8 stud tubeless rims to suit 1973 Denning

It maybe another expense but might be worth another look at the alignment. If that is your issue then thats cheaper than buying new wheels and tyres.
If it has too much toe in or toe out then you can imagine that the tyres are scrubbing sideways as you drive forward.

Thanks Cobbadog

That makes a lot of sense. I think another alignment may be the way to go.

Cheers

Ash

Here is a scientific study on heat build up in tyres done by the US Army.

Link to whole study below this paragraph.

DISCUSSION OF RESULTS
Tire surface temperature can be measured routinely using "averaging" type
radiation thermometers such as the devices described in Table I, item 1, 2, and
3. No operational problems occurred utilizing the instrumentation on the outrigger
or in the drum room test cell. The data described in this report represents
maximum expressway speeds of 80 mph under typical midwest summer conditions.
Rosd surface temperature, free air temperature, and direct solar heating of tire
surfaces influence tire operating temperatures more, under some conditions,
than speed or load. Developed tread and sidewall temperatures are directly
rel.ted to road surface temperature as can be seen in Figure 9, and, road
surface temperature is a function of air temperature and solar load as shown
in Figure 10.
The road surface heated by solar radiation can therefore be warmer or cooler
than free air temperature. After these influencing effects were measured and
understood, tire temperature data taken under any environmental condition could
be normalized to a standard condition or referenced to a desired road/air
temperature combination for data comparison purposes.
The three most important operational factors affecting the temperature of a tire
under highway performance are inflation, load and speed, in order of importance.
Inflation affects sidewall temperature more than tread temperatures as can be
seen in Figure 7. This indicates that the road is able to conduct more heat away
from the tread than the sidewall which is interfaced to the cooling air. And, as
speed decreases, siaewall temperature increases since there is less available
cooling air.
Next in importance is load. As load increases, sidewall and tread temperatures
increase (Figure Tread temperature again is influenced more by road
surface temperature than from heating as a result of load. The effects of the
load are predominantly seen as an increase in sidewall temperature. As the
rated load of 1650 pounds is reached, sidewall temjerature starts to increase
at a more rapid rate indicating the importance of following loading recommendations.
Speed produces the least effect in tire temperature. As speed increases from
30 to 80 mph, a slight cooling effect is noticed in the sidewall area as opposed
to a slight heating effect for the tread area (Figure 6).
Tread temperature is less affected by a speed as shown in Figure 17.
Sidewall cooling is a result of the increased air flow at higher speeds. Tread
heating at higher speeds is a result of increased friction between road and tire
offsetting the cooling effects of ram air.

apps.dtic.mil/sti/pdfs/AD0755817.pdf

Interesting information, although a load rating of just 1650 lbs means they are looking at light car tyres and not truck tyres where the dynamics of load and speed might well be turned on their head. Rubber is a good insulator and hence when in mass, such as a tube type tyre, dumping temperature to air would be slow. Even hosing an overheated tubeless truck tyre with water takes a while to get temperature down. (long story)

Higher tyre pressures equals less rolling resistance. Less rolling resistance equal less temperature.

Steve

I think the basic maths will work for any tyre regardless of size. Certainly will not be turned on their head. Road surface temperature is not of much input and according to the weather may be adding or reducing temperature.

Cobba

As they said the three things in order are inflation, load and speed.

Lang

As they said the three things in order are inflation, load and speed.

And motor-homers like a soft ride, and carry the entire house. Hence why they have blowouts.

Ash, did you ever find a solution here? Was it an alignment issue, or did you end up finding a tubeless solution?
I'm going to be up for six new tyres soon and I'm considering options to move away from my current R20 split rims (8 stud rims on an old Leyland). As previously mentioned, the price and options for R20's are limited compared to 22.5s.
Cheers

Hi mrsafety
I changed the rims to tubeless and now they increase in pressure less than 10psi. Steering feels better and I'm happy with the changes.
jon_d pointed me to these guys - oceanicdirect.com.au . Wayne had me sorted in no time. Based in Melbourne and very easy to deal with.
I hope this helps. Good luck
Ash

Thanks for the update Ash, good to see you finally got it sorted!

I'll get in touch with Oceanic Direct tomorrow to see what they can do for me. Is there any chance you could give me a rough idea on what you ended up getting, and roughly what the price was?

Thanks again!