Go Bottom Go Bottom

mixed R4 tires and PSI

View my Photos
David LaBrie
Join Date:
Posts: 1
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-25          28572

When my Kubota, B2910 was delivered 2 weeks ago the R4 tires hadnŐt come in yet. The dealer agreed to swap the ag tires when the R4Ős came in. That was done today. On the back are Goodyear 12.4-16 R4Ős and on the front are Titan Track Loader 23X8.50X14 tires. Is it unusual to have two brands of tires on a tractor ? The tire pressure is set to 32PSI in all 4. Is that too high? my manual says 35psi for the front but 20psi for the back. Also the front tires look so small. Is that just my imagination?Thanks,David

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Bird Senter
Join Date: Jun 1999
Posts: 962
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-25          28574

David, I think I would prefer having all 4 tires of the same brand; however, my B2710 came with Goodyear tubeless tires on the front and Firestone tube type on the rear. Of course I have R1 (ag) tires. I never did remember to ask the dealer why; just sort of assumed maybe they put the tube types on the rear in case you want to use some corrosive liquid ballast. And I don't know about the right pressures for R4 tires, but with my ag tires, I'm running 12 psi in the rear, 16 in the front if I'm not using the loader; 24 if I am. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Roger L.
Join Date: Jun 1999
Posts: 0
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-25          28575

As you seem to suspect, the ratio between the front and rear tire "rolling circumference is critical on a 4wd. Your dealer may have gone to two diffent brand tires to make sure that the original ratio was maintained. It is easy enough to check if you have both sets of tires available, otherwise it does tend to take up a saturday afternoon. I'd assume that the dealer knew what he was doing, but it is always fun to check.
We can start with checking in an armchair fashion. Taking the size information off of your original tires, go to that tire manufacturer's website and obtain the figure called "loaded rolling circumference" for the front and the rear tires. Sometimes this is just called "rolling circumference". Divide one number into the other and save this ratio. We are making the assumption that this original tire ratio was designated by the manufacturer and is a perfect match to their internal front to rear gear ratio. Do the same with the new tires, and compare the new ratio with the old. They should be within 5% of one another.
If you want to dig deeper, there are several ways to determine the actual ratios of both the gears and the loaded circumference. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
David LaBrie
Join Date:
Posts: 1
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-26          28601

Roger,
Unfortunately, I never looked at the size of the Ag tires that were on the tractor so I can't compare them. They supposedly ordered the new wheels and tires from Kubota because they couldn't find another dealer to swap with. I don't have much faith in this dealership. I went to lube the FEL at 10 hours and found 2 of the fittings broken off. They had installed the boom cylinders upside down and the fitting snapped off when the bucket was raised and the fittings hit the frame . I sent this question about the tires to Kubota via there web site but haven't heard grom them. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
David LaBrie
Join Date:
Posts: 1
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-26          28602

Bird,
I thought the pressure was too high, Hopefully Kubota will answer my email about it so I can set it correctly. When I went to take the cap off the rear tire, a secondary part of the valve unscrewed and started to leak. I tightened it with pliers then was able to take off the cap. Is there anything I should know about this type of valve? I've never seen one like it. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Roger L.
Join Date: Jun 1999
Posts: 0
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-26          28604

David, the only problem if the tires are mis-matched would be driveshaft windup due to the ratio between the front and rear tire circumference being different from the front and rear internal gear ratio. Usually this will make itself known because the tractor will be very difficult to shift out of 4wd. Of course it is common for there to be a slight mismatch, and for that shift to be difficult.....so it isn't a perfect test. If you have doubts about the tires, then don't use 4wd on surfaces with good traction. My little Yanmar is horribly mismatched and I've run it for almost 20 years because I like the overall tires and stability. (extra wide turfs). I'm careful to use 2wd to travel when the bucket is full and in fact I don't use 4wd unless the traction is too poor for 2wd. When traction is that bad, you don't get driveshaft windup anyway because the tires can slip on the surface. Hopefully you will hear from Kubota. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Bird Senter
Join Date: Jun 1999
Posts: 962
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-26          28609

