Custom Truck Pulling Sled - Show Me Scalers

[thisdougsforu]

Finally had my truck pulling sled out for the first time today for some testing at a trail run and it worked great! We built this sled in our machine shop (sorry folks, it's a one off piece) years ago but due to being out of the hobby it sat dormant. This summer I dug it out of storage and finally finished the refurb!

It weighs about 12lbs unloaded and I have about 30 lbs of custom cut steel weights to add to it to stop any type of TTC vehicle on dirt or cement. The weight box is operated by a chain drive that is engaged by inserting a pin through the box onto the drive (like a roller coaster). When the weight box tops out (geared to top out around 25 ft for true 1/10 scale) the pin hits the top sprocket and starts to "float". This way the box does not lock the wheels up and allows the trucks to stop naturally from a dragging weight (again, like the real thing). Here are a ton of pics and some video from the testing session!

We had a GoPro "chase truck" for a few shots of video!

Here are a couple short videos. These videos are public so you shouldn't need a facebook account to view them if you don't have an account.
https://www.facebook.com/photo.php?v=10151097800493155
https://www.facebook.com/photo.php?v=10151135830588195

This is just a start. At all trail runs we are now going to be doing truck pulling!

 

[smuggl1n]

Who won? Was it the summit?

 

[thisdougsforu]

There was no competition because we were just testing things out, but the Summit easily outpulled the other trucks. Can't really compare that though since a Summit is nothing like a scale truck.

 

[thisdougsforu]

We had our first official pull yesterday as part of our TTC challenge. We ran a "street stock 4x4" class which was open to any trail truck to be run exactly as they were on the trail. We also had a fun "Unlimited" exhibition class for clodbusters/Summits.

We had several SCX10's make a full pull, and I won the pull-off with my blue bronco. We had a ton of fun and several club members are now looking into purpose built pulling trucks.

 

[JavelinSST390]

Nice shots, man! Looks like your sled works good!"thumbsup" Hoping to get something similar going here, I just gotta build the sled first!:lmao:

 

[Badd]

The weight box is operated by a chain drive that is engaged by inserting a pin through the box onto the drive (like a roller coaster). When the weight box tops out (geared to top out around 25 ft for true 1/10 scale) the pin hits the top sprocket and starts to "float". This way the box does not lock the wheels up and allows the trucks to stop naturally from a dragging weight (again, like the real thing). Here are a ton of pics and some video from the testing session!

Would you share more info and some pics on how the pin and float system works on your sled ? I would love to see how it works . thanks "thumbsup"

 

[thisdougsforu]

The weight box is operated by a chain drive that is engaged by inserting a pin through the box onto the drive (like a roller coaster). When the weight box tops out (geared to top out around 25 ft for true 1/10 scale) the pin hits the top sprocket and starts to "float". This way the box does not lock the wheels up and allows the trucks to stop naturally from a dragging weight (again, like the real thing). Here are a ton of pics and some video from the testing session!

Would you share more info and some pics on how the pin and float system works on your sled ? I would love to see how it works . thanks "thumbsup"

There is a small pulley at the top of the sled. When the box rolls all the way to the stop of it the pin slides on top the pulley therefore making the box want to slide back down. Because the sled is still in motion when the box tries to slide backward off the pulley the still moving chain reengages the box. It repeats this cycle until forward motion stops creating a smooth "floating box" on top of the sled which lets friction naturally stop the trucks.

 

[SlickRockSpider]

The weight box is operated by a chain drive that is engaged by inserting a pin through the box onto the drive (like a roller coaster). When the weight box tops out (geared to top out around 25 ft for true 1/10 scale) the pin hits the top sprocket and starts to "float". This way the box does not lock the wheels up and allows the trucks to stop naturally from a dragging weight (again, like the real thing). Here are a ton of pics and some video from the testing session!

There is a small pulley at the top of the sled. When the box rolls all the way to the stop of it the pin slides on top the pulley therefore making the box want to slide back down. Because the sled is still in motion when the box tries to slide backward off the pulley the still moving chain reengages the box. It repeats this cycle until forward motion stops creating a smooth "floating box" on top of the sled which lets friction naturally stop the trucks.

Doug

I love the truck and tractor pulling. Not very big in the Oregon. More pics would really help describing the pin function.

Watching the video. What do you think makes a trail truck perform better in pulling. The reason that I ask is in our club some of the trucks didn't even get the sled to move. This is on gravel/dirt. Some did very well. On our pulling sled the skid does not pivot. It is rigid.


Questions

The white plastic skid. It pivots (?) free ??.

When you get to a full pull is the all of the sleds weight on this skid. If so do the sled tires come off of the ground.

Thank you

Evan

 

[thisdougsforu]

Here is a video from last weekend. I didn't get very much pulling on it, but near the end you'll find a few runs. I was busy operating the sled so I neglected my camera!

Show-Me Scalers R/C Hill Climb, Creek Crawl, & Truck Pull - YouTube

Evan, the skid on my sled isn't plastic, it's a sheet of aluminum! My sled weighs around 15 lbs with no load. I use a different amount of weights depending on the class pulling. For standard trail trucks on concrete I normally just add about 7lbs of steel to the box. Traxxas Summits and modified clods pull over 20lbs in the box with no problem and I'm getting more weights made up to put the brakes on big stuff like that.

