Looks like most of the 27x8.50-15 tires are around 26.7" in diameter.
The MOST critical measurement is the loaded radius, this is the measurement that actually determines the distance the tire travels per revolution.
The inflated circumference does not.
I would expect that Goodyear/Titan R14 will have very similar dimension regardless if it's an R-4, R-1 or R14.
Also you can easily adjust the loaded radius by varying your tire pressure.
27x8.50-15 Firestone I-3 Super Traction Loader Tire
The Firestone I-3 Super Traction Loader Tire was specially designed for skid steer loaders. The Firestone I-3 Super Traction Loader Tire features deep overlapping bar cleats and low-profile design provide excellent traction and flotation. The Firestone I-3 Super Traction Loader Tire is a great tire for medium duty service use and has a tough sidewall for long wear. For the Firestone I-3 Super Traction Loader Tire call or order from our online tire store today.
Manufacturer: Firestone Tire
Manufacturers Part Number: 350-672
Recommended Rim Width: 7 Inches
Section Width: 8.4 Inches
Overall Diameter: 26.7 Inches
Static Loaded Radius: 12.1 Inches
Tire Weight: 27 lbs
Ply Rating: 6
Load Range: C
Max Load: 2480 lbs
27x8.50-15 Carlisle Trac Chief Skid Steer Tire (6 Ply)
The Carlisle Trac Chief Skid Steer Tire was designed for increased traction, puncture and abrasion resistance and long service life. The Carlisle Trac Chief Skid Steer Tire features a built in rim guard to protect the bead area from debris. The Carlisle Trac Chief Skid Steer Tire is commonly used on skid steers, backhoes, subcompact tractors, aerial work platform lifts and rough terrain forklifts. For the Carlisle Trac Chief Skid Steer Tire, call or order from our online tire store today.
Manufacturer: Carlisle Tire
Manufacturers Part Number: 51S339
Ply Rating: 6 Ply
Mounted Diameter: 26.7 inches
Mounted Width: 9.0 inches
Recommended Rim Width: 7.0 Inches
Rolling Circumference: 79.8 Inches
Max Load Capacity at 5 mph: 2400 lbs
Max Pressure: 50 psi
Tread Depth: 17 (32nds)
Tire Weight: 37 lbs