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-   -   Tip: How to reduce the friction in LCC and LNC. (http://www.rccrawler.com/forum/team-losi-comp-crawler/414056-tip-how-reduce-friction-lcc-lnc.html)

Olle P 11-21-2012 03:57 AM

Tip: How to reduce the friction in LCC and LNC.
 
(Extracted from an older thread.)

When I first ran my at the time brand new LCC it was sluggish, weak (as in low torque), and in three minutes the motor overheated.
Obviously something was wrong!
It took me half a year to identify (and handle) all the sources of uneccessary friction in the rig. Now it's only the inherent sources (mostly the worm drives) that are left.

Here's what I've found, and how to handle it:

Lubricants
The LCC (excluding the motor) can do with only two(*) lubes:
1. A spray-on dry film lubricant (DFL) based on either PTFE (Teflon), which is great but expensive, or Silicone, which is good and cheaper.
2. A water resistant grease that can handle high pressure and beatings. "Marine grease" or something Molybdene Sulfide based will do nicely.

What to check
(Going from the motor out towards the wheels.)

1. Pinion.
The pinion should mesh nicely with the idler gear. With the pinion in place you should be able to rotate the idler a little (like 0.2mm or 0.01") without it touching the pinion.
Lubrication of the pinion, as well as all other cog wheels in the LCC, isn't necessary. If you want to do it use DFL. (Grease will attract dust and dirt, therefore dry lubrication is the way to go.)

2. Gearbox center plate. (LCC only)
The three screws holding this plate to the housing are typically drawn too tight, which cause an axial strain on the main bearings and thereby friction. The screws should be drawn all the way in, and then losened ~1/4 rotation.

3. Dig forks. (LCC only)
If you actually use the dig apply DFL (or a thin oil) on the dig plates where the forks run.
If you don't use the dig, remove the dig forks!

4. Drive shafts.
The joints do wear a bit. Dissemble and apply DFL (or just apply some thin oil without dissembling, risking dirt to stick and make the situation worse).
While you're at it, apply DFL to the entire exterior of both shaft halves to make them slide easier over obstacles.

5. Worm drives.
Make sure the spools are properly seated by pushing them side to side. There should be a hint of room to wiggle the spool between the bearings. Adjust by adding/removing shims if necessary.
Apply a liberal amount of grease. The task of the grease is not only to reduce the heat generated, but also to transfer the generated heat from the gears to the casing.
(It gets even better if you also replace the front drive with HD parts, since they have a different gearing causeing the front wheels to spin slightly faster than the rear. The difference in speed decrease friction while turning, which is what you do most of the time.)

6. Rear axle.
The long screws holding the rear hubs are often overtightened, making the spacer press against the bearings causing axial pressure and friction.
The proper way to mount the rear hubs, axle and bearings is to
a) place the rear axle (shaft) into position (inserted in the worm spool).
b) place a bearing at the inner edge of the hub.
c) thread the bearing and hub onto the axle and push it into position.
d) add the long spacer and the outer bearing to the axle.
e) mount the hub end by turning the screws all the way in and then back them out ~1/4 turn.
f) add the short spacer.

7. Wheel hexes.
In their standard shape the ring like "shim" on the inside of the hex will press against the bearings if you draw the weel nuts tight, causing friction and gradually wearing down the bearings.
The easy fix is to not tighten the wheel nuts.
A better fix is to grind off the rings from the hexes, like this:
https://public.bay.livefilestore.com...uts.jpg?psid=1
That way you can tighten the wheel nuts as much as you like.

Results
I've done all of the above, including removing the dig forks, and there's a huge difference compared to the original state!

(*) You will probably want a third, O-ring grease, to keep the shock absorbers fit as well. That's not so much about driving friction though and therefore out of scope for this article.

Charel 11-21-2012 06:26 AM

Re: Tip: How to reduce the friction in LCC and LNC.
 
Great info thanks "thumbsup"
I have done all of the above mentioned except the wheel hexes.
I read this thread before I got my LCC and was looking at improvements that I can do, while I got the rig striped as i got it second had, and was a service due.

