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MG MGB Technical - Tube-Type Rostyle/s

We have a '74 B/GT which came equipped with a tube-type Rostyle wheel from the factory. This car is a PED (Personal Export Department) car destine for the USA. The key difference in the two wheels was the elimination of the stamped grove to hold the bead of the tube-less wheel. I changed those out many years ago because of random punctures due to rust/scale on the inside of the tube-type wheel/s. I still have them stored (somewhere).

Question would be then, why? And, has anyone else witnessed this type of wheel in the UK (or down-under), and if this would have been a special order?
Larry C '69 Midget

Larry. Could you post a photograph of the wheel? I have never heard of this and was fitting tubeless tires to a 61 Sprite back in the late 60's. You note that the car was a Personal Export Delivery vehicle. Where was it delivered and what country was it set up to be exported to? When I took delivery of my original 79, also a PED car, there was no wheel option noted on the special order form. By the late 60s/early 70s, tubeless tires were the standard for disc type wheels. But, I do remember places in Southern Europe where most of the local tires were tube types and your car may have been ordered with that in mind.

Les
Les Bengtson

Les,

The original owner (a neighbor) was a DuPont textile engineer working in Geneva, Switzerland. They ordered the car through an MG dealer in London, and not through the popular (at the time) Nemet Auto International. I still have a copy their catalog that I picked up in Saigon on my return home from Vietnam. Remember them?

The car was transported and shipped directly from Longbridge to the port in Baltimore, Maryland. I have most all of the documentation. The wheels are in storage, and it may take a day, or two before I can post a photo.

Regards,

Larry C.
Larry C '69 Midget

Hi Larry
Interesting that you should bring this up I had been thinking about this very subject only this morning.
I don't know about the Rostyles but on our Elan, which is a 70/71 model the wheels are tube type without the ridges around them. It also was an export spec car.
Years ago we got knocked back at scruitineering for a speed event ,and it wasn't until then that I knew what we had been spearing around on being these wheels with tubeless tyres on them without tubes AND that's how it was delivered new as it still had the original tyres on it when we bought it back in the early 70's
If I remember correctly series one XJ6 Jaguars were the same as another guy got pinged the same day as me
I have always run tubes ever since---

Willy
William Revit

And I suppose you run into plonkers who fit the tyres that say the tubes are illegal.
Best response I've heard is "OK, how are you going to stop the air getting past the spokes then ... "
(WW not rostyles, but a good line :-))
Paul Walbran

This is all new to me. How can you tell if the wheels on the car (I have an Elan like Willy) are intended for tubed or tubeless tyres? As for tube-only Rostyle wheels, that's news to me too. I would have thought all Rostyle wheels were intended for tubeless tyres.
Mike Howlett

Mike
Here's a pic of both type of rim

On the left is the rim refered to as tubeless but really it is what is called a safety rim
As you can see it has a raised section just inside where the bead of the tyre sits. The raised "ring" is there to help keep the tyre on the rim if the tyre gets flat or during very spirited driving

On the right is a non-safety rim which can/is refered to as a tubed type rim

IF I remember corectly safety type rims began being used in the early to mid sixties on some cars but it wasn't till 1970 here in Australia (When Australian design rules compliance plates were introduced) that they became compulsory on new cars

If you have the non safety rims I would strongly recomend fitting tubes, especially on an Elan which runs fairly low tyre pressures compared to most cars
You don't have to take the tyre off to check steel rims as the groove pressed in the rim can be felt/seen on the other side

willy


William Revit

I always thought that the "J" in the wheel size - i.e. 5Jx14 - referred to 'tubeless' or safety.
Dave O'Neill 2

...or at least to the profile of the bead seat, and whether it was suitable for tubeless tyres.
Dave O'Neill 2

By 1974 the factory (and anywhere else) would have been fitting tubeless tyres for years.

I can't understand the need for a special tubed wheel as an option, regardless of market. If for any reason you need tubes e.g. poor quality tyres that don't keep the air in very well (like Federals on my 2004 ZS!), then tubes can be fitted to tubeless wheels perfectly well.

Wanting to fit tubeless tyres to a wheel designed for tubed tyres only *would* be a different matter, which makes having tubed wheels a positive disadvantage.

Not easy to photograph as they are buried in the shed and it is cold and wet outside, but these are from my 73. There *is* a groove, but only on the outer bead seat, arrowed in the attached on the middle wheel of a group of three. Perhaps not unreasonable, on severe corners the outside wheel would be trying to push outwards moving the bead seat away from the bead, the inside wheel would have much less weight on it.

Paul Hunt

'J' is one of several profiles and refers to the physical shape of the bead seat, see http://www.carbibles.com/tyre_bible_pg4.html. Except that whilst I can see that 'J' is a physical shape in the example, I don't see how K, B, P, D etc. could be.
Paul Hunt

No I'm baffled. My Lotus Elan is a 1971 Elan Sprint. It's original steel wheels show no sign of a groove as you can see in my photo.

My MGB has alloy Minilite type wheels purchased new in about 2000. You can see a line on these but it is the wrong way round, that is to say it is raised on the outside, so on the inside of the rim it would be a lower section and wouldn't hold the tyre.

My local tyre fitter, an extremely helpful and knowledgeable bloke didn't bat an eyelid fitting tubeless tyres to both cars.


Mike Howlett

Attached is an end-view of one of my original Rostyle wheels without the safety groove. In many tyre shops here the technician's are simply too young to know anything about tube-type wheels, and the young ones really don't want any advice about how to do their jobs.

Regards,

Larry C.

Larry C '69 Midget

Mike
On the alloy MGB wheel you have shown, I reckon that line around the rim is just where the edge machining of the wheel finishes and from then on inwards it's as cast
Being a 2000 model set of wheels you can almost bet that they are safety/tubeless rims
On alloy wheels the ridge is machined into the rough casting when the wheel is made and won't be visible from the outside like a steel rim which has the ridge rolled into it and therefore leaves a matching visible depression on the outside
Your Elan wheels are exactly the same as ours(non safety) As has been mentioned there are plenty of cars running around with them and probably a large proportion of those are fitted up tubeless BUT for your own safety I would fit tubes. The only reason I hadn't picked up on the fact that our car had these rims is because it's a S4 SE and the SE's came with a narrow chrome trim ring that is almost impossible to get off without wrecking it, and it sits exactly over where you need to see - that's if you're looking like I wasn't.
See pic.
Just out of interest, I have a genuine old magnesium 10" Minilite off the old Mini racer.It's from the late 60's -early 70's Best wheel you could buy at the time and there is no sign of a safety lip, BUT we had to run tubes then to stop the tyres pulling off the beads
Speaks for itself I guess.



William Revit

"so on the inside of the rim it would be a lower section"

That's what the bead seat on my Rostyles are like i.e. having a groove not a raised section.

On Larry's picture the outside face of the wheel is to the left? That being the case I can see a clear depression where the bead would sit next to the rim.

There were two Rostyle wheels, having different offsets, the later wheel had a slightly wider track. On the earlier wheel the centre protrudes out slightly from the rim as in the attached. In the later it is virtually flush.

Still can't see why anyone would want to specify a wheel suitable only for tubed tyres.

Paul Hunt

This thread was discussed between 04/02/2015 and 06/02/2015

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