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Disc Brakes - a 1-year test with a No. 22 Great Divide Disc

About a year ago we built customer and friend Seetoh Lang a No. 22 Great Divide Disc. Below is his bike, and his thoughts. Thanks to Seetoh for the words and photos (with help from his friends)..."When deciding on a new road bike a year ago, I was nervous about the idea of potentially switching brake systems. I’ve happily ridden thousands of miles on caliper rim brakes, and they’ve been tried and tested by riders for decades. But my experience with disc brakes on mountain bikes got me curious - how would the all-weather prowess of a hydraulic disc brake system translate on a road bike?

My curiosity got the better of me, and I got delivery on a No. 22 Great Divide Disc a few months ago. I’ve since ridden 4,000 km on it in various conditions - from group rides in tropical downpours, to solo descents in desert heat, to hating the weather in winter ice and snow. [Note: now Seetoh lives in Austria, so add the Dolomites to that list]

This is what my experience with disc brakes on a road bike has been so far.THE DECISION:

First, there were the choices of which standards to go with. There were quite a few of them.

Wheel mount:

Quick Release / 12mm thru-axle / 15mm thru-axle

Brake caliper mount:

Flat mount / Post mount

Disc mount:

Centrelock / Bolt On

Rotor size:

140mm / 160mm

Cabling:

Hydraulic / Mechanical / HybridSince disc brakes are relatively new in road biking, this is all a leap of faith. The industry hasn’t had enough time to settle on reliable standards yet, so my choice was based on weighing calculated risks.

Eventually, I went with the following: 12mm thru-axle, flat mount, 140mm, centrelock, and hydraulic.

Build-wise, this translated to Shimano ST-RS685 brakes and Shimano SM-RT99 Ice Tech Centrelock rotors, mounted to White Industries CLD hubs on No. 22’s Great Divide Disc 12mm thru-axle system.THE RIDE: 

In good weather, these disc brakes have noticeably more power than my previous caliper brakes do, but it’s not out-of-this world different. As for modulation, these discs are definitely an upgrade, providing finer control of speed. The whole system is definitely an upgrade over rim brakes when the sun’s out, but not enough that I’d go screaming to the hills about it. Probably the biggest difference is being able to brake later into corners, which is an advantage in descents.

In rain, grit, mud, ice or sleet however, conditions that previously had me begging for my rim brakes to bite just don’t bother me anymore. They are incredible - the different between rim brakes and disc brakes in bad weather is absolutely significant. Bad weather has little effect on the modulation or stopping power of disc brakes.Out on the road, this means I think less about braking. For example, if it’s raining on a descent, I don’t have to start braking earlier to clear water off my rim brake track, and I never wonder when my brake pads are going to bite. These brakes give me modulation or pure stopping power consistently everywhere, all the time.

As for the specifics, disc rub is quite rare on this system, which I am thankful for. They only squeal in very grimey conditions when the pads and rotors are in need of cleaning. When there is rub, the fix is usually really easy. I am relieved about this, as noise was one of my biggest trepidations when taking the leap. I did warp a disc from leaving the disc on the wheel when traveling, and have since learnt to take the discs off before the wheels go in a bike bag, which is very easy to do with centrelock.On group rides, I’ve had the opportunity to test them in challenging use cases - like on a big group ride in a tropical downpour where everyone else is on caliper brakes. It may be of no surprise that it was a completely normal experience. I just naturally braked at the same rate as everyone else did.

On descents, disc brakes are absolutely confidence-inspiring. I get finer control over speed and far greater stopping power, which translates into more speed on the straights, and later braking into corners. This just means faster and more confident descending, period. Not to mention there is no worry abut heat build-up.

Overall, this disc brake system works very well. I spend less time thinking about braking, and more time thinking about how I can (try to) ride faster.THE SYSTEM: 

12mm Thru-Axle

The thru-axle system has functioned well, keeping my wheel, and importantly, disc centered. It’s plenty stiff. Mounting wheels is a mindless operation, I just align the hub with the dropout, push the axle through, and tighten the axle with an allen key. Unlike a QR system, the thru-axle wheelset aligns itself to the frame or fork automatically, no adjustment needed. 

The whole process requires slightly more time than a QR system would because it requires the use of a tool, but I find the extra time is insignificant in the real-world. That being said, I look forward to seeing more systems being developed that don’t require a tool.Flat mount

Works fine. I honestly haven’t even noticed it, aside from liking how clean it looks.

