Cooper Discoverer STT PRO LT305/55R20 F Discoverer STT Pro
Cooper

Discoverer STT PRO

LT305/55R20 F
All-Season M+S
$376.49/tire $501.99
Set of 4: $1505.96
Minimum order: 4 tires (sizes can be mixed) ? Selling in sets of 4 is how we keep our prices this low — and a matching set keeps your car balanced and safe.
Most drivers replace all four for even wear and handling.
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Specifications

SizeLT305/55R20 F Discoverer STT Pro
Width305 mm
Aspect ratio55
Rim diameterR20
Load index122/125
Speed ratingQ
Ply rating12
SeasonAll-Season
Tread depth20/32"
Weight68.1 lbs
Max pressure80 psi
Severe snow (3PMSF)No
Run-flatNo

About the Cooper Discoverer STT PRO

All-Season All-Terrain Passenger Light Truck tire.

Features

* 3-2 inner tread ribs* Alternating shoulder lugs* Mud Slingers™ 2.0 offer deep, wide trenches with additional notches* Stone Armor™ Technology* Earth Diggers™ Technology* Armor Tek3® construction* Rock Climber Sidewall™ Technology* M+S Rated* Standard Limited Warranty

Benefits

* Unique hybrid 3-2 tread pattern reduces noise and increases stability* Enhance traction in mud and soft surfaces* Continuously clear thick mud from the tire* Protects the tire from damage caused by sharp rock and debris* With large shoulder scoops and lugs, digs deeper into mud, sand or dirt* Provides incredible tread and sidewall durability on tough terrain* “Climber cleats” and flex grooves that grip jagged rock and power through mud

Understanding the LT305/55R20 F size

In the size code 305/55R20, 305 is the section width in millimetres (about 12"). 55 is the aspect ratio — the sidewall height is 55% of the width, or roughly 167.8 mm. R20 means radial construction on a 20-inch wheel, giving an approximate overall diameter of 33.2".

The load index 122 means each tire supports up to 3,307 lbs — about 13,228 lbs across a full set of four. The speed symbol Q certifies the tire to 99 mph under its rated load. Always match or exceed the load index and speed rating listed on your vehicle's door-jamb placard.

What the Cooper Discoverer STT PRO is built for

The Cooper Discoverer STT PRO is an all-season tire, balancing dry grip, wet traction and tread life across spring, summer and autumn conditions. It carries an M+S (mud and snow) marking for light winter service. It is classified for all-terrain (a/t) use.

Price and value

At $376.49 per tire, a full set of four costs $1505.96. That is about 9% above the average of the 62 tires we stock in this size, reflecting its position in the range.

Frequently asked questions

What does the tire size 305/55R20 mean?

305 is the section width in millimetres, 55 is the aspect ratio (sidewall height as a percentage of width, about 167.8 mm), and R20 indicates radial construction for a 20-inch wheel. Overall diameter is approximately 33.2 inches.

What are the load and speed ratings of the Cooper Discoverer STT PRO LT305/55R20 F?

Its load index of 122 allows up to 3,307 lbs per tire. Its speed rating of Q is certified to 99 mph. Check your door-jamb placard and do not fit a tire rated below the vehicle's requirement.

How much does a set of 4 Cooper Discoverer STT PRO LT305/55R20 F tires cost?

A single tire is $376.49 and a set of four is $1505.96.

Does the Discoverer STT PRO come in other sizes?

Yes — we stock 42 additional Discoverer STT PRO sizes besides LT305/55R20 F. Fit only a size approved for your vehicle.

Other sizes of this model

Similar tires in 305/55R20