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  • Ball Bearings

    I have only recently gotten into 1/32nd scale racing. I have been building my own cars -- because -- I'm into building my own cars.

    I've been using ball bearings I purchased on eBay for minor money, knowing full well that they are not first-quality. But they were cheap and they ARE ball bearings.

    Now I'm considering paying a whole lot more for ball bearings, trying to up my game. But I do have questions.

    I have been using flanged, open ball bearings. And I have not been oiling them. Why? Oil is viscous. Even light oil will create some drag. Bearings operated without lubrication will wear out sooner, but there is a long tradition of racers abusing equipment to gain an edge. Use 'em up and replace them -- that's my strategy.

    And open bearings? Those seals may also create drag. Yes, sealed bearings will exclude most dirt -- but maybe not all. Open bearings can freely admit dirt, but can also expel it. Oil can catch and hold dirt -- hold it right where you don't want it, in the race. Ideally open, dry bearings will expel any dirt that they collect. That's the theory.

    I am willing to swallow hard and pay high bucks to buy quality, sealed and lubricated bearings if they'll perform better. Will they perform better than cheap, loosey-goosey eBay bearings? Since they are lightly loaded, I wonder.

    Then, of course, there is the option of lubricated bronze bushings. Cheaper yet and dirt simple. And, if nicely toleranced, maybe a better option overall.

    We wonders, yes we does.

    So spill. What's your experience? Your thoughts?

    Ed Bianchi

  • #2
    There are plenty of dry lubricants available that will make your bearings last longer but not add drag. Check your local bike shops for dry chain lube.

    Comment


    • #3
      Originally posted by HO RacePro View Post

      I have been using flanged, open ball bearings. And I have not been oiling them. Why? Oil is viscous. Even light oil will create some drag. Bearings operated without lubrication will wear out sooner, but there is a long tradition of racers abusing equipment to gain an edge. Use 'em up and replace them -- that's my strategy.

      And open bearings? Those seals may also create drag. Yes, sealed bearings will exclude most dirt -- but maybe not all. Open bearings can freely admit dirt, but can also expel it. Oil can catch and hold dirt -- hold it right where you don't want it, in the race. Ideally open, dry bearings will expel any dirt that they collect. That's the theory.

      I am willing to swallow hard and pay high bucks to buy quality, sealed and lubricated bearings if they'll perform better. Will they perform better than cheap, loosey-goosey eBay bearings? Since they are lightly loaded, I wonder.

      Then, of course, there is the option of lubricated bronze bushings. Cheaper yet and dirt simple. And, if nicely toleranced, maybe a better option overall.

      We wonders, yes we does.

      So spill. What's your experience? Your thoughts?

      Ed Bianchi
      In red above.
      1. In my 20+yr. history in Aerospace as a Senior Test Engineer, no, most if not all foreign debris will almost instantly (at the rpm's that "C" sized motored cars run) be ground into the inner, and outer race by the balls. If debris enters the bearing assembly, it will most likely get caught up in the spinning balls. At any sort of race speed (rpm), no debris would be going fast enough to enter, and miss the balls, and then exit the assembly. The race damage may or may not instantly create additional drag...but will get worse over time (time at speed...unknown), including the creation of drag.

      2. Correct, in the testing that I've ever done or have been a part of, sealed bearings DO create drag. BUT...I have never tested the bearings this small as fully sealed. Even axles that rotate VERY slowly...drag is noticed. So the faster and or higher load, I'd bet money that any sealed bearing even of this size will create drag.

      3. In open bearing configuration, a fine powdered graphite or dry Moly lube may be of some advantage. But would be best as..."run-in" before a major race, then "lightly" be blown clean with a LIGHT blast of clean air.

      Have fun.

      Mike


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      • #4
        I have only recently gotten into 1/32nd scale racing. I have been building my own cars -- because -- I'm into building my own cars.
        Ed, can we assume from this that you're fabricating the chassis from brass, rather than modifying manufacturer's existing plastic chassis?

        So spill. What's your experience? Your thoughts?
        My experience is essentially with re-building manufacturer's cars, using better components. And for this, improving the existing bushings - which can include replacing them with ball bearings - can make a dramatic difference; but it will be part of a process of ensuring chassis or pod stiffness (the vital thing being to perfectly locate the motor and the rear axle in conjunction, whilst using fine spacers to reduce drag). This will of course also include modifying/improving all other aspects of the chassis from the guide to the gears. Perfection is demanded when you're using bits of lead weight instead of magnets, as any faults in re-construction of the car will be clearly revealed by the lap times.

