The combo of a geared road bike with 53/39 in the front and a fixey with a 42 x 16 setup is having some amazing effects on my fixed gear riding. I thought it would be just the other way. I thought that the strength and turnover, the general pedal efficiency gained from fixed gear riding would be solely beneficial towards riding a road bike.
But here is how I am finding it works the other way. I am starting to learn how to really hammer down hills when I want to on the fixey. The geared bike allows for really hard smooth pedaling downhill when the chain is in the big ring in the front and one of the smaller rings in the back. If you have ever pedaled with this set up rather than simply coasted downhill at the speed which gravity sets, you know how fun it is. Before when I was racing on the fixey I felt like the only thing I knew how to do was try to relax my legs and hips, not bounce too much and just let the pedals flow underneath. I would try to remain composed and I was learning about high cadence where I know the number was exceeding 150 spm (strokes per minute). But thanks to the geared bike I am learning a new way to approach certain downhills--step on the gas. Lean into the pedals and actually stomp on them. This is faster and I actually feel more in control. Now I am hitting speeds of 30 mph on short steep downhills. Before when I was letting gravity dictate, I was only going about 24 mph. It's really fun.
There is one more way to go downhill on the fixey. Take your feet off. A year ago this was terrifying and rightly so. This technique means that the only points of contact are your hands, your butt, and the wheels. It's a pretty squirrley feeling. But as my comfort and bike handling skills have progressed, I use this technique sometimes because it is the only way to give a true breather to my legs.
To brake or not to brake, that is the question.
I have kept both front and rear brakes on my fixed gear bike. To some this will make me an embarrassment to the fixey community, but I don't care. I don't own really tight jeans anyway. I've ridden many city miles without the use of any brakes and it is fun, but generally I have two trumping priorities. First, I want more facilities at my disposal when encountering objects such as people, trees, and cars--particularly the last obstruction on the list. My experience is that drivers do not compress their brakes more and earlier just because I have none to use. I ride with pretty "big muscles" on the road, figuratively speaking. I take my space on the road and try to imagine myself firm and resolute. I still don't want to get hit by 2,000 pounds of car particularly when brakes could have avoided or slowed the impact.
Second, and actually much more important to me, I don't want to apply all that reverse pressure on the pedals. The only way to slow down without brakes is by applying negative pressure on the pedals. I like to go fast and I think it is an awkward motion at high speeds and puts a lot of pressure on the back of the knees. I do think this muscle contraction can be built up slowly, but I don't want to overdo it. I like to balance my use of reverse-pressure pedaling and standard brakes. Yes, the bike looks a lot cooler without brakes. But come on, my bike still looks cool. This really isn't debatable.
Skid stops--haven't figured that one out yet and trying to avoid the temptation. I disdain punctures and don't want to put undue stress on the rubber which is so important in the riding experience. In the fall I experienced a month or two of hair pulling frustration when it seemed I couldn't ride a mile from the house without a flat. Never could figure out the cause, but once I lowered my air pressures from 130 to about 100psi (pounds per square inch), I have been good to go. Flats are so deflating.