Centrelock

No problems so far either, and I imagine they’ve contributed to the relatively little disc rub I’ve experienced, although by how much is beyond my analysis. One significant benefit of centre lock over bolt on discs is they are far easier to remove from the hub when traveling - takes a few seconds with the right tool.

140mm

Personally, I haven’t desired more braking power out of this system, and feel 160mm rotors would probably be overkill. Aesthetically, I feel the smaller rotors match road bikes better as well. That being said, I would be totally fine with running 160mm rotors. Hydraulic

This is the most interesting change, as it’s a very noticeable difference from mechanical caliper rim brakes. Modulation progresses at a more linear rate compared to my previous system. Slowly squeezing the lever gives me very small increments of braking power that eventually build into a lock-up - there is more fine-tuned control.

The lever throw also feels different, more like pulling on a soft pillow than a hard spring; it feels great. The hoods are comfortable in my hands, and I don’t notice that there’s a reservoir sitting in them. Braking is effortless and controlled, and they have worked well in both 35 deg summer heat and -10 deg winter weather. I haven’t bled the system in over 4,000 km's and they still feel good.One caveat of this hydraulic system is the lack of a ‘quick adjustment’ dial to change where the brakes fully engage on the lever progression path - the brakes have to be re-bled in order to change this bite point.

Another inconvenience is that a little plastic piece has to be inserted between the pads when the bike is disassembled for traveling, to prevent the pads from being pushed toward each other unintentionally - but this is ordinary for hydraulics, just like on a mountain bike.

The overall system is slightly heavier than a caliper rim brake system, but this is something I personally don’t mind. And there is a school of thought that disc brakes are less aerodynamic, but I don’t have a wind tunnel to test that.

In general, I personally prefer far better braking performance over a slightly lighter, slightly more aero bike. I was very curious how hydraulic brakes would feel on a road bike, and I’m happy to say the experience is very natural on a road bike. CONCLUSION:

Disc brakes may be seen by some as a marginal upgrade, but to me, they’re a game changer. I feel more confident on a disc-equipped road bike in all conditions, because living through winters in Toronto, I ride in marginal weather more than I wish to. Snow, grime, rain, salt, mud, moisture, whatever the condition. I don’t worry about those things anymore as far as braking is concerned, and feel more confident in traffic.

That being said, I’m not a disc evangelist claiming that caliper brakes are dead and that everyone should switch over, but I will say that disc brakes are, simply, a superior technology. It’s quite remarkable that it all already works so well in its first stages of development for road bikes, and it’s clear that Shimano and SRAM are benefitting from their experience in the mountain bike world. I’m excited to see how Campagnolo’s system turns out, especially with Magura’s long-running expertise in the fold.

Overall, I completely sold on discs for road bikes, and the reasons for it also go beyond stopping power. Disc brakes free rim manufacturers from designing around the constraints of a brake track, and they allow frame builders to design bikes with much better tyre clearances, and even the ability to take multiple wheel sizes. All these additional plus points add up to an even greater whole.SHOULD YOU SWITCH?

For racing or competitive sportive riding, disc brakes are a no-go because they aren’t UCI-legal at the moment, and it remains to be seen how the trials will play out. If you intend to take part in UCI-sanctioned events, it naturally makes the most sense sense to stick with rim brakes for now so all your bikes and wheelsets are on the same system, and you can wait for the proverbial dust to settle. [Note: things have now largely settled in Canada, Australia, etc.] 

For gravel, ‘adventure’, and cyclocross riding, I think the benefits of disc brakes make the choice a no-brainer decision - both for better braking performance, and for better tire clearance. For recreational road riding on tarmac, I think the upgrade value is largely dependent on what weather conditions a rider is often in, and whether they descend a lot. For example, riders in the U.K. who experience inclement weather and elevation changes would be first in line to experience the benefit of disc brakes, and it’s no coincidence that markets like the U.K. have been a driving force for disc brake adoption, with new brands like Mason entirely devoted to discs.

Overall, the industry still has a way to go on the topic, and it’s a toss-up on whether disc brake technology will become a new normal. However, if all-weather braking consistency and greater stopping power are things you desire, and you’re willing to take the chance on new standards, my whole-hearted recommendation is you should absolutely take the leap."Seetoh Lang is based in Toronto where he works in digital marketing and rides bikes the rest of the time. You can find him on Instagram @SeetohLang. Thanks to Seetoh, plus Lifeisabeautifuldetail, Jeff Tin, Rob Hester, and J. Braynard for the awesome shots. Also, Seetoh wrote this a few months back, sorry for taking so long to post!!

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