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Wheels (offset)
medic_dan - 1/7/11 at 07:41 AM

I am using cortina hubs (I think! lol) - is there a standard offset for the wheels I need? Or does the offset change per setup?

If it does change how do I work out what offset I need.

Is there a current car that uses the correct wheels?

Sorry for the amateurish questions.

Dan


wicket - 1/7/11 at 08:56 AM

ET19


medic_dan - 1/7/11 at 09:03 AM

quote:
Originally posted by wicket
ET19


Thanks Wicket - is that what I have to look for? Wheels I have been looking at are quoting a PCD?


dlatch - 1/7/11 at 09:53 AM

pcd you need is standard ford 4x108


Humbug - 1/7/11 at 09:56 AM

There's several things you need to know about wheels (apologies if you already did know!):

* Diameter - obvious e.g. 13", 14", 15"

* Rim width usually e.g. 6J, i.e. 6 inches and J beading seat (not sure if J is supposed to be the shape or is some code, but most if not all of the wheels I have seen seem to have this type of designation)

* Offset = the distance in mm of the hub face on the inside of the wheel from the notional centre line of the wheel towards the outside of the car. Given as e.g. ET19 (can't remember what ET means) meaning the hub face is 19mm closer to the outside of the car than the centre line of the wheel. Higher positive numbers make the wheel closer into the wheel arch; lower numbers (or negative numbers) make the wheel move further out. Note that you need to decide how wide you want the wheels before deciding the offset because the centre line of e.g. a 6" wide wheel is in a different place relative to the hub from a 5" wheel with the same offset.

* PCD = Pitch Circle Diameter, usually expressed in number of stud/bolt holes x PCD in mm e.g. Cortinas and lots of other Fords are 4x108, i.e. there are 4 holes and the holes are on a notional circle of 108mm diameter. N.B. a lot of FWD cars including Fords have quite a high offset e.g. ET35 so might not be suitable for your car.

* Centre bore diameter for Fords (relevant to your hubs) this is 63.4mm

So, some wheels e.g. Peugeot might have the right PCD and ET, but a different centre bore. If the wheels are not centrally seated correctly you can get wobble. You may be able to get spigot ring adapters for such wheels; some people don't bother and just make sure they are careful about lining up the wheels on the hubs as they tighten the nuts.

[Edited on 01.07.2011 by Humbug]


mcerd1 - 1/7/11 at 10:03 AM

ford use a 108mm PCD (Pitch Circile Diamiter)



4 studs on a 108 PCD = 4x108 ( '4 by 108mm' )

the centre bore is 63.4mm - thats the hole in the middle that locates on the spigot of your hubs
(most aftermarket wheels use changable 'clip-in' spacers so its not a big issue)

the offset varies a bit depending on the model: ET19 for the cotina (sierra's are ET35 or 38, focus's are ET52......)


[edit - too slow again......]



[Edited on 1/7/2011 by mcerd1]


medic_dan - 1/7/11 at 03:48 PM

Thanks guys