Patrick “Tree” Miller’s business card lists him as Specialized R&D Technician, but Miller likes to think of himself as the voice of the mechanic. When the bike maker’s engineers come to him with new ideas or prototypes, it’s Miller who puts it to the initial test.
“If for example an internal routing is too hard or too time consuming, I raise the red flag,” says Miller, who’s 6-foot-8, thus the nickname. “My main goal is to consider the real world mechanic.”
Miller’s wrenching career started with a string of bike shop jobs before making the jump to Specialized where he does “all the biddings of the engineers” and occasionally gets called in to wrench at various media events, which is where we ran into the perpetually smiling mechanic.
“A lot of people look at being a bike mechanic as just a place holder job until you move onto something bigger and better,” says Miller. “I like to show people that you can make a career out of it. I have gotten to the level where I use it to do research and development for one of the world’s biggest bike companies.”
RoadBikeReview sat down with Miller at a press event in Santa Cruz, California in early February to talk disc brakes, thru-axles, and find out what his No. 1 tech tip is.
RoadBikeReview: Word association: disc brakes on road bikes…
Patrick Miller: I Love them. I think we need them. I just wish all companies would sit down and agree on a standard. Say for instance we are going 130mm spacing with 140mm rotors. Right now we are using 135 spacing with 140mm rotors. If we all could just agree, then we make pro peloton standard. That would be awesome. As for the danger argument that you hear people trotting out, where someone is going to get cut by a rotor. If it was going to happen I think a chainring would have already done it and we haven’t seen that. As far as hot swapping wheels, disc are just as easy.
RBR: How about thru axles?
PM: In the consumer world I think things are moving that way. For instance the Specialized Diverge has them and you can really feel the difference, especially with climbing or other high torque areas. But as far as racing is concerned, I don’t think you’ll ever see anything besides quick releases. Just too slow and you certainly can’t do a bike swap every time someone gets a puncture. Right now you can’t change any of the current thru-axles fast enough.
RBR: How about best rotor size for road bikes, 160mm or 140mm?
PM: I think 140s are enough. I’m a big guy and they are fine. What’s more important are things like proper tire selection. The reason brakes work is because the tire grabs the ground. It’s not just a disc brake that stops you. It’s the contact patch on the ground. When you start using lower end tires you can end up locking up brakes faster than you want to. So just using a good tacky tire goes a long way. The one time I might want 160s is when you know you’ll be on a really long descent or if your bike is going to be loaded up for touring. But I think 140s are generally enough braking for everyone.
RBR: What about concerns of boiling hydraulic fluid?
PM: The reality is the problem isn’t the hydro fluid boiling, it’s the boiling of water inside the fluid. And there are two ways to deal with water, either absorb it or separate from it. With DOT fluid, which is what SRAM uses, when it comes into contact with water it absorbs the water and now the DOT has a percentage of moisture in it. At a certain point if you have a certain level of water in the fluid, then its possible for the heat to boil it off because the amount of pressure. The concern is that the water in the system vaporizes, turns into a gas and now it can compress and you have no brakes.
The other type of fluid is mineral oil, which is what Shimano uses. It just separates from the water. So water just sits there. The worry is that if water gets past the seal and piston, then you start braking and it turns to gas and the brakes are gone. But Shimano mitigates that with ceramic pistons, air cooled brake pads, ice tech rotors, etc. and it never boils over.
So am I worried? No, as long as you have proper maintenance. That means every two brake pad changes with Shimano systems you go through you also bleed your brakes. And if you use a SRAM system, then every year or year and a half, you need to do a bleed. If you don’t follow those guidelines and ride hydraulic brakes for three years without bleeding them, you can boil them over and it will be dangerous.
RBR: Road tubeless, yes or no?
PM: Like it. When you have this fight between tire and tube, that rolling resistance causes a lot of issues that road tubeless can address. The problem is that with our current systems, I don’t feel like we have a good enough sealant to seal up tubeless at the PSI we are currently using for road tires. With mountain bikes it works great because we are only using 20-30psi, so sealant wont blow out of the tire. Also seal time on road tubeless is too slow. Most of the time you get a puncture and maybe drop down to 40-50psi before it seals up. That’s not going to work on the road so you’ll probably still have to put in a tube. But better ride quality can still be achieved with road tubeless because you can run lower pressure without getting pinch flats.
RBR: What’s your No. 1 tip for the home mechanic?
PM: Simple, keep your bike clean. When your bike is clean you’ll realize things have gone awry quicker and it brings up the respect level of your bike. The simple act of wiping down your bike will help you avoid having do major things like full drivetrain swaps. The next thing is keeping components well lubed. So after you wipe everything down make sure you do the proper maintenance and lube things. That will go a long ways to helping keep your bike running smooth. Treat your bike