Watts linkage bearing/bushing

**nathanblaise** · 04-03-2021, 06:11

Hi all, hope you are keeping well in your part of the world.

Im just putting together an adjustable watts linkage and am having trouble making my mind up about the best bushing or bearing for the watts pin/swivel. I’m converting an existing English axle kit to chassis mounted. The original came with 2 thrust washers, but since I need to offset the swivel for nut clearance (not as much of a problem as I’m getting older) my thoughts were that I could either use a poly bushing affair like Gary’s or a couple of thrust bearings.

what I can’t decide is poly bush or thrust bearings - it’s a hillclimb/ track car so I was worried about the poly bushings being too compliant. Also I’m not sure it I use thrust bearings if it work ok from a tightening down point of view.

any insights appreciated - probably over thinking it. Cheers

**Graham** · 04-03-2021, 08:20

i dont know the answer but a couple of thoughts.

some times a small degree of flex in the system is a good thing, if you remove all compliance it can remove feel and give the driver very little warning of whats going on. a degree for flex can also be a good thing from the point of view that it reduces strain on components and welds, also if the geometry isnt spot on the suspension might bind up rather than move as intended.

**katana** · 04-03-2021, 10:57

Likewise thrust bearings like to be scrupulously clean - dirt or grit can 'freeze' them rendering them 'pointless'. Poly bushes can be obtained in fairly stiff consistancy but still allowing a bit of 'give' - and if necessary treat them as a service item and change every couple of years as they ain't very expensive?

**nathanblaise** · 04-03-2021, 11:39

Thanks both for the points of view. Yes I am definitely thinking poly bush with crush tube now - cheaper and simpler all round.

Like mentioned, can always be replaced if I think its becoming to worn.

Cheers

**nathanblaise** · 06-03-2021, 04:59

....and a follow up question haha. I was also considering making the watts adjustable from within the car. Now, assuming I have the screw in place and it travels up and down correctly how do I approach the swivel assembly. My current assembly would squash the swivel in place until there is no play (either bushing or oil less thrust washer). But does this approach need to change if I want it to move on the screw? My main concern is that if it’s loose enough for the screw to pull the assembly up/down does that make it too loose to work correctly? Cheers.

**katana** · 06-03-2021, 10:57

Originally Posted by nathanblaise

....and a follow up question haha. I was also considering making the watts adjustable from within the car. Now, assuming I have the screw in place and it travels up and down correctly how do I approach the swivel assembly. My current assembly would squash the swivel in place until there is no play (either bushing or oil less thrust washer). But does this approach need to change if I want it to move on the screw? My main concern is that if it’s loose enough for the screw to pull the assembly up/down does that make it too loose to work correctly? Cheers.

I don't follow your thinking! Why would you want to adjust a Watts linkage 'in use from inside the car'? Once the bars length is set - thats it, they pivot up and down, axle stays central. there is no more adjustment unless you radically change the height of the car to necessitate changing the body mounts to try and keep the bars roughly horizontal / parallel to road? Nothing should be getting crushed or binding - thats what the bushing / sleeve in a poly bush is for, likewise the rod eye ball won't allow any tighter than its width - so i'm confused?

**nathanblaise** · 06-03-2021, 19:29

Hey katana, it’s a type of adjustment for use when tuning or reacting to different conditions - effectively tuning the rear roll centre. Many of the chassis mounted items have peg types where you get under the car with tools and move the pivot up or down pegs. Many also have the pivot on a screw so you can adjust it without tools and from inside the car. It’s a luxury item but I know but technically not that difficult to make I would think so attempting one.

**katana** · 07-03-2021, 14:00

I've seen the alternative pivot holes but can't see something that is adjustable - without mechanical locking - being safe?
Its almost like having a tie rod with rod eyes at both ends and no lock nuts fitted - they will unscrew themselves!

**nathanblaise** · 07-03-2021, 18:55

Correct, I think what happens is that the whole assembly is move up and down so my issue would be an issue. Anyhow went forward with a basic one yesterday, got the 2 plates made and looks ok for what I want initially. Cheers

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**nathanblaise** · 07-03-2021, 19:19

Pic didn't come through

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**nathanblaise** · 09-03-2021, 07:37

So this is where I'm at. I have made an alloy spacer to keep everything in line but the spacer is not fixed - do we think that will be a problem with movement.at the moment the assembly is thrust washer, swival, thrust washer, spacer...