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Unimog U1300L Year unknown, but it has a Bundesheer rebuild plate dated 96
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Discussion Starter #1
Gentlemen, I have posted before about my search for The appropriate tyres for my Unimog 1300L here in Poland. I am finally getting closer to the tyre choice that will fit my needs 'in the long run' and be cost effective. As I posted before I was offered some Russian 'Forward Traction' tyres as fitted standard to 'Kraz' and 'Ural' russian military trucks. The tyres were beasts with a heavy MPT Tractor like tread (which I need here in this clay soil) They also stood much taller than my Michelin XZLs in a 12.50 equivalent size, probably due to the massive depth of the treads. I tried to fit these tyres but was foiled by the valve position of the Unimog 6 stud wheel, the heavy rim of the Russian tyre would interfere with the valve operation and may even have popped it out under heavy flexing. OK.... options suggested were have the rims cut and moved and the valve hole moved. Good suggestion, I think from Normalbloke, many thanks it is still an option. But better yet I have found that there is a massive supply of split rim (Bolted...many bolts like 'custom' alloys) wheels which are/were fitted to the 'Star 266' Poland,s 6x6 answer to the Unimog 1300L.....only problem is they are 8 stud. So my new option is a one off payment to have 4 adaptors made (cheap here in Poland) I can then fit the 8 stud..'Star' 20" wheels....which are built for the Russian Tyres in the first place.....another benefit is that I can change my own tyres with little difficulty due to them being bolted split rims. (I intend to keep this Unimog for many years, so changing my own tyres is an advantage that will pay off in the long run) Now I have just found that the Poles do a copy of the Russian 'Forward Traction' tyre, it is called the STOMIL T45....made in Poznan....in 12.00x20 or 14.00x20. Now what puzzles me is that some people on this site have stated that they fit 14.00x20 tyres on 6 stud rims and have no clearance problems.....well they would with these Stomils!!!!! the 14.00x20 Stomil T45 has an overall diameter of 1260mm which seems altogether way too BIG for my U1300L..and it is 420mm wide (this is the size that is fitted to the Russian KRAZ 10 Tonners) so my question to you Tire Wizards is this: will the 12.00 x20 Stomil T45 be a good option? (will it comfortably fit under my wheelarches?) it looks like it will, here are the specs 12.00x20..... 10 Ply rating.....minimum rim 9.0x20...... Overall Diameter 1130mm......width 330mm....Speed rating 85Kmh......certified for use with onboard tyre inflation systems...(Not that that Poles bothered with that much complication in their home built trucks.) This Stomil tyre is going to be cheaper than the Russian version and probably 'e' marked = for sale and fully safety tested in Europe = stringent testing) ....it solves the speed problem I currently have with the Michelin Power CLs and is a Much taller tyre. (Thats a part of my question for you Tire Wizards...."how come this is a 12.00x20 Tyre and my old Michelin XZLs were supposed to be 12.50x20...yet this and the Russian tire and the Polish Stomil is wayyyy bigger in overall size (almost fills the arches in 12.00x20 and is obviously much too BIG in 14.00x20 size??? (Though I have to say that the pics don,t do the 'lugs' on this tyre justice they are every bit as big as any I have ever seen on a true Agri Tractor tyre)). Lots of questions here....I hope I havent complicated things too much? I thank you in advance.
 

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U500 with Unicat camper
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798 Posts
Apples and oranges...
The 12.00-20 and 14.00-20 are "100 series" aspect ratio - IOW the sidewall height is 100% of the section width.
the 12.5-20 and 14.5-20 are "80 series" aspect ratio: 80% as tall as the width.
The tallest tire recommended for a 1300 is usually a 14.5-20 (or 14.5R20 or 365/80R20, all basically the same size casing), ~43" tall.
A 14.00-20 or 14.00R20 is ~49" tall.
The 12.00-20 is ~45" tall but beware, it usually (see pdf below from Michelin) calls for a narrower rim; 9" wide is pushing it, 8" or 8.5" would be better.

