Chapter 21: Brakes are overrated.

Posted: May 12, 2010 in bugatti go kart, building a go kart frame, go kart pedaling, vintage go kart
Tags: , ,

Brakes. Who needs ’em. Well, come to think of it we do…especially now that we’ve completely removed the coaster brake on our drive wheel. I know, I know, you’re thinking “Well, why did you go and do that? You had such a nice solution.“A couple of reasons.
First, as you know we needed to remount the rear wheels. The simple offset block of wood we had just wasn’t cutting it, and second was an observation I made with our coaster brake setup. You see I realized that no matter what I did, since we had move the coaster brake bracket to the opposite side of where the actual clutch mechanism for the brake itself exists, well the brake would never really work or at least work well. In fact after a few dry runs I realized that the setup we had would actually inhibit the wheel to gradually work loose each time you applied the brakes! Either that or the wheel would gradually lock up. Either way, as Luke would say “That’s bad.”.

To solve my problem with the brakes I just decided to simply gut the wheel hubs and remove the brakes altogether. By doing this I effectively made the hub a “free-wheel” (where you can pedal backwards, coasting, but engage the sprocket going forward).

After doing a fair amount of research to determine whether or not I could actually make the coaster brakes do what I wanted them to do (I even went so far as to say please) it was simply easiest to not use the coaster brake at all but rather build a hand brake system. We’ll get to actually building the brakes  on another day, first we needed to settle the wheel hubs and mount them. To solve the problem with the mounting I opted to completely eliminate the brake and axle assembly from each rear wheel. In lieu of the factory axle on each wheel we would use a single solid axle that would go through the frame, and through each wheel.

Drilling for our new rear axle.

I headed to Home Depot and picked up a 36″ length of 3/8″ steel rod. I decided I would run a single axle through the frame, and mount each wheel onto the axle. This would insure that the wheels were not only parallel but would give them that much extra strength to hold the riders weight.

First we needed to determine exactly where to put the axle. I realized after some earlier test rides that the wheels were a bit too far forward in that a heavier rider would have just enough weight behind the rear wheels that the front wheels would just barely come off the ground. Based on this I decided to move them back a good 2″. This will require we build a longer chain, but that won’t be too big of a deal.

Once we had our holes drilled we needed to determine exactly how we would hold the axle in place. I realized that the pipe floor flanges we had used earlier were perfect in that the axle would fit just right through the threaded hole.

Good ole pipe flanges. They've proven quite useful in this project.

With our axle holes drilled we positioned our pipe flanges on each side, marked the holes, and drilled mounting points.

Next with our flanges drilled and mounted we set our sights on the axle itself. We placed the rod into our bench vice and proceeded to thread approximately 5″ on one end. We used a die that was the same thread as that of our wheel axles, which will allow us to reuse all of the threaded pieces that came with the wheel. With each step I took here I constantly would ask myself “Now, why didn’t I do this to begin with ?”. The fact that I was being barraged with questions like “Dad, when is this going to be done?” and “Dad, can I ride the go kart now?” didn’t help either.

The threading process went quite smoothly with the boys chipping in here and there though they always seemed to have one ear cocked towards the street awaiting the now almost daily ice-cream-man pilgrimage.

Threading our axle to match the old ones so we can reuse the wheel hardware.

We threaded one side and slid our drive wheel into place on the axle. I intentionally only threaded the one side so that we could slide the axle into place to get a measurement of how much to cut off before we threaded the other side.

I carried the wheel and axle assembly over to our kart and slid the axle into the frame. Next I went to tighten the outer wheel nut in place and realized the outer wheel ball bearings had fallen out of the wheel somewhere during the 20′ journey I had just taken across the garage. I just had them… didn’t I? They’d turn up eventually I figured so I continued with the rough assembly to get a measurement of our axle.

Axle with one wheel mounted and one wheel hub removed.

I placed the axle into the frame, all the way through, and out the other side. We had at least 8″ of excess coming on the other side. I positioned the wheel approximately where it would be and measured how much length of axle it used. I then used that measurement on the other side and made a mark to indicate where we would cut off the excess length.

Next we pulled the axle and wheel back out of the frame and cut off the end we had just marked. With our axle now the proper length we then threaded the other side to prepare to mount this second wheel. I went ahead and repacked the wheel bearings of the second wheel since we will be assembling that wheel onto the axle next. While I was doing this I realized that my trusty assistant had disappeared into the house. I knew he had greasy hands so figured I’d try to catch him before my wife did. New couches + greasy hands =  bad news for sure.

I found him in the hall bathroom…washing the missing ball bearings in the sink. At least we found them, and now they were now clean, cleaned with hand soap no less.

Both wheels mounted with our axle through the frame.

With all of our hardware now present and accounted for we pressed on. I positioned the axle into place, reassembled the primary wheel with it’s found bearings, and attached our second wheel. The wheels looked nice and straight and strong to boot.

With the axle in place next we threaded 1/4″  bolts through each of the four holes in our pipe flanges. These not only provided a nice solid hole for the axle to go through, but also provided a bit of extra strength to hold it all in place with the four bolts. Solid wheels, solid axle, it was all looking quite good.

By this time it was about 7:00 pm. With the weather warm and longer days the boys were all playing outside. I asked one of them if he wanted to take a little test drive with the rear wheels remounted. Not only did he reply with; “Yeah!!!” but he proceeded to announce to every child on the street that their go kart was finished. Of course it wasn’t quite. I knew very well where this was headed. Within minutes a steady stream of children ranging from two to twelve were suddenly lined up in my driveway to take a spin with each screaming “I’m first! I’m first!”. Of course the chain wasn’t on yet so I found myself acting as an amusement park ride operator, pushing each child down the street only to turn around and do it again with the next in line. The smile on their faces and shouts of “This is awesome!” was well worth the lower back pain that I was later greeted with. After I was about half way through the line of children my wife opened the front door, smiled, and yelled: “Hey, is that an airplane?”.

Everyone’s a critic.

Next up our fancy new brakes…

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