Balancing ?

[Mike-]

I did a "search" and didn't find anything current.

Any of you out there take the time to balance your wheel/tires and gears ?
I know on most plastic tracks, the max. speed isn't that high, but some-many of you have wood tracks, like I do. I saw an old video the other day about balancing.

I remember back in the 60's we did balance our armatures (we did our own rewinds back then) and wheel/tires too, but we used razor blades as the axle plane, not magnets like today. Then it came to how well you leveled your block with the razors in it.
It made a notable difference on the long commercial track straights.

Mike

Note - this would fit in the 1/24 racing section too.

[Kevan]

I 3D printed a magnetic balancing block a few weeks ago and had a play with it but don't use it as the marginal gains made wouldn't be worth the time spent with our hard body 1/32 cars. To be honest it's just another reason new guys get put off and it's hard enough keeping the club going as it is.

[HO RacePro]

I printed an axle balancing block that uses razor blades. I included leveling screws and a bubble level. With the precision that filament printing achieved I thought the project turned out really well. I played with balancing axles a little, but then sort of forgot about it.

IMG_3291.jpeg

The effect of any significant axle/wheel/gear imbalance goes up with the square of the speed. Two times the imbalance means four times the eccentric load.

On the straights any imbalance increases drag in the bushings. If you use ball bearings instead of bushings that drag should be minimal.

In the corners, however, is where an imbalance is going to hurt you more. It will drive a tendency for the car to hop. Even if it is not severe enough to actually make the car hop it will upset the car's traction. What may save you is the fact your car will be going slower, and that square relationship will help a ton.

Before you spend any time worrying about an axle imbalance you really want to check out the straightness of the axle and the slop in the bushings. Either of those are far more likely to cause significant issues. Roll the bare axle on a glass plate. If it doesn't roll nicely, replace it with one that does.

Bushing slop? If you can feel it there is too much. To really check it out you need gauge pins and a micrometer. For a free-running axle in bushings two or three thousandths on an inch clearance is all you want. For ball bearings, none at all.

Ed Bianchi

[RichD]

For the rear axle assembly I locate the wheel and gear setscrews 120 degrees apart. If you put a car on a dynomometer and gradually increase the voltage if there is a balance or runout problem with the rear axle the car will want to jump around at certain speeds.

[Mike-]

I 3D printed a magnetic balancing block a few weeks ago and had a play with it but don't use it as the marginal gains made wouldn't be worth the time spent with our hard body 1/32 cars. To be honest it's just another reason new guys get put off and it's hard enough keeping the club going as it is.

Kevan -
I don't understand the comment. "New guys get put off". Get put off of what ? Doing a little work for a more precise running car ? Seems pretty counterproductive, not interested in putting in the work....IF that's what you mean. Where do the "new guys" put their tuning, or even learning (for that matter) limits ?

HO -
I like your razor stand. Understand all of the basics, and more ! One thing about the corners and being affected more. While true, the wheel rpm is also much less, so the effect will also be less. I'd see any out of balance at lower rpm's still affect the cars dynamics but to cause bouncing, at least in lower rpm corners. In high speed commercial track corners...yes absolutely.
Bushing (and bearing) slop, can be on both the ID. and the OD. of the bushings. I've seen cars with the bushings a very loose fit into the frame, and then yeah, the cars that have a super loose fit, axle to bushings. Especially the cars with splined axles. The bushing ID. has to be large enough to slide over the splines, then has a very sloppy fit at the axle. And even at slower speeds, yes, the axle just does a rotational about the large ID of the bushing, rather than an axial spin. But from what I've seen the better cars Slot.it, NSR, Thunder Slot and some of the others, the bushings and bearings have a reasonably good fit to the chassis and the axles fit within the bushings well.
Axle straightness, sure, that's a given. My quick and dirty method is the roll method. I do have a tool to check pushrod straightness for my race engines that uses a dial indicator, but haven't seen the need to try to use it for the slot car axle if the roll method works. I've tried replacing axles on cars that seem to have a bouncing in the corners problem, but so far to no avail. I've found that stiffening the chassis, or hot gluing the motor to the motor pod has so far been more effective, than tracing a bent axle. Not saying that a slight ben might do the same thing and possibly be helped by stiffening the plastic chassied cars. Hell, even the tires can help "hide" a slightly bent axle, being that they do act as a spring.

Rich -
Yes, I've done the same thig since I got back into slot cars. So far I haven't seen a problem. In my faster Group 12, Group 20, Gr.27 and even one Gr.7 motored cars, I use the hollow (drilled thru) set screws which helps a bit, along with the 120° rotation. In my plastic chassied cars, I just do the rotational spacing, and so far, nothing bad has been obvious.

