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· Nobby Berkshire
1,987 Posts
Discussion Starter · #1 ·
These things are really nice to get into small cars, but they demand very small numbers of pinion teeth as they have little braking capacity so all depends upon gear ratio compensation.

I have a load of 1.5mm pinions for them, but the smaller you go in tooth number then the narrower the diameter of the pinion and the weaker the axlegear mesh is. I hate them! These motors are so flawed

And if you bump up the axlegear tooth number then most smaller cars these motors are in cannot take the extra size of the axlegear

I'm thinking of using normal diamter 8t and 9t pinions for standard motors to better the gearmesh, but does anyone have any advice about how to 'sleeve' the narrow 1.5mm motor shaft to get the wider pinion hole to fit?

All I can come up with is a sleeve of paper or bacofoil soaked in CA glue but this seems so crass and temporary.

Any ideas from experience and experimentation? Or any ideas based on guesswork?


· re member
5,199 Posts
MRRC do pinions in brass for slimline motors with the 1.5mm shaft. SRP 1112( 8 tooth) and SRP 1113 (9 tooth)

BWA offer pinions as well...I belive they are back in business but Pendle have the MRRC ones.

I thought Scaleauto did the 1.5mm pinions as well but???

· Registered
154 Posts
Remember that while you can get pinions to fit 1.5mm motor shafts, the problem is that pinion presses and pullers are made for 2mm motor shafts, just like the lateral locator slots on crown gears are made for 2mm shafts. So enlarging the shaft from 1.5 to 2mm by using a sleeve is the best route. Pre-cut sleeves exist, but it's far cheaper to buy longer stainless metric tubing from an industrial supplier, and cut it to fit, using a rotary tool. I got stuff from McMaster-Carr in the USA; I'm sure there are plenty of Euro sources. Just look for 1.5mm ID, 2mm OD, .25mm wall thickness.

There are 1.5mm gear pullers, made for R/C helicopters. Available online and from hobby shops catering to those folks.

Regular CA glue is not the ideal solution for press-fit parts like this; you'll be better off using bearing adhesive (a variant of CA glue, much like threadlocker). Soldering is another option, but you risk destroying the motor by applying too much heat.
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