Topics
Background
Hauling cargo typically requires securing it with some kind of tie-down — cords, straps, nets, tarps, or chains — attached to anchor points in the truck floor or wall. The Ute aluminum bed walls should not be used for anchors because they lack the strength of the vehicle frame and might be bent or dented, and therefore anchors should be located on the truck bed floor.
Floor anchors can be either movable suction cups or permanently fixed using hardware. Fixed anchor options include surface or recessed mounted D-rings that lie flat when not in use, or eyebolts. Some eyebolt designs utilize an outer sleeve that makes the eye removable.
Strength specifications
The Federal Motor Carrier Safety Administration (FMCSA) publishes performance requirements for cargo loads:
- 0.8 g deceleration in the forward direction
- 0.5 g acceleration in the rearward direction
- 0.5 g acceleration in a lateral direction
The Ute’s maximum load capacity is about 900 pounds. Using the F = MA equation with the FMCSA requirements means that tie downs must be able to handle a force of about 700 ft-lbs. This force would be distributed between at least two anchors so we need anchor holding strength of 350 lbs and strap working load limits (WLL) of 700 lbs (or 350 lbs if two straps are used with four anchor points).
Suction cups
Stanley suction anchor holds up to 200 lbs
Suction cup anchors can only be used on smooth surfaces; the extruded aluminum floor provided in the Smyth kit cannot use these! Our finished oak wood floor is smooth enough to handle suction requirements.
The Stanley S4004 cup anchor is rated at 200 pounds. Four cups — 800 lbs of total holding force — could handle the Ute’s maximum load capacity.
Most loads could be easily handled with just two cups. The advantage of movable suction anchors is that they can be optimally positioned for specific cargo needs.
The Stanley anchor accepts standard 1-inch tie down latching straps typically rated at 600 lbs, enough to handle the maximum Ute load (two straps with four anchors).
Fixed anchors
Wood surface mount D-ring anchor (light duty only)
Unlike movable suction cups, fixed anchor locations must be determined in advance. The usual location is close to the four corners of the truck bed floor. In the Ute’s case, this means anchor designs with machine threaded bolts must pass through the front and rear trays. While the rear tray is accessible underneath for fastening a nut, the front tray would require rivnuts.
Alternatively, anchor designs with user-supplied hardware can be fastened with wood screws directly into a wood floor.
