Road Shifters Just Aren’t Right For Bullhorns (being honest)

from Rookie’s keyboard,

Hello, friends

Yesterday, on my way to work, I saw an old road bike with bullhorns what appeared to be road shifters (probably STI) on it.

My take on the combo? It’s just weird. I know. I know. Let me explain why before you start screaming.

Where do I even start?

The first issue is:

1. Poor Breaking Actuation

This is a major issue.

Road shifters are designed for drop bars. When installed on bullhorn handlebars, the brake levers hit the bars and limit brake actuation, leading to suboptimal braking performance.

This issue is less significant on bullhorn models with a larger curve near the ends.

To avoid this problem, some riders reduce the slack in the brake cable to a minimum via the barrel adjuster and sometimes even manually pre-flex the brakes ever so slightly while tightening the pinch bolt. As a result, the brake lever doesn’t have to move as much to maximally trigger the brake.

This “hack” has the following downsides:

Subpar Brake Modulation

By shortening the brake cable and pre-flexing the calipers, the modulation of the brakes is reduced to “unhealthy limits”.

The term brake modulation indicates the rider’s ability to control the amount of braking power applied at any given time.

If brakes have too much modulation, the levers will bottom out (reach the end of their travel) before full braking power has been reached.

If there’s too little modulation, there’s little feedback, and the brakes work in on/off mode with no phases in between.

Reversing STI Shifters

A high-IQ way to circumvent the brake lever actuation issue is to install the STI shifters backward. Or in other words, the levers will point in the opposite direction.

This orientation allows the lever to move as much as needed and makes the cable housing setup a bit easier.

There’s a major disadvantage, however – shifting becomes “inverted” and may feel weird and uncomfortable, at least in the beginning.

For that reason, this setup is more common when the brake levers and shifters are independent of each other.

I am actually running this setup on my road commuter. It works really well. BTW I am running downtube shifters.

Weird Cable Management

The cables and housing of brake-shifters come out of the base (handle) and go back towards the tops of the handlebars. If you use drop bars and wrap them correctly, the set-up will be sweet.

On bullhorns, however, brake-shifters complicate cable management because the cables are going forward and up with no bar to support them. The solution is to make a loop so that the cables go back towards the rider.

Unfortunately, cable loops harm the lever’s actuation.

Lower Mechanical Advantage

When you are in the “drops of drop bars”, you can apply more force on the brake levers for 2 reasons:

a/ The lever is triggered near its end. (The moment arm is longer.)

b/ Most of the force comes from the index and middle finger (the strongest fingers).

But when road shifters are on bullhorns, you can’t squeeze the levers with the same mechanical advantage because the index and middle finger are far away from the bottom of the lever.

(The reverse orientation mentioned above fixes that issue too.)

Compromised Ergonomics

The hoods of STI shifters reduce the gripping area when mounted on bullhorns. As a consequence, you can’t comfortably grab the “horns”.

And that’s kinda sad because the horns are one of bullhorn bars’ nicest features as they make climbing so much easier.

Ugly

If you think that this setup (bullhorns + road shifters) is ugly, you’re not alone.

Alternatives

Below you will find a list of set-ups (shifters and brake levers) compatible with bullhorns:

Plan A: Brake-Shifters

1. Shimano Metrea Brifters

Shimano’s Metrea series has a variation designed specifically for bullhorn handlebars.

The brake-shifters are installed at the end of the bars and offer sweet cable management. The Metrea series is more popular in Europe and works only with disc brakes.

2. Shimano Di2 TT Brake-Shifters

Shimano’s Di2 TT brake-shifters are another option. They are built for time trial and can be installed at the ends of the bullhorns.

Plan B: Independent Shifters and Brakes

A cheaper solutions is to use brake levers and shifters independent of each other.

Brake Levers

You cannot use regular flat bar brake levers on the horns of the handlebars because the orientation of the cable would be wrong.

Bullhorns operate with reverse brake levers designed for time trials and triathlons. 

Reverse brake levers have their cable and housing inserted from the opposite side.

If you plan to install the brake levers on the tops, however, you can go with regular flat bar levers. You could also install small inline brake levers working in conjunction with your main brakes.

Shifters

The following shifter options are available:

  • Downtube shifters (my favorite)

If your frame has mounts for downtube shifters, you can consider a set. The con of downtube shifters is that you have to move your hands away from the bars during shifting.

  • Bar-end shifters

Bar-end shifters are a very popular choice because you can trigger them without moving your hands away from the brake levers.

  • Stem shifters

You could also install old-school stem shifters. They’re closer to you than downtube shifters.

Some people consider stem shifters dangerous during an accident because they’re fairly close to the abdomen.

  • MTB shifters

MTB shifters are build for bars with a smaller diameter (22.2mm) and won’t fit on drop bars and bullhorns by default. However, you can file the inside of the clamp and put them on road bars anyway.

You can use an MTB shifter for the rear because Shimano’s 7,8,9 and 10-speed road rear derailleurs have the same rear shift ratio as Shimano’s 7,8 and 9 MTB rear derailleurs.

  • Retro Shifters Next To The Brake Levers

Some bullhorn fans install retro thumb shifters right under the brake levers. Old school shifters have a friction mode which allows you to mix MTB and road parts because the movement of the shifter is guided by the rider.

One example of such shifters would be Shimano SIS SL-MY20.

Search for shifters that have a band-style clamp and replace the bolt with a longer one. This is necessary because bullhorn bars have a 23.8mm clamp area.

  • Paul Thumbies

The company Paul Components makes a mount that allows you to install bar-end shifters on flat bars. The product is called Thumbies. You can use it to attach thumb shifters to bullhorns.


Until next time,

Rookie


Posted

in

by

Comments

Leave a Reply

Your email address will not be published. Required fields are marked *