Plan 2020 - Clincher Rear Wheel, aka "The DT Wheel"

One of the many critical things I need for training is a clincher fixed gear rear wheel. For the uninitiated, it's not just a matter of "converting a wheel". A track rear wheel is narrower, has a different hub, and is a specialized piece of equipment. With all the wheels I have, one thing I don't have is a knock-about fixed gear training wheel.

I do have a nice hub, so using that as a starting point, I built myself a nice training wheel.

Wheel building kit

Back in the day I built a lot of wheels, but wheels back then were simpler things. Nowadays the rims are taller, have a lot of nooks and crannies where you can lose a spoke nipple or something, and usually have lower spoke counts. Weight doesn't count as much as aero, and there's a whole new category of rims for disc brakes. With disc brakes the rim isn't the brake so the rim can be lighter and, most importantly (ha!), it can have decals on the side.

I decided to get a rim with decals on the side. I went with DT R460 rims just because they looked cool, they were clinchers, and they were relatively inexpensive.

Before my bike shop days ended I had gathered some wheel building supplies through a DT sponsored, in-shop course. Can you believe someone came to the shop and taught us how to build wheels?

Part of the kit included the pen-like gizmo in my kit above, a device designed to hold a spoke nipple so you could thread it onto a spoke deep inside an aero wheel.

I never used it until I build this wheel.

I also used spoke nipple washers (never used until this build). They're the cone shaped washers in the bag in the top right of the bin.

The crooked screwdriver is made to screw on nipples quickly. It's like a speed handle screwdriver.

The old wheel, before I tore it apart. Note cog on hub.

Built wheel, still to be tensioned.

Building the wheel took forever, probably about 2.5 -3 hours. Building it ended up being a calming experience, meditative experience. For the first time in a while I was lost in the process, focussed, and only realized how much time it was taking when I realized that I had to keep an eye out so I wouldn't be late picking up Junior (this was before the shelter at home thing). I left the wheel untensioned so there's a bit left to go, but otherwise it's all set.

Cog. I didn't remove it, built the wheel with it on the hub.

It's a bit funny, we used to joke about using cogs so small you could change a spoke without removing the freewheel. Well, this was my race wheel from 2009, and I just left the cog on through the entire tear down and rebuild process.

The other side of the hub.

It may not be pristine but for now it'll do.

Training - Spin Ups

With the off-season in full swing (for us non-cyclocross racers anyway, in the northern hemisphere), there's been the normal uptick in the training and fitness questions. With more time to think about the next season and any season disappointments fresh in their minds a lot of riders, including me, have been thinking about ways to do a better season in 2014.

In one of the posts I linked to the track clip, where I do some high rpm spin ups. I linked to it as an illustration of doing high rpm work, basically to explore the limits of possibility.

My intent was to illustrate that a normal, reasonably healthy 18-45 year old male will be able to hit 200 rpm pretty much the first time out, and improve that to 220-240 rpm in short order. Fast pedalers will hit 250-280 rpm, and the really good ones are 300+ rpm.

The inspiration came from an article about Scott Berryman, a US National Team sprinter back in the day. In a small side note the magazine (I think it was Winning) showed him astride a relatively normal looking spin bike and it said something about doing x rpm in y seconds. It worked out to 300 rpm.

One quiet winter day at the shop (back in the day) we all took turns on a Schwinn DX-900 fixed gear exercise bike. We would do max rpm efforts, trying to get the computer to read higher than the others. I managed to get a reading of 286 rpm, in sneakers using the wide loop pedal (not really toe clips).

One rule we had was that we had to stay with the pedals on the spin down - if we ejected out of the pedals we could really bump the peak number, by 20-30 rpms (I think I hit in the high 290s but I don't remember, and my normal high rpm was in the 270s). We felt that ejecting out of the pedals wasn't a true test so we collectively decided we had to ride the pedals back to normal speed.

I really enjoyed the spin ups, enough to go and buy a used DX-900 many years later. I bought and installed some 3 piece BMX cranks, to replace the very inexpensive Ashtabula one piece crank (similar to ones you see on department store kids bikes). The cranks are 175 mm cranks, to replicate my road bike cranks, not 170 mm or 165 mm, which would make it easier to spin fast.

