Nylon Race Washers - Talk to me about them.

[Tazio]

I know about the nylon race washers that fit between the A frame and the de-dion, in fact they are the only ones mentioned in my old build manual.  My query is, on the Caterham Parts website, it states that you require 16 of these on the rear suspension, so where are the other 14 fitted?, as I said there is nothing in my build manual about them.

Alan

[Jonathan Kay]

https://caterhamparts.co.uk/fixings-other/1438-nylon-racing-washer-shim-175-x-32-x-1.html

"16 used on the rear & 12 on the front suspension"

i don't know: have you used the button to "Ask an Expert"?

Jonathan

[ECR]

I guess wherever the suspension loads are sideways which is pretty well every joint in the rear suspension. Every where there is a pivot point?

I've only ever heard of them being used at the a frame/dedion joint though

[John Vine]

I suspect it's a typo, and that CC are really referring to the chamfered spacer washers used on front lower wishbones and the A-frame forward mounts.

My 2008 kit included two nylon washers, and the Assembly Guide stated:

JV

 

[Tazio]

Thanks everyone for your inputs, much appreciated, I suspect like JV said, it's either a typo, or a subtle attempt to increase spare parts sales revenue lol.

Alan.

[22daz]

Tazio, I bought a pack of 10 on eBay for the price of two from CC.
 

I could also get two washers into each side which I assume would work better than one washer being chewed up from each side. 

Nylon washers 30x17x1mm

22daz

[ScottR400D]

#6 why didn't you just get 2mm thick washers?!

[Tony P]

When I've fitted these in the past, they were supplied in two sizes - the smaller ones fitting the forward bushes of the rear radius arms and the forward bushes of the upper front wishbones. The implication here, surely, is that you fit them everywhere.

[raw]

I wouldn't bother, most I have seen recently, particularly on the A frame to Dedion centre bolt have had massive holes worn in the middle and thus are contributing very little.

Andrew

 

[7 wonders of the world]

Rose joint is a much better solution....

[22daz]

I figured that the metal A frame and Dedion would try and chew up a single washer from each side, which could be the reason they don't last long.
Using two means they at least have a chance of sliding over each other.

22daz

[rkeywood]

'Race washers' generally fitted on all the 636 and 2030 bushes front and rear to pack the bush so the outer length is closer to the inner, in the same way as you'd fit the nylon thrust washers on a Powerflex bush. A standard 636 has a bore length of 35mm and outer length of 32mm.

[John Vine]

Very interesting thread. 

I bought some nylon washers recently, but when I went to fit them, I found the gaps between the sleeve of the metalastic bush and the A-frame arms were occupied by small washers:

I have no idea how they came to be there.  I certainly didn't fit them during the build (2008), and can only assume that either CC did it during some chassis repairs or Millwood during a service.

When the joint is fully tightened, they have the effect of extending the length of the sleeve.  They don't appear to interfere with the operation of the bush at all, or affect road behaviour in any way.

Any thoughts?

JV

[Drakman]

Hi John,

 

I had the same set up on my 2014 factory built Roadsport. 

Did the bolt that goes through the De Dion  mount have washers under the bolt head and nut?  Mine didn't, I assumed that the washers had been placed in the wrong location so i put them under the bolt head and nut.  I made up some graphite impregnated nylon washers to replace them. From memory the OD was 37 mm so much larger than the steel washers.

The steel washers were a perfect fit to slip inside the De Dion mount.

 

Dave

[John Vine]

#14  Well, I certainly didn't fit washers under the bolt head or nut when I built the car (as per the Assembly Guide - see #4).  I'd need to check whether there are any there now.  I'll have a look when I'm next under the car.

[ETA  If yours was factory-built, perhaps that's the way CC did things then.  My chassis repair was in 2014.]

CC's nylon washers are 17.5 x 32 x 1.  Mine are 17 x 30 x 1 from RiCo Plastics, so I'd need to enlarge the hole a bit.

JV

[Geoff Brown]

Strange...the only fitment I know of for the nylon 'race washers' is interposed between de Dion & A frame. Otherwise it is chamfered metal washers or packing washers elsewhere on the suspension points.

JV #13 - No metal washers required there !  Surprised that your car did not feel a bit 'loose' at the back end or indeed emit any strange knocking noises ? 

