as in, the spokes didnt curve back, but actually curved the other way, so more offset was needed.

[Lukey]

Sorry to bring this back up again but I'm still a bit confused.

So bigger (positive, +38, 45, etc.) the offset the closer to the brakes and stuff the wheel is?
And the smaller (negative and neutral, 0, -10, etc.) the offset the closer the wheel is to the guards?

[LUD35]

Sorry to bring this back up again but I'm still a bit confused.

So bigger (positive, +38, 45, etc.) the offset the closer to the brakes and stuff the wheel is?
And the smaller (negative and neutral, 0, -10, etc.) the offset the closer the wheel is to the guards?

^^ sort of correct. think about it this way:

the higher the offset, the higher chance of bigger brakes not fitting - obviously it depends on the design of the spokes but you get the picture. by having a 35 offset(over a +50 offset) for example, you are creating 15mm of distance that can be further filled in by bigger brakes...

the small the offset the "flatter" the spoke design and the closer it is to the hub, thus there is a much smaller area given for the brakes to occupy.

[NightKids]

Thinking of getting these rims for my EG5:-

http://i15.ebayimg.com/07/i/000/e9/e7/e1b6_1.JPG

These are 15" . What would be a good offset? +35 or +40? Not too sure i just want it to look like EG5 (Yonas) car....

[LUD35]

^ they will fit over standard brakes, but if u want to eventually upgrade to something bigger ie. spoon,endless than you will have to sell them...or get spacers which i wouldn't recommend. personally, rims with a lower offset look a whole lot more tough than a higher offset.

imo get the +35 offset.

[Lukey]

I get it now. :D