Tire Size comparison
- Thread starter hotchkiss
- Start date
- Views: 7420
art
Super Member
You didn't state what tractor they are going on. That does make a difference, some things that count to the tire size. Two or four wheel drive, the tractor weight, and the use. To me the 18.4 30 is the most common size but most commonly used on 70 horsepower tractors! That would mean to fully utilize them you would need more weight to get traction or you would be spinning a lot. 34" or 38" are the most commonly used tires when you get to 100 horsepower four wheel drives. Two wheel drives we might option to 42" to balance the traction although if it is loader equipped we might go back to the 38" to still leave power with the additional rear ballast needed to offset the loader.
xring100
Veteran Member
- Joined
- Dec 9, 2012
- Messages
- 1,532
- Location
- Livingston County, Michigan
- Tractor
- Kubota M8540, ZD1211 60"
Yes they are definitely more common but cheaper is only relative there is nothing cheap about any of these tires, i was curious how much a titan radial 18.4-30 was for my m8540. if i remember correctly list price was well north of $2k each. Decided i really hoped i never scraped a tire. A guy at work was complaining about the cost of tires for his vette i told him 1 tire on my tractor cost more than as all 4 of his.
Dave
i would be looking at a 34r or a 38r for that tractor i kubota has them two choice for 70 to 95 horse over 100hp 38 s if you can get 34 s go foe it but be aware of the wieght rating of the tire ask what the rating is on each tire choice i know my 30x16.9 on my 70 hp kubota are rating lower them the tires on my 3500hd srw truck
The 420/85R4's are R1W's so they are 50% deeper tread than the 18.4R30's and also I have experience with those 18.4R30s on a 5085M and they are not as good as the 420/85R34's
I have a pair of 480/85R38s Firestone's on my 6715 and they only have worn 5%-8% in 1400 hours. It has seen roads almost every day in the spring to fall. Guessing about 10 miles a day with employees driving it.
18.4R30 Goodyears on a 5085M about 400 hours, wore about 5%-10% Seen probably less road but still wears down quickly.
With the deeper thread you'll get more traction and better wear. Since your getting more tire.
The 420/85R34's are just 16.9R34's