I have noticed that the wheel nuts undo themselves rather quickly, especially in the rear, so I carry a wheel spanner with me the whole time and must probably tighten the rear twice in once 1300mha Lipo pack.
I was worried that I might over tighten them, but it leaves you no choice, you have to clamp down on them.

I will try to dremmel off the little ridge you are talking about, to see if I tighten the nuts then if the will still come loose.

Thanks again for the thread."thumbsup""thumbsup"

Olle P 11-21-2012 08:24 AM

Re: Tip: How to reduce the friction in LCC and LNC.
 
Quote:

Originally Posted by Charel (Post 4025539)
I have noticed that the wheel nuts undo themselves rather quickly, ...

There are two solutions for this common problem:
- Replace the nuts, every time you've removed them. (A pretty expensive solution.)
- Use thread lock. That's what I do.

losikid 11-21-2012 04:07 PM

Re: Tip: How to reduce the friction in LCC and LNC.
 
Get serrated flange nuts...

WAM 11-21-2012 06:15 PM

Re: Tip: How to reduce the friction in LCC and LNC.
 
What is your point on your "proper" assembly sequence of the rear hubs? If that's the right way to do it, what would be the wrong way? Just trying to see what you're getting at.

DRCrawlGood 11-21-2012 06:21 PM

Re: Tip: How to reduce the friction in LCC and LNC.
 
Wheel hex is a great idea, I can personally vouch for hanging up the axles by over tightening the wheel nuts.

Charel 11-22-2012 12:07 AM

Re: Tip: How to reduce the friction in LCC and LNC.
 
Quote:

Originally Posted by Olle P (Post 4025611)
There are two solutions for this common problem:
- Replace the nuts, every time you've removed them. (A pretty expensive solution.)
- Use thread lock. That's what I do.

Thanx Olle, I will try some thread lock, never used thread lock before on wheel nuts but will give it a go."thumbsup"

Quote:

Originally Posted by losikid (Post 4026202)
Get serrated flange nuts...

Thanx for the input losikid, can you please show me a pic of these nuts your talking about?

Olle P 11-22-2012 03:59 AM

Re: Tip: How to reduce the friction in LCC and LNC.
 
Serrated flange nuts grind on the rims every time they're tightened. Not too good in the long run, IMO...

Quote:

Originally Posted by WAM (Post 4026374)
What is your point on your "proper" assembly sequence of the rear hubs? If that's the right way to do it, what would be the wrong way? Just trying to see what you're getting at.

The key objective is to make sure the inner bearings are seated as far in as possible.

My way of doing that (Step B-02 in the manual) is to:
1. Take the shaft (A3184) and slide on the inner bearing.
2. Press the hub (A2030) onto the bearing, but only so that it "stick" to the narrow part of the hub.
3. Wiggle/turn/twist the shaft into position in the worm spool and push the hub onto the axle housing. With that push the bearing will be forced into the correct spot.
4. Slide the longer spacer (A3185) and outer bearing onto the shaft.
5. Slide the outer hub end onto the shaft.
6. Draw the screws (A6268 ) all the way in (making the bearings press at the distance, which is bad), and then unscrew them 1/4 turn.
7. Attach the outer spacer, pin and hex.

The wrong way of doing this is to mount the hub before sliding in the bearings, using the spacer to push the inner bearing into position.

KBrog 11-22-2012 10:06 AM

Re: Tip: How to reduce the friction in LCC and LNC.
 
Quote:

Originally Posted by DRCrawlGood (Post 4026378)
Wheel hex is a great idea, I can personally vouch for hanging up the axles by over tightening the wheel nuts.


X2. Had I know this info back then. It would have saved 2 or 3 sets of worm gears.

losikid 11-22-2012 10:27 PM

Re: Tip: How to reduce the friction in LCC and LNC.
 
Quote:

Originally Posted by Olle P (Post 4027034)
Serrated flange nuts grind on the rims every time they're tightened. Not too good in the long run, IMO...

I ran aluminum serrated flange lock nuts for 2 years with losi plastic wheels and a year with aluminum hubs...works great for me, and don't every back off.

losikid 11-22-2012 10:29 PM

Re: Tip: How to reduce the friction in LCC and LNC.
 