The three piece cranks allowed me to install the SPD-R pedals on the DX-900, pedals that I ended up using on the track as well. Because I can't unclip easily from the SPD-Rs this really forces me to "pedal down" with the bike. There's no bailing out if I need to hit my shoe with my fist to unclip.

I thought that the high rpm work would accentuate any knee alignment problems, and with the then-new idea of video taping fit session on a trainer, I decided that I would do the same thing. I videotaped my knees from a few different angles.

I ended up inserting those spin ups into the track clip.


In that clip I hit a max of 244 rpms, peak, with two efforts netting a lower peak rpm, in the 230s somewhere.

One forum member questioned the accuracy of the numbers, claiming that there's no way I could have hit 240 rpm, 220 rpm, even 200 rpm, saying that I was hitting 180 rpm "if that". He linked to a clip of a national level team sprinter hitting 257 rpm, coasting at the end (i.e. the same as bailing out of a fixed gear).

I assured him that I did hit 240 rpm, peak, and agreed that it was a peak number.

Still he basically called me a liar, saying I got nowhere near 240 rpm, even 220 rpm, and stood by his 180 rpm claim.

I know I can hit close to 180 rpm on rollers, higher than that on the road, and easily hit that before making a big effort on the spin bike. Therefore the idea that this guy not only doubted the number but absolutely dismissed it grated on me. I know that stuff I post can be checked, Googled, researched, and all that, and I don't post anything that I think is inaccurate.

I was thinking of using the spin bike this winter because of my lack of a sprint this year. I was thinking of doing it later, like in November (I did this a bit in 2011), but this inspired me to make the effort a week or two early.

So when Junior was at day care I went downstairs, moved the spin bike to the spot where I normally have the trainer or the rollers. I realized that I could use the phone camera, and I thought of things I would want to see as proof. The things that I'd want to see included the following:

 - single magnet on the cranks, to avoid doubling the rpm reading on the cyclocomputer.
 - wire from cyclocomputer to the crank, so the computer isn't reading off of something else, like a derailleur pulley or something mounted on an electric motor.
 - some real time thing in the background, like a clock with a second hand, a video playing on a TV, or even audio, something hard to fake.
 - actual footage of the cyclocomputer as it reads the various rpms, from low to high, to show that it's reasonably accurate.

The length of the effort would be easy to figure out - the computer updates its display each second, so each rpm number would be a one second number.

I popped a DVD in (a Ghent Wevelgem), the clock with the second hand was broken, and I moved the cyclocomputer to the side of the bars for easy videotaping.

The last bit bothered me. I get pushed when I have a visible goal, like sprinting for a line at a race, sprinting after a truck, or, in this case, sprinting to hit a particular minimum rpm. Moving the computer to the side meant I had no idea what I was doing because I couldn't see the rpm reading.

I was running out of time so I had to hurry things up. I got on my Sidis with the SPD-R cleats, put on a current Expo kit (because I was videotaping this), and got on the bike. It took me a minute or two to figure out that the pickup was a bit out of alignment. I fixed that, made sure the computer read a number, and started soft pedaling.

Since I needed some idea of how many seconds I could hold - I was guessing 5-10 seconds - I put the timer display up on the screen of the TV. I waited for it to reach zero seconds and ripped out an effort.

I had no idea what I did so I was a bit curious. It felt slow, that's for sure, and I was hoping that I wouldn't have to go back and post that, yeah, I hit 198 rpm, not 240 rpm.

On review I'd hit 241 rpm, with other seconds being 238, 234, with 225 rpm straddling them. My effort lasted 7 seconds.

241 rpm, max.

Because it looked sort of dark I decided to bring in another lamp - my bike room is intentionally very low in illumination so I can focus on either the TV or on nothing visual while I'm listening to music.

I did another effort, my legs slightly warmer, and with a huge 45 seconds for my second warm up I lashed out again.

247 rpm, for 3 seconds, preceded by 230 and then followed by 241, 240, 234, and then 222 rpm. This effort lasted 9 seconds.

247 rpm, max.

I knew that if I kept going I might increase it a bit but hitting higher than 244 rpm (the "claimed" max) I decided to stop. I knew that if I did more than a couple efforts my legs would be super sore the next day.

I posted the two pictures and transferred the video to the computer in case the forum poster questions my Photoshop skills or something like that.

