Hey guys!
I was wondering if someone knows the size of an actual wheel/tyre. There seem to be no resin alternatives for Trumpy tractor, so I thought I might use what is available for other vehicles and is of more or less the same size.

All hope is not lost Paul

http://www.mrmodellbau.com/_shop/product_info.php?language=en&products_id=246

H.P.

Thank you, but I had known of that set. They represent the solid rubber (non-pneumatic) tyres as found on an actual vehicle rescued from bog/river some years ago. I'd like to have more widespread, standard tyres for my non-armored
artillery tractor.

I knew there was something strange with these wheels...

According to this chart (and this webpage as well) , the Sd.Kfz 8 is fitted with 11.25 x 20 tires on 20" rims...

H.P.

Thanks again! Was it the only vehicle with tyres of this size?
There should have been some others, maybe sd.kfz.234?

I checked some books I have but didn't find any other German vehicle with this size of tires.
Maybe you could do some resin casting and make copies of the Trumpeter tires?

/ Robin

Thank you Robin!
Still, I am considering Sd.kfz.234, Mercedes-Benz L4500 and Bussing-Nag 4500 wheel sets as possible alternatives. Trumpy kit is on its way to me and I don't have any of the above mentioned kits for SBS dimension comparison, but it's hard to believe that a wartime mass-produced vehicle was not unificated with something else...It is possible to cast resin copies using OOB parts, but they lack certain details, such as sidewall lettering etc.
...I am now trying to find specifications for tyres made by Continental and Fulda at the time, but to no success so far. There should be some archives, shouldn't there?

Sd.Kfz. 8 : 11,25 - 20

Mercedes-Benz L4500 : 9,75 - 20 or 270 - 20

Büssing-NAG 4500: 270-20 Gelände, the B-N 500 had 9,75 - 20

Sd.Kfz. 234: 270 - 20 bullet proof

All of them have 20 inch rims, the problem lies in the other numbers. The width and height of the rubber is defined by 11,25 , 9,75 and 270 respectively:
11,25 means that the rubber is 11,25 inches or 285,75 mm wide and high
9,75 works out as 247,65 and the 270 is already given as mm.

So the diameter of the rims will be tha same but the width will be wrong:
Sd.Kfz. 234, M-B L4500 and Büssing-NAG 4500: 285,75 - 270 = 15,75 mm difference which is 0,45 mm in 1/35

Büssing-NAG 500: 285,75 - 247,65 = 38.1 mm -> 1.1 mm in 1/35

For the total height we get 0.9 mm difference for the L4500 wheels and 2.2 mm for the B-N 500.

It also depends on if the various manufacturers of 1/35 wheels have got the measurements correct ....

Up to you to decide

/ Robin

Link to pdf where some tire measurements are explained:
https://www.punctureseal.com/documents/Punctureseal-tyre-dimensions-explained.pdf (also includes bicycle tires ...)

The 270-20 is from the time when there were no low profile tires, today it should probably be written 270/100x20 ...

Once again, thank you very much Robin.
So it seems like the 234 family and 4500 truck wheels are close, but not perfect match to the Half-track ones, while the FAMO ones, I suspect, are a tiny bit larger. Thus, there is no other option but try and cast OOB rubber wheels in resin. Maybe I should direct certain AM makers in that direction. After all, it would be nice to have not only the wheels, but tarps as well...

I'll buy a set or two of those resin wheels.

Des Kits from France did a Sd.Kfz. 8 in resin many years ago, 35076 & 35116 (armoured). There was also 35C08 by JP Hobby.


Des still have it on their website but maybe it's easier to make resin copies of the wheels from the kit than trying to buy only the wheels from Des.
http://deskit.online.fr/01_systeme/pages_systeme/home_page.htm



/ Robin

OK, I'm considering Black Dog, Panzer Art, DEF.Model and Legend as candidates to produce the wheels and tarps. My choice is based on personal experience. Those four have high quality casting standards and more or less responsible attitude towards accuracy and authenticity of their products.

An unexpected discovery!
After a closer look at Panzer Art product range I realised they have
two sets of front wheels for Sd.kfz.8. They just mislabeled them:
http://panzerart.pl/index.php/welcome/produkt/516
http://panzerart.pl/index.php/welcome/produkt/517

"mislabeled"

Have you measured them or do you trust the 270-20 numbers on the sidewalls?
I wonder what the customers who bought these wheels for their Sd.Kfz. 9 think about it
/ Robin

Well, those sets were announced here on Armorama as new products for November:
http://armorama.com/news/27131
Thus, they are either not on sale yet or were bought by very few modelers so far, in part because of confusion caused by mislabeling...
I identified them as 12-tonner wheels because they have the same centerpiece as Trympy's OOB parts and Panzer Art have had 'true' FAMO wheels in their range for quite a while now.
Do I think they are correct? Hmmmm...270-20 may sound a bit odd, but how accurate are the measurements given in the links above? The tyres in those two sets look a bit wider than Panzer art's own wheels for Sd.kfz.234, MB4500 and Bussing-NAG 4500.

The official tire size for the Sd.Kfz. 8 was 11.25x20 which would be 285x20 if mm is used for the rubber part.
The difference in diameter would then be slightly more than 15 + 15 mm for a total of slightly more than 30 mm for the total diameter or 0.9 mm in 1/35.
This assumes that PanzerArt has got the correct size for their wheels. They could be a fraction too large or too small. Too large would be good since then it is only a matter of changing the size-numbers.

Only way to find out is to buy a set and measure. Worn tires could account for a little of the difference ...
/ Robin