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Rollers Positions

Discussion in 'Beginner's Corner' started by Alex Soon, Jun 14, 2020.

  1. Alex Soon

    Alex Soon Screw

    Jun 1, 2020
    Likes Received:
    Hi all, I have 3 questions:

    Q1: Distance between front rollers and rear roller: I am thinking the further apart the front and rear rollers, the shorter the distance the car travel around a corner, hence the faster the car turns the corner. But this will make the corner a sharper turn and stability can be an issue. Is my understanding correct?

    Q2: Height of the front and rear roller: I know the lower the rollers, the lower the point of gravity, and hence the more stable the car. However, does this theory only applies to the bottom rollers or both the bottom and top rollers? In other words, should the top rollers also be placed as low as possible?

    Q3: Width of the car: I define width as the distance between the left and right fronts roller as well as distance between the rear left and right rollers. The wider the car, the more stable and its always a golden rule to max out the distance between the front/rear left and right rollers. Is my understanding correct?

    Thanks All.
    Last edited: Jun 14, 2020
  2. ltr74

    ltr74 FRP H-Bar

    Oct 17, 2017
    Likes Received:
    Torrance, CA
    Rollers closer together is actually better. The car will corner faster and stability in the corners is not really an issue. I don't have a good real life example of this but build a mini4wd and put the rollers as far apart as legally allowed. I would use the stock 13mm rollers as well as a stock motor for this test. Put it on the track and time it. Now, change the roller stays to the fully cowled pieces as close to each other as you can and time it again. The fully cowled pieces will be faster.

    Bottom roller as low as possible and a top roller of smaller diameter as high as possible, Using 30mm cap screws for the front and rear is the best option. Many people here just fo 30mm in the rear and 25mm in the front as the cap screws from Tamiya come with 2 30mm and 2 25mm screws.

    Yes, maximizing width is a very good idea. The only time I have ever run less than max width is with the blocking straights from 2018 Japan cup. The obstacle made the track narrower using little bumps that were very tough to get through. This is the track that really originated the front pivot and rear anchor designs and to some degree independent sliding dampers(though that was more 2019 Japan Cup). On our initial tests on a 3 lane version, I ran 17mm rear rollers with independent sliding damper to narrow the car slightly to more easily narrow the car to fit through the track. on the 5 lane version, you had to use Pivot and Anchor to get through with any speed.
    Alex Soon and Feroce like this.

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