Photo by Jason DeVarennes

Thursday, August 16, 2012

Belt Drive Fixie

"Why fixed?"

It's a question that I hear lots. Actually I hear this question mostly when I am riding fixed. Which isn't always, but this month it has been a lot. In a blog posting last week, I mentioned that I would be doing Mt. Washington on the pixie fixie again. So leading up to that event, I've been avoiding those shifty bikes in favor of fixed. Therefore it seemed like an ideal time to do an extended test ride of the Seven Cafe Racer S set up with a Gates Carbon Drive belt and a fixed cog. I'd first spotted this bike at Ride Studio Cafe last year. It was set up as a single speed. I took it out for a short test ride last spring, and then asked Rob about fixing it, and letting me take it for some extended rides. He ordered the fixed cog right away, but the bike was actually booked on a flight to London for a some test riding and reviewing there, so I'd have to wait a little while before I could really put it through the paces.

I hear the bike had a great time traveling, and may have even sent a postcard home. This particular bike has S&S couplers, so it is made to fly. And as a single speed, it is also super simple to disassemble and pack. So while it was off having fun in England, I waited patiently...

Soon after seeing the bike reappear at RSC last month, I asked Rob again about getting that fixed cog and taking it out for a few days.

Last Wednesday, I headed over to RSC to get the bike. I took it out that afternoon for a short spin - well actually 26 miles. It was still in single speed mode and had a narrow man's saddle/torture device. Obviously I noticed the saddle, and I will also admit to noticing the funky Tiberius handlebars - more on them later. But I determined right away that I will never make a good bike reviewer. Other than these personal preference contact points, the bike pretty much disappeared beneath me. I saw some lovely bluebirds as I passed through the golf course. I noticed that the golfers, at least the one's at this golf course, seem to favor a more subdued fashion than the brightly colored plaid knickers that some pros seem to like. As I climbed up the hill past the Campion Center, I noticed that this year's poison ivy crop was thriving. If I could find a commercial use for poison ivy, I could solve the world economic crisis!

What I didn't notice... was noise from the bike - and that's not because, as John believes, that I can't actually hear the squawking of a dry rusty chain, but because there isn't any noise to be made. This is one of the advantages of belt drive - a pretty much silent, no-maintenance drive train. Another advantage is complete lack of chainring tattoos on one's calf.

Since the belt doesn't need to be lubed, it is completely clean, making it possible not just to avoid this mark that often invites ridicule, but also to be able to remove a rear wheel to fix a flat and handle the belt - all while keeping one's hands clean. This is great for a commuting bike, or a bike that gets loaded into a car, or for anyone who just can't be bothered with lubing a chain until flocks of birds join the ride believing the chirping noise from the dry chain to be a call to follow.

The other big advantage is weight. According to Gates, the weight of a belt and the two pulleys, their name for the chainrings and cogs, is less than the weight of just a chain. As a weight weenie, who rides fixed, partly because fixed is lighter than a bike with derailleurs, cassette and excessive chain, getting something lighter is even more appealing!

So now this brings me back to "Why fixed?" as in why fixed, versus single speed. My little 26 mile spin on single speed reminded me. Most people know that with fixed, you cannot coast, and that is indeed true. And it's picturing a rider going downhill, legs spinning fast and wildly, that usually causes folks to start asking "Why?" To be honest, descents are part of the appeal. One can get a nice consistent workout, pedaling for the entire ride, never coasting. And it's a great way to keep warm in the winter. But the real advantage isn't that you have to pedal all the time, it's the push you get uphills. Yes, applying force to the pedals makes the wheel go around, but the momentum from the wheel going round helps push your feet around. Yes, even on a steep climb, you actually get a little help turning the cranks from the momentum of the wheel. It seems to be worth about 8-10 gear inches for me. I can ride up the same hill in a much higher gear fixed than one that is free.

It's like a legal performance enhancer. Just don't tell WADA - they'd surely ban it.

Of course, there is the matter of selecting the proper gear, one that works well for both the ups and downs for whatever roads you are riding. It is a compromise, something low enough to get up, yet high enough to get down without spinning your legs out of the joints, and good for whatever lies in between. And of course there is being able to adjust to changes in cadence, rather than changes in gear.

Now, the first thing I did after my 26 mile ride was to change the saddle for my own. I took one from my Bike Friday, which isn't seeing much use these days due to my complete lack of commuting into the city. And wow, what a pleasure it was to discover that Seven Cycles seat post.  This seat post was designed to make changing saddles easy. I don't understand why all seat posts don't have this as a primary design goal. The design allows for separate fore-aft and seat angle adjustment. And the clamping plate rotates out of the way, so one can place the saddle, move the clamping plate back into position and tighten the bolt, without the need for 6 extra hands and some special incantations or swearing! Getting the saddle level was an easy adjustment. Not that I change saddles a lot, but now I want new Seven seatposts for all my bikes. If you've ever struggled with changing saddles on an uncooperative post, definitely give this one a look.

