Wire wheel offset - help required

[Heuer]

I am in the process of compiling a Forum 'Knowledge Base' thread on wire wheels and I now have the offsets for S1, S2 and Competition wheels (all different). Does anyone have an original S3 wire wheel to hand they can use to do a couple of measurements for me?

Find the overall width of the wheel (rim to rim). Divide this width in two to give the centre-line depth. Lay a straight edge across the inner rim of the wheel. Measure from the straight edge to the mounting rim of the wheel to give the back spacing. Subtract the centre-line depth from the mounting rim depth. This gives the offset (or inset).


Examples: Competition wheel = 5 1/2" wide so centre line is 2 3/4". Inner edge to mounting rim is 3 7/16", so offset is 3 7/16" minus 2 3/4" = 11/16" (17.5mm).
Standard S1 curly hub = 13/16" (20.6mm)
Standard S2 flat hub = 23/32" (18.3mm)

I would also be interested in the same measurements for:

1. Reproduction 5", 5.5" and 6" wire wheels from MWS and Dayton
2. Original steel S3 wheel
3. Non standard Jaguar centre laced wire wheel i.e:


If the crap quality of the repro spinners is anything to go by (wrong shape, wrong weight, wrong graphics, wrong machining) I am expecting some 'interesting' results! All responses will be much appreciated.

[64etype]

I've been trying to establish which tires will work with the 6" centerlaced Dayton wheel. In response to my query on J-L, a gent responded offline that the backspacing for the Dayton center laced is 3.5" and the backspacing for the 6" Dayton bead laced wheel is 3.88". He said he got those numbers from Dayton.

[Heuer]

Eric

Assuming they are both 6" wide that gives us offsets of:

1. Dayton centre laced = 1/2" (12.7mm)
2. Dayton 'bead laced' aka edge laced = 7/8" (22.3mm)

Many thanks - I had given up on anyone responding

[kingzetts]

David,
It so happens my 6" centre-laced Daytons are off the car at the moment having new tyres fitted so I will take some measurements before refitting them.
John

[64etype]

Eric

Assuming they are both 6" wide that gives us offsets of:

1. Dayton centre laced = 1/2" (12.7mm)
2. Dayton 'bead laced' aka edge laced = 7/8" (22.3mm)

Many thanks - I had given up on anyone responding

David,

I'm currently trying to nail down tire options for the Dayton 6'" center laced wheel over on J-L. There are numerous strings about tires, but the posters typically aren't specific as to wheel dimensions...particulary the distinction between 6" center and edge laced. With offset information I could at least check sheet metal clearance for tires on local cars that use the quite common 6" edge laced Dayton wheel, and then make some educated guesses. In any case, tire clearance/installation might also be helpful if you're creating a matrix. By the way, I believe MWS offer a 6.5" width for their center laced....maybe both 6 and 6.5"...not sure. If I remember correctly, their web site lists this sort of data where Dayton does not.

Thanks for doing this.

[kingzetts]

Hi David,
I'm not entirely sure how you want the offset expressed -the concept of the mounting flange in the diagram you show is for bolted wheels which have a clearly defined flat mounting flange.

The mounting of the wire wheel is defined by the position of the machined conical section on the inside of the inner hub. As this is sloped its hard to measure.

See the diagram. I've given two options, one to the rear side of the bqck ring of the centre hub, which is not necessarily comparable from one type of wheel to another. The other is to the root of the splined section which should be comparable between wheels.

Also of note is that although this is a 6" rim the edge-to-edge width is significantly more than that. Hope this helps.

[Heuer]

John

I was working on the basis that the measurements were taken as being:

Width of wheel - between the ridges where the tyre bead sits which is the true measurement of wheel width I believe.

Backspace - from the edge of the wheel to the face of the hub(if you laid a piece of wood across it.

As Eric mentioned Dayton quote the backspace of their centre laced wheel to be 3.5" so work from there - yours should be the same.

[kingzetts]

By that definition of backspace then I measure it as 87mm or 3.425 inch ( only 1.9mm short of 3.5") so confirming that figure. I could easily have been a millimetre or so out as the light was not perfect and I didn't have my reading glasses to hand).

