BobbyG

TL/DR: I want to add inline/interrupter brakes to the uppers. Do they need to be V-brake compatible?

(I searched BF and didn't find a concise or definitive answer.)

I recently converted my old straightbar MTB with V-Brakes to drop bars. I fitted long-pull, V-brake compatible brake levers and everything works great!

Now I want to add inline/interrupter brakes to the uppers. Do they need to be V-brake compatible?

I've searched for V-Brake compatible inline/interrupters and find nothing. Is that because they are already V-brake compatible.

I also see some of these brakes called "cross-levers" and thought maybe those were for V-brakes, but I saw one that said for "caliper and cantilever" which are short pull. Is that mentioned because most cross levers are for long pull?

I asked one of my trusted lbs mechanics and he didn't know. I suppose I could ask my other mechanic, but bikeforums is right here in front of me,

Please help me, I am confused.

dsbrantjr

Interrupter levers are designed to be used on the tops of drop bars which are typically associated with short-pull brakes, so I would suspect that their amount of cable pull (housing push, actually) might come up short of what is needed for V-brakes.

Newspaper_Nick

I have used interrupter brakes with "long pull" calipers. They work. They actually do not pull any cable. They work by pushing the cable housing. Don't ask me how that works cause i still couldn't get my head around the buggers Very insteresting piece of equipment. Somebody with some physics knowledge can maybe clarify how they work in this thread.

PS: Interrupter brakes can also be used as stand alone brake levers. To do this, you insert the brake cable from the other end. And in this kind of use, they actually pull the cable when you actuate them.

Andrew R Stewart 

Whether the brake caliper is acted on by shortening the inner cable or lengthening the casing doesn't matter. Andy

dsbrantjr

Making the inner wire effectively shorter, which is what the regular levers do by pulling, or making the housing effectively longer by pushing, like interrupter levers, has the identical effect at the brake end of the cable. The housing pushes just as hard on the brake mechanism as the wire pulls. Derailleurs, too, except that the housing pushes on the frame stop, on most modern ones.

AeroGut

Paul components sells one with adjustable leverage that can be used with v brakes: https://www.paulcomp.com/shop/components/cross-lever/

dabac

Apart from the Paul’s, one option would be to switch back to short-pull levers, add Travel Agents, then add the interrupter levers.
Or simply install a standard pair of interrupter levers and accept that they may not allow wheel lock before bottoming out, depending on how close you run your brake pads.

BobbyG

Thank you everybody!

dsbrantjr

The other side of the lever also pushes against the housing (or the housing pushes against the lever), but you don't notice this because they are clamped to the bar.

Newspaper_Nick

That quote you referred is when i talk about using interrupter brakes as the "only" brakes on any given bike, which is possible. For this kind of use, you insert the cable from the opposite end of the lever so that the ball of the cable rests on the cable ferrule. So when you pull the levers, you actually pull the cable.

buck1973

They are no longer in production, but tektro made long pull interrupters. The model numbers were RL740 and RL741.

AndreyT

For a Bowden cable - i.e. a cable in a flexible, but incompressible housing - there's no difference between "pulling the cable" and "pushing the housing". Both are just two different ways to look at the same action.

BobbyG

Thanks, I found a used pair on ebay for 14 bucks....but they were for a smaller br diameter. Mine are 26mm.

Plus I had already purchased a pair of new Tektro units for $19.95. Many comments across the web said they worked just fine with V-Brakes especially if the pad to rim gap is small. My gaps are small, so we'll see how these work. I checked the units on my other two bikes, a 1984 Nishiki 12-speed and a 2015 disc brake Charge Plug, and the in-line levers move very little before full braking force is applied...especially the 12-speed.

So I am fairly confident my purchase will work.

I will post a follow-up (which may be a few weeks depending on weekend obligations).

Again, thanks to everyone for their input!