Next up was actually fixing the bike. Rob had been kind enough to get a fixed pulley, but we would need to provide a compatible wheel. The plan was to use one of our fixed-ready wheels that would take a threaded cog. Surprise, surprise, the Fixie Pixie has a few fixed gear wheels.  The candidate wheel was one with a White Industries hub from John's Cielo, since John's being all shifty these days, so it wouldn't be missed for a week. Also this wheel is relatively lightweight, compared to my heavy duty commuter wheel with the Phil Wood hub. The one issue is that this wheel takes a splined fixed cog on one side and a freewheel on the other. The fixed pulley from Gates was threaded. It would go onto the freewheel side, but with backpedaling would presumably just come unthreaded, without a proper lockring. John assured me that once I'd climbed my first hill, it would stay put, and this was indeed the case. We put plenty of anti-seize on the threads, but it's going to take more than backpedaling to remove that cog after a week of climbing!

As it is John's wheel, it has a cushy 28mm (measures 30mm) Grand Bois tire. The nice long chainstays and thoughtful design of the Seven with the brake set up with pads at the bottom of the slot meant the wheel with the cushy tire would fit just fine. I had plenty of room with a nice comfy ride for our bumpy New England roads.

Plenty of clearance for the cushy (measures) 30mm tire - with a Dura Ace brake

I then added a bottle cage/bottle, pump, small seatbag with basic tools, a GPS mount and was ready to go.

And go I did. I logged over 350 miles in the week that I had it. I did both solo and group rides and I had a blast. I really hate to return it.  It is light, smooth, comfortable, stable, fast and all things a bike should be. As in the initial ride, it continued to disappear beneath me. Again what I noticed most was what I didn't notice - noise. And of course, no chainring tattoos!

Belt-drive is definitely on my wish-list now.

The gear is a little lower than what I'd typically use for group rides around here, but can easily be changed with a larger front chainring - um, pulley. The gearing is currently 50/21, but I held my own with most of the group. I might be able to keep up with the young guns or contest a town line sprint with a 55/21, but that's just gearing choice, nothing to do with the belt. Currently the only thread-on (fixed) pulley is 21. But front pulleys are available in 39, 42, 46, 50, 55 and 60.

(There are several other rear pulleys available for single speed or internally geared hubs. The Gates website has all the details for various gear combinations, belt lengths and chainstay lengths.)

The Seven Cafe Racer S with belt drive is a great climbing bike. I even managed to set a few Strava PR's on climbs this week! I can't get the low-low Mt. Washington type gearing though, so I'll have to give it back and go back to my heavy, greasy chain fixie for the race. But I wonder if I can get Gates to make me some custom pulleys and belt for next year...

Using a tugnut makes setting the belt tension easy. Also note the bolt that joins the seatstay and dropout. This is necessary to install/replace a belt. It is the only downside. The frame must be designed for belt-drive, with a split at the dropout or seatstay.

Pulley alignment is very important with the CenterTrack belt and was easily accomplished with a single spacer behind the threaded pulley to match the pulley on the crank. 
Front Pulleys are available for 4 arm 104 BCD or 5 arm 130 BCD cranks.

 Near the end of my last ride, I noticed the rear tire was soft. I opened the quick release, backed off the tugnut, pushed the wheel forward and pushed the belt off the front pulley, then freed the rear pulley, so I could pull the wheel out. My hands were still clean. In fixie mode, I had used the front brake, but had barely touched the rear, so even after fixing the puncture, my hands were still clean. I slid the wheel back into the dropouts, re-mounted the belt - rear first, then front, then pulled the wheel back to a reasonable tension, tightened the tugnut, then the quick release, and was on my way - with clean hands

The Tiberius Commuter Bars drew almost as much attention as the belt and the fixed gear. These are very nice bars, and awesome, as designed for commuting, but maybe not my choice for longer distance rides. To be fair, I was really not using the bike as it was intended to be used. Who does 80 mile rides as a commute, on fixed?

Even with couplers, the bike is soooo light that it flies!

Just what I need to get me to the coffee shop fast!

Quality work from the fine folks at Seven

If you still want a chainring tattoo, you could get a permanent one!


  1. What an impressive use of the bike! I rode this bicycle last Autumn, though not fixed and not for 300 miles. Maybe 10 miles. Really liked it! Fast, weightless, and that same disappearing-act ride quality I've felt on other Seven bikes. It would make an excellent long-distance commuter with some fenders and a lightweight rack or two.

  2. I had the pleasure of riding that bike, set up as a single speed, for 20 miles last month and it was fabulous. As you describe, the ride is silky smooth and acceleration is quick, even with the single speed. I rode with the Schwalbe tires inflated to 100psi (I weigh ~160). Nothing like Ti, except a finely tuned steel frame, perhaps.