ATB M2100C L-shape steel mount brackets, black powder coat, pair

ATB M2100C L-Shape Steel Mounting Brackets for C-Frame, Grade 8 Hardware, Set of 2

$221.25
Freight shippingCalculated at checkout Only 5 leftIn stock now  Estimated delivery
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Features

  • 3/16 Gauge Steel: ATB builds the M2100C from 3/16 gauge steel, a bracket it calls super heavy duty, with a welded angled cross support.
  • 500 lb Load Rating: ATB rates the M2100C set for C-frame mount applications up to 500 lb.
  • 28" x 25" L-Shape: Each L-shaped bracket is 28" tall and 25" deep, and the pair weighs 42 lb.
  • Grade 8 Hardware: The set comes with Grade 8 hardware for fastening the brackets to the frame.
  • Predrilled Brackets: The brackets have predrilled holes for easier mounting, and rubber strips go between bracket and frame.
  • Primer And Powder Coat: A zinc epoxy primer and a baked black powder topcoat protect the steel.

Description & Fitment

The ATB M2100C is a pair of fixed L-shape steel brackets for hanging an underbody or utility box from a C-frame truck or trailer. Each bracket is 28" tall and 25" deep, made from 3/16 gauge steel with a welded angled cross support, and ATB rates the set at 500 lb. The steel is zinc epoxy primed and finished in a baked black powder coat, and Grade 8 hardware is included.

Fitment & Compatibility

How to choose: the M2100C suits boxes up to 500 lb loaded on a C-frame. Check that your box sits within the 25" bracket depth and that the frame has room for 28" tall brackets below the deck. You will drill two 9/16" holes per bracket in the frame web unless it is already predrilled.

Fits: C-channel truck and trailer frames; boxes up to 500 lb loaded

Application: C-frame mount

About ATB

ATB

American Truckboxes (ATB) builds aluminum and steel truck boxes, tanks and storage in Blanchard, North Dakota, and has done so for more than 25 years, by its own account. Its range covers pickup crossover, side-mount, chest and drawer boxes, service-truck boxes and packs, fuel tanks, and heavy-truck and trailer boxes.

Authorized ATB dealer. Prestige Truck is an authorized ATB dealer: every box on this page is built by ATB to the part number shown.

Frequently Asked Questions

Will these fit my truck?

The M2100C bolts to the web of a C-channel frame on a truck or trailer. Check the frame web height for two bolt holes per bracket and the box's loaded weight against the 500 lb rating; follow the truck maker's manual for frame drilling.

What boxes does the M2100C carry?

ATB lists its M2000 and M2100 series L-shape brackets for frame mounting its underbody and utility boxes, such as the SG, SR and UG series, on C-frame trucks and trailers.

How much weight can the brackets hold?

ATB rates the M2100C set at 500 lb maximum. For heavier loads ATB builds the M2101C and M2102C in 1/4 gauge steel rated to 700 lb.

Do I have to drill the frame?

Usually yes: ATB has you drill two 9/16" holes per bracket in the frame web unless the frame is already predrilled. Never drill the top or bottom flange and never weld the brackets to the frame.

Is there a cross beam for these brackets?

ATB offers an optional L-CB series steel cross beam for its M2100 series brackets, sold separately.

What finish do the brackets have?

The steel gets a zinc epoxy primer and a baked black powder topcoat. Touch up any scratches or drilled spots with paint to keep rust away.

Installation

Install time About 1.5 hours
What's involvedBolts to the C-frame web through two 9/16" holes per bracket, with rubber strips between bracket and frameno welding
Tools
  • 3/4" ratchet wrench
  • 3/4" wrench
  • Tape measure
  • Drill with 9/16" bit
  • Utility knife
  • Blocks

Here's the short version. Follow ATB's install sheet (below) for your truck's exact positions and hardware.

  1. Check all parts against the parts list and look over the frame area to make sure there is room for the box.
  2. Take the brackets to the frame and raise them on a jack or wood blocks to the height and width where they will mount. If the frame is already predrilled, skip to step 4.
  3. Mark the bracket hole pattern on the frame, spacing the holes as far apart vertically as the frame height allows. Remove the brackets and drill two 9/16" holes per bracket, following the truck maker's manual for frame drilling.
  4. Apply the 3" rubber strips to the brackets, cut the bolt holes in the rubber with a utility knife and set the brackets back on the frame.
  5. Insert the bolts with the large heavy washers from the bracket side through the bracket and the frame, add a flat washer and lock nut on the back of the frame, and tighten all nuts securely.
  6. Never drill the top or bottom flange of the frame and never weld the brackets to the frame.

Stuck on a step? Ask our install experts

What's included
  • 2 M2100C L-shape steel brackets (left and right)
  • Grade 8 mounting hardware

Specifications

BrandATB
Part NumberM2100C
TypeL-shape mounting brackets, set of 2
Material3/16 gauge steel
Size28" H x 25" D
Load Rating500 lb max
Weight42 lb per set
FinishBlack powder coat over zinc epoxy primer
HardwareGrade 8, included
Made inUSA

Warranty, shipping & returns

  • Warranty

    ATB covers its standard truck boxes with a 60-month (5-year) limited warranty for the original purchaser; it is not transferable.
    • For a warranty claim, contact us with your order number and photos and we will work it through with ATB.

  • Shipping

    Ships by freight from the ATB factory in Blanchard, ND; lift-gate delivery available.
    • Alaska, Hawaii and Canada: contact us for a freight quote before you order.
    • We email your tracking details as soon as it ships.

  • Inspect on delivery

    Check the box when the freight arrives, before the driver leaves: look over the lids, doors, corners and welds for dents, scratches or shipping damage. Note any damage on the delivery receipt and send us photos. Check it as soon as it arrives.
    • Look for crushed ends, punctures or tears in the carton.
    • If something looks wrong, take photos of the box and the parts (and if a driver asks you to sign, note the damage on the receipt).
    • Open the box and check the parts against the parts list before you install.
    • Email support@prestigetruck.com right away with your order number, a short note and photos. We send a replacement or a full refund at no cost to you.

  • 30-day returns

    Return it within 30 days of delivery, unused, in the original packaging, with proof of purchase.
    • Email support@prestigetruck.com with your order number. We reply within 1-2 business days with instructions.
    • Damaged, defective or wrong item: we send a prepaid label or arrange a pickup.
    • Changed your mind: you pay return shipping. No restocking fee.
    • Refunds go back to your original payment method within 7 business days of approval. See our returns policy.
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