Charlie

PS I see on the Stomil site the 12.00-20s call for a 9" rim. They have a relatively low load capacity (maybe not a problem on the 1300L with an axle load capacity of only ~4 ton) and of course are not radials.
 

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'91 U1250 '02 U500NA
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Stomil T45.jpg

Specs :
Tire size 12.00-20
Tread shape T45
Type TT
Rim size 9.0-20
Tube size 12.00-20
OD diameter - new 1130 mm
OD diameter - in use 1155 mm
Width - new 330 mm
Width - in use 340 mm
Max. load 2400kg
Max. pressure 65 psi
Max. speed 85 km/h


BTW Stomil in Polish means "sto mil" - 100 miles :).
I hope they get better milage though - just kidding,
they are pretty well made.
 

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Non MB 1975 Volvo C304, 1958 Kramer U540, 1959 unimog Westfalia 411
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1,381 Posts
Thanks for the pic, they look like a good choice.
 

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Unimog U1300L Year unknown, but it has a Bundesheer rebuild plate dated 96
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554 Posts
Discussion Starter #5
Thanks guys....I took the trouble to talk to the local 'Straz' = Fire Brigade they have a brand spanking new Star 266 on these tyres, they say it will go anywhere with the diff locks in, but the tyres are hellish noisy (can,t be noisier than the Michelin Power CLs I have on now which are a loader tyre and only rated for 30kmh (I,ve done 60kmh for several kilometers in hot weather with no overheating or any other problems except noise! though elementary physics says noise = energy = wear!!) The Straz also run an old ex army 'Star' 266 6x6 as the snow plough (theyre just readying it for the snow) and they say these tyres are hard as old boots and will stand anything, the ones on the truck are many years old, they are the originals that came with the truck from the Army....they only get use in the snow but still have a lot of tread on them yet, they say they are so hard that the only way to change them is to split the rims...the rubber is so hard.....but they,ve never had to repair a puncture..ever! But why do tyre external diameters differ so much for different manufacturers???....you have to see the depth of the cleats on these tyres to believe.....the picture is good but still doesn,t show the brutality of this tire.....no wonder it looks good on a Kraz (which is just a brutal copy of the old Diamond T of WW2) I am preparing to go ahead and purchase 5 of these 'Star 266' split rim wheels and then go ahead with having manufactured the adaptors. (I am aware that this will increase my track by many inches....I asked at the yearly test station and they informed me that tyres outside the mudwings will make no difference to the test????? which is great....and I rarely carry any more than a ton of load on the bed of the Mog....so I dont see increased bearing load as a really big problem. If anyone thinks of any problems I may encounter...please let me know. I will post pics when this eventually happens....(It also has the effect of another 4 inches at least of ground clearance....on so callled 12.00x 20,s!!!)
 

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Unimog U1300L Year unknown, but it has a Bundesheer rebuild plate dated 96
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554 Posts
Discussion Starter #8
I did read your post again Charlie and I do sort of get it. I would love to fit the 14.00x20 version,(but I,m only really going to know if they would fit without problems on spring deflection, buy offering them up. I know where there are a part worn set in a scrapyard so I may try that.) but will inevitably go for the 12.00x20. One of my reasons for going for the 12.00x20 is the fact that there are just so many of them going cheap on the internet....Allegro.pl (similar to e bay) have some almost new going for 200zl each....(thats peanuts) at that cost I could afford to buy ten and store them in the roof of my barn until needed. I will post pics when the adaptors are made and the tyres/wheels are fitted. Although this will cost initially, purchase of the 'Star' split rims (you will probably be amazed - so will I - at how cheap they are going to be) the adaptors will cost. I will be buying one new full set of Stomils and probably something like ten good used spares to store away in the roof of the barn. If that happens I have drastically reduced my tyre costs for the next ten? years.
 

