X-5 squared shredded belt and pulley!

[YoungChazz]

I'll try to clarify one thing: 3209 remains the standard Kit belt, even in the Squared. We use it because of its length -- it's shorter than 3213.

As posted in another thread, we're using 3213 with the Double Pulley Upgrade Kit (OP 040). The big pulley is to the front, and the belt simply goes around the outside of both just as Chris says. With two pulleys and extra wrap, the longer 3213 belt fits correctly.

This is actually amazing to me -- I've never seen a belt shredded like this where the problem was other than the rear diff pulley. The more I think about it, the more I suggest a VERY close inspection of the rear diff pulley. What usually happens is the problem starts there. The belt rubs against the pulley flange and a filament comes out of the belt which wraps itself around the slipper shaft, and the belt is toast. When the filaments wrap around the shaft the belt stops abruptly, but the shaft, under power, does not, and the pulley melts, sometimes with the sonic welded flange coming off. But the problem always starts with the rear diff pulley. Not saying yours did this, but most are like this.

It is important to get the belt running in the center of all pulleys. I suggest shimming each individually to get them right. Drive pulley is EZ to move, and the idler(s) can be moved by shimming the bushing or sanding a bit of aluminum off. Diffs can be moved using Losi outdrive bearing shims.

Check it by running the car on your Turbo 35 or other charger with the bottom cover off -- you can easily see everything that way.

[Fiddybux]

Hey thanks YoungChazz...that is exactly what happened to mine.

There were loads of belt fibres wrapped around the tension pulley and the drive pulley
was completely melted (and yellow!).

Tonight I took all the diffs out and the flanges have weakened and partially come off on both of them, and furthermore they seem a bit wobbly.

I've dismantled the diffs and they seem fine (not melted), but when put back together and tightened up the diff pulleys wobble slightly when you hold the outdrives and waggle the pulley. Is this normal? I don't recall checking this when I built the car? I'm hoping they are supposed to be like that and act just like the slipper does to run true under power. Don't get me wrong its not flappy and wobbly, you have to push it a bit, but its not that hard to make it wobble either. Their currently soaking in white spirit to get everything cleaned up.

I also noticed that I may have neglected to shave the plastic burs off the diff pulleys, so this could in fact have caused the belt to get chaffed up and ruined. So I'll be seeing to this as well

Anyway, lessons learned. What a mess though!

Final question (for now!!), what are these white diff pulleys that I've seen - the ones I have are black?

Cheers.

[Chrislong]

Hey Russ,
The diff pulleys are meant to wobble, its because it cannot be wider than the diff balls otherwise there would be no diff action. Therefore, the diff does move, but its right.

The black pulleys are the new ones, the material changed last year and the old gears were white (or more beige), the new black ones are the ones you want to use.

Chris

[Fiddybux]

Cheers there Chris. Glad to hear its normal for the diffs to wobble. Unusual though.

As for the flanges coming off, I guess more glueing action is required to put the flanges back on.

Another (final thing, promise...at least for tonight) - are these LOSA3039 DIFF DRIVE RINGS & SHIMS or is it the LOSA6230 Shim Set:3/16,1/4,1/2 that I need to shift the diffs left and right so the belt runs in the dead centre?

[Chrislong]

Nope, its not usual either, LOL. I think the B4 diff has little pips to reduce it, but any 4wd has the wobble, less things to touch = freer diff.

Im not sure about the shims, you'll have to have a look on the dreadful new Losi website for the CR manual, LOL. When shimming, do test it with the belt off though, as too many shims puts side load on the bearing which stops it spinning.

Chris

[Fiddybux]

I'll take a chance on some shims then next time I put an order in. Or I might try Lesro tomorrow.

I agree the new Losi site is rubbish compared to the old one. They've changed their packaging too - no more yellow and blue / green, it's all grey and red now like the website.

[YoungChazz]

Fiddy: REPLACE all your pulleys. Don't muck about with this. Throw the old ones away! You only want to go through this once...

Our #5100 pulleys have been black for more than a year now -- for the last production run we had some black material so we used that. Previous ones were kind of biege.

The white ones are the D.D.P. CNC machined pulleys available from us or Lesro. Dialled!!!

[saw]

i ended up running the green xxx4? belt with a xx4 center and rear diff pulley with the lesro one way up front and my drivetrain was golden all year long. the best thing i did was use two idler pulleys and i made a idler bearing that kept the belt on the center pulley. that allowed me too run a looser belt. the stock stuff may work fine but i trashed two complete stock drivetrains, until i ralized my chassis had a flaw in it that let the spur gear run crooked. after that i decided to run the wider belt.

jim mann