What pinion with Robinson slipper/spur

[SoCal_80]

My stock slipper died so I decided to upgrade to the Robinson slipper/spur. I bought a motor mounting plate that has extended screw slots but I can't get a pinion gear to really mesh with the spur. I picked up a 18 tooth and that almost meshes correctly. I am running a HH crawl master , thoughts on how to get this up and going? Larger spur? If yes, hoe bad will my final drive ratio be?

Thanks!

[Eric0424]

What size spur is on there now? You may be able to go up on the pinion and spur to stay close to the ratio you have depending on what spur gears Robinson has available.

[SouthernComfort]

48p or 32p

Make sure you get the Extra Hard pinion ..

[SoCal_80]

It is a 80t 48p spur from Robinson. Thanks for the help!!

[Eric0424]

80/18 = 4.44:1 (your current spur/pinion ratio)

84/18 = 4.66:1

84/19 = 4.42:1

87/19 = 4.57:1

87/20 = 4.35:1

88/19 = 4.63:1

88/20 = 4.40:1

I don't know what gears are available for the Robinson slipper, but if you have one of the above combos available it won't be too far from your current gearing.

[new2rocks]

Not sure what you mean by "how bad" the ratio would be. You typically want to be in the neighborhood of 5:1 spur/pinion ratio as a starting point on a Wraith. When I ran 48p in my Wraith, I used the 88t RRP slipper with 14-16t pinions and had no fitment issues with the stock motor plate. The downside is that I was burning through pinions about every 2-3 packs running a ROC412 3100kv on 3S. I switched to the 56t 32p RRP slash slipper and 9-10t pinions, and haven't had to replace a pinion since. So... my recommendation would be the 56t spur with pinions in the 9-11 range. Hope that helps.

[Eric0424]

Originally Posted by new2rocks

Not sure what you mean by "how bad" the ratio would be. You typically want to be in the neighborhood of 5:1 spur/pinion ratio as a starting point on a Wraith. When I ran 48p in my Wraith, I used the 88t RRP slipper with 14-16t pinions and had no fitment issues with the stock motor plate. The downside is that I was burning through pinions about every 2-3 packs running a ROC412 3100kv on 3S. I switched to the 56t 32p RRP slash slipper and 9-10t pinions, and haven't had to replace a pinion since. So... my recommendation would be the 56t spur with pinions in the 9-11 range. Hope that helps.

I assumed he just wanted to keep as close to his current ratio as possible.

[new2rocks]

Originally Posted by Eric0424

I assumed he just wanted to keep as close to his current ratio as possible.

Original post didn't mention what he had been running, only that 16t pinion was too small to mesh with 80t spur. Since 80/16 is already 5:1, going up in pinion size would mean lowering the ratio and maybe result in taller gearing than he'd like, depending on the rest of his setup and how far he'd have to go with the pinion. Implicit in my recommendation was that a taller spur (either 88t if staying 48p, or 56t if going 32p) would enable 5:1 and give more flexibility in choosing the right ratio for him.

[SouthernComfort]

With the RR steel slipper you need to run the RR Extra Hard pinions or you will burn pinions often..

[new2rocks]

^ Yes, and even the RR pinions didn't last long for me at 48p. I've had no problems with 32p gears. But that was a ROC412 on 3s being run hard. His setup might be different.

[Eric0424]

He stated 18-tooth pinion and 48 pitch in a subsequent post with the Robinson slipper and 80-tooth spur (which I took as his current gearing). Being a stock Wraith with 48-pitch gears it was most likely 80/20 to start with. Since he dropped to 80/18 (4.44:1) gears that will not mesh, an 84/19 (4.42:1) would be close and probably mesh together if 84t spur is available. If not not, Robinson does have an 88 spur and 88/20 (4.40:1) would still be close to the 4.44:1.

If he was happy with the stock gearing, then he could use the two combos below without altering his stock ratio. I'm assuming he wanted to drop a little lower with the new 18t pinion and 80t Robinson spur as the stock 20t pinion should mesh just fine with the Robinson spur.