My future plans include finding a cheap drop bar and maybe bolting on something (top half of a broken fork?) to hold a normal stem and bar. The bike, as it is now, has the super short stem really close to the saddle. I can't replace it because it's not a standard stem diameter thing, and I'd like to move the bars forward a half foot or so.

Ideally I'd be able to use a threadless stem and one of my old bars - I have a track bar I'll probably never use on the track and I'm sure I could fit it to some stem. If I can get drop bars on the thing that would be awesome.

The other thing I want to do is to get a better saddle set up on the DX-900, a two step thing. First, even in just 3 minutes the saddle was extremely uncomfortable, to the point that it was painful (a Turbo saddle). I'll put one of my other saddles on there.

The second bit on the saddle is that the effective seat tube angle is like 60 degrees. Great if you're plodding along on the original tractor seat type saddle but not great for someone doing max rpm sprints. I need to move the saddle forward some crazy distance, like two or three inches. I haven't done any measuring since, at this point, moving the saddle forward would put my bars in my stomach.

If I can get those things done I'd be using the DX-900 a lot more.

And maybe one day I can hit 286 rpm again.

Equipment - Road vs Track geometry

Over the past few years the "fixie" trend has permeated the cycling industry. Although it involves all aspects of life, the focus on the fixie is riding a fixed gear bike, usually on the road. Until now fixed gear bikes belonged in the velodrome ("track bikes") or under fearless bike messengers (although, truth be told, many messengers simply used converted bikes, i.e. not a "track bike").

Since road bikes have slightly different needs from track bikes the cycling industry set about to fill this new gap in the product line - the road going fixed gear bike.

True track bikes have a few features that prevent them from being ridden safely on the road. Two stand out over the rest, other than the fact that a track bike has no brakes.

1. On a real track bike the fork blades were round. Since there are no potholes on a track, the frames were not designed to resist impacts very well.
2. On a real track bike the fork is so slickly packaged there isn't even room to drill a hole for a brake. Most track forks are not drilled for a brake.

If you're looking for a real track bike it's tough to find those tidbits when looking at a spec sheet. There isn't a column that says "round or oval fork blades", and in many pictures it's tough to tell if the fork is drilled for a brake (unless there's a brake mounted on the bike already).

There are other ways you can check a potential candidate frame - you can compare geometry specs. Focus on headtube angle, fork rake ("offset"), trail, chainstay length, and BB drop.

I've found two bikes, from the same line, as an example.

Track
Road

For a 52 cm track vs a 52 cm road bike check out the differences:

HT angle: 75 deg vs 72 deg
Rake: 35 mm vs 45 mm
Trail: 61 mm vs 63 mm
Chainstay length: 380 mm vs 410 mm
BB drop: 45 mm vs 69 mm

The steeper head tube angle allows for quicker steering, meaning to actually turn the bike right or left. On a road bike it might be much, even if outfitted with a proper fork. The Spago team in the late 80s used such steep angled head tube Rossins that I thought Scott McKinley (on a long solo break) had crashed his bike and partially collapsed his frame.

In order to make the bike stable with a steeper head tube angle you need LESS rake (to give you about the same amount of trail; however, most track bikes have less trail). In the case of the two geometries above the track bike is only slightly less stable than the road bike, with just 2 mm less trail.

(The idea of less rake for more trail is counterintuitive, but think of a shopping cart - it has a really steep "head tube angle" of 90 degrees. When you push the thing forward the wheel drops back behind the pivot - that is what trail does, sort of auto-aligns the wheel for stability. Well a shopping cart wheel has something like negative 50 mm rake because the "fork" that holds the wheel actually points back, not to the front.)

Shorter chainstays means you have a bike that's more maneuverable, especially out of the saddle. Once you're seated it's not as noticeable. It also allows you to put more weight on the bars without having the rear wheel get loose under you.

A higher BB (meaning less BB drop from the axle height) means more clearance, necessary when riding slower on a steeply banked track. You can see the difference is substantial here - about an inch. This means your whole bike sort of moves up the same amount, since sizing is taken off the BB. Due to the higher BB height, everything else is taller. My 50 cm track frame looks like a 53 cm because both the head tube and seat tube are so much longer than what I'm used to.

Any "track" or "fixed gear" frame that has normal looking numbers is meant for road use.

Track bikes are different creatures.