ZOOM HB-100: Upgrading cable-operated disc brakes to hydraulic calipers

[cyclebuddy]

I'm just wondering if anybody else here has tried upgrading their mechanical disc calipers to hydraulic and what your thoughts are? Are these ZOOM HB-100 hydraulic calipers a good compromise or waste of time?

With these it's only the caliper that's hydraulic, so you don't have an oil reservoir at the brake handle. It means you keep your existing cable brake levers with their motor cut-out switches, and don't need to route new hydraulic hoses through the bike frame (if that's an issue for you). So you get some/much of the benefit of a hydraulic brake without the complication of using a more expensive full hydraulic system. These are only £20-£24 a front & rear set on AliExpress, inc VAT and post. They're a direct swap fitting wise, and use standard Shimano resin pads too.

 

[Nealh]

Probably worth a punt, reviews are favourable for their better stopping power over cable brakes and better then avid bb5/7's and crappy promax, twin pad actuation so might be ok. The only worry might be the oil boiling in such a small calliper reservoir.
They appear to be bleedable but tricky to do, two bleed ports so be careful not to undo them in error.

 

[cyclebuddy]

Well they're here, so I'll give them a go on my Fiido D11 - currently generic Chinese Mechanical Calipers with sintered pads on 160mm rotors that work well enough but (sometimes) squeal.

Yes, good point: Boiling/expanding oil on a long, fast descent! That could be fun... or not if the pads lock onto the rotors and the wheels lock up! Mmm. Heat dissipation might be an issue.

There's a better but far more expensive version of cable-pull hydraulic caliper brakes by a company called Juin Tech - about £100 a set - which road racers and the US e-bike crowd are raving about, although for that money I'd just go for a "normal" hydraulic set. On an £800 cheapy folding ebike with frame-routed cables, I'll see how these £23 ones go.

 

[cyclebuddy]

The Zoom HB-100 hydraulic calipers are on. Took all of 15 minutes - a direct swap, no fiddling, no shims needed, using the existing brackets rather than the supplied ones... although I'll need to check alignment after some riding to ensure pad/rotor contact/wear, but the fit looks right (I've put a solvent based red marker line across the disc to ensure the pads make full contact). They look good, and the feel at the lever seems much nicer. The pads by area are probably twice the size of the previous mechanical brakes so all seems promising.

I'll bed the pads in and take it for a good spin over the weekend.

 

[Nealh]

They look fine, for the price the upgrade over conventional cable callipers has to be worth it as the brake performance will/should be far better. Just don't take a chance of going weeeeeeeeee down a steep hill until toy are sure they will take it.

 

[cyclebuddy]

After bedding and one decent ride out, here're my thoughts on these Zoom HB-100 hydraulic calipers:

Neals foresights were pretty accurate. Although I have a 15% 1-mile long hill I've often screamed down at 35-40 mph on my regular e-bike with Shimano hydraulics, I didn't and wouldn't try such a stunt with these Zoom HB-100 hydraulic calipers. They can get quite warm in regular use which is fine, but there is no means for excessive heat to dissipate in the way it does in a regular hydraulic system.

The big and unexpected surprise for me was the force/effort needed at the levers: By direct comparison, these need a fair bit of squeeze to actuate - I rode with a minimum of 3 fingers on the lever rather than 1. That need may relax with more use. There's also slight "springiness" of the cable stretching as you notice with mechanical calipers when applied hard.

For my purpose - a second "deliberately keep it cheap" 20" folding e-bike for shorter journeys - I think they're fine and represent good value. But they're no substitute for even a low-cost/entry level full hydraulic braking system like Shimano's MT200. That would be my choice on a regular use or only e-bike.

The good things:
Low cost - £20-£24 delivered, inc post and VAT.
A notable improvment in braking performance - both pads are actuated
Resin pads - larger surface/contact area, no squeal
Uses standard Shimano pads - easy to find and cheap to replace
Retains existing brake levers with motor cut-out switches
Simple and quick to fit - no need to change levers or re-route hoses
Pre-filled with mineral oil - no filling or bleeding

Not so good things:
Requires much greater force than conventional hydraulic systems - no 1-finger braking here!
Tiresome on longer journeys due to the squeeze effort needed
Lacks the finese/smoothness and effortless feel of a conventional hydraulic system
Heat dissipation may become an issue on long/steep/fast desents

Worth doing IMHO if:
You can't/don't want to spend too much or
You have a low-cost e-bike with basic mechanical disc brakes
You don't suffer from any weaknesses in your hands/fingers
You don't travel long distances where your fingers/hands could quickly tire

This is the Fiido D11 e-bike I tested on (here with original unbranded Chinese mechanical disc brakes and 160mm rotors):

 

[Nealh]

Well done CB for posting some nice honest thoughts on them, they probably were never going to be fantastic but for an average rider who likes just to pootle about they may be an option if cable braking is a bit iffy.

 

[GLJoe]

After bedding and one decent ride out, here're my thoughts on these Zoom HB-100 hydraulic calipers...

Worth doing IMHO if...

Thanks for the writeup. Very interesting and informative.

I think there is one popular scenario that you haven't mentioned though, and that is for people with drop handlebar bikes!
Because here, the added complexity of hydraulic brakes in the STI style shifters means that a true hydraulic system adds a considerable cost, so you often find otherwise decent bikes at the bottom of the pricing range, get cable disk brakes as the way to achieve the lower price point, because then they can fit standard (but decent), low cost shifters in something like the claris range, while still having the in vogue disks!
I know, because I own a very nice Giant gravel bike that has this exact setup! Its an excellent bike in all ways .... apart from the fact the brakes could be a bit better
I was actually looking at some equivalent cable to hydraulic converters about a year ago - I think they MIGHT have been by Tektro, and Decathlon were stocking them at a reasonable price, but I haven't seen them in stock since then.
I will investigate some more now on these Zoom versions to try and work out if they will fit on my gravel bike!

