AG Tire sizes

[dknarnd]

I was given two options today for tires sizes to include on a tractor TC40 or 45. Available is 14.9x24 and 8x16 or 13.6x24 and 7x16 and price difference abour $400.

What are some thoughts on using one size over the other? My initial thoughts are to go wide for more stability on hill sides and better flotation in wet areas.

 

[Birdhunter1]

Wider tires will have lots of advantages, more stable on hills, less ground pressure=less ground compaction, floatation.

Disadvantages: less traction, if trying to do any row crop work with wider tires you may or may not have problems knocking crops over while trying to straddle rows, a wide footprint.

 

[Fredex]

I would go with the larger sizes. Why . . . .?

Higher weight capacity - important for FEL work. Also, for FEL work, a high ply rating adds weight capacity.
Other reasons already stated.

Also, I don't necessarily agree that wider tires have less traction. I once had a 14.9x28 and a 16.9x28 on the same axle for a small time while waiting for a new tire. The 14.9 always slipped first. That's not scientific nor definitive, just my one case observaton. My analysis would be that, so long as you have sufficient weight to make the lugs on the wider tire bite into the dirt the wider tire will have more traction by virtue of having greater lug area.

 

[Birdhunter1]

The wider tire will have less traction because there is less weight per square inch of ground contact, which is the same reason there is less ground compaction.

 

[dknarnd]

I would like to hear what sizes people are using that have the AG tires and any comments.

 

[Farmwithjunk]

The wider tire will have less traction because there is less weight per square inch of ground contact, which is the same reason there is less ground compaction.

Less pounds per sq. in., but MORE sq. inches contact area providing traction.......More flotation AND more traction in a great many cases. At the very least, more flotation with SAME traction. Unless tire size is increased in dramatic fashion, it's almost always a wash. Variable in the traction issue is traction SURFACE tire is riding on. Some cases, wider tires get MORE traction, some circumstances wider get less due to "floating" on top of a muddy surface as an example.

I'm not sure on 24" rim size, but with 28" rims, 13.6X28 are more than 3" SHORTER than 14.9X28 resulting in some difference in over-all gearing, as well as variation in ground clearance. The theory of wider = more stability needs to address over-all tire height. Center of gravity plays in to stability. If the wider size IS taller, maybe a wash on increased/decreased stability . Actually, it's the over-all width of the TRACTOR, not width of each tire individually that adds or subtracts stability. Narrow tires with wheels set out wide would accomplish more than wider tires with wheels set in.

My MF150 had 13.6X28 originally. I turned up the fuel screw (on injector pump) to increase PTO HP from 38 to 47 back many years ago. It ran out of traction when plowing or heavy pulling. I changed to 14.9X28" when it was time for new rubber. Replacement rubber is 3-1/2" taller and 1-3/4" wider than O.E.M. tires. There's more than ample traction now. That could come from one of three reasons, or cumulative effects of all three; (1) WIDER tire-more rubber on the ground. (2) TALLER tire- change in over-all gearing, geared higher (3) More FLUID in the rear tires by about 10 gallons per tire. Amounts to about 200 lbs additional weight.(cal/chlor&water filled)

Often times, tire size options are given on new tractors to offer price reduction (with smaller size) as much as any other good reason.

All things being equal, I'd opt for the LARGER size if it were me.

 

[scott_vt]

Narrow tires with wheels set out wide would accomplish more than wider tires with wheels set in.


Mornin,
Im not sure I can add anything more helpful than the advice youve gotten allready ! I just wanted to mention that on my MF-1040 my tire combination is 13.6x24 rear with 8x16 up front. The rear rims our dished out for stability and the traction is adequate. The tractor weighs in dry weight 3800 lbs without the FEL and or implement.

Im including a picture of the machine with the above mentioned tire sizes. As I said previously, traction is adequate grading my driveway bottom to top with a 6ft rear blade, and I have had that blade loaded.

