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  • Guide placement and handling

    Just curious, how does the distance the guide is mounted from the front axel effect the handling of the cars? And why are some guide flags longer in front of the mounting post than others? It seems there are many different versions on my small selection of cars.

  • #2
    Actually it is how far the guide is in front of the rear axle that has a big effect on the handling of a car. The longer that distance is the more stable the car tends to be. When the rear of the car slides out in a corner the rear wheels slide farther, scrubbing off energy. It reduces the tendency of the car to spin out.

    As for how long the guide flag is, that has much less effect. A long guide flag will center itself better in the slot. But if a guide flag is too long it can bind in the slot of a tight radius curve. A very tight radius curve. Not too likely.

    Ed Bianchi
    Ed Bianchi
    York Pennsylvania USA

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    • Kevan
      Kevan commented
      Editing a comment
      I've never measured my best handling cars but suspected for a few years there must be an ideal 'guide distance from rear axle -to-overall-width' aspect ratio. I always find the longer you make the guide lead the slower the car is round corners, it makes a car safe & ponderous whereas a short wide car is quick through corners but can deslot in a jiffy.

  • #3
    In many cases the position of the guide flag is dictated by the shape of a car's body. I do not know of anyone that has done a study of how a 1/32nd car's guide position would affect handling. The Slot.it HRS2 chassis has the guide flag holder as a separate part so it can easily be moved without changing anything else.

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    • #4
      Food for thought.
      I have done a few Monogram 55 Chevy's using the hrs2 Slot it chassis. To keep from cutting a chunk out of the front of the car to allow room for the guide, I slide the guide bracket
      behind the front axle. I was not sure if it would work or not.
      I figure the guide is setting 3/4 to 1 inch back from where it should be.
      Alexis from Greece is in the process of making me some 3D chassis with this configuration.
      The rest of my 55'S will get this set up.
      The result is flawless with the guide placement.
      Eric Foster
      Port Republic Va

      Comment


      • one32
        one32 commented
        Editing a comment
        Scalextric track.
        I used a 2 post mounting set up for the 55. I prefer at least a 3 post, but cant quite do it with the hrs chassis. The chassis Alexis makes has a 3 post mount, and is more suited for this car.

      • one32
        one32 commented
        Editing a comment
        The front body screw is behind the guide. turn the guide, and you can see it.

      • oldskool62
        oldskool62 commented
        Editing a comment
        I am using the HRS2 chassis kit on all my builds now. The guide positioning is a big advantage.
        In saying this I want the try the scaleauto chassis kit as it has similar flexibility and appears to be a better quality.

    • #5
      The serious 1/24 guys say 3/4 in front of the front axle or maybe 1 inch is the best. I don't know, I don't think there is a number written in stone.
      Matt B
      So. In
      Crashers

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      • #6
        Interesting thoughts in the distance from rear being the important part, makes sense like a pendulum. I guess unless you reall have the fronts supporting the body they don’t effect much.

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        • #7
          Originally posted by Michael Squier View Post
          Interesting thoughts in the distance from rear being the important part.
          The term guide lead has for some time referred to the distance from the rear axle centerline to the center of the guide post hole,........and guide lead has a significant effect on a cars' handling. The cars wheelbase and the relationship between the guide post hole and the front axle is far less important........in "tripod" set-ups (commonly found on magnet cars and Commercial track cars) the front axle guide post hole distance is virtually a non issue , as in these cases the front wheels are either off the track, or, in the case of most Commercial track cars, not even there,

          That said, there is no "best" distance, with many variables affecting the "best" measurement.

          A few general rules............(there are a few other considerations/characteristics , but these are the main ones)

          A short(er) guide lead car will transition quicker and will therefore perform better on tighter turns, typical of most shortish home plastic/wood tracks.......eg. Slot-it Alfa T33's are great on tight/twisty tracks.

          A longer guide lead car will be an advantage on wider radius corners/fast flowing tracks, where the stability that the longer guide lead provides, will enable the car to track much more smoothly on these wider corners.

          On a track without , or with very narrow borders, a shorter guide lead may be beneficial, as for any given slip angle, a shorter guide lead car will use less of the tracks' width, therefore allowing it to slide at greater slip angles without running out of track room/falling off the edge.

          Definitely worth trying different guide leads on your track. !!

          Cheers
          Chris Walker
          Last edited by chrisguyw; April 2, 2021, 05:16 PM.

          Comment


          • #8
            It certainly is true there is no overall 'best' in almost all cases, context matters.

            I aim for 1/2" spacing of the guide pivot point in front of the front axle, with an overall guide lead of about 3 3/4" for my oval car builds. The preferred outside lane has a radius of around 18", which I would think qualifies as a wide turn generally speaking for a home slot car track. With 5 1/2' of room from the slot to the outer wall the cars have plenty of room to safely power slide thru the corners.

            My only experience with a car that had the guide pivot point behind the front axle was a Carrera Pontiac GTO which was terrible on my track. I felt it scrubbed off a lot of speed in the corners.

            Comment


            • #9
              Michael,

              Your pendulum analogy is a good one. You can think of a car having a 'natural frequency' based on the size of the guide lead. Shorter, faster. Longer, slower. The physics are entirely different, but like I said, an analogy.

              The impact of the front wheels, as you mention, has much to do with how much weight they carry. In many cars they carry little or none at all. But they also have potential to scrub off energy if they are carrying some weight. And they will scrub off more the farther they are from the guide.

              The whole business of damping and shock absorption is commonly underappreciated in slot car design. But it is vital. It isn't achieved with shock absorbers as such, but a good chassis design and car setup will provide ways to lose shock energy quickly. Floating weights, rattle pans, a loose motor pod and body mounts all help.

              Look up "Newton's Cradle". It illustrates how a shock can be transmitted through a series of masses. If a shock to the motor pod gets bounced into a slightly loose chassis and body, the shock energy gets transmitted away from it, and that energy gets dissipated.

              Ed Bianchi
              Ed Bianchi
              York Pennsylvania USA

              Comment


              • Michael Squier
                Michael Squier commented
                Editing a comment
                These reply’s are all very helpful. Confirming what I was thinking and answering unknowns. Of then you add in a new one, floating weight? 🤔 LOL, just one more thing to ponder as I mess with my cars.

                So far with my small fleet of older RTR cars I’ve found the simplest chassis’s seem to be the best. I have a small track with not so big curves, this all answers why my GBtrack Chevron is the fastest, even with its tiny guide it just won’t come off my track. No magnets.
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