Announcement

Collapse
No announcement yet.

How To Check The Drive Wheels For Trueness

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • How To Check The Drive Wheels For Trueness

    This is an easy way to check your drive wheels to make sure they are running true.

    I remove the tires from the drive wheels and mount a piece of 1/16th tubing to the motor with a rubber band.

    The chassis is set on the tire sanding fixture and a plastic shim is set under the wheels.

    I spray some glass cleaner on the wheels for lubrication.

    Run the wheels as slow as possible and watch the tubing. If the wheels are true the tubing will be stationary.

    If the wheels are out of true, the tubing will amplify the wheel's movement and the tubing will move up and down. (see video)

    http://s164.photobucket.com/albums/u...WHEELVIDEO.flv

    To determine which wheel is untrue, place the plastic shim under one wheel at a time.

    Dave
    Last edited by davejr; 09-08-2008, 09:13 AM.

  • #2
    Might want to re-do the video. with the camera jumping in and out of focus, it was hard to see what, if anything, was happening.

    Scott

    Comment


    • #3
      I didn’t have any wheels that where untrue to demonstrate this method for testing wheels. That is why the tubing isn’t moving.

      This video I made was darker, but you can see that the wheel insert in this video is untrue and the tubing isn’t moving, indicating that the wheel itself is true.(see video 2)

      http://s164.photobucket.com/albums/u20/davejr-photos/?action=view&current=WHEELVIDEO2.flv

      Dave

      Comment


      • #4
        OK, I understand what is happening now. The second video is easier to see.

        Scott

        Comment


        • #5
          This raises some more questions, of course ...

          Dave, if a wheel proves untrue (oh no I feel a country song coming out of this) do you have a method to determine whether this is caused by an axle that is too narrow, or a wheel with too large a bore, rather than a wheel that is not concentric?

          Assuming you are dealing with a wheel that is properly bored, but proves to be out of round, what method would you use to true the wheel - assuming this is possible. Can you just use a flat steel file, like the ones they bake into cakes to help prisoners escape from jail?

          Finally (sighs of relief all round), if you have a wheel that you know to be true, and you have then glued and trued a tire on it, is there any reason why you couldn't now use the same method to ensure you have trued the tire properly as well?

          Comment


          • #6
            Sometimes ya hafta explain every little thing

            Why not?

            I have been using this method for ages, but simpler still. I just hold the car on the track, feed it some throttle, and see if the rear end of the body bobs up and down as the wheels slowly revolve. Yes, you have to hold the car in place by blocking its forward motion with your hand in front of the body. And you have to be easy on the throttle. Just pull the tires off to see if it is the wheel or the tires. You can run it up on blocks if the gear is bigger than the wheel.

            It is absurdly simpler still to determine if your wheel is bored over sized. Place the wheel on a Slot.It axle (known to be precisely made), leave the set screw loose, and see if you can rock it on the axle. That is, with your left hand holding the wheel, grab the end of the axle with your right hand and move it around as if it is a gear shift, and you are trying to shift gears. If it can move in the hole, the hole is too big for the axle. Yes, you can see a thousandth of an inch of over sized hole. Try it.

            addendum:
            To actually true an out of round or eccentric wheel, you can try a flat file, but the chassis or whatever is holding the axle needs to be held in place firmly, as does the file, and you need a way to advance the wheel into the file, or the file into the wheel. Your best bet is to put those wheels on a car where it doesn't matter, and get some better wheels.
            Last edited by Robert Livingston; 09-08-2008, 03:01 PM.

            Comment


            • #7
              Nice tip Davejr.

              But I guess this tip is meant for those setting up the ultimate race cars, most of us only need to take the rim of the tire add a little power and put the fingertip against the rim to confirm that something is out of round. There are just way too many RTR cars that comes with way too bent axles or untrue rims.

