Deore XT ST-M739 Brifters

[GT-TJR]

Question on these. I'm running a mixed brake set up on my RTS, kept the original Canti's on the rear and V's on the front. Currently using a travel agent for the front V brake to adapt the pull ratio of the short pull levers it came with.

I've seen in the Shimano instructions these XT lever have an adjustment block to alter the braking force. Being as these are V Brake levers, does altering this block to the high leverage position effectively convert these to short pull?

Any thoughts or experience on this would be much valued.

 

[GT-TJR]

Got me a set of these to answer my own question.

With the adjustment block removed from the lever and the cable anchor at its lowest point (closest to the pivot) gives you a radius of around 25mm. This is a bit to big for the canti brake. Meaning you don’t get great leverage and a weak brake.

I also found as you apply the brake the anchor roller runs back up slot and further reduces braking power. So I made little spacer to wedge in there and stop it free moving in the slot. Tacked then in place with some super glue.

After a test ride, still didn’t quite get the power I needed, so resorted to enlarging the slot closer to the lever pivot, with a round file. Now have a radius of around 23mm. And all is working well.

Can now happily run V front and Canti back.

 

[Prodigal Son]

Question on these. I'm running a mixed brake set up on my RTS, kept the original Canti's on the rear and V's on the front. Currently using a travel agent for the front V brake to adapt the pull ratio of the short pull levers it came with.

I've seen in the Shimano instructions these XT lever have an adjustment block to alter the braking force. Being as these are V Brake levers, does altering this block to the high leverage position effectively convert these to short pull?

Any thoughts or experience on this would be much valued.

The 739 is a vbrake lever. The adjustment affects the progressive x harsh feel of the lever. It´s not remotely suitable for cantis. The travel agent converts canti brake levers to pull v brakes, not the other way around.

 

[GT-TJR]

Have you actually read the full post before wading in?

I know they are V Brake levers. But by applying some engineering and thinking outside of the box, they can be converted to use with cantilever brakes too.

Shimano themselves on their modern Sora/Tiagra flat bar levers have a slot and a little chip to lock in two modes (see below). Long/short pull. I applied this same method to the old M379’s and it works. Job done.

 

[Prodigal Son]

Have you actually read the full post before wading in?

I know they are V Brake levers. But by applying some engineering and thinking outside of the box, they can be converted to use with cantilever brakes too.

Shimano themselves on their modern Sora/Tiagra flat bar levers have a slot and a little chip to lock in two modes (see below). Long/short pull. I applied this same method to the old M379’s and it works. Job done.

I was just trying to help since i have these levers and used them for 15 yrs. Good luck.

 

[ATBOY]

Have you actually read the full post before wading in?

I know they are V Brake levers. But by applying some engineering and thinking outside of the box, they can be converted to use with cantilever brakes too.

Shimano themselves on their modern Sora/Tiagra flat bar levers have a slot and a little chip to lock in two modes (see below). Long/short pull. I applied this same method to the old M379’s and it works. Job done.

Someone asked me this recently (Difference between Old and new paul love levers). I’ve tested canti/vbrakes using Avid ultimates, speed dials, LX M600’s. From my experience, what you have done has defo matched the same pull needed for cantilever brakes. From what I’ve read, it wasn’t intended, just like the previous poster said about the harshness of the braking. Possibly, and I‘m no expert, those spacers allowed for adjusting the progressiveness of the braking in other words. No doubt forum members on here have tested it way more than I have

 

[Spanky22b]

Ah the M739 XT V Brakes with the half moons in the levers and my testing technique is still fresh in the memory. Had them on preorder for the very first day they came out to be fitted on my bike. Then decided to do a basic test to see if they back up what Shimano says about the power compared to cantilevers.
All what was required for the test was my street my gate post a screwdriver and some chalk
The test was very technical in that i had to go to the end of my street (roughly 100 metres in length) and ride flat out to the gate post and slam both brakes on and mark where i stopped
First run with all the half moons in was done and stopped very quickly, and chalk mark put down,i was impressed.
Second run with the first lot of half moons removed resulted in a big difference to the first run, now i'm thinking these are the nuts.
And then the third run with all half moons removed, can these brakes get any better, surely not.
I line up and head down there flat out get to the gate post and grab both levers and the bike just stops dead and now i'm going over the bars arms out waiting for impact with the floor and one arm bends as i hit it the other doesn't and promptly puts my left shoulder straight out the back and dislocated it
As i was recovering for a few days after having the shoulder put back in i came to the conclusion that Shimano was correct about the power of them and that i should leave at least one half moon in the front brake lever from now on to calm it down a bit, it was a bit grabby