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Gasket



Member Since: 30 May 2020
Location: Manchester
Posts: 629

Wheel offset confusion…
There’s plenty of knowledgable folk on the forum, so thought I’d ask here.

I understand basic offset figures in relation to LR wheels.

So the smaller the offset figure, the more the wheel “sticks out”. So a Wolf rim with a ET20.6mm offset would sit further into the arches than an aftermarket Wolf rim with an ET0 offset.

For a Range Rover Classic project, I’ve been looking at custom Rostyle steel wheels - there’s two companies that remanufacture these wheels using original factory centres reseated into brand new tubeless wheel rims (so they’re not banded).

One of them has published the offset information - but it’s not in a format I recognise. They say:

“7"/16 TUBELESS DEEP-SET Rostyle steel wheels.

What makes them different?

NEGATIVE OFFSET 4.5". POSITIVE 3.5".
FOR REFERENCE:
STANDARD ROSTYLE WHEELS ARE NEGATIVE 4.7/8" AND POSITIVE 2.3/8".
LAND ROVER ALLOYS ARE NEGATIVE 5.3/8" AND POSITIVE 2.7/8"

STANDARD ROSTYLE WHEELS ARE 6" TUBED. OUR REMANUFACTURED WHEELS ARE 7" TUBELESS TO TAKE A BIGGER TYRE. COMPARISONS ARE IN THE PICTURES.”.

Now that sounds great. I believe that with a 235/70/R16 tyre that this will fill the arches nicely in standard suspension without creating any interference with the arch, nor straying outside - so no monster truck look.

However I have no earthly idea how this ‘negative’/‘positive’ measurement compares to an offset in mm as I would understand it.

The reason I ask is that a set of these rims is enormously expensive (£1200 for the set) and, while I can live with that for the tubeless safety aspect (and the nice looks) - if there is an existing rim that would do the job (like a 6.5j Wolf - evocative of the old camel vehicles that rode on 5.5” steels) then I may have to take the cheaper/less pretty option.

Can anyone help me translate this offset into a standard measurement so that I can plug it into a tyre/wheel visualiser?
Post #977668 12th Jan 2023 1:30am
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 16812

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
The offset of a wheel is the measurement of the distance from the hub face of the nave plate to the centreline of the tyre. A positive offset means the centre of the tyre is inboard othe nave plate datum, a negative offset outboard.

The spec you have quoted has been written by someone who doesn't understand this definition as is providing some fairly random measurements, either because they're dim or because offset is actually quite hard to measure. What they have done is provide the distance from the nave plate to the inside and outside beads. Adding 4.5 and 3.5 suggests the wheel is 8" wide. The centre is therefore 4", so the nave plate is offset 0.5" (or 12.7mm for those who speak foreign). I isn't clear whether it is a positive or negative offset but I'd guess it more likely to be positive.

It is curious that having given measurements that add up to 8" they then say the wheels are 7" wide. Perhaps they're measuring to the outside of the rim? This won't alter the 0.5 result but just adds more doubt to the technical competence of the seller.
Post #977677 12th Jan 2023 8:24am
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jpboost



Member Since: 13 Apr 2021
Location: Gatwick
Posts: 374

United Kingdom 2014 Defender 110 Puma 2.2 SW Keswick Green
I Agree everything that BW has said above, but most importantly the bit about the seller.

Also, I don't think there is any real difference between a set of wheels you describe (old centres welded into some different rims) vs some wheels that have been banded.

I know that banded wheels can be a bit of a taboo subject, but if you're comfortable with the idea of someone welding an old centre into a new (different) rim, then why would that be preferable to someone welding a band into a rim?

Personally I've got no issue with either method (as long as they are done correctly), but I'd struggle to see why one type was worth several times more than the other - particularly if the seller doesn't know how to measure and describe them!
Post #977684 12th Jan 2023 9:04am
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Gasket



Member Since: 30 May 2020
Location: Manchester
Posts: 629

Thanks both.

Glad to hear I wasn't the only one that was confused.

I'll go and have a look at them in person - will check out the setup and will measure the offset myself.

There are two companies that make them so will check them both out as well as their weld inspection process (I work in Engineering so this part would be my home turf).

I have nothing against banded wheels if done right, just a higher chance of failure due to the length of the weld runs involved and the fact they have to hold air, but from a personal preference I wouldn't fit them. Regardless, a banded steel wouldn't help here as the aim is twofold: get a tubeless rim and increase width to 7" to open up the tyre choice. Banded would just make the tube-type rim wider. I know you can have extra beads welded on to act as tubeless retainers, but I've seen these up close and they wouldn't be for me. Happy to pay for a well made new set on quality barrels, but want to understand the offset first.
Post #977726 12th Jan 2023 12:57pm
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Shroppy



Member Since: 25 Feb 2016
Location: Shropshire
Posts: 846

United Kingdom 1986 Defender 130 V8 Petrol HCPU Aintree Green
Just to throw another option into consideration:

What about sourcing a set of Rostyles (and perhaps even a set of 6.5" or 7" rims) and taking them to a professional outfit to be mated? I am sure such companies exist and would I hope have the capability/knowledge to determine load capacity etc.

I too am from an engineering background and whilst the process doesn't scare me (as others have said, how do you think wheels are made? Rolling with laughter), the thought of Joe Bloggs hacking the centres out and welding them into new rims does. I consider myself to be pretty competent at MIG welding, but would I weld up a set of wheels for road use? Hell no. 1985 127 V8 Build Thread
Series 2 109"
Series 1 80"
Post #977739 12th Jan 2023 1:59pm
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