              [grump mode]
              I really hate it when I buy a new nice looking car only to discover the axle is severely bent or rims are sitting off angle on the axle. It's especially frustrating when they have knurled axles which translates to 20-30 bucks in a complete new rear end with tuning parts and 2-3 weeks waiting time for the parts. Alu rims and tuning parts are great for racing cars, but for most of us home "drivers" reasonably straight axle and rims should not be to much to ask for!
              [/grump mode]

              The urge to get a lathe grows every time I buy a "unusable car". I really like the looks of many of the stock rims, so I've have this idea that with a lathe I could make me some sets of over-sized rim-jigs in alu/delrin with an ID that slip over the OD of the stock plastic rim. Then the stock plastic rim could fit into the "jig" and then I could glue the center hole and re-bore it with a center drill-bit on the lathe. Does this sound doable? has anyone tried this to restore stock rims? But do I really need to cash out $600-700 for a mini lathe? could this be done on a Huddy or Slot.It tire truer? I'm open to any suggestion on how to restore an out of round center hole on stock plastic rims.

              BTW: Thanks again for the tip Dave I will try this to check my CPR cars.
              Last edited by 356speedster; 09-08-2008, 03:12 PM.

              Comment


              • #8
                Once a wheel is made there is not much that can be done to re-bore it, unless you have a lathe. The time and effort that you would put into turning your own holder, inserting the plastic wheels into the holder, and re-boring the hole would be better spent making your own wheels and using the plastic ones as inserts. If you don't want to buy a lathe, buy true wheels. They are out there (Slot Car Corner, BWA, among others).
                Last edited by Robert Livingston; 09-08-2008, 03:26 PM.

                Comment


                • #9
                  Originally posted by Robert Livingston View Post
                  They are out there (Slot Car Corner, BWA, among others).
                  I know Robert, I have a lot of them, but it gets so d**n expensive to upgrade a couple hundred cars with alu rims, and I still need that lathe to turn down the stock rims into inserts, or are there simpler methods for that?

                  BTW: If I sound grumpy today It will wear off soon, I just received my new CPR GT candidate in the mail, the humongous but excellent looking Revell Mercedes 300 SEL

                  Comment


                  • #10
                    I think you deserve a lathe. You will not regret the cost.

                    I have filed don wheels into inserts by hand; that is simpler, but it takes more time. Mostly I use a drill press.

                    Comment


                    • #11
                      On a wood track you can hear a drumming sound if the car has wheels/tires that are not true. With silicone tires you can examine the tread and see high and low spots.

                      Comment


                      • #12
                        Originally posted by Wet Coast Racer View Post
                        Dave, if a wheel proves untrue (oh no I feel a country song coming out of this) do you have a method to determine whether this is caused by an axle that is too narrow, or a wheel with too large a bore, rather than a wheel that is not concentric?

                        Assuming you are dealing with a wheel that is properly bored, but proves to be out of round, what method would you use to true the wheel - assuming this is possible. Can you just use a flat steel file, like the ones they bake into cakes to help prisoners escape from jail?

                        Finally (sighs of relief all round), if you have a wheel that you know to be true, and you have then glued and trued a tire on it, is there any reason why you couldn't now use the same method to ensure you have trued the tire properly as well?
                        I don't want to even touch the country song connotation, but iffin' yo wheels don' be true how can I be lovin' you? Assuming the possibility of an un-true axle to circumference relationship, if the wheel can be firmly affixed to the axle, it can indeed be trued with a common file, or sandpaper glued to a stick. The rotating shaft needs to be steady, as does the truing device. If the file (etc.) bounces up & down, during the process, the wheel will just get smaller without getting truer.

                        Going out on yet another limb, I'm guessing that the axle bore in the wheel is too large. Especially if it was pulled off of a knurled axle. It will make for a serious wobble upon re-assembly. The only real cure is to replace the originals with aluminum wheels... pretty simple, unless you are dealing with Ninco, which have an odd, and un-uniform sized axle. Then no after-market wheels will fit on the Ninco axles. You are stuck with using Ninco wheels, unless you want to switch wheels, axle, bushings and gear with something more rational.

                        Greg

                        Comment


                        • #13
                          It's at times like this that I recollect a line from one of our SCI Members (I wish I could remember who) in response to a Thread about plastic wheels falling off; something along the lines of "You picked a fine time to leave me, loose wheel ... "

                          There are a couple of reasons I directed this multi-part question at DaveJr in the first place. The primary one is that he has what I consider to be a very creative yet practical mind, and so his solutions are often very simple. Note what a straightforward rig he came up with to test wheels for trueness, whilst mounted on the actual axle with the actual bushings and motor that are all going as one unit into the slot car. Wow. That's just like real life.

