The lip goes to the bearing and the thrust bearing gets the flat side of the washers. And use Associated "Black grease" on the thrust bearing.

the little lip on the black plastic piece does go against the diff hub's outer flanged bearing. That little lip on the plastic piece centers it on the flanged bearing properly. The design intent is for the caged thrust bearing to ride sandwiched between the the two metal washers, and riding in the machined round bottom groove that is provided in one face of each metal washer. Having said that, I've found that the Slapmaster's diff's action is a little more free (albeit perhaps not quite as long lasting) if the flat face of the two metal washers faces the caged balls rather then the grooved side. Please note too that the hole in the middle of the metal washers is a slightly bigger diameter than the other washer. So the order of assembly is - black plastic spacer piece first (flanged lip resting against the hub's outer ball bearing), then the bigger hole metal washer, then the caged thrust bearing, then the smaller hole metal washer, then the adjusting nut. Happy motoring. The Slapmaster diff setup, while not quite as free spinning as a brand new plain bearing, is quite a nice deal because it does last pretty much forever without ever getting a crunchy feel.

+1 for the slapmaster setup. I also found using the Yokomo C3 thrust bearing is just as good. I use them in all my axle setups. I keep the Slapmaster as a backup in case of a hard crash.

How much steering lock do most of you use?

With a setup station I always try to get 21 degrees lock (at inner wheel) with the dual rate at 100%. On track I would adjust this if I need less steering, but I feel this only works to a point, anything less than 80 to 85% dual rate (maybe only 18 degrees steering lock) should be solved with car and tire setup.

Some tracks have so much traction that with I can only setup the car with max. 17 or 18 degrees steering to not griprol, front tires only applied 2mm of additive. With a touringcar I know what steps to take to make the car behave like I want. 12th scale and foam is somewhat new to me ;-)

I'd advise against the black grease. Treat the thrust washer the same as the main spur gear - very small amount of silicon grease on each ball and them assemble the diff.

The grease is only to help the balls roll in the cage. Black grease is to lubricate under high loads. That last thing you need is to lubricate the balls in the thrust washers - we want them to grip, not slide.

Yes, you may well get better performance from the diff is you use the washers the other way round. This build will give you more point load on the balls making it grip more with less end load. Also, there will be no friction between the balls and sides of the grooves as they rotate.

Providing the washers are hardened on both sides (they should be) this is worth a try to see if you get a better diff action. HTH :)

This is correct and should give a 3' to 4' turning circle

However, grip roll is not something I would adjust lock for, there are better ways to tune for that

High grip tracks demand small tires
39.5 Fr
41.5 Rr

FYI...Brian from "Slapmaster" told me to use black grease on the thrust bearing and to use the flat side of the washers while I was at IIC this year.
He has a detailed explanation as of why, so if the manufacture says to use there product this way why not. He also told me use steel diff balls and not ceramic. And this is what I have been doing per his instructions. My diff feels a bit better and last longer between rebuilds.

What are you hoping to achieve with 2mm stagger f-r? .5mm-1mm seems to be the normal trend.

Hey all, I haven't snooped on this thread in a while. Sure enough, I find questions when I do! It sounds as if answers were found by some knowledgable folks, thanks for the rescue.

I like to use the flat side of the washers vs the groove side. I tell customers that the thrust bearing will last at least 2yrs using the flat side. Well honestly, I don't know how long they will last. I have several that have racked up multiple birthdays and still perform as new. Occasionally I get a customer that has the thrust cage drop a ball or two. Contact me, I will replace them! Years ago, I used brass cages. Those could have a ball wear enough and could roll up on the cage, locking the system up. No good. I went to stainless retainers and it's been all roses since. The thrust washers are custom ordered with 4.15mm ID on both sides, so no need to go looking for the small or large ID like common thrust bearings have. I do use black Asc grease on the thrust, just a light smear. No need to pack it full. It's just for a little lubrication between the cage and the ball. It really does not serve a purpose to lubricate ball to plate as there is no driving force being applied there (like a spur gear). The thrust bearing does add just a little parasitic drag to the diff action vs a brand new hub bearing, but is far more durable. If you use the groove side, you increase that drag. I have asked my supplier if I could get washers without grooves, the answer was no. So look at it as "options".

The lip on the delrin spacer always goes towards the hub bearing. The delrin spacer is the spring. Some folks like to blend their old aluminum spacer back into the mix. Don't do that! It defeats the purpose of the thrust bearing.

Heads up folks!!!! Some axles are coming with 4mm threaded studs such as Xray and VBC. It's my understanding CRC will soon (if not already) be coming out with 4mm threaded studs. My black anodized nut is 8-32. If you try to use the black nut on your 4mm axle, it could gaul or cross thread, damaging both axle and nut. I will be including 4mm nuts as well as 8-32 in my future thrust kits. So pay attention!

Brian

One of my cars still has a brass one in it and still works like the day it was new.

Thanks for the heads up Brian, I have always used the grooved side in the past. I'm going racing this weekend and will switch them around to see how that feels.

Thanks Brian. Wow learning new things after this long. I have had mine in for 4 seasons and I had it with the grooved side to the balls next cleaning I'll flip it around and see how she feels

Yes 2 would be extreme for grip roll issues

Brian, thanks for the reply. I agree completely, and also about the drag you can get from using the grooved side of the thrust races. We'll agree to differ (ha ha) on the grease being used, but we do agree that there must be a light mount in the thrust race!

The old Corally thrust bearing came with flat washers, but they had a 7mm id to suit the Corally axle. That thrust bearing also had a plastic cage. Silicon grease was fine in that bearing and it also worked well.

Looks like we're getting a carpet track here in NorCal.. Yaaaa

Well I haven't run 12th scale in awhile and was wondering whats the current tire setup for 17.5, last time I ran was Black n yellows I think...:sweat:

Also any rollout suggestions for a track 90x48 to get me in the ball park.. :D

Thanks,