1 x Drivetrain with Shimano Di2 for Tri Bike ……advice pls


Hi All,

I’m considering a change to 1 x on a Tri bike …am looking for any advice / pitfalls etc –

Currently im thinking of going Ultegra Di2 (just to keep cost down) with right side controls being Di2 shifters

1 x RHS - Pole/Extension Di2 shifter

1 x LHS – Pole/Extension Blanked over

1 x 3 port Di2 Junction Box

1 x RHS Basebar Di2 Shifter & Brake lever unit

1 x LHS Mechanical Brake lever only

1 x Rear Derailier – Ultegra Di2 long cage ….enable an up to 32 tooth I believe

1 x Battery & charger with wires etc to connect

With Chainring …to suit terrain etc ….

Thoughts, feels, advice, recommendations, on this set up ? thanks all!!!


I ran 1x on my tri bike for around a year. It worked well and I enjoyed the simplicity. Bike has since been returned to a 2x (I live in Utah and needed a bit more gear) My was mechanical so I don’t have any input as far as Di2 parts are concerned though sorry… but this sounds like a pretty sweet set up.


I’m also only in the discovery phase but 2 things stick out…

Ultegra GS rear mech now goes to 11-34 and aren’t you going to need a SM-JC41 to link the 3 port junction box, battery and rear mech together.

Keep us posted. Only ordered my frame yesterday and have a 3 month wait for it to be delivered so am avidly reading about new parts for me which are Di2 and hydraulic brakes.


Check Rotor 1x13. They should release it early 2019. With different size cassette’s you can tackle most flat or hilly environments.


thanks all! if i pull the trigger on this project (and i certainly hope to) i’ll keep this thread alive with progress!

thanks - Paul