 

[daTeacha]

Go wide. If nothing else, it looks better!

I went with the bigger tires on my DX29 for the aforementioned reasons. I do mostly loader work in the woods and wrestled with Ags vs. R4s for a while before deciding on real traction and ground clearance over visual traction and tough looks. The higher ground clearance from the Ags resulted in the ROPS being higher, but the tractor just makes it into the barn without folding the ROPS -- I have about an inch to spare. The garage is a different story, but that wouldn't have worked with the R4s either.

I think you will find the rims are different width, too. You are making a lifetime decision, so to speak.

 

[rdln]

I wish I was given the choice when I bought my tractor. I believe those two sizes were available. I got stuck with the smaller resulting in all the disadvantages mentioned plus the rear wheel disc to rim connection was only 4 bolts compared to the 14.9-28 which would have been 6 bolts. Within a year I had a issue with bolts loosening (did not check torque as manul probably says to). Solved issue by making spacers for 4 optional blot locations between disk and rim resulting in 8 bolts.

seen here http://www.tractorbynet.com/photos/showphoto.php/photo/2609/sort/1/cat/500/page/1

 

[tydp]

I'd go with the larger tires, but the price sounds steep. Just a guess but the price difference shouldn't be more than $200.

 

[IH3444]

The wider tires act just like the tracks on a dozer in most soil conditions. The low ground pressure is more than offset by the total contact area of the treads. Dozers have much less ground pressure, but why do they grip so well? Contact area.......Plus larger tires offer more floatation over boggie areas, another consideration. Narrower tires with high pressure will sink, and then possibly dig themself into a hole. As mentioned before also R4 tires have usually a higher ply rating, allowing the FEL to be used to it's full extent. Ever look at R1s with a full load in the bucket?

 

[dknarnd]

For me AG's will be the only way to go except one used tractor I am looking at has the R4's on. I already priced out a set of 14.9x24 at $240 each and 8x16 at $150 each installed, plus tubes or stems if needed. Now that I'm speaking prices my stealer wants $2789 for the 14.9" and 8" R1's which also includes wheels, this is if I go with a new tractor.

 

[AndyMA]

I disagree that wider R1's have less traction. I always go for the largest R1's available on each tractor that I have purchased. I have used both TN's and 2120's with smaller tires than I have and in both cases there was a significient decrease in traction. The dozer analogy above is right on.

Andy

 

[LeadPoison]

I have 14.9-28s on my Kubota M4900 and no complaints.

I disked 6 acres last weekend at 5 mph and had zero problems.

 

[daTeacha]

The wider tires act just like the tracks on a dozer in most soil conditions. The low ground pressure is more than offset by the total contact area of the treads. Dozers have much less ground pressure, but why do they grip so well? Contact area.......Plus larger tires offer more floatation over boggie areas, another consideration. Narrower tires with high pressure will sink, and then possibly dig themself into a hole. As mentioned before also R4 tires have usually a higher ply rating, allowing the FEL to be used to it's full extent. Ever look at R1s with a full load in the bucket?

Just two comments in reply: 1) Many dozers have steel lugs on their tracks which act in a manner similar to the lugs on Ag tires. They dig into the soil while the soil on either side of them is supporting the weight of the machine. The soil has to be displaced laterally while being pressed vertically before the things will slip. 2) My DX29 tractor/loader with the wide Ag tire option came with 4 ply rears and 6 ply fronts. The fronts do not deflect much when the bucket is heavily loaded. I have them running at the recommended pressure as per the tire sidewalls -- somewhere around 35 lb. if memory serves -- rather than the manual.

When checking with the dealer about tires, check the ply and load ratings in addition to the size. If you will mow a lot, you want low pressures. If you will do a lot of loader work, you want higher pressures in the front. Air pressure is cheap and easy to change. It makes a huge difference in how your tractor performs in areas ranging from traction to damage to your lawn
yet most people just set the tires once and forget it until something breaks or leaks.