So we now continue with our introduction to the track bike. We left off with the tires during the last post. We will nor share with you the other parts of the track bike.
Track cranks are shorter than road cranks. Smaller riders will ride 165mm cranks, where on the road they likely ride 170’s. Larger riders will ride 167.5mm or 170mm cranks, where on the road they might ride 172.5mm or 175mm cranks. The main reason for this is the higher cadence of track racing. Much more on that below. But suffice it to say that if your typical racing cadence on the road is 90-100rpms, a typical cadence on the track is 120-130rpms, with accelerations up to 150rpms. For that, shorter cranks are more efficient. But crank length affects pedal clearance, too. Short cranks have better clearance on the outside pedal in the corners.
The chain on most track bikes will be a 1/8”-width chain. These chains are visibly wider than any chain you would find on a road bike. The idea is that they are stronger and flex less.
That said, entry-level track bikes (e.g., a Bianchi Pista) will often come with a 3/32”-width chain, which is narrower and closer to what a road bike uses. (More precisely, road bikes used to have 3/32” chains, before the chains started to get narrower still in order to accommodate more cogs in the rear.)
The only practical thing you have to remember about track chains is that while the larger 1/8” chain will work with any chainring or cog, the narrower 3/32” chain will not work with the wider cogs or chainrings designed for 1/8” chains. So if you end up with a mixed collection of chains and cogs, just be aware of that.
A final note – some six day racers in Europe use 3/32” chains on their track bikes because the chains are a little less rigid, and they say it’s easier on their legs. Since I ride on both types of chains, I’ll say that I find this believable. The narrower, more flexible chain makes the ride a little more comfortable, though I wouldn’t attempt to explain exactly how.
One optional item on a track bike that has no analogue on a road bike is called a chain tensioner. If you tend to have problems with your wheel slipping forward in the rear dropouts, it will solve that problem. This problem would tend to arise on standing starts (chariot races, time trials, match sprint), where the effort you put into the pedals has the effect of pulling the right side of the rear axle forward, and you “pull a wheel”.This stops the bike dead, and you fall over, and you look silly. It’s embarrassing, and incredibly frustrating.
The problem of pulling a wheel is most likely to arise if your rear dropouts are shiny or too rigid. Because the grip of the rear axle bolts into the rear dropout is the only thing keeping the wheel in place, the best bolts are big and grippy, and the best dropouts are of a somewhat softer metal, and painted – it grips better than chrome.
That said, if you have a wheel/dropout combination that doesn’t seem to hold very well, just cranking down on the right-side axle bolt will eventually cause you to strip the axle threads, the bolt faces, or both. Don’t do that. Just get a little device called a chain tensioner, and you’ll be all set. You can’t pull a wheel with a chain tensioner on. It also may make it a little easier in general to get the right chain tension and wheel position when you’re switching gears.