Disc brakes on race bikes it's a hot topic and the trend du jour. Last week Trek showed it wasn't a trend they would be ignoring wit the release last week of the Domane Disc. Their first foray into t he world of disc-equipped performance road bikes will initially be available in two versions, the £1,600 Domane 4.0 and the £6,000 Domane 6.9.
The bike created a few talking points. So we had a chat with Trek's Road Brand Manager Michael Mayer and Senior Road Product Manager Ben Coates about the Domane Disc, asking them for their view on the future of road bikes with disc brakes and to explain some of the new technology in the Domane Disc.
Do you think disc brakes the future of road bikes?
That is a complicated question, while the easy answer is yes, the reality is that is not that simple or cut and dry. For some applications, disc brakes are not only the future but they are the here and now. There are plenty of riders that see the value of versatility and braking performance that disc brakes offer.
The bigger question that I believe you are asking is, if they will be common place for the future on all or most road bikes? That is where it gets complicated. Taking into account UCI regulations (which might change), weight, aerodynamics, cost, rotor size, chain line, brake rub etc, there are a lot of hurdles to jump over. That said, as an industry, we are in a similar position that mountain bikes were in not too long ago. Only time will tell if we can jump over all of the hurdles to make disc brakes common place.
Why did you choose the Domane to launch your first road bike with discs, and not the Madone?
Domane platforms makes sense for how the bike is ridden, where the bike can be ridden and the growth of the endurance crowd. Just like the Boone is spec'd with Disc brakes, the Domane is the next obvious choice.
Yes, disc brakes offer superior braking performance over calipers; but the brakes, rotors, and wheels are a bit heavier than their rim brake counterparts. Plus, there are simply more rim brake wheel choices available, particularly on the high end, and riders are more likely to have a few pairs of those already in their stable. But for that adventure-seeking customer looking for supreme braking performance in all conditions, disc brakes are the way to go. Domane Disc fits this crowd.
Have you had to make many changes to the frame and forks to account for the disc brake forces?
No changes to the frame and fork geometry. New completely designed fork top to bottom designed for post mount Disc brakes. New carbon layup to handle the stress of disc brakes. New designed chain stay for the same purpose.
Is there any weight penalty in the frame and fork compared to the standard Domane?
Yes, there is an overall weight addition when adding Disc brakes. Slight increase to frame and fork itself and more to the addition of the brakes themselves.
What sort of tyre clearance can we expect on the frame?
With the removal of the caliper and brake bridge you have an increase in tyre clearance.
25c is the max tire we can spec legally. We have some selling restriction because of CPSC and CE clearance models. We feel tire size is definitely a preference and 25c a great all around size. We cannot say we recommend a bigger size.
Why bolt-thru axles? Most new disc road bikes are appearing with regular quick releases.
Thru axles significantly stiffen the frame-wheel interface for more steering precision and better cornering, thanks to less flex in the system. They also ensure that the wheel is precisely placed in the dropout each time it is installed. This helps eliminate disc rotor rub from the wheel being crooked in the dropouts because of improper installation. Domane Disc is also compatible with quick-release wheels.
All Domane Disc models come set up with thru axles, but are convertible to QR if you're looking to run an existing wheelset. The rear converts to the 135mm QR disc standard.
Do you see bolt-thru as essential to the future of road disc bikes?
We feel the bolt-thru is a benefit to the road category. Just like mountain bikes evolved to this technology and acceptance, we feel road will also follow this path or develop an even more improved method over both.
UCI racing discs will most likely develop new technology.
Many disc skeptics talk about slow wheel changes. Is that the case with bolt-thru?
I think the one place this can effect is if the bike is raced in a road race. But otherwise changing a wheel is not that much hassle. The time on the bike and ride performance outweighs the wheel change time. Disc brakes rubbing on a MTB sucks. Disc brakes rubbing on a road bike is unacceptable.
Plus, one of the beauties of our interchangeable dropout system is that you can swap the front dropouts from left to right. That means you can put the lever on the traditional side (left)—or you can keep the lever out of the way of the rotor by putting it on the non-disc side (right).
Can we expect to see this new technology feature on future road models in the Trek range?
I am not exactly sure which technologies [we meant disc brakes] you are referring to but in all, the answer is that we are already cross-pollinating technologies where it makes sense and developing new technologies where it doesn’t. We have borrowed knowledge from our MTB friends in the building on thru-axles, balanced post mount and carbon armour. We have put IsoSpeed and disc brakes on the Boone platform. OCLV is a company-wide technology that we continue to leverage. We will continue to utilise the right technology for the right products in the future.
After working on this new Domane, what do you see as the next development of this sort of bike?
The Domane is an amazingly versatile platform with an incredible ride that is focused squarely at going fast by being smooth and efficient. The opportunities to increase speed by targeting those two focal points are tremendous. A little imagination and reflection on the current bike will help us drive to the next one. What will that be? Good question…
Thanks to Michael and Ben for their time. Some interesting answers there, especially his views on bolt-thru axles and the UCI's stance (and whether that will change) on disc brakes in the professional peloton, and how this might push the development of frame and fork designs and bolt-thru axles. Are we about to see a lot more new road disc bikes with bolt-thru axles in preparation for a change of the rules by the UCI?
Most new disc road bikes coming out are sticking with conventional quick release axles that have been used since Tullio Campagnolo invented the concept in 1927. It hasn't changed much since. We saw a lot of disc road bikes at Eurobike last September and the majority had conventional axles, but a few brands like Giant and most notably Storck bucked the trend with bolt-thru axles. Some think this is the way forward for disc road bikes.
When we chatted to Markus Storck about his use of similar bolt-thru axles on his new road bike, he explained to us that it's is the extra stiffness they provide, but also allowing the fork and rear stays to be designed with fewer layers of carbon fibre, because the axles provide a lot of the necessary stiffness. So there's less carbon in the sides of the fork legs and in the seatstays and chainstays.
There are a lot of people in the industry who reckon the disc brake revolution is coming, as we found out when we interviewed the likes of Keith Bontrager, Ben Coates, Dan Jones, Mark Reilly and others last year.
David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.