I have a fixed gear bike. I want install a tt handlebars, but I don't know it can install double brakes?
-
Not quite sure what you're asking here. Can you add a photo of your bike's bars as they are now? I guess you're wanting a second set of brake lever that can be actuated from the aerobars? – Criggie♦ Nov 25 '19 at 8:56
As long as you can find a way to physically attach the brake levers you want to use you should be able to install a dual brake lever system on your bike. There are so called 'inline brake levers' which you could use for this purpose, they don't require you to buy a brake line splitter which makes them easy to install. They look like this:
Alternatively you could use a 'brake cable splitter', something similar to this:
Another option:

The 'cable splitter' approach is needed if you want to use 2 sets of bar end levers, since these (to my knowledge) don't come in inline versions.
-
They are also called "cross brake levers" or "interrupter levers" depending on the supplier. – mikes Nov 25 '19 at 22:08