different tire sizes

alpha33

New member

Equipment
Kubota B3200
Sep 8, 2021
3
1
3
Vermont
I have a Kubota B3200 I bought new 10 or 12 years ago. The original front rim is 7.00-12 and the tire size is 180/85D -12. This past weekend I found a pair of rims/tires off an older B7800, rim size 7.00-12 and the tire size is also 7.00-12. This set of rims/tires fit perfectly on my tractor. My question is about how much taller the 7.00-12 tire is compared to the original tires. They are approximately 2 inches taller. Question is, will this height difference create or cause problems/damage to the front end or rear for that matter?????
The tire on the left is the original.
Thanks alpha33
 

Attachments

85Hokie

Well-known member
Lifetime Member

Equipment
BX-25D ,PTB. Under Armor, '90-'92-B7100HST's, '06 BX1850 FEL
Jul 13, 2013
8,468
689
113
Bedford - VA
Alpha

at 2" taller..... that is going to be a hellva difference in RC..... which will not make the drivetrain very happy!

If you use them - I would not use in 4wd!!!

Typically in all 4wd scenarios - the fronts "pull" the rears a bit, in your case it is gonna drag them!!!

I would tread lightly here!
 
  • Like
Reactions: 1 user

Rbmedic75

New member

Equipment
L5030
Sep 9, 2021
2
0
1
WV
Don’t mean to hijack a thread by any means but similar question. Recently bought a L5030 with R3’s that are well dry rotted. Put same size new on the fronts already which are 29 x 12.50 a 15. Noticed it seems to drag in 4 wheel so started researching. The rears are 44 18.00 - 20’s. Using factory rolling inches specs my lead lag is 7.69% which appears to be out of recommendation. Wouldn’t mind a little taller tire in the rear and a rolling circumference of 136” would get me to 4.76%. Any knowledge of what tire size I should be looking for in an r3? Would like to keep same rim if possible
 

85Hokie

Well-known member
Lifetime Member

Equipment
BX-25D ,PTB. Under Armor, '90-'92-B7100HST's, '06 BX1850 FEL
Jul 13, 2013
8,468
689
113
Bedford - VA
Don’t mean to hijack a thread by any means but similar question. Recently bought a L5030 with R3’s that are well dry rotted. Put same size new on the fronts already which are 29 x 12.50 a 15. Noticed it seems to drag in 4 wheel so started researching. The rears are 44 18.00 - 20’s. Using factory rolling inches specs my lead lag is 7.69% which appears to be out of recommendation. Wouldn’t mind a little taller tire in the rear and a rolling circumference of 136” would get me to 4.76%. Any knowledge of what tire size I should be looking for in an r3? Would like to keep same rim if possible
One thing to do to cheat the system is to deflate or inflate the tires a bit - this will change the RC a bit, probably not enough to really matter but as mentioned once you get past about 2-3% lead-lag, bad things tend to happen.
 

Rbmedic75

New member

Equipment
L5030
Sep 9, 2021
2
0
1
WV
Thought I would post this back on here. I learned something today while trying to sort through the lag time issue I mentioned above. So not all 44 18.00 -20 tires have the same RCI. Titan 6 ply have a rci of 132.3” with overall diameter 44” while the Titan 4 ply (both R3 turf tread) have a rci of 135” and overall diameter of 45.9”. Kinda BS but is what it is. The kubota L5030 with 29 12.50 -15 fronts needs the taller 4 ply. Changes the lag time from 7.35 with the 6ply to 3.56 with the 4 ply. Ain’t that some crap..
 

thirdroc17

Active member
Dec 25, 2013
172
27
28
Michigan
Thought I would post this back on here. I learned something today while trying to sort through the lag time issue I mentioned above. So not all 44 18.00 -20 tires have the same RCI. Titan 6 ply have a rci of 132.3” with overall diameter 44” while the Titan 4 ply (both R3 turf tread) have a rci of 135” and overall diameter of 45.9”. Kinda BS but is what it is. The kubota L5030 with 29 12.50 -15 fronts needs the taller 4 ply. Changes the lag time from 7.35 with the 6ply to 3.56 with the 4 ply. Ain’t that some crap..
Just goes to show the most important specification, which usually isn't listed, is rolling circumference. Many people will insist "same size", which doesn't mean squat.
 
  • Like
Reactions: 1 user