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Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640

What would put the Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 ahead of the Bridgestone Dueler A/T Revo 3 LT265/70R18 124/121R MPN 000029 and the Cooper Discoverer Rugged Trek LT275/70R18 125/122Q MPN 170054007?

Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 is recorded as an exact MPN row, so shoppers can compare one tire size instead of a broad family label.

Put it next to the Bridgestone Dueler A/T Revo 3 LT265/70R18 124/121R MPN 000029 and the Cooper Discoverer Rugged Trek LT275/70R18 125/122Q MPN 170054007 and the Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 leads for one kind of buyer while giving ground elsewhere. None of the three is the automatic answer, so read the package, fitment, and install rows before you read the price.

Nicole, Fitment Pilot editor

Reviewed by Nicole

Fitment

Chevrolet Silverado 2500 HD current Duramax trucks when LT245/75R17 121/118S specs stay inside the checked route limits

Verify first

Use these tire rows only when the selected LT size, load range, wheel width, service description, and positive-offset wheel package stay inside the Silverado HD route limits.

Part number
355640
Choose it when
Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 is recorded as an exact MPN row, so shoppers can compare one tire size instead of a broad family label.
Pass when
It stops being the right call the moment this holds: Dual-rear-wheel, ZR2, Sierra HD, or aggressive-offset setups without their own route check
Our cross-product compare

Same category. Different reason to buy.

Evidence level B
Best for
Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 is an exact SimpleTire row promoted into the truck tire catalog for 2024 Chevrolet Silverado 2500 HD LT Crew Cab 4x4 Duramax planning with official tire-family...
Bridgestone Dueler A/T Revo 3 LT265/70R18 124/121R MPN 000029 is an exact SimpleTire row promoted into the truck tire catalog for 2024 Chevrolet Silverado 2500 HD LT Crew Cab 4x4 Duramax planning with official tire-fa...
Cooper Discoverer Rugged Trek LT275/70R18 125/122Q MPN 170054007 is an exact SimpleTire row promoted into the truck tire catalog for 2024 Chevrolet Silverado 2500 HD LT Crew Cab 4x4 Duramax planning with official tire...
What's included
Tire size: LT245/75R17 121/118S
Tire size: LT265/70R18 124/121R
Tire size: LT275/70R18 125/122Q
Product approach
The 2024 Chevrolet Silverado 2500 HD LT Crew Cab 4x4 Duramax route keeps offset, diameter, load, and rim-width checks visible before the offer is treated as a match.
Documented fitment only -- no standout approach beyond exact application is recorded for the Dueler A/T Revo 3 LT265/70R18 124/121R MPN 000029.
Documented fitment only -- no standout approach beyond exact application is recorded for the Discoverer Rugged Trek LT275/70R18 125/122Q MPN 170054007.
Install burden
Moderate install. Exact tire MPN, tire size, and four-tire price
Confirm the Dueler A/T Revo 3 LT265/70R18 124/121R MPN 000029 installation procedure and hardware before ordering.
Confirm the Discoverer Rugged Trek LT275/70R18 125/122Q MPN 170054007 installation procedure and hardware before ordering.
Fitment
Confirm the exact Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 application for Chevrolet Silverado 2500 HD current Duramax trucks before ordering.
Confirm the exact Bridgestone Dueler A/T Revo 3 LT265/70R18 124/121R MPN 000029 application for Chevrolet Silverado 2500 HD current Duramax trucks before ordering.
Confirm the exact Cooper Discoverer Rugged Trek LT275/70R18 125/122Q MPN 170054007 application for Chevrolet Silverado 2500 HD current Duramax trucks before ordering.
Choose it when
Choose the Open Country A/T III LT245/75R17 121/118S MPN 355640 when it is the exact match for your truck and the Bridgestone Dueler A/T Revo 3 LT265/70R18 124/121R MPN 000029 and the Cooper Discoverer Rugged Trek LT275/70R18 125/122Q MPN 170054007 do not list your application.
Choose the Dueler A/T Revo 3 LT265/70R18 124/121R MPN 000029 when it is the exact match for your truck and the Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 and the Cooper Discoverer Rugged Trek LT275/70R18 125/122Q MPN 170054007 do not list your application.
Choose the Discoverer Rugged Trek LT275/70R18 125/122Q MPN 170054007 when it is the exact match for your truck and the Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 and the Bridgestone Dueler A/T Revo 3 LT265/70R18 124/121R MPN 000029 do not list your application.
Current decision file

Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640

Part ST-355640

Best for
Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 is an exact SimpleTire row promoted into the truck tire catalog for 2024 Chevrolet Silverado 2500 HD LT Crew Cab 4x4 Duramax planning with official tire-family...
What's included
Tire size: LT245/75R17 121/118S
Product approach
The 2024 Chevrolet Silverado 2500 HD LT Crew Cab 4x4 Duramax route keeps offset, diameter, load, and rim-width checks visible before the offer is treated as a match.
Install burden
Moderate install. Exact tire MPN, tire size, and four-tire price
Fitment
Confirm the exact Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 application for Chevrolet Silverado 2500 HD current Duramax trucks before ordering.
Choose it when
Choose the Open Country A/T III LT245/75R17 121/118S MPN 355640 when it is the exact match for your truck and the Bridgestone Dueler A/T Revo 3 LT265/70R18 124/121R MPN 000029 and the Cooper Discoverer Rugged Trek LT275/70R18 125/122Q MPN 170054007 do not list your application.
How we compared

Compared from exact part-number documents, documented fitment, included hardware, install notes, and current seller access. Retailer star ratings are not treated as proof of what owners think.

Wheel & tire owned fitment checklist visual
Visual unavailable
Illustration
Where to buy it

Price references

No paid offer is live here. Treat any price shown as a reference only, and use the other retailer searches below to check current availability.

No current price reference

Use the retailer searches below and confirm the exact manufacturer part number before ordering.

Other retailers to check

These other-retailer searches use the brand and part number shown on this page. We earn nothing if you buy through them.

Other retailer

SimpleTire

An online tire seller sorted by brand and size, useful for lining up the exact size, load range, and quantity.

Browse by tire brand, then confirm the exact size, load range, quantity, and service description.

Browse tire brands
Other retailer

Summit Racing

House fitment data and manufacturer spec sheets ride along on their pages, which makes it a good spot to sanity-check the part number.

Search with the brand and part number shown on this page, then confirm the manufacturer part number before ordering.

Search Summit Racing
Other retailer

Walmart

A broad marketplace where third-party sellers vary widely, so check who is actually selling and how returns work.

Search with the brand and part number shown on this page, then verify the exact seller, item condition, fitment, and return terms.

Search Walmart

Price checks build up as sellers are rechecked over time. The seller's checkout page has the final say; make sure stock, exact SKU, and seller details all agree before you order.

Report an issue
Decision trail Check these before you buy.
Part Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 Part ST-355640. Toyo resource available.
Fits 2020-current Chevrolet Silverado 2500 HD current Duramax trucks Use these tire rows only when the selected LT size, load range, wheel width, service description, and positive-offset wheel package stay inside the Silverado HD route limits.
Watch for Wheel & Tire Clearance checkout checks Confirm load rating, wheel offset, tire diameter, rubbing risk, TPMS needs, and spare-tire planning before checkout.
Other retailer · Seller 3 other retailer searches Search with the brand and part number shown here, then confirm the exact part and fitment with the retailer.
Photos Category visual The photo shows the category, not this exact part; an exact product photo appears once image rights are confirmed.
If unsure Compare, read, or report If the seller page, vehicle details, or photos do not line up, compare sellers, read the guide, or report the issue.
The evidence

Fitment and install resources

Reviewed 2026-09-21

Editorial method

What we checked on this page

We check the Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 for exact part identity, seller options, stock and price dates, photo rights, and official resources. FitmentPilot combines automated vehicle database indexing with human automotive editorial review. Rather than presenting generic affiliate catalogs, our system evaluates the exact mechanical constraints of each chassis platform — from bolt circle geometry and motion ratios to factory package exclusions — giving truck owners complete confidence before checkout.

Sellers3 seller destinations

Paid offers and other retailer searches are labeled separately so you can choose where to check.

FreshnessConfirm stock at the retailer

Check current stock and price with the retailer before ordering.

PhotosCategory visual only

This photo shows the part category, not this exact product. Confirm SKU, size, and kit contents before ordering.

Resources2 official resources

Install, fitment, spec, or warranty resources are available before checkout.

An exact product photo appears here once image rights are confirmed.

Choose it, pass, or verify

Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 is an exact SimpleTire row promoted into the truck tire catalog for 2024 Chevrolet Silverado 2500 HD LT Crew Cab 4x4 Duramax planning with official tire-family docs and a current seller price snapshot.