Yeah, thanks guys, I was just a bit curious what others do.

Mike

[HO RacePro]

Rich and Mike,

One thing I have done is use two set screws per wheel or gear, on those where the set screw hole has been drilled and threaded all the way through. Not only does it help to balance the assembly, but it reduces the -- admittedly small -- chance of them coming loose during a race. Yes, a small chance, but it has happened!

Parts that have been drilled and threaded through are actually pretty common. It is actually easier to do that than to only drill and tap half-way. And if the manufacturer hasn't been so kind, it isn't that hard to finish the job yourself.

Ed Bianchi

[Kevan]

Kevan -
I don't understand the comment. "New guys get put off". Get put off of what ? Doing a little work for a more precise running car ? Seems pretty counterproductive, not interested in putting in the work....IF that's what you mean. Where do the "new guys" put their tuning, or even learning (for that matter) limits ?

Mike

We don't have the luxury of dozens of guys turning up every week, newcomers often see the work others put in and don't come back.
It's a small club and winning at all cost has long since stopped being any kind of priority.
Yes it's easy grains but when there's very few guys to prove yourself against its all a bit pointless.

[Slot Car Crazy]

Kevan -
I don't understand the comment. "New guys get put off". Get put off of what ? Doing a little work for a more precise running car ? Seems pretty counterproductive, not interested in putting in the work....IF that's what you mean. Where do the "new guys" put their tuning, or even learning (for that matter) limits ?

HO -
I like your razor stand. Understand all of the basics, and more ! One thing about the corners and being affected more. While true, the wheel rpm is also much less, so the effect will also be less. I'd see any out of balance at lower rpm's still affect the cars dynamics but to cause bouncing, at least in lower rpm corners. In high speed commercial track corners...yes absolutely.
Bushing (and bearing) slop, can be on both the ID. and the OD. of the bushings. I've seen cars with the bushings a very loose fit into the frame, and then yeah, the cars that have a super loose fit, axle to bushings. Especially the cars with splined axles. The bushing ID. has to be large enough to slide over the splines, then has a very sloppy fit at the axle. And even at slower speeds, yes, the axle just does a rotational about the large ID of the bushing, rather than an axial spin. But from what I've seen the better cars Slot.it, NSR, Thunder Slot and some of the others, the bushings and bearings have a reasonably good fit to the chassis and the axles fit within the bushings well.
Axle straightness, sure, that's a given. My quick and dirty method is the roll method. I do have a tool to check pushrod straightness for my race engines that uses a dial indicator, but haven't seen the need to try to use it for the slot car axle if the roll method works. I've tried replacing axles on cars that seem to have a bouncing in the corners problem, but so far to no avail. I've found that stiffening the chassis, or hot gluing the motor to the motor pod has so far been more effective, than tracing a bent axle. Not saying that a slight ben might do the same thing and possibly be helped by stiffening the plastic chassied cars. Hell, even the tires can help "hide" a slightly bent axle, being that they do act as a spring.

Rich -
Yes, I've done the same thig since I got back into slot cars. So far I haven't seen a problem. In my faster Group 12, Group 20, Gr.27 and even one Gr.7 motored cars, I use the hollow (drilled thru) set screws which helps a bit, along with the 120° rotation. In my plastic chassied cars, I just do the rotational spacing, and so far, nothing bad has been obvious.

Yeah, thanks guys, I was just a bit curious what others do.

Mike

I understand your reply, BUT, I have seen way to many times with the new to Slot Car Racing, to be so discouraged that they quit the sport as soon as they have started. The commercial tracks seem to cater to the lexan body cars and brass chassis and not to the RTR cars. The new generation of racers by the most part, have no desire to build or do all the tuning, they just want to have fun and be competitive. To grow the sport , the sport needs more RTR stock classes and or IROC. Starting kids out or new to the sport in a lexan, brass chassis is very intimidating and way over their skill level. Just my 2 cents.

[Slot Car Crazy]

We don't have the luxury of dozens of guys turning up every week, newcomers often see the work others put in and don't come back.
It's a small club and winning at all cost has long since stopped being any kind of priority.
Yes it's easy grains but when there's very few guys to prove yourself against its all a bit pointless.

Agree 100%!

Bob

[Mike-]

I understand your reply, BUT, I have seen way to many times with the new to Slot Car Racing, to be so discouraged that they quit the sport as soon as they have started. The commercial tracks seem to cater to the lexan body cars and brass chassis and not to the RTR cars. The new generation of racers by the most part, have no desire to build or do all the tuning, they just want to have fun and be competitive. To grow the sport , the sport needs more RTR stock classes and or IROC. Starting kids out or new to the sport in a lexan, brass chassis is very intimidating and way over their skill level. Just my 2 cents.

