Maintenance: Sanding rear tires/ Regrip

With one of these old Clutch Poppers, there’s a good chance the rear tires have become quite shiny. This means they will not grip as well to a surface, therefore not travel as well/fast or spin out if going too fast on a shiny surface. There may also be some rubbish embedded in there that it would good to sand out/even out. They are made of pretty hard wearing rubber, and a light sanding can bring them back to full grip.

So take a small piece of sandpaper (120 grit or so) and just hold the rear tire and sand it lightly to rough the surface, slowly moving the tire around around doing a bit at a time until it is all even. Do the same to the other tire. Then as an optional extra you can tape a piece of sandpaper to a bench, spin up the tires to full speed and then slowly lower them onto the paper evenly a few times.

Now the thing with doing this, as well as the other two steps (axles and lube), is that if the motor is still in proper working order, the car may well go very fast if it gets revved up to max speed, and that’s where you’ll see whether you need to address any of the next maintenance steps. This one is one of the main fixes/hacks that will help it stay straight(ish) going very fast on a smooth surface, the other is weight which I’ll do another post about.

5 replies on “Maintenance: Sanding rear tires/ Regrip”

Are you still planning to add articles on the other maintenance topics? I’m curious if you’ve had success adding counterweights to straighten a toy’s path.

Hi Brody, sorry missed this comment before. Yes was thinking about this today actually (adding a post), bit didn’t get a chance. Will put something together soon as have some good tips here I think. In a nutshell around 20grams (I find lead fishing sinkers are good as you can hammer them into a shape) added to the opposing side that the car tends to turn, add to either the side tray (right on the edge) or right in the front (in front of the axle right up by the bumper), stick in with blutack or similar so you can rejig if needed. The other thing you may need if they are running very fast on a smooth surface is a grippy runway for the first couple of meters or so, I find a pvc no-slip mat (like you put under a rug) works well. Now the thing is sometimes they are just going too fast and would take a silly amount of weight to correct any variation, and then they don’t run well at more standard speed, so there is something to be said for not trying to push them to absolute maximum revolutions/charge then set off immediately. In saying that my kids think its a blast when they go careering off at full tilt so go figure:)

Quick update on this – just had a go rebalancing a particularly fast and sensitive one (one I had foolishly added a teflon lube to the internal gears, which just made it run too fast), and found that 20grams added into each side tray, left and right, pretty much did the trick, still will curve off a bit at close to max speed but just pointing it on an angle helps with that. Will put together a post on it with a few ideas. Have you had any luck sorting your one out?

Thanks for the reply! I had tried securing a stack of about 8-10 dimes (interestingly, about 20-22 grams) on the opposing side to the pull direction and it made some difference, but I wasn’t very careful with the experiment. I wonder if this was helping with the balance or just slowing the curve through added inertia. What do you think?

I think its probably a combination of both, and from what I’ve found tinkering with these things (about 15 of them now!) is that they range, some go pretty straight just as they are, others veer off a bit, some spin out wildly, and weight (+grip mat if needed) fixes some of those that curve badly. But the complicating factor is just how fast those wheels turn, which magnify small variations both within the motor & axle and the surface that it is on. Honestly I think they could have reduced the speed output transmission by a bit and still would’ve been plenty fast!
Anyway I did a bit more playing with this in the weekend, and made another discovery (I think), and its to do with the back wheels and whether they move from side to side very much. They all do a little, but if there is quite a lot of movement this could be source of the problem for some of them. Inside the motor, on that axle, there is a brass gear on the right that stops the axle moving any further that way, and a brass ring on the left that stops any movement that way. Now what happens (I think) is that over time and many heavy crashes, those two pieces push against the steel framing and move it (just a tiny bit with a heavy hit), after many of those you now get a slightly bigger gap between the brass piece and the steel wall – the effect is the wheels move more side to side. So I took one (the one I mentioned before) that had this problem and tried to push the walls back together a bit (had to drill the motor out again), a very not-scientific process that involved a vice and pliers:) and after a fair few tries and thinking I had totally stuffed it for good, got the gap closed to normal (there is always some small movement), and it goes great now! Anyway I think I definitely will do a post about it now as needs some pictures to get these ideas across! I would not recommend the drilling out and pushing the side walls in unless the car has serious issues (and is therefore worth a go) though as I still haven’t worked out a safe/reliable way of doing that. Hope that helps!

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