Cross RC - Sloppy Diffs
 

Just picked up a Cross RC SU-4C.
So far its been a quality kit and a fun build.

Question to others with Cross kits...do the diffs feel "sloppy"?
May not be the best word, but there is certainly more play than in my SCX10.
Not side to side, but when you rotate the wheels forward and back.

Anything to improve that?

TIA

Re: Cross RC - Sloppy Diffs
 

I think you may need to shim either the pinion or the diff ring gear, or both. I don't own one of these rigs, but some slop is common among almost any of the RC axles.

Re: Cross RC - Sloppy Diffs
 

Basically the same tolerances apply to an rc as they do to a full size rig. They are far more amplified at 1/10 the scale though.

I've never seen an rc that didn't require some of shimming or adjusting, will definitely prolong the life of the gears and housing.

Re: Cross RC - Sloppy Diffs
 

So, it is shimmed properly.
The issues seems to be at the axleshaft - spool junction.
Lots of play between those 2 parts.

Re: Cross RC - Sloppy Diffs
 

Is the axle shaft a solid one piece shaft? If so, is the diff locked to it by pins?

I had ordered an Xtra Speed K44 axle set from Ebay for my 70 Blazer build. I ended up with a damaged pinion in the front axle and I found that, not only was it not shimmed correctly, but the hole for the pin the keeps the spool in place on the axle, was over-sized. In the rear, it was drilled correctly, but the front was so loose, it would allow the spool to rotate almost 2 pinion teeth. I found some brass tube that was correct for both the drilled hole and the pin. I don't know how long the brass will hold up, but if it fails, I have some 5mm steel rod that I can make a new one with.

Hope this helps.

Re: Cross RC - Sloppy Diffs
 

Ah, you could try flat shims but they'll most likely wear through eventually.

This has always bugged me too, pretty much the only reason I'd go aftermarket on the shafts, and I can't get a definitive answer on what would fix that slop.

Re: Cross RC - Sloppy Diffs
 

Im looking at a Cross RC kit, but unsolvable slop is a deal breaker. Id be willing to buy upgrade parts to get it tight if thats even possible.

Have you made any progress on this?

Re: Cross RC - Sloppy Diffs
 

If you watch the RC Review video, he discusses the excessive play in the Cross Demon drive train.

https://youtu.be/nyPU9g27IEc

Fast forward to about the 7:20 mark.