David, I'm not sure what you have when you talk about a secondary part of the valve coming unscrewed. If they're tubeless tires, then I assume you have the metal valve stems instead of rubber type commonly found on cars. Of course, the metal ones are fairly common on some truck and tractor tires. And if they're tube type tires . . ., well, usually the valve stem is part of the tube, but there are some that have a separate stem screwed onto a fitting on the tube. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-27          28627

I've got valve stems something like those on the rear tires on my Ford 1710. One started unscrewing when a valve cap was on too tight. I just interpret them as extensions and never wondered about them. But then, I do have some familiarity with them. I had them on a '53 Chevy that had very big hub caps. Spinners, they were called. Fashionable in some circles during the late '50's, but you couldn't get an air hose on the valve without the extensions. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
David LaBrie
Join Date:
Posts: 1
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-27          28628

Bird,
The tires are tubeless and the stem is metal. First you have the base that comes through the wheel. Then screwed to that is the part with the valve core. Then the cap. When I was taking the cap off, the valve core section loosened up and started leaking. I tightened the valve core section with pliers and it seems ok now.
David ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-27          28629

Sometimes, lifting the front wheels with the loader bucket makes it easier to shift out of 4wd. Most tractors have some lead on the front wheels, so there's always some windup. Lifting the front wheels unwinds the windup I guess. It's good to take a tractor out of 4wd on pavement even if the tire sets are matched. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Bird Senter
Join Date: Jun 1999
Posts: 962
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-27          28632

OK, David, I understand what you have now; sounds like someone just didn't tighten it properly when they put in in the wheel. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Peters
Join Date: Feb 2002
Posts: 3034 Northern AL
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2001-05-27          28639

OK where's Murf when you need him. The rear tires are designed to be filled with water if desired. The stems are two sections so you can remove the valve and fill/drain (more importantly drain) the tire's water. It is difficult enough to lower the pressure on the tire through the valve. You can remove the valve but the hole is small, therefore there is a second section that you can remove from the stem with a larger hole. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-28          28663

Thanks Peters. So that's what those valve stem sections are. I'll take a good explanation how ever it comes. Guess it’s obvious that I'm one who has never has a flat tire. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Art White
Join Date: Jan 2000
Posts: 6898 Waterville New York
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2001-05-30          28767

Roger it gets a little more in depth than just the rolling diameter of a ag tire as the different manufacturers have different tread heights. This is a area I know I made a big mistake in a number of years ago and cost me a bit so I haven't forgotten it. Turf tires I'd say would work as they ride on the outer tread. Ag's don't, as the bars are not what they normally ride on in loose soil. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Roger L.
Join Date: Jun 1999
Posts: 0
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-30          28777

Art, you are sure right that the depth that the different lugs sink into the
soil affects the rolling circumference. It isn't a trivial deduction, and
like yourself I spent some time and a few dollars convincing myself that it
needed to be considered.
Uh...as a sidebar:just to keep the terminology straight, we ought to use
"rolling circumference" instead of your "rolling diameter". The tire industry uses rolling circumference in their specifications and we should too. The two measurements are different because - since we are not dealing with pure circular motion - Pi times diameter doesn't apply. In fact, Pi times diameter won't get you close enough to avoid driveshaft windup. Remember that arithmatically, "Static loaded radius", NOT loaded diameter, is the measurement most closely related to loaded circumference.
As far as the point about bar height, it doesn't apply by tire industry standards, but that doesn't mean that we can ignore it in our tractors. The way the tire industry calculates things, they define rolling circumference as being both at the tires rated load and on a hard surface. Obviously our tractors are not at either point. But the industry definition is aimed at being repeatable enough to design transmission gearing. I suspect that this - and not the lead/lag argument - is the real reason for the +- 5% that is so often quoted.
When in doubt, measure. It is fairly simple to do, but like I said somewhere in the previous messages, doing so can take up most of a weekend afternoon. The payoff is a good tire ratio that shifts well and protects the driveshafts.
....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Art White
Join Date: Jan 2000
Posts: 6898 Waterville New York
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2001-05-30          28778

Roger I stand corrected! ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Murf
Join Date: Dec 1999
Posts: 7249 Toronto Area, Ontario, Canada
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2001-05-30          28782

Actually Roger there is one more variable in all of that I discovered. A number of years ago we had a problem with one of our units. The culprit turned out to be a combination of large turf tires and constant, relatively high travel speed. It turns out the high travel speed was causing the soft turf tires to 'grow' from the centrifugal force, the smaller fronts did not do this as much proportionately. The result was enough difference to cause a problem. Best of luck. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Brent B
Join Date:
Posts: 1
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-05-30          28799

I was thinking about the importance of matching front and rear tire rolling circumferences, and have some thoughts if anyone cares to discuss.

