BIG Tires

how much bigger tires can I put on an old H it has 11.5 by 38 now will 13.6 by 38 look funny or be real uneven?
Bob

Bob: Every farm tractor rear tire has printed on it the ideal width rim. That is the size that will give the very best traction for that tire. You get that off very far, and you'll find that big tire wont pull as much as the smaller one.

I have 3 Hs and they all have different size tires on them. One has the 11.2X38 one has the 12.4X38 and the other one has the 13.6 X38 tires and they all look just fine

13.6 will be ok, 14.9 will wrap a little more than you want. I"ve seen them all!!!

Old: Yes, but are thay all same size rim. Besides looks doesn't give traction.

Evan: He said 11.5, must be 11.2 on a 10" rim. Here's betting a 13.6 wont give him as much traction as 11.2. I farmed too many years to believe that one. It might on soft ground but definitely not on hard road.

An H does not need or desire 13.6's, use 12.4's.

As far as I know all the rims are the same but I'm also not going to go out and measure them to be sure

I have 12.4's. They look great. I've seen 13.6. They fit, but look pretty big. Almost oversized. I can't comment on work performance, just looks.

From the factory only 10 x 38 (11.2 x 38) or 11 x 38 (12.4 x 38) were available on the H. You can put on larger tires but to me they will look too big and will not pull any more, if as much as the 11.2's or 12.4's.

Harold H

My uncle bought a new 1941 H. Being WWII and rubber was in short suplly he had to take it on steel. He was able to get cupons for tires for it but the only tires he could get were a 15?. I don't remember the correct size but were bigger than the 13.6s the Ms & SM had later, closest in size were the 15.5x38s that came on the 450 we bought in the late '50s.

Those tires looked emormous on the H but the tracto spent close to 90% of it's life as a lodaer tractor so they worked out good for that. Only time I can ever remember it being used in the field was pulling a double roller rolling wheat & a couple times pulling a 4 section drag harrow.

We also had a '47 H that had the 12.4 tires and was appropriately called the "Little H" because of the smaller tires.

Any time you have more ground contact you will have more traction, especially on a hard surface. If the tire can dig in sometimes a narrower tire will get more traction. The tires need to be right for the rims. We always ran 13.6x38's on an H but on M rims. The M's then got wider rims for 14.9x38's. If you don't need the traction I think 12.4's look best with 5.50x16 fronts, they are a lower profile like a 15.5x38....James

We had a 300 on 13.6's, and I had an H on 12.4's, and I preferred the look of the 13.6's.

jwal: I think you got that one backwards, narrow tire will give best traction on hard surface, and wide tire is best traction on soft surface.

Now, if you don't believe me, why do folks remove their duals for tractor pulling? Why did my 1066 stop leaving wheel tracks behind cultivator, when I removed chloride and added duals? I could give you 50 other examples.

Why do you think they put big wide tires on drag racing cars? Tire speed and more tire contact on the pavement. The bigger around and wider the tire is the more ground contact. That is why radials get better traction, more ground contact. Old AC tractor pullers put big 38" rubber on instead of the little 28" tires. All tractor pullers want more ground contact and as much weight on the rear as they can without losing the high hitch advantage when the front tires come up. A 18.4x 38 or even a 16.9x38 tire has a lot more ground contact then a 15.5x 38 tire. You don't see pullers run 15.5x38's, even Farmall M's now run 18.4x38's. A 706 came out with 18.4x34 but 14.9x38 duals got a lot more traction especially when seperated by 8-12" on a non weight transfer pull like a disk or cultivator. My brother pulls a 1466 with 20.8x 38 tires with axle duals both loaded and a lot of weight and with the screw turned up it will out pull his 1566 with single 20.8x38's, same horsepower, same total weight, same pulling track, he loses traction on singles. It is all about weight transfer and ground contact. The hitching point on the tractor is high and low on the sled so it puts weight on the back of tractor trying to lift the front. Kind of like pulling a 3 pt. subsoiler, you need duals to keep from digging in and spinning and front weight to keep the front from coming up. Heavy pull, duals will work better with more weight transfer. A lot of big heavy weight, pulling tractors that run in the slow pulls run duals, but high horse power, low weight tractors need big wide tires and wheel speed.

2 different things your cultvator needed speed and had no weight transfer. Slow tractor pulling is all about weight transfer and ground contact.

Did you run the tractor with chloride and duals? It would have pulled more on a heavy load. Your cultivator was a straight pull no weight transfer, it needed ground contact to float. I had a 4240 JD, came with 18.4x38 bias tires with calcium, I ran duals for breaking down ground with heavy 20' harrow, 20'disk and pulling a 14' grain drill with a 14' rollerharrow in front. I needed ground contact and needed to keep the tractor up on top of loose ground. I would run 1 dual when plowing in the furrow and 2 if on land. If a little greasy the in furrow plow gave down draft and would work better. On land had no downdraft, had to have duals and a lot of weight dry or wet. I went to radials, no calcium. Worked for plowing in the furrow but for the rest it wasn't worth a damn, bounced all the time, added all axle weight to make up for calcium weight, still no good, removed weights and put calcium back in, tractor ran smooth and pulled in 5th gear powershift. Every situation is different, but the constant is weight and ground contact. More weight, more ground contact, more pull. Now a narrow tire that will dig in on a hard surface and find traction with weight transfer can outpull duals with no weight transfer that just spin on top. It used to be old tractors had low horsepower but lugging ability so they ran slow and dug in. 20 horse JD BR or W-4 IHC with 10x24" tires, full of calcium pulled 2 bottoms at 2 miles/hr on a pull plow with weight transfer and no weights. Now, new tractors need wheel speed and need to stay on top. No weight transfer so they have triples on the back and duals on the front to get traction to pull 24 row planters and 60' cultivators at 8-10 miles/hr. If you take that same tractor, you can't pull an onland plow that fast and if you try you need 30-40 horses per bottom at 6 miles/hr....James

It all depends on lbs per square inch of ground contact, if the tractor weighs the same and on a hard surface, like a road, a wider tire spreads the weight if it can't dig in. Older tractors were built to dig in. If the tire and ballast weight makes the same pressure/sq. inch on the ground surface the wider tire will make more traction. 2 seperate issues. A tractor was made to pull a load the more weight the more traction. If only for show it makes no difference, does it?. Car tires have gotten bigger and wider and their weight has gotten less, tire componds have gotten stickier for more ground contact, even tractor tires, Air pressure makes a big difference, less air pressure and a tire has more ground contact....James

It should have been, Car tires have gotten bigger and wider while the CAR weight has gotten less....James

James: Well, well, well, your a bucket of brains. I only read to the part where you started comparing drag race tires to farm tractor tires, said to myself,"Now there is a guy out to lunch." Good night.