What spring tension or brush hardness should I use for older motors?

[McAnic]

I have some older brushed motors that I purchased used. On some of these motors, I can tell the spring isn't original and the brushes need to be replaced. The problem is there's no instructions or documentation and it's challenging to find old information online. The only thing I can tell is they use upright brushes. So my questions are:

1. Without knowing the spring tension or brush hardness, is there a standard or safe rule to go by when finding replacements for these older motors?

2. And for example, if I have a 12T motor, or a 17T, or 27T, can they use the same specifications for springs/brushes?

3. I see silver and copper brushes, should I even worry about the material?

4. Can I just use generic brushes, let's say from Tamiya for a 12/13T Reedy?

Sorry for the newbie questions. Thanks in advance.

[juicedcoupe]

For general use, I use a soft or medium/soft serrated brush with medium tension springs.

This seems to be a good balance for comm and brush wear, leaning a little more to limiting comm wear.

[matt1ptkn]

The harder the brush material, and the stiffer the spring, the faster the motor should run, but the commutator will wear out faster. Softer brushes and springs will prolong the commutator life at the sacrifice of performance. *Most 540 sized RC motors, that allow brush replacement, will use the same standard size brush, but some will be a "stand up" while some will be a "lay down". They will be the same physical size, but the concave brush surface will be cut on different planes. As mentioned, a medium spring with a copper brush should give good performance and longevity.

[juicedcoupe]

Here is a old Trinity brush chart. While you might not be able to find these exact brushes, it should serve as a good guide

[McAnic]

juicedcoupe and matt1ptkn, thank you for responding—this is very helpful and I really appreciate it! Just ordered some medium tension Trinity springs and will look into brushes.

juicedcoupe, thank you for posting that reference from Trinity! Looks like the standard and slotted copper brushes will work for what I need (since I don't race). And as you mentioned perhaps serrated if I can find one.

[juicedcoupe]

If you just want a basic serrated brush, check Tekin. They have brush and spring kits for standup and laydown.

If I didn't already have a stockpile of brushes, springs, and the tools to modify them, they would be my most likely choice.

Reedy, Team Brood, Jconcepts, and others still offer new brushes and springs as well. I recently bought a bunch from Integy that were marked way down.

[McAnic]

If you just want a basic serrated brush, check Tekin. They have brush and spring kits for standup and laydown.

If I didn't already have a stockpile of brushes, springs, and the tools to modify them, they would be my most likely choice.

Reedy, Team Brood, Jconcepts, and others still offer new brushes and springs as well. I recently bought a bunch from Integy that were marked way down.

I looked at the Tekin brushes (stand up hard) and looks like they’re for crawlers. Does it matter if I’m using it buggy?

[juicedcoupe]

If you just want a basic serrated brush, check Tekin. They have brush and spring kits for standup and laydown.

If I didn't already have a stockpile of brushes, springs, and the tools to modify them, they would be my most likely choice.

Reedy, Team Brood, Jconcepts, and others still offer new brushes and springs as well. I recently bought a bunch from Integy that were marked way down.

I looked at the Tekin brushes (stand up hard) and looks like they’re for crawlers. Does it matter if I’m using it buggy?

As long as it isn't a low turn modified, I wouldn't worry about it. I asked Tekin about it a while back, they said that they didn't see any reason not to.

[McAnic]

Thanks! Really appreciate it. I'm going to try the Tekin one.