Pulling on gravel or loose dirt is not advised as the trucks just can't get traction. The best pulling surface (and most scale, obviously) is on hard packed dirt. If that's not available then flat concrete works ok as well.

We are going to be running 2 classes. "Street stock" is legal to all 1.9 or 2.2 trail trucks and can't be modified from what they run on the trail. We are adding a "Pro-Stock 4x4" class where the rules are - 8 lbs max weight, 1.9 DOT style tire only, must run on 2s Lipo. This class is going to allow guys to run scale weight boxes on the front of the trucks and lock the suspension so all the weight goes into traction.

 

[Ffnye79]

I love the sled. It seams to work really good also.

 

[SlickRockSpider]

Here is a video from last weekend. I didn't get very much pulling on it, but near the end you'll find a few runs. I was busy operating the sled so I neglected my camera!

Show-Me Scalers R/C Hill Climb, Creek Crawl, & Truck Pull - YouTube

Evan, the skid on my sled isn't plastic, it's a sheet of aluminum! My sled weighs around 15 lbs with no load. I use a different amount of weights depending on the class pulling. For standard trail trucks on concrete I normally just add about 7lbs of steel to the box. Traxxas Summits and modified clods pull over 20lbs in the box with no problem and I'm getting more weights made up to put the brakes on big stuff like that.

Pulling on gravel or loose dirt is not advised as the trucks just can't get traction. The best pulling surface (and most scale, obviously) is on hard packed dirt. If that's not available then flat concrete works ok as well.

We are going to be running 2 classes. "Street stock" is legal to all 1.9 or 2.2 trail trucks and can't be modified from what they run on the trail. We are adding a "Pro-Stock 4x4" class where the rules are - 8 lbs max weight, 1.9 DOT style tire only, must run on 2s Lipo. This class is going to allow guys to run scale weight boxes on the front of the trucks and lock the suspension so all the weight goes into traction.

Doug

The sled is and look awesome and work great too. "thumbsup"

Pulling on gravel or loose dirt is not advised as the trucks just can't get traction. The best pulling surface (and most scale, obviously) is on hard packed dirt. If that's not available then flat concrete works ok as well.


It was not the surface that stopped rigs from pulling. I think it was placement of the hitch. Some of the rigs hooked up. Gravel was the wrong word.

I have watched 1 to 1 pulling sleds. When the weight is completely over the the skid the sled balance point changes lifting rear tires are off the ground. When you say full pull you are dragging the sled on the skid with no tire contact ?

Thank you

Evan

 

[SlickRockSpider]

I have watched 1 to 1 pulling sleds. When the weight is completely over the the skid the sled balance point changes lifting rear tires are off the ground. When you say full pull you are dragging the sled on the skid with no tire contact ?

Thank you

Evan

I wanted to give more info. I found a very modern pulling sled from NTPA. The info above was an old style sled. They work on the same principle. The TRIP and PUSH DOWN SYSTEM relate to the my question. I will turn it over the the NTPA.

The sled can be adjusted in many ways to create a desired pull. Weight can be added or removed from the box. Adding weight on the pan can give more starting weight to the pan of the sled. The box gearing can be changed to move faster or slower, and the starting position of the box can be moved among a two feet area, affecting the distance of travel. The final adjustment is the placement of the trip, which applies the push down system to expend the full weight of the sled on to the pulling vehicle.

• Box- Contains the weight used to stop the vehicle and moves up the length of the sled rails progressively during the pull, driven off the front set of sled wheels.
• Weight Block- Most sleds use a “full block” that weighs 2,000 pounds and a “half block” weighs 1,000 pounds.
• Pan- Applies the force of the weight to the ground creating needed friction. The sled starts with only the front of the pan touching the ground. Bars attached to the bottom of the pan help make added friction at the end of the pull to stop pulling vehicle.
• Trip- Sits between the frame rails of the sled. As the box moves up the rails the trip is hit and starts the push-down system. The trip is adjustable.
• Push-Down System- Uses hydraulic cylinders to lift the back half of the sled in the air,allowing 100 percent of the sled’s weight on the pan.
• Kill Switch and Hook- The kill switch is always hooked first, allowing the sled operator to stop the engine of the attached vehicle in the event of an emergency or if the vehicle breaks free of the sled. The hook is used to connect the sled to the pulling vehicle and extends the weight of the sled to the vehicle’s hitch.
• Sled Operator- The driver of the sled. Has the responsibility of maintaining a controlled pull at all times. May pull kill switch if they feel something is out of control.

Hey Doug thank you for building a sled and starting a thread on it. "thumbsup"

Evan

 

[thisdougsforu]

Evan, no the wheels dont lift in the air. It would be sweet to have on board hydraulics that could accomplish that!

 

[UP2NOGOOD808]

That's a sled! Someday I'll get to try one.

 

[m00nst0ne69]

This is an awesome sled! What are you running for gear ratios? It looks like you are using mini pitch chain and gears with 1/4" shafts. Do you happen to have a build thread?