84/21 = 4.00:1

88/22 = 4.00:1

[new2rocks]

My mistake on 18t vs 16t, but it actually bolsters my recommendation to the OP. To the OP: assuming 19t is the smallest pinion that would mesh correctly in your rig, the highest spur/pinion you can get is 4.2:1. My setup (ROC 412 3100 kv on 3s with Rock Beast 2.2s) gets hot at 4.6:1, so I keep it at or above 5:1. Without knowing the rest of your setup, my recommendation would be to get a larger spur (88t @ 48p or 56t @ 32p) to enable more options for usable gear ratios. You should still be able get down to 4:1 (or very close) if you really want, but a higher spur/pinion ratio will give you more options for volting up and/or running more powerful motors. And as between 48p and 32p, I'd recommend 32p for durability and longer pinion life.

[Dirty 'Yota]

Maybe I'm confused, but if the OP switched to the RRP Gen 3 slipper setup that uses the steel 80T 48p spur, there are no alternatives for that specific slipper? Except maybe the 2wd Slash 32p spur from RRP if it fits the Wraith setup?

[new2rocks]

Originally Posted by Dirty 'Yota

Maybe I'm confused, but if the OP switched to the RRP Gen 3 slipper setup that uses the steel 80T 48p spur, there are no alternatives for that specific slipper? Except maybe the 2wd Slash 32p spur from RRP if it fits the Wraith setup?

He can run the 80T spur with a pinion larger than 18t, but that means he can't get a spur/pinion ratio higher than about 4.2:1. The RRP slippers come as a package with spur and slipper. As far as I know, RRP does not separately sell just the spur piece to fit their slipper, so the easiest way to change the spur is to buy a new slipper package with the spur you want. The 88T version is labeled as being for the AX10 but fits the Wraith just fine. The 56T 32P slipper is actually made for the Slash 2WD but fits the Wraith, as well. The 32P Slash unit can sometimes rub the spur cover (if you use one) ever so slightly due to slightly less offset. If it does rub, it's easy to fix by either shimming the spur shaft slightly or removing the gear cover. Apart from those three options (80t 48p, 88t 48p, 56t 32p), I'm not aware of any other RRP slipper options that will fit a Wraith. Does that make sense?


Sent from my iPad using Tapatalk

[Eric0424]

Originally Posted by SoCal_80

My stock slipper died so I decided to upgrade to the Robinson slipper/spur. I bought a motor mounting plate that has extended screw slots but I can't get a pinion gear to really mesh with the spur. I picked up a 18 tooth and that almost meshes correctly. I am running a HH crawl master , thoughts on how to get this up and going? Larger spur? If yes, hoe bad will my final drive ratio be?

Thanks!

Considering you've already bought the slipper and pinion, you may want to just buy a small round file and open up the motor slots until you get the 18 tooth pinion to mesh. I see Robinson doesn't sell replacement/optional spur gears for their clutches. So unless there's another brand of gear that fits you're stuck with 80/20, or possibly 80/19 without reworking the motor plate.

Or you could try to exchange the 80 tooth Robinson slipper for the 88 tooth version to give you a few more gearing options.

[SoCal_80]

Thank you all for your responses.

Is it me or is it weird that Robinson sells this product for the Wraith however it really doesn't seem to support it (easily or much at all).

I am frustrated that I thought this bolt on upgrade has turned into somewhat of a cluster.

[new2rocks]

I understand. Out of curiosity, what is the rest of your setup? And are you considering any other changes (eg, motor, ESC, battery)?

[Eric0424]

Originally Posted by SoCal_80

Thank you all for your responses.

Is it me or is it weird that Robinson sells this product for the Wraith however it really doesn't seem to support it (easily or much at all).

I am frustrated that I thought this bolt on upgrade has turned into somewhat of a cluster.

I think it's a little odd they don't have optional spur gears for their clutch. If all you wanted to do was install their slipper with a stock ratio 20-tooth pinion it would have been easier, but most people change their gearing.

I converted my Wraith and SCX10 over to Associated V2/VTS clutches and gears, just made more sense to use gears and clutches I currently have that can also be used on my other cars/trucks.

[maslin]

Something is wrong if you can't get a 18t to meet the 80t spur. Aftermarket motor plates generally extend the holes the other way, to allow for wider spacing. Switching the motor plate back is probably all you need. You should be able to drop a 14t pinion in there easily.

[Dirty 'Yota]

I had trouble using an STRC motor plate and HR tranny case on my Wraith. I think the smallest pinion I could use with the 80t RRP spur was an 18t or 20t. Even after hogging out the motor holes and grinding the gear cover backing plate until the motor itself hit the tranny case, the smallest I can run is a 16t.