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Dealing with slop: Is this something that everyone does?

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Dealing with slop: Is this something that everyone does?


Old 05-01-2017, 01:25 PM
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For ball cup joints there are a few different ways to take out the slop. Using an o-ring around the ball stud works but can cause a little binding. Many people use a piece of cellophane that you put over the ball stud when you snap the ball cup on. But this too can cause binding. I find the best method for me is to use cotton in the ball cup. This way you can add or subtract cotton to get the least amount of slop and have no binding.
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Old 05-01-2017, 01:30 PM
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No need to argue endless. We all know what to do. Take out slop just leave 1-2 tenth of a millimeter. But don't think you will go a lot faster, because you will not. A proper geometry will pre load the suspension. Even a TT02 will drive straight with all its slop in the steering. Still without slop the car will handle more consistent and a good driver will profit from that.
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Old 05-02-2017, 12:40 AM
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Originally Posted by Nerobro View Post
I'd love an explanation on how that could be? Any time you don't have control over a tire, you're looking at random tire behavior.

Tell me about your examples.

Now, I've also been bad, and tighened up things to the point they had binding. That is probally more detrimental than having slop. It at least makes servo behavior funny....
My F1 cars have steering slop, esp with a bellcrank setup where theres a lot of linkages and ball cups. Theres probably 5degree of play in my setup and yet I can run circles around anyone else on the track.

Another F1 car with a cracked front wheel hub. The wheel just flops around the shaft and yet it handles fairly well on the track.

My touring car with a loose lock nut which worked itself loose throughout the race. I didnt notice a thing until after i had the car back in the pits to find the locknut is holding on to a few threads.

Is slop good? Depends. Like others have said, some world class drivers intentionally add slop, but thats a whole other level of chassis tuning where the average weekend warrior doesnt have the time or resources to experiment with. I would worry about improve your driving line than perfecting a 100% slop free chassis. I few tenths of a mill here and there is fine, but if your talking about a few millimeter then I would look into replacing the part.

Its pretty much the same with suspension binding. I have reflex racing tell me they intentionally setup their 1/12 cars so the steering knuckle does not turn freely because having the servo overcome the friction is better than having slop. Another example is my ball cup and stud on my shocks, they bind a little and cant freely move, and yet I am able to consistently put down decent lap times.

What Im trying to say is, your driving has a way bigger affect on the slop and binding on the car. Im not saying all slop or bind is good, but theres no point pulling your hair out trying to eliminate every thing.
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Old 05-02-2017, 10:12 AM
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Oh, it's definitely not an obsession. It's something "I can work on when bored in front of the TV." :-) And dealing with slop has made going down the back straight a lot easier for me.

There may be a "like tires" relation as well. Low profile tires provide better feedback, but have lower ultimate limits of traction than do high profile tires.

.... I wonder how we could test this and take the driver out of the equation.
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Old 05-02-2017, 10:24 PM
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I would say that removing all the slop in a car is really only for someone who will meticulously clean their car after a handful of runs many. I went about removing most of the slop from my xv-01 with ultra thin metal shims. Worth it in the end because the car drives much more precise and predictable. The diffs are super smooth, the steering is very precise. However in the search to have 0 play in my suspension, no stiction and generous flop, after a couple of street runs I found that the arms started to bind because of debris from the road. Road grime built up an caused the suspension to stick. So with that I removed a couple of 0.2 mm shims and lived with a tiny bit of slop but now basically maintenance free.

If you want to keep things super slop free, shims and all, a drop of light oil usually does the trick it lubricants the joint, while pushing the crap out. Wipe clean then go driving. That little bit of maintenance might be all you need to run slop free. I think it's worth it. I can't stand sloppy mechanical parts.
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Old 05-03-2017, 03:26 AM
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Personally I use liquid lubricants as little as possible, except in roller bearings, as it is a dust magnet. I use powered graphite in all my ball cups and other suspension areas.
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Old 05-04-2017, 09:25 AM
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Yeah, removing slop to the nth degree is seriously OCD. I confess.

I guess it comes from insecurity about your driving. After many years of doing it all, I just gave up and live with the slop. Especially after realising that even a slop free car develops slop simply due to use in the next five races, so you're back at square one.

I think the key point is to start with as tight a car as you can get away with but then leave it alone after it is run in and develops its own flavour of slop. That's what I do anyway.

Running on carpet is a bit more forgiving when you have very tight tolerances, but outdoors I too found that grit and gunk would bind the car if it got where you don't want it.

One thing I do not tolerate is poorly machined balljoints. There is no excuse for that and I have expressed harsh critique against manufacturers who still have such crap in their $500+ kits (to much chagrin of the fanboys). You can however find the perfect balljoints and cups that have absolutely no slop, so there is no excuse for slop in steering, suspension links, etc. Brand loyalty doesn't always help here, so shop around.

Another problem is the bearing play which you simply can not take out. If you did, your car wouldn't move. There are high precision bearings but in that size they're not cheap, and if you get tapped, your expensive bearings are toast like the cheap ones. They do however serve to show beyond any doubt that your driveshafts are well undersized. Buyer beware.

Besides, our cars don't have any real power. A seized bearing will let you know about it. A bearing that drags will also let you know about it. Leave it sloppy.

The only thing I do these days is use internal spacers in the hubs so wheel nuts don't pinch the bearings. Other than that, if I don't have to duck when spinning the wheels, I consider it passable.

This philosophy does require some adjusting to taking readings on the setup station. I pull the wheels out and in when taking toe readings, steering throw, camber, etc. and check what is the range. If it varies not too much and around the same values left to right, it's a pass. My cars track straight as an arrow (as they did when they had no slop).

Oh, and by the way. I invested at some point in tool steel to make my own hinge pins. Guess what. That's the best way to find out the precision of your toy car's machined parts doesn't measure up to industry standards.

That, and tools steel is very brittle.

It will still take your suspension arms and blocks with it on the way out though. Bleah. Back to magic beans steel from toy manufacturers for me. At least that way, the suspension blocks survive.

Talking about suspension parts, I am yet to find a suspension arm with concentric hingepin holes. Don't tell me about any of the major manufacturers, 'cos I tried them all. None is a saint.

And generally speaking, manufacturing tolerances are about as reliable as the global economy.

And yes, I have shimmed a Tamiya mini within an inch of its life. Sits very comfortably and slop free on the shelf. Drives very well, but it's no race car.

Meh. Live with it.

Last edited by niznai; 05-04-2017 at 09:42 AM.
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Old 05-06-2017, 02:34 AM
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Off road cars have an incredible amount of slop.
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Old 05-06-2017, 04:47 AM
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The TRG 117 F1 instructions comes with a front slop adjustment to change steering "feel".
The adjustment is putting a set screw in the steering knuckle locking it with the kingpin.
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