you've got options.
All these tires are Goodyears.
Sure Grip Lug
http://www.goodyear.com.gt/tirecatalog/img/supergrip.jpg
-- 27 x 10.50 / 15
skid steer tires 27 x 8.50 / 15
30.4 x 10.4 / 16.5
Wide, Flat Tread For Firm Ground Contact
Directional design Excellent traction
Wide, sturdy overlapping lugs Long wear
Optitrac DT812 Radial
-- 27 x 7.8 / 16
V-tread tractor tires 29.2 x 9.6 / 16
31.8 x 11.1 /16
36.9 x 12.8 /16
Next Generation For Improved Traction In Heavy Soils.
Advanced lug design shape Outstanding mobility in wet and dry soils
Increased sidewall flex-zone Improved damping
Excellent flotation Minimum soil compaction
Super Terra Grip 29 x 12.5 / 15
V-tread tractor tires
31.5 x 15.5 / 15
38.5 x 18.5 / 16.1
Built For Extreme Floating Applications Deep shoulder lugs
Excellent traction
Traction Sure Grip (Traction) -- 28.8 x 7.4 / 15
V-tread tires 29.6 x 7.8 / 15
31.5 x 8.3 / 16
33 x 12.5 / 15
36.9 x 12.8 / 16
44.6 x 18.5 / 16.1
43.6 x 21.6 / 16.1
Maximum Traction For All Farm Implements
Aggressive ruler straight lug design Excellent traction
Open tread center Self-cleaning action for increased traction maneuvering
http://www.goodyearag.com
http://www.beaurepaires.com.au/content.asp?Document_ID=48&page=2
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i'd take a look at what those 31s, 33s, and 36s cost. maybe try running them.
here's a link to a post i made on another board about this.
http://nboffroadclub.com/viewtopic.php?t=2015&highlight=optitrac
i'm OffRoad on that board as well.
question: are tractor tires a lot heavier than comparable off road tires?