Inline gear mesh question

[Mickey thumbs]

Is it better to allow the groove on in the crown gear to ensure gear mesh or should you use axle spacers to hold the mesh? If spacers are best, should you go ahead and trim the motor shaft to eliminate friction with the crown groove? I hope this question is clear. The wheels are set screw aluminum, not plastic press-ons.
Gears are slot.it.
I must add that this post was triggered by an answer to a gear noise question on another forum, SFI. I wanted to bring it to a broader audience for more discussion. Sorry for the initial lack of attribution.

[Busterfla]

I usually use set screw axle collars to ensure that the motor shaft does not touch either side of the groove of the crown gear. As far as cutting off the motor shaft after the pinion, I usually don't do that for two reasons (1) The shaft acts as a fail-safe in case the axle collar slips and (2) it allows me to remove and reuse the motor in another car if needed.

Buster

[Mitch58]

I have had other racers tell me that they use a spacer and cut off the end of the shaft to cut down friction in the corners. The shaft doesn't fit tight inside the gear, there should be a bit of slop. I have built them both ways and cannot tell a difference. It would seem to me that the collar rubbing in the corner would cause the same amount of friction.
Buster is right about cutting off the shaft limits the use of said motor

[Slalom4me]

More food for thought

If the resources are available, widening the slot/groove in the hub of the crown is a low-consequence option. No need for a collar, only the crown is altered, the motor remains unneutered and ready for action in all other pairings. Not all racers will have the ability or means, but some will.

Reducing the diameter of the armature beyond the end of the pinion until there is adequate clearance with the slot in the crown hub (and good mesh between pinion & crown) offers a different solution. This modification to the motor can be achieved by anyone possessing basic skills and hand tools. No need for a collar. The motor/pinion pair remain suitable as is for use with alternate crowns in this and other other IL applications. Motor suitability for AW/SW applications is not affected.

[Mikeinclover]

Scaleauto actually makes their inline crowns as a 2 piece, the gear and the motor guide part are separate. So you can use the motor if you hand but also set your mesh lash, or you can just install the gear and use stops or spacers.

[HomeRacingWorld]

Yes I have used the Scaleauto and they work just fine.

Scaleauto Crown Here

[Slalom4me]

Scaleauto actually makes their inline crowns as a 2 piece, the gear and the motor guide part are separate.

A 2 pc crown gear will make adjusting mesh after pinion swaps much simpler.

Thank you.