Metalastic bushes

[rcs]

Does anyone know why Greeves used metalastic bushes in the swinging arms of the road racers? I'm guessing it was easier to use what was already in existence on the road/trials/scrambles models.

I'm struggling to see how it can be any advantage over a conventional bronze bearing, You would think the swinging arm would be subject to a slight twisting? Yet I have been told they handle "best" with the metalastics fitted.

[dave higgins]

It could be something to do with the fact that p/bronze needs a source of lubrication, a bit more involved on the production line, adding seals/ grease nipples etc, as well as cost wise i guess.
Another thought is that they do act as a slight buffering, to compensate for lack of cush drive on some models.

[druid]

Metalastic bushes

The 2 main advantages of Metalastic bushes are a) they are maintenance free (relatively) and b) they are somewhat self aligning, very handy on welded assemblies like frames where you can't guarantee to get the S/A holes in line after welding.
I personally prefer bronze or nylon bushes, at least you can remove the pins and bushes when you need to.

Druid

[Mike Norris]

TGS Anglian

Hello John.
The bushes on the banana forks on my Anglian are worn and I believe need replacement although it has today passed the MOT.
I have asked Terry Sewell and Steve at Villiers Services if they either have or know where I might get a pair but neither could help.
I hope that you can help.
Mike

[Rob]

Mike,

If you are talking about the metal bushes, these are standard items and can be obtained from a bearing stockist, eg. Brammer. If you need more info, let me know.

Rob

[Phil Hyde]

Banana bushes

If the white metal bushes are worn then chances are the pins are too. I believe Simon Bateman makes/stocks the hardened pins.

[Rob]

If you are an 'economist' like me, you can make your own pins from 3/4" ground stock. Case harden and away you go! The drawings exist for all of these parts including the 'wear plates' (shims).

[John Wakefield]

If you are an 'economist' like me, you can make your own pins from 3/4" ground stock. Case harden and away you go! The drawings exist for all of these parts including the 'wear plates' (shims).

Make your own, now thats a good point Rob, what has happened to the engineering skills. In my younger days just about everyone was 'hands on' if you could not work on your bike yourself then you did not ride as the cost of taking it to a dealer was prohibitive. In the 60's & 70's many people were still employed in engineering based industries, and had access to machine tools even if it was a mate working in the tool room or maintainance department. Many a 'foreigner' (home work) was done in the lunch hour or in firms time when the foremans back was turned. Bushes turned up & pressed in, cylinder heads skimmed, etc. Where have these skills gone?

[pluscab]

When rebuilding a set of girder forks I was told in no uncertain terms that using Silver steel was A BAD IDEA. Although ready finished and can be hardened it is not good for shock loadings, too brittle. Check the steel type and tempering if you make your own pins.

[John Wakefield]

When rebuilding a set of girder forks I was told in no uncertain terms that using Silver steel was A BAD IDEA. Although ready finished and can be hardened it is not good for shock loadings, too brittle. Check the steel type and tempering if you make your own pins.

Quite correct there pluscab, silver steel is a high carbon steel which when heat treated hardens throughout, & as you say can be brittle especially if not tempered enough. I think Rob was refering to ground mild steel which can then be case hardened to give a hard wear resisting outer with still a soft core. For girder fork spindles you need a high tensile steel.

[Rob]

Yes, quite agree. However, the bearings on the banana forks are retained with a bolt that takes most of the load. In girders, the spindles are everything. I tend to use En16T for anything questionable.

Agree with what you said about skills though John. My old metalwork shop at school was converted to 'technology', bending bits of coloured perspex! I still have a scar from my days there and I've always been careful with sheet metal since. No suing or parents involved then, just a trip to casualty in the teacher's car, a quick repair job (no 4 hour wait in those days) and back to lessons.

Anyway, my bananas have not broken yet!