Converting Triumph T20 Road Frame To Tr20

[Prototype]

Hi Guys 

 

I would like to know . how to convert Triumph T20 Road Frame to TR20 specification

I believe swing arm will be wider/length .. Is there any changes required in the frame. 

if someone have some measurements that will be great.  any info will be helpful.

 

Regards

 

 

 

 

Edited May 6, 2016 by bsa4life

[brucey]

It all depends how much you want to spend, what skills and facilities you have and how much you want to modify the bike.  

 

Without knowing the above it's hard to say.  There are a number of companies selling modified parts.  I would suggest as a starting point looking at an aftermarket trials swing arm and footrest/back brake kit. Then cut unnecessary lugs off the frame and fit a bash plate.  

 

There are loads of photo's (including some of my Cub) in the pre 65 section somewhere.

 

I built my own Cub and widened and lengthened a standard swing arm.  My bike also uses a standard frame with strengthening gussets around the headstock.

 

Choose your budget and plan accordingly.  Have fun building it!

 

Hope this helps.

 

Bruce.

[goudrons]

As Brucey writes, it can all get a bit pricey and complicated.

Yes the swinging arm needs a bit of length and width as the original design was never made to fit such a large/wide rear wheel/tyre.

But this is only half the puzzle.

 

The wider tyre now gets in the way of the chain!

 

You now need to think about moving the sprockets out further.

The simple way at the rear is to fit a SM Products swinging arm conversion, it's wider, longer, comes with a chain tensioner, it also comes with a spacer to move the rear sprocket out from the hub. (doing this can give a brake plate issue later, but it can be sorted quite easily)

 

There are other ways, but they are a real headache.

One is to lace up the rear wheel so you get the right sprocket clearance, but you can't use a standard hub or you'll end up with one sides spokes at odd angles, the rear wheel will look like an open umbrella rolling down the road!

You really need to widen the hub to get the spoke angles even both side.

 

Once you have the rear sprocket moved over, you need to move the front over to match it.

 

Again another headache as there's little you can do to the front sprocket except move the engine over on the frame.

This requires you to move the front and rear engine mounts over slightly, but not too much or you'll not get the exhaust to fit the cylinder head as the down tube will get in the way.

 

It's all possible with a bit of trial and error and fitting up and tacking before welding up solid.

I did it and no one warned me before hand, it had me in tears, but I got there in the end!

 

Edited May 10, 2016 by goudrons