Bar end mirrors.

^^^ I don't these will work on a late speed as the bars aren't hollow on the ends, they have a threaded insert in them.

 

Wouldn't the one that clamps to the bar end weight work for you?

 

I have those (blue tint ones) on my bandit, great mirrors swapped to these as past 100+ on previous cheap bar ends they would bend in and id have to keep folding them back to the right place. But these are much better.

 

My T100 had the threaded bar inserts as well, so when I fitted my bar-ends I took off the expanding wedge bit of the mirror (the bit that would normally go into the bar) and used the the supplied bolt straight into the insert. Worked like a treat and much quicker to install.

 

SpeedIII's are a bit of a pig, as standard there's no bar end weight just a thin ali cap that screws into a fixed threaded insert quite close to the end, so can't use the expanding collet type end weights or mirrors (unless you butcher the bars). Added to that there appears to be two different sizes of thread depending on model (or VIN?), my local dealer sent genuine Triumph mirrors but they were the wrong ones, the screw was bigger and shoulder on mounting bung was different.
They didn't have stock of the correct ones so I contacted Bevans, they checked via my VIN and sent the right ones. Impressed with their on-line / phone service, arrived next morning, fitted a treat.
Triumph bar-end mirrors are excellent quality (and still give good view), but bloody expensive. Tried some Chinese ones first, not so good (and didn't fit anyway) so sent them back....guess sometimes you get what you pay for.
Happy with my Chinese brake levers though!