Ah yes, the computer game crowd..!

Too bad. People need (should need) the sense of accomplishment in learning the car, being able to both set the car up AND drive it. Understand the car, realize when something is amiss, other than when the car just...stops !
I feel sorry for those that just want to push a button or squeeze a trigger when they get into later life and have no clue as to how things work.
I'LL FIX IT...CALL THE "GUY" ! Or...YOU'RE THE GAS MAN, YOU FIND THE FILLER CAP !

Mike

[RichD]

This is getting off the original subject but several years ago Shoreline Model Raceways started to include one IROC style race on each race night. In addition we had loaner car available for new racers. I am not certain that doing those things helped much to attract and keep new racers. For me tuning cars to make them better is as much of the fun as the actual racing.

[HO RacePro]

The newbies most likely to stick are those who have been playing with a slot set at home and have already 'popped the hood' on their slot cars and started to tinker. You do need to offer them a gentle on-ramp. Loaner cars and controllers, and IROC races will give them a chance to develop their driving skills without being totally embarrassed on the track.

The loaner equipment needs to be competitive.

Once they start showing up with their own cars a bit of gentle mentoring is in order. Experienced help with setup, and maybe some driving tips.

But most of all the atmosphere must be friendly and encouraging.

One thing I don't think helps is a seasonal championship. I think that puts too much emphasis on winning all the races. Every race should be its own event. You can put a loss behind you and look ahead to the next race.

Ed Bianchi

[Mike-]

That's ok Rich, been off target for a few posts !

I'd bet that some, if not most of the non-interest in the mechanical side, is that they've never been exposed to it, in any manor.

Me, I grew up with my dad in the garage messing with the family cars. His factory hot rods, and keeping mom's car running well, was much more fun to him than a chore. So...for me watching ol dad do stuff, had my interest from before I cold see over the work bench !

My first indoctrination into slot cars was with the "reed" powered HO cars. What was I doing...messing with the reed angle, adding a second tire to the rear wheels for a "dual slick" arrangement on open bodied cars. Lightening the big full bodied cars. I remember a big Ford Galaxy that I had (geeze...I must be old to remember all this). There was only a couple of us that went to this hobby shop, at least the hours that I could go.
Then a few years later a full sized commercial shop opened near by. I learned to build my own frames, wind my own armatures, basically build my own cars. I'm betting that the computer kids of today would have little to no interest in all of that, and that's too bad. Beside being a LOT of fun, it also taught me a lot of different things in life. Beside the mechanical part of things, it taught me how to make friends, and deal with all kinds of people. The rich kids and the poor kids like me ! The older "adults" that were racing along with the younger kids that were there on a regular basis. It was a lot of fun.

Before I retired, I was asked a few times to "mentor" the younger set on work programs as they came out of college and into the work force. Except for a few, I was appalled at the level of these college folks that wanted into the Mechanical Engineering field. Their lack of basic interest, their lack of the basic mechanical skills that it took to complete the work that I was doing. Many of them just wanted to sit behind a computer for 8 hours. For MANY different reasons, that was NOT...going to get them a job in the Aerospace industry..!

I'm glad I'm older, I really don't want to see the world in the next 8 or 10 years.

Mike

[HO RacePro]

Mike,

Cheer up! There is a new generation of gear-heads coming along. They call themselves 'makers'. They do their designing on computers, and fabricate stuff on 3D printers and CNC machines, but the end result exists in the real world, and they have to learn how to cope with hardware as well as software.

In the slotting world they make 3D printed bodies and chassis, and a few branch out into custom scenery, tools and track sections. But once again they do have to assemble, test, tweak, modify and upgrade their creations in the real world.

Ultimately they have to learn about the old-school stuff, because not everything can be done with printing and CNC. Nuts and bolts, wrenches and torque, saws, drills, mills, lathes, soldering, brazing, welding -- all that stuff are still essential tools in the fabricating toolbox. These 'makers' soon find their way into the machine shop, and start to learn.

Yup, it is a new world. There have been new worlds ever since a hominid first picked up a rock. Ain't about to end now.

Ed Bianchi

[Mitch58]

Back to your original question, we also race mostly on wood tracks here in Portland. I replace the plastic wheels with metal set screw wheels on anything I plan to race. Then I true the tires on my machine, and it makes a huge difference.

Just yesterday I did this to a Fly racing series Corvette and it went from running like a stock Scalextric to a Slot It with only the heavier body holding it back a bit.

As far as balancing the motor I don't have the tools or skills for that. But it doesn't matter as much in an 18K motor as it does in my 1/24 cars turning 60K and those you can buy balanced.