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Sold .....1987 U1250 Unimog
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1400R20 are big.... 48" tall stock was 46" tall I have them on a U1250 with 8 lug axles and increased GVW truck.. so a U1600 capasity on a U1200 width and size..... The more I look the more I wish I had a smaller tire... I think the 1200r20 will be perfect
 

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1980 U1000 Turbo...
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You may find a 12 inch wide tyre will still let the U13000L sink in soft clay.
I had 12.50r20 BKTs on my U1000 when I first got it aqnd had several stoppages where it wanted to sink quite quickly. I went up to 16 in after that and it has been quite an improvement.
 

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Non MB 1975 Volvo C304, 1958 Kramer U540, 1959 unimog Westfalia 411
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The overall footprint or psi is as critical as treads, I run Goodyear Suregrip ags occasionally on my Cummins Dodge and they are only 11'' wide traction is wicked but they sink in the soft stuff, oh the traction is wicked.Goodyear MV/T in 395/ 85 /20 are like aggressive car tires off road albeit very tall. It really depends on where you want to go and driver skill and judgement Judgement I cant spell it so I probably lack it . Go around not through when in doubt. I won't be content till I have something in the order of 20'' width.
 

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Alaskat I'm thinking about buying the 20'' wide flotation tires on the exchange mainly for the rims, but thats the problem I only want the rims.(cheeper to just make some from scratch, I want to put the firstone terra tires on them, that would be so sick in the snow and mud. My 425 XM-47 on 14 beadlock rims float pretty good and run super true down the road, this is the only tire I would recomend for hard wheeling and street use. I want to deflat them further and see how they run the lowest I've ever taken them are 10psi I think with beadlocks I can take it a bit further, what do you guys think? I'm mainly worried for the tire carcus over heating or getting torn?

Those Russian tires look kinda nasty but I bet the rubber compound is super hard. They are most likely made for much heaver rig's like Urals and 813 tatra's. I would imagine they would be fine for offroad and dirtroad only. Yes anything round roles on pavment but being such a hard compount will make the tires very slipery on wet road surfaces and rocks. Have you looked into the tires their runing on the older Kraz trucks they look like the ones in the picture only a little wider, from utube videos I watched they look a bit softer too. You say it's quite muddy over there, you would benefit from a wider wheel and tire combanation. Sounds like very similar tarrain as Canada, muddy and lots a snow, some but not much rocks, mainly loose scree.
 

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Unimog U1300L Year unknown, but it has a Bundesheer rebuild plate dated 96
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Discussion Starter #19
Thanks for all the inputs, Dave, looking at your avatar I think you are right, I cross a lot of deept ditches so although 14.00x20 would help, I would get too much rubbing on full deflection. These very Tall 12.00x20 seem the right ones for me. Normalbloke I know what you mean about sinking with thinner tyres, but this weird clay has to be seen to be believed, Ive driven all over the world and in most of Africa and South America, but never met stuff like this!!! you need a tyre that digs through the slippery top stuff and then bites, floaters just float and spin helplessly here! My other consideration is that here they are going to be dirt cheap...OK a new set is not so cheap, but there are so many piles of barely used ones sitting in yards all over the place. Yes the rubber is a hard compound, but the 'Star' 266 is only a 7.5 tonner comparable to the Unimog....read what the fire brigade say about them? (unpuncturable)!!! and while it is some time since I drove trucks on 'cross plies'... I will only be doing 60kph with short runs of 80kph. I did take the unimog out for a run of about 5 Kms on the Russian version and although noisy, I would rate the handling good!!!! I did push her on some twisty country roads. I don,t say this is a good option for everyone, but for me it seems to be the best option yet. Cheap tyres in the long run, with a good life, a good speed rating and the kind of grip in need in this clay. I will keep us posted about the adaptors, how far the 'star' split rims stick out and just how much they and the adaptors cost.
 
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