 

[cyclebuddy]

A very good point @GLJoe! I haven't had a drop handlebar bike since the 1970's when they were THE bike of choice and rim brakes were standard! It didn't even occur to me that the newer breed of drop-bar Gravel bikes would have similar fitting complications.

I mentioned in post #3 the Juin Tech R1's - they may even be the ones you were thinking of? I think these Zoom's were probably based on them. My understanding is the Juin's are the cable-pull hydraulic caliper brake of choice in the proper drop handlebar road-racing market, and probably for all the reasons you cite. Juin make great play of the fact their calipers are forged and these copycat types are simply cast... but my impression is that the Juins were "properly" designed for "very nice bikes" like yours. These Zoom brakes are aimed more at the e-scooter market where cheapness is key. Your application is somewhat different to mine and may give better results though (maybe a straighter line of the cable routing?).

Cost aside (R1's are £100+), my feeling is the Juin Tech R1's might be a more refined choice for a "very nice Giant gravel bike" like yours where a conventional hydraulic brake system is impractical. You'll easily find Juin Tech R1's on Amazon, AliExpress etc. Worth a look anyway.

Whatever you do I think it's definitely worth trying. It's easily reversible if they don't deliver quite what you hoped in the way you might be expecting. I hope you let us know how you get on.

Here's the Bolton Ebikes video that originally woke me up to the possibilities, but here he's using a variant of the Juin Tech:

 

[Nealh]

I'm surprised to here the Giant doesn't have hdb's, my 2019 Arkose 2 was £1250 and I snagged it ex display for £850. It has nice Tiagra 105 group set with Shimano 7000 hdb's.
Some of the models differ and I think the 2021 Arkose 2 has the crappier TRP brakes and a crappier SRAM group set.
One thing to watch is that gravel bikes generally use road bike set up so the brake mounts for disc brakes isn't the isis std 68mm used on mtb/hybrid bikes.

 

[cyclebuddy]

One thing to watch is that gravel bikes generally use road bike set up so the brake mounts for disc brakes isn't the isis std 68mm used on mtb/hybrid bikes.

Yes, the Juin Tech R1 are for road and gravel bikes, the Juin Tech M1 are for MTB and e-bikes. The Bolton Ebikes video shows the M1 variant. There's a 4-pot version called the GT too.

With these Zoom HB-100's, I'm wondering if there'd be any benefit using an adaptor and a 180mm rotor at least on the front for better heat dissipation?

 

[AndyBike]

IMHO Brakes are singularly the most important aspect of an ebike, especially given the combined weights involved.
Cheap brakes like anything are cheap for a reason and might well not be up to the task set, especially in that emergency situation.
I favour Hope brakes because I know they are quality and can be relied upon.

OK, I acknowledge they're expensive, but not if you go 2nd hand, and a set of mono mini m4's can be picked up via ebay for about 100 quid a bikes worth.
But its not just price that should be your consideration, but also how easy are they to maintain, availability of pads and whether those pads are up to the task set.
One thing you see a lot of ,especially in the more obscure brake brands is people having difficulty bleeding them, and the inevitable 'tips' that seem for more complicated that they should be.
Hope and the higher end shimano are easy to bleed,therefore maintainn and hope can be rebuilt time and time again with the parts easy to find and lots of vids on how to do it.

 

[GLJoe]

I'm surprised to here the Giant doesn't have hdb's,
...
One thing to watch is that gravel bikes generally use road bike set up so the brake mounts for disc brakes isn't the isis std 68mm used on mtb/hybrid bikes.

Giant's gravel offerings go under the rather 'unusual' name of Revolt and they've been doing them for quite a while - certainly before 'gravel' became super popular.
The higher end models such as the Revolt Advanced 0 is a beast, with the top of the range everything (I think its sram electronic shifting etc, with a £5K price tag!)

Then you start going down the range. Normal hydraulic offering, then a bit lower, they use Giants propitiatory converter system (Conduct?) where you have a cable levers to hydraulic brake converter build into a special 'blob' on the stem.

Then all the way at the bottom is mine
Which uses totally a conventional cable system.

Good info on the spacing differences though! I'd assumed that road and MTB disk mountings would be the same! Oops.
So what do flat bar hybrid bikes tend to use??

 

[potato]

Have converted a drop bar bike from BB-5 cable disc brakes to Tektro HyRd ones in the past. Fiddly as hell to get the cable adjustment just right - but once done they were basically indistinguishable from normal full hydraulics.

These are much cheaper - if I had any bikes still running cable discs I'd be on it in a heartbeat. My old cable discs on my cross bike used to need adjusting every ride. One particularly muddy wet ride they needed adjusting mid ride - discovered by trying to descend dunkery beacon and discovering I had virtually no brakes.

 

[GLJoe]

Have converted a drop bar bike from BB-5 cable disc brakes to Tektro HyRd ones in the past.

Ha! yes ... Hy/Rd Tektro/TRP was the type I was trying to remember that I'd looked at previously, that Decathlon used to have in stock at a semi-reasonable price.
It would be good to see a comparison of those against these cheaper ones, but somehow I doubt that exists.