R1 to R4 on a M4950DT, what is the correct size?

[Drewdaman]

Hi, the R1 tires on my M4950DT are pretty worn, especially the rears, so I'm considering getting new tires and maybe switching to R4's as I understand they would be a better match for my purposes.

The current tires on the tractor are 8.3-24 in the front and 14.9-28 on the rear, and I just double checked the Owners Manual and confirmed those are the correct sizes.

So my questions are:
1) What size R4's do I need, front and rear?
2) Can I buy R4's and put them on my current rims or will I need new rims, too?
3) Doubt I'll do this but thought I'd ask just in case it's a viable option: the fronts are not that worn, so I'm wondering if I could just replace the rears with R4's and leave the R1's on the front, or is it a bad idea to mix R1's with R4's?

Thanks in advance for any assistance, I'm stoked to get some new rubber!

Drew

 

[85Hokie]

Your machine DID not come with R4's as a natural choice.....so now the game begins......
Your tires when new - were ratioed together for the 4 wheel drive system, even as they have worn, that magic ratio is still there. Finding new tires in the AG sizes might be a chore, then again maybe an easy find, BUT, here is the big BUT - changing to R4's will change the whole game, they are typically "flatter" in design and may or may not be placed on the same rims you have now - need to ask those who know.....

look at this post and notice tiredguy's info - he may be able to tell you what you need to know, tires can be a crapshoot - sometimes it is an easy fix - most times a royal PITA!

http://www.orangetractortalks.com/forums/showthread.php?t=2744&highlight=tireguy

as for mismatching the tires, fine, ONLY fine if you hold the same rolling circumference, and thus my lad is where the game comes to a screeching halt.

I hope you find the right RC - otherwise, you might be buying WHAT came on the tractor, that IS if they are still made!

 

[North Idaho Wolfman]

You can do 16.9-28 R4's on the rears and keep the 8.3-24 R1's on the front.
That will let you keep the rims you have.
There are other combinations of R4's but they almost all have you changing both the front and rear rims too to make it work.

 

[85Hokie]

You can do 16.9-28 R4's on the rears and keep the 8.3-24 R1's on the front.
That will let you keep the rims you have.
There are other combinations of R4's but they almost all have you changing both the front and rear rims too to make it work.

the 14.9-28 R1's you had new - had a RC of close to 162" IF you do like Wolfman said the new R4's will be very close - 164" +/- 1".

that would be a damn close fit......

here's the bad news, looking at the $$$$$

http://www.ebay.com/itm/16-9-28-12p...372485?hash=item4d34dce0c5:g:TC0AAOSwNphWZ1ar

then again, tires aint cheap - these would last a dang on near lifetime however!

 

[Drewdaman]

Thanks a lot, guys, this information is very helpful!

And a couple of follow-up questions, if I may.

1) I'm familiar with the importance of the RC numbers, however I don't recall ever seeing any posts on here with a link to the best source for these numbers - is there a particular website or table that provides the RC's for various tires?

2) Based on NIW's info, I'm now planning to get the 16.9-28 R4's for the rears, and if I want to get R4's for the front in place of my current R1's, what size would be required?

3) Would the correct tires for the front require me to purchase new rims?

Thanks again,
Drew

 

[North Idaho Wolfman]

1) I'm familiar with the importance of the RC numbers, however I don't recall ever seeing any posts on here with a link to the best source for these numbers - is there a particular website or table that provides the RC's for various tires?

Secret sources...
I get the numbers all over the place, Firestone, Titan, and others.
You take all the information you can grab and compile it.
So like three tire sites all give different #'s on a tires RC, you just average those #'s, unless your lucky enough to know the exact manufacture of a tire and if that manufacturer post those #'s.

2) Based on NIW's info, I'm now planning to get the 16.9-28 R4's for the rears, and if I want to get R4's for the front in place of my current R1's, what size would be required?

3) Would the correct tires for the front require me to purchase new rims?

You can't get front R4's to match the RC, (at least not that I found), in the size of rim you need.
You also can not readily change the rims on the front to smaller rims as they will throw off the offset of the rim and will not have enough clearance for the drive components of the front axle.
Your not going to hurt it using R4's on the rear and R1's on the front, You can also get R1's in a fat flat tread that will wear a lot better than the old thin tread that came on it.

You could go up in size on the front and rear with tires and rims, but it gets stupid large to get it to work.

 

[Drewdaman]

Thanks, Wolfman!

And my last questions for now, I think.

1) Is the RC for a 8.3-24 R1 essentially the same as a 9.5-24 R1? ETA: No

2) Will the 9.5 tire fit on my 8.3 rim? ETA: ??

2) I found a great deal on a couple 16.9-28 R1's, is the RC for those essentially the same as the 14.9 R1's that originally came on my tractor? ETA: No

If so, I may go with these R1's, due to the cost savings.

Edited To Add: Regarding questions 1 & 3 above, I did some research and while I didn't find any RC numbers, it appears that the diameters of the 8.3 vs 9.5 and 14.9 vs 16.9 are substantially different, so I'm guessing that the RC's are going to be way different.

So, how about this final question: if I buy the used 16.9-28 R1's (which are already mounted on Kubota orange rims with hoops), can I then buy 9.5-24 R1's that will maintain the original front to back ratio?

Drew

 

[North Idaho Wolfman]

2) Will the 9.5 tire fit on my 8.3 rim? ETA: ??

Yes, it should fit fine.

If I buy the used 16.9-28 R1's (which are already mounted on Kubota orange rims with hoops), can I then buy 9.5-24 R1's that will maintain the original front to back ratio?

New, 16.9-28 R4 and new 9.5-24 is a good match for RC compatibility.
Now, if they are worn about the same it, good, but old worn rear and new fronts will make it bind, might not be too much.