Custom Di2 build
hero0bun
Posts: 2
in Road general
Hi Dear BikeRadar community members,
I have been trying to figure out a way to set up a Di2 system on an unique TT bike.
The question began with the brake system.
Front: TRP TTV Aero TT Brake: linear pull
Rear: BR-5810-R : caliper brake
So, I needed to use different brake levers for each brakes.
Because there is no choice, I bought a pair of V-Brake lever (TTLVR) knowing that I would not use one side.
Now, I began wondering on shifting.
Option 1. If I buy a Single Di2 lever (ST-6871, which has two buttons,) could I shift up/down front/back Di2 R8050 derailleurs via their synchro-shift?
Option 2. I could shift using a brake lever: ST-R8060 and SW-R9150. Each of them has single button. I have called Shimano USA and they said basically "a switch is a switch".
These buttons will be connected through Junction A: SM-EW90- (A or
(3 or 5 connections).
Shimano USA did not explain at all but I am assuming that "a switch is a switch" means that I could customize the switch configuration via a software "E-TUBE".
I was wondering if there is anyone who have been through the same situation and figure out the solution.
Thank you so much
I have been trying to figure out a way to set up a Di2 system on an unique TT bike.
The question began with the brake system.
Front: TRP TTV Aero TT Brake: linear pull
Rear: BR-5810-R : caliper brake
So, I needed to use different brake levers for each brakes.
Because there is no choice, I bought a pair of V-Brake lever (TTLVR) knowing that I would not use one side.
Now, I began wondering on shifting.
Option 1. If I buy a Single Di2 lever (ST-6871, which has two buttons,) could I shift up/down front/back Di2 R8050 derailleurs via their synchro-shift?
Option 2. I could shift using a brake lever: ST-R8060 and SW-R9150. Each of them has single button. I have called Shimano USA and they said basically "a switch is a switch".
These buttons will be connected through Junction A: SM-EW90- (A or
(3 or 5 connections). Shimano USA did not explain at all but I am assuming that "a switch is a switch" means that I could customize the switch configuration via a software "E-TUBE".
I was wondering if there is anyone who have been through the same situation and figure out the solution.
Thank you so much
0
Posts
Shimano Di2 has TT switches for the aero extensions and a brake levers with built in switches to operate the derailleurs. One operates the rear derailleur, one operates the front derailleur.
Maybe I'm missing something here, but building a TT bike isn't that difficult. Plenty of TT bikes have TRP brake callipers and don't need special brake levers. Plenty have Di2.
This is what I was puzzled first.
It is not recommended to mix "Standard pull" and "Long pull" systems.
• Standard pull: These are designed to work with caliper brakes (as found on a BMX or road bike) or with traditional centre-pull cantilever brakes (as found on Cyclo-X bikes).
• Long pull: These work with direct-pull cantilever brakes such as the v-brakes found on many MTB bikes, as well as MTB cable disc brakes.
Their lever ratios are different so that you will not have a good brake control with a "Standard pull" lever and "Long pull" V-brake. All Shimano Di2 levers are "Standard pull" and Shimano specifically stated that these levers can't be used with "Long pull" V-brakes.
Of course, if you have strong grip, it may not matter.
That's one thing.
What I'm hoping to achieve a kind of a "hack" due to this need.
When Shimano upgraded their Di2 system, they introduced "Synchro-Shift". In a sense, you can control both front and rear with one switch seamlessly. Now, you need only a UP button and a DOWN button. Then, they made single UP button on right brake lever and single DOWN button on the other, left brake lever.
Also, via the firmware upgrade and e-Tube, Shimano let us use this "Syncrho-Shift" with the older Di2 system. So, you can shift both front and back derailleurs using the older brake lever with "two-buttons" that used to shift only one derailleur.
Then, do you need another brake levers with "two-buttons"? If I want to keep the manual shift mode without Synchro-shift, yes. But, Shimano officially began using "single button on each brake lever" system.
I'd rather try "two-buttons" on one side configuration and "save money" by buying a single brake lever instead of buying two expensive brake levers. Obviously, this is not a good option for Shimano. So, I was a little bit skeptical if their E-Tube system let me do this.
Given that you've already got the brake levers, the most sensible solution is to buy the SW-R9160 or SW-R8060 and insert them in the bar ends of your aero extensions (as StillGoing said above). These two switches are designed to be used with the Synchro-Shift feature so that one button goes up, one goes down and you never (manually) control the front derailleur.