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Making a Front Bumper Tensioner (17/07/2005)

By:: Glenn M. Cauley

The low flat front bumper of pancar gascars (my 1:8 Veteq as an example), while made of a strong and resilient material, may bend downward after repeated collisions, sometimes causing it to scrape on the ground and making it very difficult to steer the car.

There have been many suggestions over time to eliminate this problem; a stiffer bumper (which stays bent when it does bend), carbon plates joining the ends of the bumper to prevent sagging (which break easily), and others.

At a recent club race in Montreal, Quebec, racer Steve Levy had come up with a very good idea for solving the issue of the "sagging bumper." My thanks goes out to Steve giving me the idea of writing this article.

Bumper Tensioner

A very good way to prevent the front bumper from sagging is to connect something to the ends that causes the ends to bend upward slightly, but which is not so inflexible that it will break when there is a collision. The method described here, a fuel-tubing tensioner, is very easy to make using spare parts, fuel tubing, and a bit of fastener hardware.

Parts and Tools Needed

Fuel tubing
Small cable ties (4)
Parts to make 2 short linkages (4 ball joints & 2 threaded rods)
#6-32 x 1" flathead machine screws (2)
#6 flathead screw head cups (2)
#6 flat washers (2)
#6-32 nylock nuts (2)

Hobby knife
Drill bit (approx. 1/8”)
Moto-tool with cutoff wheel
Threadlock (medium)
Safety glasses

Step 1: Assemble Linkages

Using spare parts, make two short linkages using ball joints and threaded rod. The ball joints for the ends of shock absorbers work very well; they are typically short and heavy-duty (thicker).

Step 2: Mounting the Linkages

1. Using the drillbit, drill a single hole near each end of the bumper as shown in the image.
2. Place a head cup on the head of a machine screw, and thread the screw upward through the hole from the bottom of the bumper.
3. Place one end of a linkage over the screw, then a flat washer, then a nylock nut. Threadlock is recommended.
4. Repeat for the other linkage.
5. Tighten the nut against the linkage, then BACK IT OFF slightly so the linkage can be tilted upward slightly.
6. Cut off the extra length of screws above the nuts.

Step 3: Installing the Fuel Tubing

1. Loop a piece of fuel tubing upward through the other end of a linkage. Fold the fuel tubing over onto itself (approx. 1”) and SECURE TIGHTLY with two small cable ties.
2. Stretch the fuel tubing behind the body posts, and loop through the linkage at the other side of the bumper. Apply enough tension to achieve the desired amount of lift on the bumper ends. Again, SECURELY TIGHTLY the fuel tubing with two small cable ties.
3. Cut off the extra fuel tubing.

Bumper Tensioner

Assembled Linkage

Mounted Linkage (1 side)