New 19’s finally arrived..

[coyote]

Adam, your stock rim is 7.5" wide. Standard Spec.B is 7".

Offset is ALWAYS measured from the same place, the centre of the rim. That's why it is called offset. I hope whoever told you that is not in the wheel or tyre industry, because they have no idea.

Different 225s will have different section widths and tread widths. Some manufactures will publish that data for you. Tirerack can be a good resource for this.

[AdamW]

Adam, your stock rim is 7.5" wide. Standard Spec.B is 7".

Most literature you read is about the Spec-B, I guess I usually only remember these numbers.. I think I need to compile my own detailed list of Spec.B STi specs..

Offset is ALWAYS measured from the same place, the centre of the rim. That's why it is called offset. I hope whoever told you that is not in the wheel or tyre industry, because they have no idea..

ALWAYS is such a strong word… I am sure there are such rules in place, that doesn’t mean all the wheel manufactures around the world follow these rules..

THE OFFSET RULE- “The distance between the middle line of the centre of the wheel width and the mounting surface of where the wheel bolts to the hub on the vehicle…” In some cases wheel manufactures measure & reference their off set form places other than the mounting plate surface.. ie centre or outside of mounting plate.. or with reference to the bolt head.. Even thou this is incorrect, it still happens.. There are always exceptions to the rules..

[PHAT GT]

offset is the same world wide measured from the centre of the rim

tyres makers on the other hand have different ways of measuring
Eg: if buying a 19x235 +35 from one company it may measure a tread weight of 215mm and another company will measure 241mm on the same size tyre

[AdamW]

offset is the same world wide measured from the centre of the rim

This is only half the story.. You need two reference points to get a measurement of offset.. Its the second reference point that some manufactures get wrong..

[PHAT GT]

the two points you need are the outer and inner edges of the rim..some measure from the inside of the beed and some from the outside od the bead to get the overall size than get the center from that

not sure who told you theres two point of measerment but iv been ordering wheels for customers for over 6 years ( over 250 sets) from the US GER and Japan and always the same center line measurment


there so many articals on the net about this and all state offset is taken from the center no matter what language you look it up in

maybe the Irish measure different ????

some wheel info

http://www.procarcare.com/icarumba/reso ... wheels.asp

http://coolcarrims.com/wheel-customization/

http://www.rx7.org/Robinette/wheel_offset.htm

[coyote]

Adam, where did you get that quote from? It is wrong, just ask any "reputable" wheel manufacturer.

[AdamW]

You can not have a measurement of distance with out two points of reference.. Its physically impossible.. Be it a measurement of offset or any other measurement of anything.. The offset is one number but it is a measurement from Point A (we can call this the centre of point of the rim).. Without a second point of reference, this means nothing to no one.. So there must be a point B (point B is meant to be the mounting surface of where the wheel bolts to the hub on the vehicle).. Now the distance between these two points is the offset.. So yes I definitely agree that the offset measurement is taken from the centre point of the rim, but with out this all important second point of reference, the offset as a measurement would not exist.. It would just be the centre point of the rim..

[AdamW]

Adam, where did you get that quote from? It is wrong, just ask any "reputable" wheel manufacturer.

THE OFFSET RULE- “The distance between the middle line of the center of the wheel width and the mounting surface of where the wheel bolts to the hub on the vehicle…”

Let me brake it up a bit..

Lets say a wheel has a offset of 45.. What does this actually mean? It means the mounting surface of the wheel is offset 45mm from the center line of the wheel (in the direction towards the otter edge of the wheel, as it is a positive offset).. If the offset was zero, the mounting surface of the wheel would be in the center line of the wheel.. So if you had a wheel and you wanted to know the offset, you would measure the distance from the centre line of the wheel to the mounting plate.. Therefore the offset is “the distance between the middle line of the centre of the wheel width and the mounting surface of where the wheel bolts to the hub on the vehicle”.. So the quote is quite correct…
All I am saying is that, just like with every single product manufactured out there, there are some manufactures that don’t always follow the standards.. Be it through ignorance, cost savings etc.. Is that so hard to believe?

[coyote]

Adam, we are in violent agreement about the standard. The two points of reference are the centre of the rim and the surface that mounts up against the hub. That's it, anything else is like saying that Grant Hackett's 1500m metre race should be timed from the point where he touches on his 4th lap - complete nonsense.

The quote you posted contradicts the standard we are in violent agree on.

Back on topic, your wheels are lovely, but a bit skinny for 235/35 tyres.

[AdamW]

The quote you posted contradicts the standard we are in violent agree on.
Back on topic, your wheels are lovely, but a bit skinny for 235/35 tyres.

I don’t see how the quote contradicts the standard… All I am saying is that not all manufactures conform to the standards.. I do agree on 235 being too wide for the 7.5 inch rim.. I found out the tyres are 225/40/19.. Which increase the rolling diameter by too much (should really be running 225/35/19).. and now I think they are also too damn heavy.. With the combined increased rolling diameter & extra weight I think I will really notice an adverse affect to my acceleration and handling.. emmm might be looking for new wheels before I even use these ones.. or could always get a bigger turbo I guess..

[Resonate]

Speaking of new wheels, guess what i had fitted today!

[AdamW]

Speaking of new wheels, guess what i had fitted today!

Post up some pics.. Although I can’t be too demanding here, as it took me months to get some pics up of my car (and the wheels weren’t even attached)…

Do you know if there was a difference in weights? If so did you notice a difference in handling/acceleration? From some basic research, I think I will lose over 15kW with new wheels..

[Resonate]

Unfortunately when i booked the car in a few weeks ago, i didn't realise today would be a damn public holiday (ekka holiday for qld). But the owner was nice enough to open for an hour to fit my car. Although him being the only one, he couldn't put the teins on so i'm booked in tomorrow for that. If i posted any pics of the car in the current state, the only response id get is "drop that shit!" Also i don't want to hijack your thread.

EDIT: There's a Huge difference in weight. I have the gt-b rims though and they weigh an absolute tonne compared to the aftermarket.

[Arith]

Speaking of new wheels, guess what i had fitted today!

Hoorah! Yes, the new wheels need their own thread instead of hijacking AdamW's. They look decent now, but will look much much better once the Teins are in. I look forward to pics tomorrow!

[AdamW]

EDIT: There's a Huge difference in weight. I have the gt-b rims though and they weigh an absolute tonne compared to the aftermarket.

From what info I can get from the peeps back home my new wheels weigh a heap more.. You should get a noticeable beneficial increase in handling, steering response & acceleration.. Found this relating to motorbike rims.. Theory would be the same for car rims..

Total weight / Front / Rear
10 kg / 3.5kg / 6.5kg... Std set cast Aluminium wheels
5kg / 2.1kg / 2.9kg... BST Carbon Race wheels

Weight saving 5kg or 100%
Inertia saving: 140%
Power saving to accelerate wheels from 0 to 200 km in 10 seconds: 3KW or 5hp
Increase in top speed 4-7 km/h
Increase in lap time
(depending on circuit) 103 seconds

Also.. http://www.tirerack.com/winter/tech/tec ... techid=108