Griff Wheel Offset

[steve-v8s]

Anybody know what the standard Griff front wheel offset is ? The rear of my car is on axle stands with the suspension in pieces so I can’t easily take a front wheel off. I would like to know what the offset stamped on the inside is, it will be ET2?

I have two sets of wheels, the original ones and a set of OZ Split rims and was surprised to find the rear offsets slightly different.

The OZ wheels are Rear 16x7.5 ET33 Front 7x15 ET26 The correct wheels are Rear 16x7.5 ET35 Front 15x7 ET2?

I need to know so I can choose a set of rims to run slicks for hill climbing. What do other people use ? I would like to keep the gearing the same if possible, currently I am running 245/ 45/ 16 and 205/ 55/ 15

Also what is the stud PCD, being fairly simple I don’t really understand what PCD is but measuring across the studs reveals approximately 109mm

[victormeldrew]

PCD is standard Ford, 108mm. PCD is Pitch Circle Diameter, and on four stud wheels you measure stud centre to stud centre as you have done; its more complex on 5 stud wheels! See useful guide here.

If your wheels are Extorils then from memory on my Chim 500 they are ET33 and ET25.

Edited by victormeldrew on Saturday 25th November 15:02

[GreenV8S]

The Ford "108PCD" hubs are actually imperial - the studs are on a 3" square. The same goes for the offsets - the originals were 1" inset (25mm) for the 7" rims and 1.25" (32mm) for the 7.5" rims. The inset varies with wheel style, they're all similar but not exactly the same, I think it was just a matter of TVR choosing something close. A few mm here or there is not enough to worry about.

[richb]

steve-v8s said:

Anybody know what the standard Griff front wheel offset is ? The rear of my car is on axle stands with the suspension in pieces so I can’t easily take a front wheel off. I would like to know what the offset stamped on the inside is, it will be ET2?

I have two sets of wheels, the original ones and a set of OZ Split rims and was surprised to find the rear offsets slightly different.

The OZ wheels are Rear 16x7.5 ET33 Front 7x15 ET26 The correct wheels are Rear 16x7.5 ET35 Front 15x7 ET2?

I need to know so I can choose a set of rims to run slicks for hill climbing. What do other people use ? I would like to keep the gearing the same if possible, currently I am running 245/ 45/ 16 and 205/ 55/ 15

Also what is the stud PCD, being fairly simple I don’t really understand what PCD is but measuring across the studs reveals approximately 109mm

i) It's ET25 (as Pete says 25mm) ii) Pitch Circle Diameter (PCD) i.e. the diameter of the circle round the stud centres. p.s. Have you looked at Steve Heath's rolling radius calculator on his web site? Usefull for calculating different trye sizes and keeping the original rolling radius - here: www.shpub.co.uk/tvrbooks/faq_tyre2.html

Also take a look here www.greenbear.org.uk under modifications/bigger wheels...

Edited by richb on Saturday 25th November 15:52

[steve-v8s]

Thanks everyone, as usual an instant and informed reply.

[Ricardo Bertone]

If you're getting into competition use you may at some stage want to upgrade your brakes, e.g. larger front discs. In this case you may want to consider putting 16"s all round to accomodate the bigger discs.

Ricardo

[GreenV8S]

Ricardo Bertone said:

If you're getting into competition use you may at some stage want to upgrade your brakes, e.g. larger front discs. In this case you may want to consider putting 16"s all round to accomodate the bigger discs.

Ricardo

The 15"s are fine up to 285mm which is as far as you want to go with the original calipers. I got 300mm in mine but it was a really tight fit and needed a lot of faffing about, it would only need a tiny variation in the rim to make that impossible. But 285mm is a safe bet in 15" rims.