maxants33

So managed to get some mech disk - rim brake comparison.Fitted the TRP spyres from my spares bin to an old soon-for-sale Sonder Camino gravel bike, and bedded in some new pads on a big hill I usually bed in discs at. I was surprised that it took around 10 runs for each wheel to start feeling any bite. That was with new TRP pads on TRP discs. Even after 10 descents, the brakes were not fantastic at locking up the wheels. I then decided to try some corners. With the gravel bike's 38mm tyres, you have lots of grip and could lean nicely. But I tried feathering and testing the brake's modulation entering, in the middle and the exit of the corners - and I was super disappointed. The TRPs basically did not engage noticeably until the lever was almost at the bars. Then the scope for feathering the brakes was tiny, only a few mm of lever pull to work with. This made the dose response curve (pharmacology term) of the brake pull very steep. I did ensure the brakes were setup as required. Pads teed up with the allen bolt adjusters to be as close as possible, cable tension set correctly (tried a range of cable tensions in the end). But the overall performance was very meh. Fine for a commuter bike. But not performance quality. I then put the gravel bike away and then dusted off the crit bike for its first trip out this year. The Athena rim brakes felt way better. They were responsive and could start modulating early in the lever pull. The audible noise of braking was sort of helpful too, giving some feedback on whats happening when lightly feathering at corners. Compared to my hydraulic disks, it took a bit more finger power to modulate, but as suggested, this might improve with new pads, cable ect. Based on this experience, I don't see any reason to install mech discs. The rim brakes are actually better than I remember. I still think in a really high pressure scenario, I'd probably prefer hydraulic discs, just for the ability to micro adjust with barely any finger power, and the fact I've grown very used to hydraulic discs because I'm mostly off road. But I'm no pro, and the rim brakes work really well - maybe they'll make me a better rider! I must add that I did read that TRPs sometimes work better with certain brands and generations of road levers. I used 5700 Shimano 105 levers, with non-compressionless outers. So maybe if using a different groupset I'd get different results. I hope this side by side comparison helps someone else in the future when trying to make a decision about mech discs vs rim brakes. As said, different components might give different results though.

PeteHski

I'm not that surprised to be honest. It's asking a lot to get decent power out of a relatively small disc with cable actuation. It's hydraulic or bust for me regarding disc brakes.

Maelochs

I use Spyres with 5800 105 levers .... they are on par with any good mechanical rim brake.

maxants33

I did wonder, the 5800s up have a better feel than the 5700s. But that issue of unknown compatibility with TRPs and road levers is pretty off putting for me

Maelochs

If I were you I would go rim or hydro .... in-between is nowhere.

ummed

For funsies I'm going to rebuild my old Venge with hydro rim brakes

Germany_chris

The internet loves spyers but my experience with them is much like yours. I fixed it by going with expensive cable discs because I still want cable brakes but if you're not wed to cables hydraulic is the right answer

maxants33

Yea, that's interesting. I'm still open minded to cable disks. For instance - have that classic dream of building a cable disk touring bike on a surly ogre. But would probably go for something like the Paul Clamper disks, surely something that expensive can perform.

Germany_chris

Klampers are what I use.

ummed

It's been a while since I had them, but TRP HY/RD worked pretty well.