Choose it if

  • Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 is tracked as an exact MPN row, so shoppers can compare one tire size instead of a broad family label.
  • The 2024 Chevrolet Silverado 2500 HD LT Crew Cab 4x4 Duramax route keeps offset, diameter, load, and rim-width checks visible before the offer is treated as a match.
  • Seller price, rating context, warranty resources, exact tire specs, and fitment checks are present, but final stock and shipping terms still belong in checkout.
  • Use these tire rows only when the selected LT size, load range, wheel width, service description, and positive-offset wheel package stay inside the Silverado HD route limits.

Pass if

  • The Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 is not the right choice when your truck falls outside 2020-current Chevrolet Silverado 2500 HD current Duramax trucks, or its trim, engine, and package cannot be matched to the documented application.
  • Pass when this exclusion applies: Dual-rear-wheel, ZR2, Sierra HD, or aggressive-offset setups without their own route check
  • Choose another size or construction when load capacity, wheel width, offset, rubbing clearance, ride, or spare-tire needs point elsewhere.

Verify

  • Exact tire MPN, tire size, and four-tire price
  • Load range, service description, rim width, and tire diameter
  • Wheel offset, brake clearance, seller stock, shipping, returns, and installer requirements
  • The checked shelf is a 2024 Silverado 2500 HD LT Crew Cab 4x4 Duramax route; GMC Sierra HD, dual-rear-wheel, ZR2, lifted, and heavy commercial setups need their own seller and clearance check.
Workshop & DIY Guidelines

Toyo Open Country A/T III LT245/75R17 121/118S MPN 355640 Installation & Fitment Protocol

Wheel fitment is governed by three interrelated geometric factors: bolt circle diameter, wheel offset (ET in millimeters), and backspacing (inches from the back lip to the mounting surface). Lower or negative offset wheels push the tire outward for an aggressive stance, which increases the scrub radius and swings the outer shoulder into bumper valances and cab mounts during steering.

Install Difficulty

Shop & Bench Specs

Difficulty: Beginner (1/5)

Estimated Install Time: 1.0 – 1.5 hours (Wheel Mounting & TPMS Pairing)

Required Tools

Installation Equipment

  • Floor jack & jack stands
  • 1/2" Drive calibrated torque wrench
  • Thin-wall protective lug nut socket set (prevent wheel finish damage)
  • Tire pressure gauge
Post-Install Safety

Post-Install Protocol

  • Torque lug nuts in a criss-cross star pattern to manufacturer spec in two stages (first 50%, then 100%).
  • Perform mandatory re-torque check after 50 to 100 driving miles.
  • Verify full steering lock-to-lock clearance at ride height and during full suspension compression.

Wear Triggers & Maintenance Checks

  • Wheel bearing stress and premature hub assembly wear when running extreme negative offset (-12mm to -44mm).
  • Cupping or feathering wear on oversized tires when run at incorrect cold inflation pressures.
  • Caliper bracket scoring if wheel inner barrel clearance is under 3mm.

Chassis Fitment Context

GM T1XX front IFS operates on an approximate 1:1.72 motion ratio. A 1.15-inch lower strut mount spacer creates 2.0 inches of net lift. Because factory upper ball joint cups sit at an aggressive angle from the factory, leveling beyond 2.0 inches requires aftermarket tubular upper control arms to restore droop travel and ball joint range of motion.

Debuting in 2019, the T1XX platform introduced lightweight mixed-material construction with aluminum outer closures. In 2022.5 (Refreshed interior models), GM redesigned the electronic cockpit, updated steering knuckles, and made 13.4-inch displays standard on LT and above, while suspension geometry remained uniform across 2019-2026 model years.

Pre-Installation Unboxing Verification Checklist

Step 01: Confirm Physical SKU & Labeling

Inspect outer box label against your order invoice and the manufacturer part number shown here before opening hardware bags.

Step 02: Dry-Fit & Hardware Inventory

Unpack fasteners, brackets, and instructions. Perform a preliminary dry-fit check against the vehicle before removing factory components.

Step 03: Review Torque & Thread Requirements

Identify critical torque values and whether thread locker (Blue Loctite) or anti-seize compound is required by the manufacturer.

Step 04: Plan Post-Install Calibration

For suspension, steering, or lighting parts, schedule a professional alignment and verify forward-facing ADAS sensor calibration.