                          Because maybe I'm a bit down to earth or something, but I don't believe that it is practicable to suggest to everybody out there in slot car land that they run out and buy a lathe and install it in their basement. These things take money, and space, and time, and knowledge in terms of how they work. Most of us, and few if any newbie slot car addicts, are lucky to have a bench grinder or drill press on the workbench in the garage, never mind a freaking lathe.

                          So that's why I sought DaveJr's feedback on this. I'm still hoping he will respond to the questions I asked.

                          As to the non-concentric issues, questions of off centre or over-large bores, and ideas about truing imperfect wheels, I was thinking about a few ongoing forum issues, as well as personal concerns about the cost or necessity of replacing the drivetrain of virtually every rtr slot car you buy these days.

                          Take a look in the NINCO Forum at the recent discussion about their premium parts, for instance. Consider the credibility of the gentlemen involved, and what they each have to say.

                          Meanwhile, as a slot car enthusiast who has little patience for out of round wheels and tires, but a limited amount of time and disposable income to spend on replacing all of this with premium parts, I have no choice but to purchase the occasional Slot.it rtr car, or hand my money over to the aftermarket companies (and thank you all for your excellent products) in order to be able to enjoy my race cars on the track.

                          But as a Mod here, I hope I can elicit the most useful feeback for the vast majority who simply stop by, read what's here, and then carry on with their hobby.

                          Comment


                          • #14
                            Sounds like a whole lot of issues rolled into one.

                            The art of tuning has moved to the point where minor wheel-wobble is bothersome. If wobbly wheels are a plague on the hobby, is there an inexpensive solution? No, there isn't. You either buy metal aftermarket wheels that are true, or try to true up your plastic wobbly wheels (or certain wobbly aluminum aftermarket wheels), without consistent results. As we have seen, your cannot buy plastic RTR cars without encountering wobbly wheels. Even the premium cost race versions the manufacturers are now making often have wobbly wheels.

                            Now, if you can jury rig a file and a bench vise and your own two hands such that you can hold a file, and a Dremel with a wobbling wheel on an axle, and end up with four out of four wobbly aluminum wheels (which are bored oversized) trued to the point were there is no measurable wobble, then that is an accomplishment indeed. The problem is that those wheels may have a concentric rim, after truing, but since an uneven amount of material has been removed all around the rim, they are now out of balance, and as RichD points out, you will hear a drumming sound as you run on a wood track.

                            Thus my insistence that you have only two options: get busy with lathe and make your own true wheels, or buy true wheels. Of course, there is always hope that the mfr's will begin to make their cars to satisfy the purists, at standard RTR costs, but what are the chances of that?
                            Last edited by Robert Livingston; 09-09-2008, 04:16 AM.

                            Comment


                            • #15
                              I believe the first person to sing “Loose Wheel” was D.W.

                              I don’t believe I have ever found a bad Slot it aluminum wheel, and I still haven’t found a need for after market wheels.

                              Since I own and prepare all the cars raced on my track, I try to keep the cost within reason.

                              I also try to keep the cars as stock as possible, down to the plastic wheels.

                              When I write an article, I try to keep the newer members in mind, and tailor the tools and processes to be home made and simple to use.

                              I have had decent success machining plastic wheels with my sanding fixture. The chassis is held steady by the adjustable stop and secured with heavy rubber bands.

                              I steady a file against the base and only remove the high spots until the wheel is reasonably true.

                              I try to only use rubber tires on the plastic wheels, because they are easier to true up in the sanding fixture.

                              I think it would be a waste of time and money to true up aluminum wheels. The cost of a lathe is far outweighed by the price of the newest aftermarket wheels available.

                              The biggest reason I use nothing but the NEW S1 tires on Slot it cars, is they are perfectly true. I now take the tires out of the bag, mount them on a Slot it car, and just race it. You don’t even have to sand these new tires for any reason, other than to get the shiny surface off.

                              Dave

                              Comment

                              Working...
                              X