Tire Selection B7300 front tires

[rScotty]

4get gto:
A lot of people have pointed to some 'other' tires, most now in metric, but I am leery of using something not recommended by Kubota....that Kendra tire205/65-10 is basically a 20 not 21 tire (DML Tire and Wheel Calculator). If this were not a 4WD tractor, I might consider, but until I am sure that it will not damage my tractor, I am going to steer clear. As one user pointed out, a weather checked tire with a tube might last a very long time. As I am not in any hurry, I will continue to investigate.

I've never been able to get technical information or recommendations from Kubota, but I applaud you for trying. When I do get an answer, it's such an elementary level that it's useless to me. I think they need to change, but that's just me. I haven't seen change happening, and they still have grown to dominate the small tractor market .... so from a marketing perspective they are doing everything right.

That DML tire and wheel calculator works fine for iron wheels with iron tires that never change. But it doesn't take into account what we care about in 4wd, which is how the loading on a tire changes its shape so that the rolling circumference changes from simple arithmetic and becomes a function of load, tire pressure, and sidewall elasticity.

In the case of the Kendra metric 205/65-10 tire versus the original Firestone 21-8-10 tire, the Kendra is a more heavily built 12 ply tire with a higher pressure and load rating..... Which means it will deform less than the Firestone So I wouldn't be surprised to find that it is a good match as a replacement tire. I've sent a request to Kendra for the RC spec because unlike Firestone, they don't have that spec on their website. That's not surprising, since you wouldn't need to know for a trailer tire. Anyway, they probably do have the spec, will see what they say if they respond.

But the only real way to know RC for your tractor is to measure the tire in use. In fact, you might want to measure your old Firestones so that you will have the information available. It's easy, and measuring it yourself will tell you how much your RC is different from the stated RC for your tires on the Firestone website. The way I measure the Rolling Circumference is to inflate the front tires normally, put a medium load in the FEL bucket, leave it in 2wd, put a dot of paint on the tread of the front tire... and drive down a paved road in 2wd. Go as straight as you can for 8 or 10 revolutions and then stop and measure the distance between the paint dots your tire has put on the asphalt. Average that distance and that is your Real Rolling Circumference for that tire. That is the number you want to match, and it means more to you than what the tire sidewall numbers say.
good luck,
rScotty

 

[rScotty]

Some points to ponder on 4x4's and tire rolling circumferences...
Extremely worn front tires (from heavy loader work) can reduce the RC and height by over an inch...the same goes for the inflation of the same...in my experience this reduction of over an inch from the original size of the front tires had no effect on the drive train /shaft windup etc...even when the rear tires remained within a fraction of their original height/RC...

I'm not saying not to be concerned about the RC of tires on 4x4 machines...but in my experience it is not nearly as critical as is often cited...

I agree with /pine completely. The only time RC is critical for shaft windup is when traction is maxed out. Like would happen with brand new R1 lugged Ag tires, tractor in 4wd in sticky mud with a load in the bucket. Or again with a load in the bucket, 4wd, and traveling on something high traction like a paved asphalt road with your sticky rubber turf or industrial tires.

RC never matters at all in 2WD.

In either case, if the front tires are worn and can slip traction then slipping is what will happen and the tire slip protects the drive components. You want it to be able to slip a little. You might feel this a small "jump" but usually so subtle that you will miss it if not looking for it. If it can't slip, it will be hard to shift out of 4wd.

The other effect of RC is about steering. The front tires are designed to cover more ground than the rears so that the tractor responds to the steering wheel instead of sliding the fronts. Worn tires work against you there, but I agree in that I've never found it to be a big deal. Sometimes if the fronts are worn and I'm in wet grass in 4wd and go to make a turn the front end will slide sideways instead of turning. RC ratio is part of what causes that (not all) and that's about the worst of it. Small potatoes...