[John Vine]

#16  Yes, Geoff, I was surprised to find them.  But there are no ill handling effects or knocking noises.  The washers are clamped tight between A-frame cup and the DD bush sleeve, and they're a snug fit on the bolt.  No room for movement really as they simply extend the length of the bush slightly.  When I next see Eric at Millwood, I'll ask him.

JV

[Geoff Brown]

Going back to my second Seven in 2000 even that had nylon race washers interposed.

My first a 1994 1.4K Supersport had none & no steel washers interposed.

Strange....very strange.

[John Vine]

On 11/07/2023 at 10:57, John Vine said:

#16  Yes, Geoff, I was surprised to find them.  But there are no ill handling effects or knocking noises.  The washers are clamped tight between A-frame cup and the DD bush sleeve, and they're a snug fit on the bolt.  No room for movement really as they simply extend the length of the bush slightly.  When I next see Eric at Millwood, I'll ask him.

JV

Well, I saw Eric last week when I took the car in for a service. He said he'd seen several like that, and has even fitted some that way himself.  He agreed with my suggestion that the washers simply extend the length of the bush inner.  All encouraging.

JV

[aerobod - near CYYC]

Hi John,

The hole in the nylon washer should be big enough to just fit over the bush inner steel core in my opinion. If it is trapped between the bush core and A-frame cup, it will be difficult to maintain the correct torque on the bolt. The washers should fill most of the gap between the deDion mount and edge of the cup, as opposed to pushing the cup further away from the deDion mount by trapping some of the nylon between bush and cup.

[ScottR400D]

23 minutes ago, aerobod - near CYYC said:

Hi John,

The hole in the nylon washer should be big enough to just fit over the bush inner steel core in my opinion. If it is trapped between the bush core and A-frame cup, it will be difficult to maintain the correct torque on the bolt. The washers should fill most of the gap between the deDion mount and edge of the cup, as opposed to pushing the cup further away from the deDion mount by trapping some of the nylon between bush and cup.

This. The nylon washers are  just to prevent metal to metal contact as the A frame moves relative to the DD as the rubber in the bush flexes. They don’t go on the bolt. 

I can see how small washers as shown earlier might help by increasing the flex possible before contact, ie by forcing the A frame apart a little bit. Not sure that's good or not for the bush. 

The nylon set up limits how far the bush can be stressed without metal to metal contact. The metal washer way doesn’t. 

A question may be “does a 7 create enough side load on the bush to damage it if it’s not supported by the A frame and DD touching, albeit trapping the nylon washer?” If it doesn’t then the metal washer idea is fine. I guess most owners don’t push that hard even if it’s possible. 

Edited September 11 by ScottR400D

[John Vine]

Just to be clear, I'm not referring to the nylon race washers.  It was when I went to fit those that I discovered the small metal washers.

JV

Edited September 11 by John Vine
Add photo

[ScottR400D]

Another thing occurs to me is that if the metal washer was the correct way to go, why not just make the A frame ends 1mm longer? 

The ‘race washers’ seems to me the better solution, albeit they need changing daily frequently, though that’s quick and cheap. 

[aerobod - near CYYC]

3 hours ago, John Vine said:

Just to be clear, I'm not referring to the nylon race washers.  It was when I went to fit those that I discovered the small metal washers.

JV

I see John. This seems to be to allow more lateral movement without contact between the deDion and A-frame, perhaps for a more road-biased setup without the race washers.

For a significant amount of track use I have found the nylon race washer setup inadequate, as the bush is too flexible and tore on my car even with the race washers. My solid spherical bearing solution fixed that issue. For road use the spherical bearing also doesn't seemed to have introduced any extra harshness, as the A-frame and deDion still have rubber mounts to the chassis, even if they don't have any rubber between each other.

[ScottR400D]

10 hours ago, aerobod - near CYYC said:

I see John. This seems to be to allow more lateral movement without contact between the deDion and A-frame, perhaps for a more road-biased setup without the race washers.

For a significant amount of track use I have found the nylon race washer setup inadequate, as the bush is too flexible and tore on my car even with the race washers. My solid spherical bearing solution fixed that issue. For road use the spherical bearing also doesn't seemed to have introduced any extra harshness, as the A-frame and deDion still have rubber mounts to the chassis, even if they don't have any rubber between each other.

Odd that the bush would tear when the whole thing goes solid with the race washers in, James, though I guess your use is as tough as it gets. The metal washer solution probably wouldn’t last long at all in your case.