How to increase brake responsiveness on Microshift style STI brifters paired with mechanical disc brake

Question

I have a set of microshift style STI brifters. They are paired to a generic brand mechanical brake set on a Kent Nazz gravel bike.

I can't seem to get the brakes to be as responsive as I would like. The travel before they fully engage is quite long, meaning I have to pull down until the brake lever pretty much hits the bar. The front brakes are not as bad.

I recently changed the brake housing and shifter cables to brand new ones. I also put in some semi-metallic brake pads.

I was wondering what the cause may be. Is it that the brakes are just not good enough quality and therefore they will not just bite and stop the bike even if you pull on them hard? Is it that you need a specific type of pad in order to get that almost instant bite when you pull on the lever hard?

I don't mind the the fact that the bite is gradual and typically that's how I want the brakes to work, but in case I need to stop fast in an emergency, I wonder if it is possible to have the brakes be more responsive when a quick, hard pull is applied? And how can I reduce the lever travel.

Answer 1

Edit: Per your other question you have Microshift Advent X STI style shifters. I assume it’s the ADVENT X Drop Bar Shifters 1x10 SB-M100A. You also mention Tektro MD-C510 disc brake calipers. Both brifters and calipers have the usual road brake cable pull.

So it can’t be an incompatibility.

On the internet one can read a lot of complaints about the Tektro brake pads. But since you’ve already replaced them (Swissstop or Koolstop are often recommended) that can’t be the problem either.

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Maybe the brakes are not really intended for use with STI shifters but are more or less supposed to be used with MTB brake levers. STI shifters pull in less cable, which is also the reason why they don’t work with normal V brakes. There are cable pull adapters/converters available but as far as I’m aware they are usually intended to be directly mounted to V brakes.

You can try adjusting the cable tension to move the pads as close to the disc as possible to reduce level travel. High quality cable housing which doesn’t compress as much can help a bit.

Maybe you’ve clamped the cable in the wrong place at the brakes? Some photos could help.

Answer 2

I will assume that they're compatible, i.e. that the brake calipers are a road model.

Pad choice is not part of the equation in determining bite point or lever travel. Its influence on power is primarily under sustained heavy braking, and since more aggressive pads have downsides in terms of noise and rotor wear, you should usually only go to them when you really need them.

These are the things that do affect affect lever travel, bite point, and excess squishy feel:

• Cable housing choice. Mechanical disc brakes work much better with compressionless brake housing.
• Cable and housing setup. To feel good, mechanical disc brakes have little tolerance for issues like awkward bends or housing ends not seated fully in the lever.
• Where the cable is anchored in the brake arm's travel. This is a way of tweaking mechanical advantage, intentional or not. Usually you get the best power by anchoring the cable at the very beginning of the arm's travel and using the pad adjuster to close the gap. Most brake designs have this as the highest mechanical advantage spot. But, dialing it in to balance power and lever stroke considerations is acceptable sometimes too.
• Good parallelism between the pads. To feel good, road mechanical brake setups in particular need a pretty close gap, and the levers don't have extra travel to give for pads that are gapped out in order to accommodate bad parallelism.

So, the usual procedure to take a bad road mechanical brake setup to a good one is untape it, use something like a Jagwire EZ-Bend piece at the lever and then compressionless brake housing for the rest of the housing run, make good choices with the cable routing, face the brake mount if needed, and start the brake setup by clamping the cable at the beginning of the arm travel, dial in the stationary pad adjuster(s) to give you the feel you want, and then center the caliper. Tape the bars again after everything is dialed and perfect, and then as you do, be on the lookout for any changes in the brake feel that would indicate the tape has disrupted the perfect seating of the housing end in the lever.

Answer 3

My first thought is that you were pairing road levers with mountain brakes. If the levers pull relatively little cable, but the brakes are designed for a lot of cable travel, you'll have bad results, as Michael mentioned.

However, it's also possible that you've just got bad brakes (you don't say what they are). If the force you put into the brake levers is turned into the arm in the caliper assembly flexing, rather than the pads moving, or the force being misdirected in some other way, you'll get the kind of response you describe. Mechanical disc brakes aren't necessarily bad, but there have been some notable stinkers on the market.

Answer 4

*Shifted from the follow-up post: Are road mechanical disc brakes safe to pair with a steel gravel bike

Disclaimer: It's not unsafe in my experience but I am unsure how safe this setup is, so perform this at your own risk. Some manufacturers advise against this for certain brake models (i.e. TRP's hybrid hydraulics/mechnaical brake - some content creator on youtube contacted the manufacturer).

I have a cheap MTB which I converted to drop handlebar using Sensah brifters. Those are road-pull but I managed to use them with TX805 mechanical brakes (single piston MTB disc brakes). How? Preload the brake arm.

1. Adjust the brakes like you would for single piston system
2. Preload the arm by a little (10-20%) of the arm range of movement. To preload, simply unscrew the bolt that secures your brake cable, move the arm inwards like it does during braking. Then tighten the bolt again. What this does is it makes the moving brake pad closer, which gives you more power in your brakes before the levers bottoms out.

For this to work well, two conditions:

i) Your rotors are almost straight. Otherwise, true it. It's not that difficult with an affordable tool.

ii) You cannot using Road calipers which has a far more limited range of motion. Mechanical MTB disc brake calipers should work well.

My experience with the Sensah 8-speed (Reflex) brifter with TX805 brakes was very good. Much more power, but obviously you should adjust for modulation that fits you.

Does a road-pull brake caliper guarantees a better breaking experience with the road-brifters? For me it didn't. I bought a pair of BR-R517 and the braking power was bad. And you can't preload the arm (and you shouldn't anyway since it's road-pull compatible). My front wheel won't even lock when I bottom out the brifter while rolling the bike (unseated) during testing. It was horrifying, at the least to say. The brake calipers were brand new. I returned it immediately after noticing the brakes functioning less than 40-50% of the TX805.

Again, I am not sure how safe is pre-loading the caliper arm so do this at your own risk. I've been riding the bike for about a year now, and not a single issue except you have to r-pad in every now and then when the brake pad wears.