        So I've experimented with sealed ball bearings, as well as axle tubes and similar nifty concepts, and it's been well worth the investment of $$$ and time to make it run right. And although they've never been an SCI Advertiser, I would encourage those interested in 'tune-up stuff' to check out Sloting Plus and their various offerings.

        But in a properly set up brass framed car, I'm not at all sure that an actual ball bearing will perform any better than an Oilite bushing. Good thread.

        Comment


        • #5
          I think that at 1/32nd scale, any drag created by ball races over bushes is so minute, that a 16th turn different in a front wheel height setting, a difference of a hundred RPM between two motors of the same type, an un-noticable difference in pod screw settings corner to corner, a fractional difference in gear lash, a speck of dust on a tyre, or a 1/100th of a second inaccuracy on the trigger finger in one corner of a heat; are all far more relevant in improving or impairing lap times. - Along with all the other tweaks we try and optimise, (and the 50 more the ChrisW does as well )

          I think it is a bit like the old argument of the Victorians about "how many angels can stand on a pin-head"

          I've been using cheap RC bushes for several years, and now using the Slot.it ones - which I can't tell apart; and they seem to give an improvement over using gimbal bushes with their 0.02mm manufacturing tolerance/runout/slop.
          But between bearings.... just cannot see the advantage.
          And lubing. I lube - I don't want a bearing to heat up and seize during a race. I use a low viscosity oil.
          Most cars only get run one race night a month, but I am et to wear out a ball race after a few years.
          Last edited by SlotsNZ; 02-04-2020, 03:56 PM.

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          • #6
            One thing about ball bearings is that they are not usually as fussy about alignment as solid bearings are. You do not want the axle to be loose in the bearing, but you do not want the axle to be a tight fit either. A meticulous person would use a set of pin gauges to determine the ID of the bearing and then use a drill blank axle to match. If the size match is correct the alignment of the two bearings can cause binding, using spherical bearings eliminates that problem. If you are using regular bearings they should be aligned, Slot Car Corner sells a bearing alignment kit for that purpose.
            Last edited by RichD; 02-05-2020, 07:43 PM.

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            • #7
              Actually the 1/32nd cars I've been building use printed parts made of PLA plastic. That, and phenolic perf board. All those little holes in the perf board makes it easy to bolt things together, nicely aligned.

              By RichD's definition I am a meticulous person (really?) because I have and use pin gauges and drill blanks. I also have a set of reamers in inch sizes. All are very valuable and useful tools for setting up slotcar mechanicals.

              Wanna these days I'm going to have to add sets of metric pin gauges and reamers. Same reason.

              A decent set of pin gauges ain't at all cheap, but they are one of those lifetime investments you'll learn you shouldn't be without. There is no other good way to measure the ID of holes, short of an optical comparator. You don't have the budget for an optical comparator, trust me.

              And a set of reamers is just the thing to make sure a hole is properly sized and round. Also, they are exactly the thing you need to make sure two holes are precisely aligned, so long as the business end of the reamer can fit through both of them at once.

              I have been thinking more about open ball bearings, and how to keep junk out of them. It has occurred to me that a pair of flanged ball bearings set into either end of a brass tube would be held square and also protected from debris, at least from one direction. Mount those in a frame that has clearance holes, just a tad bigger than the axle, and they will be well protected from the other direction. And that without any drag.

              Lubrication would be difficult, but if the bearings are run dry, not an issue.

              This would be perfect for sidewinder or anglewinder service. Not really suited for an inline setup.

              The problem here is the tube has to clear the motor, and there is precious little room for it. Nuts.

              This gets me back to my concepts for an idler gear twixt pinion and spur. A fussy bit of machinery and possibly lossful. But it has the potential to add braking power. I leave the proof of that as an exercise for the student.

              Another work-around is to use a timing belt drive. Timing belts small enough for slotcar service exist. You have a big choice of tooth counts and they are not expensive. Suitable pulleys are more of an issue. I've been working on that.

              Timing belts also have the potential to add braking power, and it is easier to achieve than with an idler gear. Play with that concept if you will.

              Dang it! These things are toys! They shouldn't be that complicated!

              Ed Bianchi

              Comment


              • #8
                Originally posted by HO RacePro View Post
                ..................................................
                By RichD's definition I am a meticulous person (really?) because I have and use pin gauges and drill blanks. I also have a set of reamers in inch sizes. All are very valuable and useful tools for setting up slotcar mechanicals.