First, the front and rears will never ever perfectly match each other due
to exact matches are made, tire to tire variation, different wear rates, different loadings, and different tire pressures. This means there will always
be a bit of speed difference. If there is a difference in rotation speed, no matter how slight, then there will be "torsional wind-up" in the drive train.
This torque difference has to be relieved by periodic slippage of one of the tires or else the drive drive shaft would break. On dirt you don't even notice the slight slippage. (I read somewhere that the can't even detect tire slippage until it exceeds 10%). On concrete with high traction it is harder for the tire to slip, but it does eventually.

Second, I don't think any amount of torsional wind-up would hurt the drive train, as it must be designed to take full torque through one axle in those
weird "full loader bucket, backing up a down slope, and there's little weight on the rear axle" situations.

Third, you still want to match as close as possible because tire slippage equals
more tire wear, which is not good.

Lastly, it seems to me that the front axles are usually geared slightly faster so that the front tires "pull themselves out of the way" instead of getting
pushed from the rear.

What do you guys think?

Brent
....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Murf
Join Date: Dec 1999
Posts: 7249 Toronto Area, Ontario, Canada
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2001-05-31          28830

Me thinks you hit the nail on the head Brent. In almost every case I have ever seen USE was far more critical than the EQUIPMENT was. Case in point, our local municipal government had a small fleet of compacts for such things as mowing large parks (with bat-wings) maintaining ball diamonds, and snow plowing sidewalks. Some machines were permanently "stationed" at a large park for example, some were DRIVEN from the works yard to the job and back. After a VERY short time the turf tires on the front were completely bald. The boss (with an eye to the budeget) decided to replace the 212/80R15 turfs with 215/75R15 car tires at about 1/3 the price. Every machine which was routinely driven around on the street or sidewalk had TOTAL failure of the transmission bearings within a year. Themachines which lived on grass were still just fine two years later when the fleet was replaced. The bottom line, it's not usually the machines fault, it's the 'loose nut' behind the wheel that usually does it in. Best of luck. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-06-01          28841

Don't know. I don't doubt anybody’s stories, and I've never actually heard anybody say that mismatched tires blew their drives and they were only on dirt. Still, drive trains do blow, and it gets real tricky attributing causes. I'm reasonably certain that mismatched tires do increase the stress on a drive train irrespective of operating surface. I also believe that stress is cumulative in mechanical systems, and that any stress promotes eventual failure. Whether mismatched tires would significantly reduce the mean time before failure rating or if many of us expect to run our tractors anywhere near the drive train MTBF rating, I don't know. However, for myself, I would have to have a very strong reason to knowingly run mismatched tires. Participating in this site keeps me from doing a bunch of unknowing things as well. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Roger L.
Join Date: Jun 1999
Posts: 0
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-06-01          28847

Well, I'll add a couple of thoughts as well. I do agree with what Brent and Murf are saying...it is the usage that is most important. My smallest tractor has severe driveshaft windup and is fine after 20 years because of paying attention to only using 4wd where a tire can slip - just as Brent, Murf, and Tom say. About centrifugal force changing tire size, I haven't seen it. But certainly fluid in the tires would make this a real force. The solution has to be not to use 4wd at higher speeds.
As far as stress being cumulative in mechanical systems and leading to failure, this is called "cycles to failure" where the cycles are a complete reversal of stress....rather like bending a piece of wire until it fails. Whether or not the wear is not cumulative on any one part depends on the properties of the material. In systems - as opposed to indiviual pieces - the complete system properties have to be considered and so you are probably correct, Tom. The good news is that it is pretty easy to design something so that many millions of cycles are required to create any significant damage. Doing so is basic engineering 101. You can bet that the guy who designed that system spent sleepless nights considering accumulation of stresses - and then had to defend his conclusions to a group of senior engineers. They will require it to withstand as many oddball circumstances as they can imagine. As users, our task is just to make sure that we don't get so far mismatched that we are "out of the ballpark" on total stresses.
On the issue of whether the fronts should lead or lag, I'm still tossing this around. For 4wd cars at high speed on a high traction surface like asphalt where steering and cornering are important it seems to be a consensus that the fronts should be leading. For tractors I'm not as sure. I've personally had machines set up both ways and so far it appears to be a matter of relative traction between the front and the back - which varies with soil, tire pattern, incline, and load distribution. I'm setting one up now with neutral lead/lag and am curious to see how it will work.


