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Rear Sprocket Plastic Fin.

Featured Replies

  • Author

Does anyone know what material these things are made of?

Mine is about 3mm thick on my 4rt.

I was thinking of using 3mm PTFE sheet, readily available on a well known auction site. Any good?

What do you think?

Does anyone know what material these things are made of?

Mine is about 3mm thick on my 4rt.

I was thinking of using 3mm PTFE sheet, readily available on a well known auction site. Any good?

What do you think?

I think it's (HD) polyethylene but PTFE should be fine.

Speaking as a toolmaker who now works for a plastics company the material is most likely polypropolene (PP) which is what a lot of the plastics on a trials bike are made of

I don't think PTFE would be strong enough. The ones I've made for my race bikes have either been PP, nylon 66 or carbon fibre sheet cut to suit, but that's mainly because I could get off cuts of them from work.

In reality anything will do the job but if it's likely to get knocked a bit it's needs to be able to give a bit without deforming permenantly. Personally for a trials bike I would try PP or nylon 66.

Edited by smokey125

You're right about PTFE not being the right material for the job, it's okay for a chain slider but isn't flexible enough to use as a shark fin, is more likely to snap the mounts off swingarm than flex

Have done one with polyethilene. 

It has a year now. Lot of scars but keep going.

 

 

CAM00804.jpg

  • Author

Just received a sheet of polypropylene, 3mm thick, ordered on line for less than a couple of quid, feels just like the original.

Cut out and shaped up a new fin tonight with enough spare for three more.

Fitted.

Perfect.

Thanks for the advice folks.

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