I agree that bead well width = wheel width. I was just pointing out that overall rim width is significantly greater.

[Heuer]

Thanks for the confirmation John. As long as we are all measuring from the same points the analysis is valid. So to simplify things all I need:

1. The backspace measurement
2. The stated wheel width
3. The manufacturer
4. The type of lacing - edge, centre, competition (triple laced)
5. Hub type - curly or flat (S2)

[64etype]

David,
It so happens my 6" centre-laced Daytons are off the car at the moment having new tyres fitted so I will take some measurements before refitting them.
John

I'm trying to establish a range of tire sizes that will work on the center laced Dayton wheel. I'm fairly confident that 205/65 work and of course so do the 185's. I'd like to upsize to either 205/70 or 215/65. Just wondering what you're using. (I'm waiting to purchase wheels until I have a complete picture of the tire situation).

Thanks

[kingzetts]

I'm using 185VR15 Dunlops which have just been fitted replacing 185HR15 Vredesteins (which were 13 years old). Anything wider and I would REALLY struggle to remove the rears. As it is, I have to deflate the left rear to get the wheel off although it will go back on inflated.

It would be possible I suppose to roll the edge of the arch to gain a few mm extra as the return edge is about 10mm, but I'm happy with the "look" - the centre lacing makes the wheels look wider from the side and the 185 section does look fatter on a 6" rim.

Bodies will vary so another car may easily take slightly fatter tyres, but I'd be wanting to test-fit anything wider than 185 before buying.

Also I noted recently on a Jag-Lovers thread someone commenting on his Koni shocks having a shorter fully extended length than his replacement Gaz shocks. Since I also have Konis on the rear and since that length dictates wheel droop when jacked, slightly longer shocks would allow me to use wider tyres as the tyre width is rapidly narrowing at the point where the top of the tyre fouls my wheel arch. I will think about this when I need new rear shocks.

[64etype]

I started the thread where you probably saw the remark about Koni shocks. I happen to have a new set of Koni's (purchased 20 years ago), but am OK with pulling the bottom shock mount pin to remove a tire. As for a larger tires on the rear, I received a private message from a gent who on the advice of Dick Maury is trying a set of 205/70 Michelins on center laced wheels. He sent me a photo with the wheel/tire installed on the rear...the car was sitting high on the springs because the glass and hatch were not yet installed, but his shop thinks that tire will be OK (front and rear). If I can establish that A 215/65 can be squeezed onto the rear, I will likely go with the very inexpensive Sumito 215/65 at the back and their 205/65 on the front. Less than half the cost of a set of Vreds ...

[kingzetts]

Wow! I would never put myself in the situation of not being able to change a wheel in the event of a puncture, and I certainly would not think it wise to have to pull the lower shock shaft at the roadside to do so.

But then I do long European trips. I suppose it depends on the use to which you plan to put the car. Each to his own.......

[64etype]

Right I wouldn't travel without a spare. But pulling that pin isn't all that difficult for me. Just need the right tools on board. Or maybe I'll spring for some longer shocks. Depends what tire works and how it looks.

[rolando38]

I'm catching up on this thread to ask if anyone has been measuring the offset for S3 "turbo disc" wheels ?

thanks

[PeterCrespin]

35mm IIRC . I gave it on another similar thread recently. Too cold to look again.

[rolando38]

thanks Peter !

[I-Wen Foo]

Hello All,
I notice the S2 wheels have slightly less positive offset to the S1's.. Does anyone know what the effect would be handling wise of running wheels with the S2 (reduced) offset on a S1 car (if any)?

The reason I ask is because I am planning to order a set of 5.5 inch wheels and 185 R15 tyres, and specifying the reduced offset of the S2 wheels so as to push the wheels out ever so slightly externally. I'm hoping to reduce the 'railway carriage' look from the front & back. I'm also aware of the reduced clearance that would result between the tyre and wheel arches in the event of having to remove the wheels.

Good idea / bad idea? Any thoughts welcome...
Thanks and regards,
I-Wen

1962 3.8 FHC RHD