the oem vtr lines are one to two but when you get ss lines, they are individual lines going to each side, and this works much better. Don't know if this is the result of less expansion or separate lines or both.

 

It's simply a matter of increasing the volume of fluid in the system... It's not going to make any significant change on the road, and while i understand nath's comment, it doesn't work significantly better for most people...

On a racetrack, you work the brakes hard, with little cool down periods... So you need the amount of fluid to be larger, making it part of the cooling system for the brakes... That could make a minimal difference if you are doing track days, or like nath attacking canyon roads with 100% effort, but I honestly doubt it...

On track you also need to make a wheel swap easy, so having independant lines that you can move out of the way is a lot easier to deal with than a short line after a "T" or a line going across the fender...

In terms of actual performance, there is no difference at all between the two systems... Not measurable, or physically possible... Only imagined... The M/C pushes X amount of fluid, and the laws of physics say the pressure that creates is evenly distributed to both calipers, regardless of the hose configuration...

But comparing it objectively is a bit hard, since you rarely swap around lines, and swapping to any steel braided line is a great upgrade from stock... Especially with your old lines...

 

I went for simplicty on my bike, running one line down and jumping a line from one side to the other. That is essentially what had been done on a number of Kaw and Honda Supersports over the past few years. We did it on a side car Gold Wing back in 1990, actually using a jumper line to link the master cylinder on the bars to both the left and rear brake calipers - the bike was set up for a T-6 paraplegic.

Both the double lines from the master cylinder and the jumper set up eliminate the heavy manifold usually stuck on the fork triple clamp or some clunky industrial looking steel block and hard lines that stock bikes have.

The single line to the right caliper and the jumper line mean less line length than two from the master cylinder do, which would equate to a miniscule amount less flow resistance inside the lines. Yes, there is turbulence caused by fluid movement over the surface of a pipe or tube, but the thickness on the fingers of your leather gloves probably has more effect than that. The routing is extremely simple running one line down to the right caliper and one over the fender when compared to trying to get the path for the second line to the left caliper.

So the main benefit is a bit less braided line and a tiny savings in weight of the extra line and fluid. Of course you suffer the added unsprung weight of the double banjo and an additional washer. The routing is simple for the jumper set up, but may not look as trick to some. But then you get the points for the technical knowledge of why you have that line over your fender instead of running two down from the master cylinder, but then the bother of the questions.

If all this sounds kind of goofy and of little value, well other than the easier routing, it is. It's all mind games of little consequence for all but top echelon racers - and I'm not even sure it is to them.

I haven't looked at any of the bikes at the races lately. I'll have to look this year just to see what they're doing. Interesting.