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Secrets of truing tires

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  • Secrets of truing tires

    Now that I bought a tire truing machine and MOST of the additional items needed or used to true tires, how do you do it? Remember I'm A "FNG" and not an old dog.
    Note; I purchased a 3mm pulley form Germany, used on another machine. My first real discovery, the equipment provided/not provided by the company that produced the machine. It's a PITA that we can not say the name of the company, for their plus and negatives.
    I've been guided about the PS and how to us it with regards to the amount of Amps and V used.

    I removed my first 1/32 axle/wheels, and the tires.
    Question; why are there two dimples or flat spots on the wheel opposite themselves? If this is normal, how do you true the tires if the wheel is not round?
    Question; What do you use and where do you apply glue to the wheels to glue the tires onto the rims. I understand the tires have already been slide onto the rims.
    Question; What would be the final grit of the sandpaper used to finish the truing?

    These may seem simple question, remember I'm learning!
    More to come.

  • #2
    Question #1: How serious is your racing going to be? If it's going to be casual racing then don't worry about the dimples/flat spots in the wheels. The tires are thick enough to absorb any imperfection in the wheels. If still wish to make the wheels round I will defer to anyone who actually fills the wheel imperfections.

    Question #2: For the PG tires use a clear nail polish. Sally Hansons is a good choice if it's still available. Quickly coat the outside edges of the rims and slide the tire over the rim seat the tire by twisting the tire on the wheel making sure the nail polish is spread. Let the tire set for an hour before truing.

    Question #3: I use 180/220 sandpaper to do my truing. I stop there. Some people go further with finer grit to refine the cut but I find that after a couple 100 laps it does the same thing so I omit the fine cut. Again I am a casual racer so it's not that critical.



    • #3
      I echo what Dave said. Carrera is the only company that I'm aware of that makes wheels with those massive divots on them. I'm sure there's a reason for it, but I've never heard what that is. Some people will fill it with some kind of hardening putty, then use the machine to make it perfectly smooth before gluing the tires on.

      There is no rule against naming companies or web sites. The rule is that you can't LINK to them. If you have good/bad things to say about a product/service based on your personal experience, you can post it. "Brand bashing" is when people just slam a brand without specifics, usually because they are fanboys of a competing brand. Posting about your personal experience is not brand bashing.


      • #4
        Originally posted by dw5555 View Post
        Quickly coat the outside edges of the rims and slide the tire over the rim seat the tire by twisting the tire on the wheel making sure the nail polish is spread.
        So Dave... you just do the outside edges of the rim and not the center rib?
        I have been turning the tire inside out to be sure I get the center of the tire completely coated to. It's a pain since the Sally Hansen's dries so fast.
        The tires on your cars seem fine for the way we race, so if that is the case I will stop coating the center rib section.

        As far as the Sally Hansen availability, I went on ebay and bought some when I heard it was getting hard to find. Later, I found plenty of it at all 3 of the dollar general stores, so I don't think it is really an issue.


        • #5
          I believe the recess cuts in the Carrera wheels are for production purposes (Assembly). I fill them in with super glue, sometimes you have to apply it twice to fill the recess. Let it set over night, then grind away. I use the thick super glue for this.

          To glue my tires to the wheels, I use Loctite Shoe Glue, .6 oz tube, made in Germany. Flexible, dry's clear, self leveling and can be removed. I have used nail polish in the past and had no luck with it. I use this glue for everything on slot cars, reapplying broken parts loose parts, wire, weight, magnets, secure motors and axle bushings. It just works well. Can purchase at Lowes, Home Depot, Internet.

          Last edited by Slot Car Crazy; 03-25-2023, 11:02 AM.


          • #6
            Thank you for the feedback.

            I'm casual and no I do not intend to smooth the rims. I assumed that a wheel would come round, not with two flat spots. I understand that rubber will take up the difference or it's really not that important. When you first start this process, round and true means your round and true!
            The PG tires come with a flange on one side, does it go in or out when you slide the tire on? I have both Sally and super glue to use.

            I now understand "Brand Bashing", that is not my intent. No links!


            • #7
              Originally posted by Frogman View Post
              Thank you for the feedback.

              I'm casual and no I do not intend to smooth the rims. I assumed that a wheel would come round,
              Unless the wheels are machined assume they aren't round because they're never round.


              • #8
                Even metal wheels with tires are not "perfectly round" (true). Close, maybe, and fine for home/fun/personal/DGAF use, but for competition, there is no such thing as true wheels and tires before they hit a machine for that purpose.

                What matters to you is what matters to you.


                • #9
         "perfect" !!!

                  Quality aluminum wheels are pretty **** close. PLENTY close for most ANY slot car.
                  Even Group 7 guys buy and...USE off the shelf wheels .



                  • #10
                    Well after 5-10 days of not being able to log on to the forum, my tire truing came to a halt. Needed to get answers to question before continuing.

                    The PG tires come with a flange on one side, does it go in or out when you slide the tire on?

                    I see you can use the nail harder to both coat front tires and glue the tires onto the rims.


                    • #11
                      I don't know what you mean by a flange. There is a finished side (generally rounded) and an unfinished side (usually flashing). Unfinished goes to the inside.


                      • #12
                        Most be the unfinished side, flashing means a little lip to pull over the edge of the wheel?


                        • #13
                          I have finish (TBD) truing the rear tires which are PG's. Truing them the cuttings were white. I do not have any front tires yet, so I'll be truing the stock Carrera tires. These are rubber and the cuttings are black. Is there any difference truing PG's to Carrera rubber? I assume the same process for stock tires, clean wheels, glue tire, true at low speed? The stock tires look like they are less true to start with than the PG's. More cutting coming from edge, none from middle. I assume you move the sliding sandpaper bar back and forth until tire is cutting even and no polish spots remain?


                          • #14
                            You did not say which style of tire truer you have, I presume that it is the Tire Razor type that can do the entire rear axle assembly as a unit. For serious racing I recommend gluing and truing your tires. If the tires are not glued and the wheels are not round there is the possibility that the tires may slip and the wheel/tire combination will no longer be perfectly round. If you are not going to glue the tires it would be best to true the wheels, you can do that with a Tire Razor style machine. My experience has been that rubber and urethane tires true about the same. If you use too much pressure when you are grinding tires you will reduce their diameter without making them perfectly round. You only need to exert enough pressure to knock down the high spots. I use a power supply with volt and amp meters with my tire machine. With the motor running, but not griding the amp meter reads 1 amp. When I start grinding I adjust the pressure so the meter reads no more than 2 amps. The grinding is done when the entire tread has the same appearance. After grinding the tires will probably need to be polished to get maximum grip. The tires will get polished if you run many laps on the track, but you can speed things up if you use your machine with progressively finer sandpaper.


                            • #15
                              Frogman I personally find I have to lighten up just a little on the pressure when truing rubber vs urethane. Rubber heats up faster than urethane and doesn't cut as easily as urethane. In my experience when I'm trueing new tires they will almost always true the outside edges first before contacting the middle. I also do not have the reciprocating arm that moves the sanding block back and forth. What I do is once the tire has been trued, I then move the sanding block back and forth to even out all the sanding grooves.