 | Home > Off Topic > Wheel offset confusion… |
 
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17463   
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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. |
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12th Jan 2023 8:24am |
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| jpboost Member Since: 13 Apr 2021 Location: Gatwick Posts: 377 
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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! |
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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. |
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12th Jan 2023 12:57pm |
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| Shroppy Member Since: 25 Feb 2016 Location: Shropshire Posts: 866 
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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?  ), 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" |
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12th Jan 2023 1:59pm |
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