This is what i use

Traxxas 4mm Aluminum Flanged Serrated Nuts (Blue) (4) [TRA1747R] | RC Cars & Trucks - A Main Hobbies

Charel 11-23-2012 08:08 AM

Re: Tip: How to reduce the friction in LCC and LNC.
 
Thanx Losikid,

I have dremeld off the ridge of the hexes last night so will give it a proper work out this weekend, and report back on Monday how it held up.
I will first try them without thread-lock, and see, and if they still come loose, will pull the bottle out"thumbsup"

Anyone here have some thought about play starting to appear in the axles on the side shafts, I can turn each wheel about 5-10mm before they stop...?

dentonmac 11-23-2012 09:43 AM

Re: Tip: How to reduce the friction in LCC and LNC.
 
Quote:

Originally Posted by Charel (Post 4028437)
Thanx Losikid,

I have dremeld off the ridge of the hexes last night so will give it a proper work out this weekend, and report back on Monday how it held up.
I will first try them without thread-lock, and see, and if they still come loose, will pull the bottle out"thumbsup"

Anyone here have some thought about play starting to appear in the axles on the side shafts, I can turn each wheel about 5-10mm before they stop...?

Yes, that is from the spool teeth rotating in between the worm teeth. That very slight gap translates to quite a bit when you get out to the 5.5" wheel. This also increases with gear wear. Nothing you can do about that (other than regular maintenance cycles that will reduce the rate of wear over time), but couple things to check.
- Worn spool or axle shaft connection (not likely, but still possible over time)
- improper worm shimming

One way to check the proper shimming on the worm is to see if the driveshaft and worm move for and aft at the axle housing when you wiggle the wheels forward and backward. IMO there should be a slight movement, because if you shimmed it all out it would not be as free. If there is alot of movement, add a shim; if there is none take one out. I have found that it is OK to run odd number of shims (ex. 2 in front, 3 in back) depending on the wear on your housing.

Hope that makes sense.

Charel 11-23-2012 10:34 AM

Thanx for the input.
I have a strong suspicion it might be where the shafts fit into the spool.
When I hold both wheels an rotate the one till the play is out it then grabs the other wheel and rotate it a very small amount witch will be the play between the worm and spool, and that still feels vine. That is why I think it's by the spool an shaft where they join. But the only why to check that is to open the axel. Can the play between the spool and shafts be so much, or am I missing something?

Thanx for the help guys

Charel 11-23-2012 12:31 PM

Never mined....I'm a idiot...
After reading your post again, I went back to my Losi and checked thing over again, and your rite about it being the play between the spool and worm.

I held the two wheels again and turned them together after the slop is taken up, and I could see the worm pushing the drive shaft in and out, so now I see what you ment.
I think the play on the worm is acceptable but will keep an eye on them, and shim them up if need be.

Thanx for your post, I learned allot about my car with that.

pajey 02-23-2013 05:51 AM

Re: Tip: How to reduce the friction in LCC and LNC.
 
This is an awesome thread that needs to stay where everyone can see it;-)

z50king 05-18-2013 03:31 PM

Thanks for all the tips

Sent from my PG86100 with Tapatalk 2
I <3 Tekin

MattyJ603 07-17-2013 08:34 PM

Re: Tip: How to reduce the friction in LCC and LNC.
 
I started using DFL today on some of the parts you recommended. Not only did the truck stay cooler overall, but there was definitely less noise. Thanks. Plus using blue threadlock helps on the stock wheel nuts. No issues. Day one success!

dentonmac 09-26-2013 09:14 AM

Re: Tip: How to reduce the friction in LCC and LNC.
 
Quote:

Originally Posted by pajey (Post 4196604)
This is an awesome thread that needs to stay where everyone can see it;-)

X2, doing my part!

Wicked Monkey 09-27-2013 08:14 AM

Re: Tip: How to reduce the friction in LCC and LNC.
 
Sweet info in here. I'll be doing all this when I tear down/rebuild mine.


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