....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-06-02          28877

I sure do like this Board. Most discussions gain some very high quality perspectives from use, engineering and sales/service. I have a perspective as a statistician who has done failure work. My perspective is that everything is designed to fail, not designed to last. The question is whether expected service periods are long enough, the consequences of failure low enough and the risk of being wrong acceptable enough to put a system in use. My user's job is to keep from pushing a system into a region of high failure probability as much as possible, but I also budget for maintenance because anything eventually does break. I'm curious about lead/lag as well, but my perspective is impressionistic. Maybe it's a metaphor, but I'd guess that it's less stressful for a front wheel drive train to pull itself into breaking traction than to be pushed into it. There may be issues about steering and stability as well. However, I'm starting to go into a 'think it through' mode, and I've had my quota for awhile. So, another perspective, is: Don't worry about how it works, just get the work done and enjoy it. And, that's how I'll be today--even if it is raining. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Art White
Join Date: Jan 2000
Posts: 6898 Waterville New York
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2001-06-02          28881

Tom, for you is your glass half full or half empty? Murf, I've never seen tires expand that much under 10 mph, but I've never watched that closely as ten mph is the speed on four wheel drive tractors that they should be disengaged. I've seen many four wheel drive failures that I do attribute to mismatched tires. Unfortunately for me as I stated earlier I was the cause of one of them. The most perfect lead, notice that I did not say lag, and there is one manufacturer that has a four percent lag built in, is up to five percent lead. Now for my customers beneifit of my knowledge I like three to five percent lead. This gives the least scuffing when turning and doesn't burn the front tires off prematurely. The presure we use to balance the tires front to rear for optimum performance varies on the tractor and tire combination. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Roger L.
Join Date: Jun 1999
Posts: 0
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-06-03          28909

Art, your observations may help explain what I've seen on lead and lag. Right now I have one tractor with maximum lead and it has way too much driveshaft windup...but paradoxically it doesn't seem to eat up the grass when turning. The other tractor has the same amount (about 5%) lag, and it doesn't ever seem to have drivshaft windup. And that one really does carve up the turf on turns. Then again, it might be something else and not lead/lag at all.
I'm almost ready to try out a set of tires that will be almost neutral for lead/lag. Just finishing scraping and painting the rims today before mounting the new tires. It will be interesting to see how they do. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-06-03          28919

Art: I think you're right. To most people, it probably would make little difference whether something was thought be designed to last or to fail. The half-empty or half-full question is the same for most people, but not for a lot of the work I did--design of a sampling model for government inspection of commercial propane storage and retail facilities is an example. The consequences of failure in such system s are different than consequences of front drive trains. From my perspective, the idea of trying a few lead/lag combinations to see what works best probably is the best approach to take. However, from my perspective it's also equivalent to saying that the consequences of failure aren't serious enough to spend a lot of time figuring out how/why it's going to fail. From my perspective, failure is normal, to be expected and planned for. From other perspectives failures are aberrations, accidents or somebody's fault. It's just a different way of looking at things, and probably not the most appropriate for this forum. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Peters
Join Date: Feb 2002
Posts: 3034 Northern AL
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2001-06-03          28927

This problem has gotten more press than last year political campaign. I'm afraid I could answer the first part of the question but not the second. Being tthe basic muck raker that I am, I would like to add another rinkle into the equation.
In my west coast logging and fire fighting days we had old 4 wheel drives. 90% of the time you would drive the pickup in 2 wheel drive down the company's graveel roads. When you finally did need the 4 wheel drive the thing would buck like a bronco. The front differential would be near new and the back would be badly worn. What was lead became lag or vise versa. What happens with wear?
....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Roger L.
Join Date: Jun 1999
Posts: 0
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-06-03          28929

