RC Car - Rear Toe, Shims, and Ball Ends

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Rear Toe, Shims, and Ball Ends

Comments: Awesome.. thanks... I'll try balancing the car out.... HPI didn't mention anything about that. It doesn't look like you can modify the rear toe of the car... but it looks like the rear wheels are toed in... I also noticed that the pins holding the rear drive shafts are not snug against the wheel bearings... would you recommend adding some small washers to make sure the wheels don't flop around?
Also... it seems like the ball joints in the steering have give... uhm...you can move the front tires about 2mm without moving the servo... think that could be a problem? can you buy ungraded ball joints?

Thanks again for your help.... hopefully I'll see you at the races this summer.

Response: I'm glad my last advice helped. As for the rear toe in, it may not be adjustable but it definitely must be there. Without rear toe in, your car would be almost undrivable. The rear end would be all over the place. Rear toe offers a much more stable feel to the car under acceleration (this is very important when huge ponies are applied out of a turn).

You can add shims to the rear axles to help remove some of the slop but don't over do it. If you add too many shims it will bind the bearings and rob your car of power. This could also cause one tire to stop before the others as we discussed earlier (your braking problem). Also keep in mind that when you tighten your wheels on your car, the little pin on the axle goes right inside the hex and most of the time, the hex takes up any excess slop. You want a small amount of side play in your axle.

Loose ball joints are a common problem (a few of my racing friends will not reuse a ball joint once it has been popped off, they feel if it has been popped of it is going to be sloppy and a new one is required). You can try to replace your ball ends with new ones (Robinson Racing sells a ball end with a set screw to remove end play). Some drivers also install an O-ring on the steel ball before snapping on the ball cup. This works very well at removing slop but you had better have an amazing servo to try this. It causes excessive binding in the linkage. If you are running a good servo (such as a fet servo) with 100 plus ounce inches of torque you will be fine with this method but if you are using the stock servo, don't even think about it.

Let's take off a few tenths per lap,

"PRO"
Pro Racer Secrets