Fork Oil Seals

The internal tension spring on the rubber lip faces the pressure, the amount of rubber you see is just down to the makers design/manufacturing process and more rubber helps the sealing in some cases depending on application. Norton seals are single lipped, you can get ones slightly larger on the OD with an extra lip to keep any grit away from the sealing lip.

Whilst Mark's earlier query referred to Commando forks thesubject is relevant to all Roadholder forks, in my case it's a Wideline ES2. I also purchased a set of replacement seals from RGM and noticed after fitting that the chrome seal retainingrings did not seat correctly when screwed fully in, there being about a 1mm gap between the flange and the top of the slider. Iunfortunately damaged the fitting trying to over tighten it. On removal and examining the seal I noted the discrepencies mentioned by John above. The larger extended outer lip increases the height of the seal to approx 11mm compared to an original Norton one of 10mm. My options then to leave the gap or machine the equivalent off the thread of the chrome holders. For the time being I live with the former.

I have justreceived a set of seals from NOC spares in the hope that these might be original spec, but theyare the same as the thicker RGM ones.. I haven't yet tried Andover Norton but would expect the same. Does anyone please know of a source for the single lip seals mentioned by John above, or thoughts on cutting away the protrouding outer lip to allow the holders to seat properly without having to modify original metalfittings?

Photo below shows both seals.

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According to the factory drawing the seals should be from just under 11mm to just over 11mm high.

Ours look like the left hand (supposedly original) one but 10mm we cannot do for you. Ours are at the lower end of the tolerance. 10mm sounds metric, i.e. pattern.

The NOC spares scheme does not purchase anything from us, so rest asured what you buy from us is different to what you buy from the NOC spares scheme.

Joe/Andover Norton

Thanks for you input Joe, nice to know that you read the NOC forum and take the time and effort to respond to queries. Also appreciated the direct email from Ashley which I guess is not unconnected.

Your mention that your own seals look like the original left hand one in my photo, without the protruding outer rubber lip, albeit a tad higher, have lead me to order a full refurbishment kit from you together with a pair of new stanchions. Reassuring to know that they are purpose made and not just generic seals of approximately the right size.

The NOC Spares seals are identical in size and design to those I bought from RGM. I appreciate you don't supply the former but knowing that you do provide items to RGM thought these might likely be yours, clearly not in this case.

The 10mm one in my photo came off my 1956 M99 last year. I don't know the origin so it might well be metric/pattern as you suggest. It did however fit the retaining collars very well, the replacements didn't. The sizes I quoted werenot exactjust to highlight the 1mm difference.

My present requirement is for a 1959 Wideline Single project whose seals I have now measured more accurately as 10.61mm (photo below), probably near enough to your size to make little difference. I know these to date from at least 1975 and quite likely the originals fitted in Bracebridge Street some 59 years and 33k miles ago.

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I remember 20 years or so ago buying Commando stanchions from AN and bushes from RGM (why I can't remember now). The bushes wouldn't go on to the stanchions. When I measured both, the stanchions were spot on but the bushes undersized.