Manufacturers care about the steering part of the RC spec because of what might happen at road speed if steering control was lost. (liability $$) Just for fun I once built a 4wd tractor with exactly zero lead/lag and ran it at various tire pressures to find out if I could see any steering change and nothing happened that I could feel.

But worn tires or not, with enough traction you can always cause the shaft windup to be noticible if you stay in 4wd and high traction long enough. So the answer is like so many things.... "Don't do that!"
rScotty

 

[HAR]

I still have not heard back from KUBOTAUSA yet, but as I wait, I am not quitting either. I too found that their first two responses were rather weak and almost like they did not want to be part of the conversation. While I am probably not as informed as some, I do like to research and read. I ran across this link and it has a lot of good information in it. Take it for what it is worth..... AG TIRE SIZE OPTIONS / CONVERSIONS: Why, When, How ? | AGTireTalk

 

[HAR]

My opinion of Kubota customer service at KubotaUSA has dropped dramatically. It appears, that while they invited continued questions regarding my initial request, that they have forced closed the 'event'. Here is what they said after my second request:

"Recently you requested personal assistance from our on-line support center. Below is a summary of your request and our response.
We are continuing to work on your issue. To update your question with additional information, please respond to this email."

I had responded with further clarification of my requests and asked for information, and got no response. SO I resubmitted another clarified request, to which I received the following reply:

"Subject
Replacement turf tire [Incident: 200529-000011] Kubota B7300

Response

To submit a new incident for Kubota Customer Care, please visit our support site:

http://www.kubota.com/"

So much for responding to their email at the address that they clearly indicated.

I agree with rScotty, and now believe that KubotaUSA is just ignoring or deflecting any and all requests for technical information.

While I really like my B7300, it appears that it is a truly orphaned machine and I and other owners are on our own. It truly does not make me really want to use a KubotaUSA or a Kubota dealer for anything.

 

[rScotty]

My opinion of Kubota customer service at KubotaUSA has dropped dramatically. It appears, that while they invited continued questions regarding my initial request, that they have forced closed the 'event'. Here is what they said after my second request:

"Recently you requested personal assistance from our on-line support center. Below is a summary of your request and our response.
We are continuing to work on your issue. To update your question with additional information, please respond to this email."

I had responded with further clarification of my requests and asked for information, and got no response. SO I resubmitted another clarified request, to which I received the following reply:

"Subject
Replacement turf tire [Incident: 200529-000011] Kubota B7300

Response

To submit a new incident for Kubota Customer Care, please visit our support site:

http://www.kubota.com/"

So much for responding to their email at the address that they clearly indicated.

I agree with rScotty, and now believe that KubotaUSA is just ignoring or deflecting any and all requests for technical information.

While I really like my B7300, it appears that it is a truly orphaned machine and I and other owners are on our own. It truly does not make me really want to use a KubotaUSA or a Kubota dealer for anything.

I was hoping you would have more luck, but their "no response" seems typical.

Kubota's interest appears to have shifted almost totally toward selling new tractors rather than supporting the maintenance of older ones.
The good news there is I suspect that they didn't target your model Kubota to "orphan". They are probably considering whether to go to a policy of minimal support on any model they aren't currently selling new.

And in making that kind of shift, they may well have read the US market correctly.
After all, the interest in repairing or rebuilding every kind of older mechanical device does seem to have waned in our population, right along with the increasing popularity of all things new and obtainable with easy credit.

We are part of in increasingly profit-oriented world today, and Kubota seems to be part of that.

We can see where this is going to end up. It's no mystery. A philosophy directed to favor new model sales over all else will do well for the most popular manufacturer of the moment, but it sure does diminish the importance of the having a relationship with your local dealer.

I suspect that more and more people will be buying their new Kubotas from mass importers, and then having mainenance performed by local outlets who specializing in selling a maintenance package for a wide number of makes & models. Warranty work can quickly follow the same path. i.e. Contract warranty which works like an insurance package. It's already common for cars, and appliances, so why not for tractors?

I'm not sure I would want to be a dealer today......facing what they must certainly see coming towards them.