                Another work-around is to use a timing belt drive. Timing belts small enough for slotcar service exist. You have a big choice of tooth counts and they are not expensive. Suitable pulleys are more of an issue. I've been working on that.

                Timing belts also have the potential to add braking power, and it is easier to achieve than with an idler gear. Play with that concept if you will.

                Dang it! These things are toys! They shouldn't be that complicated!

                Ed Bianchi
                Most of that stuff is available off the shelf as part of Slot.it's 4WD system, including one way cammed drive to make cornering more effective.

                Comment


                • #9
                  Originally posted by SlotsNZ View Post
                  Most of that stuff is available off the shelf as part of Slot.it's 4WD system, including one way cammed drive to make cornering more effective.
                  Perhaps related, I see that Scaleracing have introduced a metal chassis for the Slot.it Nissan & Toyota Group C cars, with other potential adaptations.

                  I wonder if they're going to come up with an AWD version soon?
                  Last edited by Wet Coast Racer; 02-05-2020, 04:55 PM. Reason: Fergot something

                  Comment


                  • #10
                    All Wheel Drive and a timing belt drive are not the same thing. AWD still uses gears to drive the rear axle. The timing belt takes power from the rear axle to drive the front axle.

                    A timing belt drive replaces the gears with a timing belt and pulleys. The front axle does not get driven. Or at least it doesn't need to.

                    With AWD the two pulleys can be the same diameter and tooth count. In a timing belt drive you need to have a reduction ratio, so the pinion pulley -- mounted on the motor -- needs to be considerably smaller than the driven pulley -- mounted on the rear axle. Sourcing the pinion pulley is the issue.

                    I have printed versions of both pulleys. But I haven't actually tested them yet. It's on my To-Do list.

                    An anglewinder setup cannot use a timing belt drive. An inline setup won't work either. Your only option is a sidewinder.

                    One advantage of a timing belt drive is it gives you great flexibility in where you put the motor. It allows you to fine-tune your weight distribution without adding weights. That is something I intend to experiment with. It is just possible that different tracks could favor different weight distributions. Swap the belt, shift the motor, and you'll probably have different handling. Another way to tweak your car.

                    Ed Bianchi

                    Comment


                    • #11
                      Originally posted by HO RacePro View Post
                      One advantage of a timing belt drive is it gives you great flexibility in where you put the motor. It allows you to fine-tune your weight distribution without adding weights. That is something I intend to experiment with. It is just possible that different tracks could favor different weight distributions. Swap the belt, shift the motor, and you'll probably have different handling. Another way to tweak your car.
                      Theoretically, being able to shift the weight balance by moving the motor location seems like a useful idea, if it can be solidly located in the pod or chassis.

                      Personally, I have my doubts. But then again, I had my doubts regarding Smokeio's Audi AWD (using essentially the same setup as the Slot.it AWD chassis). The darn thing is, that home build sidewinder/pulley system worked so darn well it still holds the lap record on my track.

                      Comment


                      • #12
                        I remember that car, it worked well in an early proxy series, but it required a different driving technique than regular rear wheel drive cars.

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                        • #13
                          Originally posted by RichD View Post
                          I remember that car, it worked well in an early proxy series, but it required a different driving technique than regular rear wheel drive cars.
                          Indeed, it outscored almost all cars in the 2008 RAA. From memory, Mike (aka Smokeio) used an SCX Audi body (very wide) on an HRS chassis; and I think the OD of the front wheels/tires was marginally greater than the rears. That meant that a technique of late braking into the turns would cause it to fly into the scenery due to the front braking effect, but early braking and then steady throttle through the turns allowed it to corner faster anything else. Ingenious, but one did have to re-learn how to drive to get the most out of it.
                          Last edited by Wet Coast Racer; 02-07-2020, 03:08 PM.

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                          • #14
                            I have been messing about with BB as well - but to a different end. I'm experimenting with using them to produce independent front wheel rotation by machining a recess into the wheel to take the body of a flanged bearing, So far, the bearing/wheel and axle/bearing attachments are via Loctite - seems to be adequate.

                            EM

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                            • #15
                              Originally posted by Ecurie Martini View Post
                              I have been messing about with BB as well - but to a different end. I'm experimenting with using them to produce independent front wheel rotation by machining a recess into the wheel to take the body of a flanged bearing.
                              What kinda chassis is that going into? It would be interesting to know your setup.

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