TIGER CUB WIDE SWINGING ARM

My bike has an 18inch, WM2 rear rim, it has a 4.1 tyre that states it fits in place of a 3.5, this is good for the purpose I intend to use the bike for, which is riding on sand and dirt, but it does create clearance issues that I will have to address as the project goes on.

Two things that can be done to help with the clearance issues is to use a wide swinging arm in place of the standard one. In the pictures below the wide arm has a straight right fork which starts at the width that the normal arm would end at. The left fork still gets wider the further back it goes, so if you lengthen the swinging arm it will bring the widest part of the tyre further back into the wider part of the swinging arm.

As far as I can work out there are 3 types of swinging arm for a Tiger Cub. Normal width, the 'competition cub' arm which is still the normal width but has a second set of mounting bolts lower down for securing the shock, this utilises an extra bracket, and finally there is a wide swinging arm. Anyone considering fitting trials tyres or wider rims on the rear of a Tiger Cub ought to use a specialist swinging arm such as a Sammy miller or one from Feked or source yourself one of the original wide swinging arms.

My plan is to lengthen a wide swinging arm and add the second lower mount and brackets to gain the best of all worlds.

I cut the ends off my wide swinging arm, fashioned extension plates and then welded these into place followed by welding the cut off ends back in place. As I wanted to retain the second shock mount feature of the original arm, I ground down the welds to allow for a bolt head on one side and the spacer on the other to lay flat. Next I had to mark and drill the holes for the bolts.

Weld lines ground down, bolt holes drilled, brackets test fitted, a little respray and job done.

Not quite done, I realised there was an extra bracket on this arm for a chain guard, as I wasn't going to fit a chain guard I cut it off.

The images below show the extra clearance afforded by the wide swinging arm in conjunction with bringing the wheel further back by lengthening the arm. The left two images are the standard arm.