I hate to compare a serious and educational discussion like this one with last year's political campaign. No, I don't know why your trucks were bucking. There is no difference in lead/lag due to differential wear until the wear is enough that some of the teeth go away entirely. Lead/lag in the differential is strictly a function of the number of teeth. Of course it will buck badly when some of the teeth break off...... ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Peters
Join Date: Feb 2002
Posts: 3034 Northern AL
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2001-06-04          28938

Some of what we are talking about does not pertain to the small tractors, but with the old 4x trucks the wear the rear drive line allows the wind up and down of the front axel. This can be so bad that it causes the truck to load and un load the front. Although it is not the same as winding it up all the time as in the tire miss match case (the U joints add to the problem in the truck). Could wear extreme wear add to the problem over time? It wouldn't it at least add to the stresses on the drive line? ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-06-04          28940

When I read 'bucking', what came to mind is 'power hopping'. Power hopping is something I've heard about mostly on farm tractors and something I haven't experienced. Guess compacts with tufts have neither the power nor traction to hop much. I've always thought of power hopping as being a traction rather than a lead/lag issue. I've heard that people cure it by adjusting front/rear ballast ratios and tire pressures. Each would have an effect on traction and I suppose a minor effect on lead/lag as well. Regarding lawn carving, I forget the conclusion about the JD front axle issue. I seem to recall that it was something like steering geometry that resulted in excessive toe-ins during turns. I believe somebody here measured about 2" of toe-in with the wheels straight. Anyway, I don't think it was a lead/lag problem. Something similar could be the explanation for why a fairly neutral tractor carves the lawn and one with windup doesn't. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Art White
Join Date: Jan 2000
Posts: 6898 Waterville New York
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2001-06-04          28953

Tom the lead on a front axle can definitly cause the tire scuffing problem deere tractors had. Power hopping can happen in any four wheel drive veichle it's just it takes a hard pull to really bring the problem to surface and for the most part I don't see that happening other than on the farm tractors. Ballast will not cure power hopping only the air pressure will rectify the problem. Air presure is the only way I know how to cure it if the tires are the right ones for the application. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-06-06          28969

Thanks Art. You provide clarification as usual. Don't know about everybody else, but I had a two-day down time on here. Glad the board is up and working again. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
CaseyR
Join Date: Jun 1999
Posts: 53 Columbia River Gorge, Oregon
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-06-06          28983

Peters -
I am guessing here. I have driven older 4x4s on gravel roads and have gotten bucking but only when turning. In running straight, I would guess that if there was a mismatch between front and rear axle effective ratios, then with the older leaf springs you could get quite a bit of axle windup until the tires lost traction and then there would be a buck as the spring unwound and then went through another cycle. If this were the case, the bucking would be dependent upon the traction of the surface and the degree of mismatch between the axles. But I could be wrong... ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
Peters
Join Date: Feb 2002
Posts: 3034 Northern AL
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2001-06-06          28987

Casey;
I am not sure of the cause, we always attributed it to the wear and the front differential being new and the rear worn. You must realize that most of these trucks had never seen a paved road except at the assembly plant. They had more than 70,000 miles or more on roads that would loosen you teeth fillings. In these roads power you drove more with your right foot than steering wheel therefore power on/off continuous and may have contributed to the ride. The best ride I had was an old Landrover (early 50's) with soft springs so I am not sure it was windup. ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo



mixed R4 tires and PSI

View my Photos
David LaBrie
Join Date:
Posts: 1
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2001-06-06          28991

I had started this thread with a question about mismatched tires and correct pressure. I just received a response from Kubota, it follows: "Thank you for your inquiry to Kubota.
The 23x8.50-14 R4 IND. front and 12.4-16 R4 IND. rear are the correct
tire combination, the inflation pressure for the front is 35 psi and the
rear is 20psi. It is common to have two different tire manufactures.
Thank you for being a Kubota customer."

Now I will let some air out of the back tires and ride easy.
David ....

Reply to | Quote Post Reply to PostQuote Reply | Add PhotoAdd Photo


  Go Top Go Top

Share This
Share This







Member Login