Problem assembling 6WD wheels from KOP

We’re a rookie team of a size like ten. We encountered this problem while we were putting on the wheels onto the chassis - the spacers seemed to wide that we have to use brute force to put them into position. Eventually when we put all six wheels on, the wheels do not lie on the plane. Three of the wheels make contact to the ground while the other three are about one or two millimeters above the ground.

So the questions are: 1) Is it normal to have to use force to put wheels and spacers into position? and 2) Will the wheels being on different levels be a huge problem?

Any help would be useful, Thanks!

The Kitbot is designed for “drop center” 6WD, that is the center wheels are 1/8" lower than the end two. This is done to making turning on carpet easier. Make sure that the center hole is indeed lower than the outer rails on both the inside and outer chassis rails. When our students assembled the Kitbot to start prototyping, they overlooked this and two of their chassis rails were upside down, meaning the drive shafts were crooked.

You shouldn’t have to use force to get the spacers in. Double check all the spacing and mounting locations.

make sure the bearing are pressed into the wheels properly sense the spacers will push against the bearings. We had to sand a little off the spacers to make them fit so that the wheels did not have any resistance from being too tight. Like the above post also mentioned, make sure the center holes are lined up with all holes on the bottom half of the frame rail.

I did notice that the spacers are a bit tight to get in there on a few of the axles. However, once assembled, this leads to a nice tight fit. The comment about drop-center is correct, the center two wheels and one or two other wheels should be touching (depending on how much stuff you’ve piled on your robot so-far).


I agree with the two posters above.

  1. Make sure your bearings are pushed in correctly.
  2. Make sure you have the frame members positioned correctly to drop the center wheel.**
  3. A little force won’t hurt on the spacers…

**my guess is that this one is what caused your problem…you might have 1 or 2 upside down…

We did a kitbuild here and it was a common problem

Also, be sure not to “mangle” the axles, as this will give you trouble every time you need to assemble/re-assemble. I’m sure that the response from artdutra04 will address your problem. You must also use care to insure that the assembly stays “square”. Use a framing square to keep it right. Good luck and enjoy your rookie season!

I think we might have had the rails installed wrong. I’m gonna check later tonight and i’ll post back. thanks for all your input!

There is also a video to help the assembly of the chassis.

There is also a video to help the assembly of the transmission too.

In our kit, some of the high-tolerance axle bolts shoulders also had “high spots” that interfered with the low-tolerance bearings. We had to file these down until the bolt slid smoothly thru the bearings…

Also, when tightening up your frame and axle nylocks, use an incremental pattern approach (like when you replace a flat tire); tightening one part/axle can affect the alignment/tightness of another, as you are actually stressing the frame parts, so “creep up” to/tune your final nylock positions…

In general, don’t assume the kitbot has great part interfaces; sometimes you have to do minor “repairs” or “enhancements”, depending on how you look at it…

Finally, don’t feel obligated to use nylocks for the frame; they are a pain, and regular nuts with spider washers or keps nuts are much easier to work with (and you will be taking it apart and putting it back together over the course of the build/competition season).