Luckily, for those of us who still prefer to do things for ourself, there are lots of older tractors like yours. And many parts problems end like your tire search: easily cured iby simply combining a little bit of mechanical thought & common sense. Just as has happened in this thread.

It's just that the knowledge increasingly comes from forums like this one instead of the historical support of the manufacturer & dealer.
Enjoy!
rScotty

 

[radios1]

it's an old, small sub compact, about the size of a garden tractor, maybe they just can't be bothered with this?. sad, but they need to make a profit.. I'm sure there are reputable tractor manufacturers that won't blow you off like Kubota does!.. sell it, and buy something good!..

 

[rScotty]

it's an old, small sub compact, about the size of a garden tractor, maybe they just can't be bothered with this?. sad, but they need to make a profit.. I'm sure there are reputable tractor manufacturers that won't blow you off like Kubota does!.. sell it, and buy something good!..

If there are companies that are very different, I haven't seen any postings about them on TBN.... or on any of the other tractor forums I've visited over the last 25 years. Maybe there are a few. I wouldn't be surprised if they are small, specialized, or even local.

I'm afraid that what has happened is simply that the world has changed, and that most modern companies consider themselves to be quite reputable by these newer global standards. New global standards which judge that "Profitable" outweighs "Concern for old Customers" as an an expression of reputation & success.
rScotty

 

[HAR]

To be honest, I joined TBN back in 2006 when I had my first run in with Kubota maintenance woes. I purchased the "Kubota" part numbered oil filter for my engine and found that it no longer fit my tractor...it was a different size, which conflicted with a hose on the engine. The Kubota dealer assured me that it was a direct replacement and should work. When I showed them a photo of the problem, they had no explanation. Luckily, I had kept the old filter, and took it to a local auto parts place, and the guy there let me do some measuring and comparing. As a result I was able to cross reference the original Kubota PN to a WIX part and I have not purchased a Kubota filter since. I also was able to cross reference the hydraulic oil and fuel filters as well. As a result, my parts price was reduced significantly. I may not need to, but I change engine oil/filter yearly. I consider it cheap insurance. I do all my own maintenance and do the other hourly services as required.

 

[rScotty]

A couple of dinosaurs, that's us.

 

[HAR]

radios1: I had a few other 'lawn tractors' before the B7300. And one that was truly a 'garden tractor', and it worked well for nearly 20 years. The was a Case 446, which I had a front mount snow blower and a rear mount hydraulic tiller, along with a 60" MMM. I used that 446 to till gardens commercially for the nearly 20 years that I owned the tractor. However, I did have to do one major engine repair (short block) and it was in need of another at the end. When I purchased the B7300, it was a major step up in so many ways. Much more than a 'garden tractor', both in capability and size. With the included FEL, MMM, 3PH&PTO, while a sub-compact, it was a real tractor. It has never disappointed with the way it handled or the amount of work that it could do. So, I think it is much larger than what today is considered a 'garden tractor'.

rScotty: I agree. We probably are dinosaurs. As for me, I am proud of it. I grew up in a large family that had survived the Great Depression and the rationing of WWII. Having minor items were a luxury to most of us. We were taught to appreciate what we did have. We treasured and took care of what we did have. We did not throw things away, just because they were 'old' or 'out of date' or 'out of style'. I have bought a few cars over the past 72 years. A couple of them made it to 291K and 272K miles, and were only taken off the road after they were so Vermont rusted that the frames were unsafe. My current 'new' car is 16 years old and has 172K and is still going strong, but is showing signs of Vermont winters.

All that being said, I was always able to find tires for the cars. I know that Firestone and other companies go out of their way making tires to fit antique cars and trucks. I have a friend who is rebuilding his grand-dad's 1915 IH truck and he found a set of 'solid rubber' tires for it. I find it hard to think that only one company ever made tires to fit this tractor. If so, that is a perfect case of planned and designed obsolescence .