While testing and running my Bugatti, I experienced a fair amount of bounce on my wheels.  Thanks to YouTube videos, you can see how best to true your wheel rims so they are pretty darn accurate.  Without too much fuss, using a Harbor Freight wheel balancer, I was able to get mine to within between 1/32″ to 1/16″ overall.  I guess if you have the patience of Job, you could nail it perfectly, but as I discovered, there are bigger problems to address.

Once the spoked wheel was straight and true, I mounted the tube and tires.  Then using the balancer again with the tire mounted, I discovered the wheels were horribly out of balance.  Using stick on weights, I found I had to add a lot of weights to get them to balance.  I tried buying spoke type weights, but could not find any, so I used the default flat surface stick on types and mounted them on the rim.  In most cases I used anywhere from 5 to 10 small weights.  They seem to stick well, I’ve not had any come off yet.  I guess one could take the wheels to a motorcycle shop and get them perfectly balanced, but I learned that this old fashion technique worked really well.  My car rode significantly smoother now.

Never-the-less, my front left wheel still bounced about quite a lot.  Even after taking it off and checking the balance which was still perfect, this wheel seemed to bounce too much to my liking.  It was enough that I could easily see it while driving.

Just for kicks and giggles I verified that the rim was still true and indeed it was, but to my amazement, the tire itself was out of round by about 5/16″!  So after doing a little YouTube research I discovered that professional gokart teams often will resurface their tires to extend their useage.  There were also some DIY, who had out of round problems with their truck and car tires, so they devised their own tire surfacer  to cure their severe vibrations.  Some DIY, had a death wish in their devised methods, it was painful to watch.  But they lived, surprisingly enough.

So I decided, I would have a go at it myself.  I ordered an inexpensive cross/sliding type table from Amazon and mounted an angle grinder with grinding disk to it.  Then I secured it to a small wood table to get the height of the grinder to the mid wheel point.  I then secured this table to my work table via several long wood screws so it would not go anywhere due to vibration.  I then nestled my Wheel balancer up to the grinding table setup using boards and screws to secure it to the bench.  It was a hack, but I wanted to see if this idea was going to work.

I adjusted the grinder so it just missed any point along the wheel then turned on the grinder.  Pretty soon, I noticed the horizontal vernier adjustment was turning on its own which moved the grinding wheel away from the center point of the tire, so i taped it with duct tape and proceeded once more.

I initially used two cutoff wheels mounted back to back (for additional strength) and realized this was causing a stink but its cutting ability was as slow as watching grass grow.  So I finally switched over to a true grinding wheel and it yield much better results.

The nice thing about my Shinko SR241 tires, is that the only part I need to cut was the center most part, not the entire tire surface.  So by incrementing the vernier adjustment 1/2 turn at a time while hand spinning the wheels, I finally cut the wheel down to about 1/16″ within of true.  It stunk up my garage with that burnt rubber smell, which then crept into the house making my wife a little unhappy, but I was very happy.  I reinstalled the wheel back onto my cyclekart and drove off.  Almost immediately, I noticed a big difference and you never saw such a big smile on a cyclekarter as I had on that test hop.  The boogie man at long last was dead!

If you looked at my reshaped tire, you would be hard pressed to see I had even touched it.   It only removed rubber from a small part of the overall tire, so I did not sacrifice any significant tire life in getting this tire trued.

So if you have a bumpy ride, check to see if your rims are straight and true, and that your mounted tires are balanced and true as well.  Once they are all true, you should have a smooth ride too.