With all the buzz lately on carbon fibre long travel bikes, 650b wheels, and enduro racing, the lowly singlespeed has fallen to the back of the cool kid pile. Recent rain has got me to dust off my singlespeed bike. Thus, I’ve got some stuff to say.
Singlespeed bikes are my more hated bikes. They hurt me. They make me climb fast at the expense of my composure. They are painfully slow going down hills. They feel like toys. They also tend to have small forks and tires. Aside from all that, they are the #1 choice of bike when it rains. With a hydraulic braking system in place, there is next to no extra maintenance to do on these even on the most miserable of mud rides. Rain rides destroy fancy FS bikes, shifting systems, dropper posts, and every single bearing in your suspension system. Keep your fancy bike warm and dry. Ride your SS hard and put it away wet. That’s what they’re for. They cost nothing and don’t ask for much over time.
I needed drop my gear a tooth. From 34-19 to 34-20. I’ve been training and dieting so I don’t have a lot left on top to push that steeper gear in Marin. I was digging through cogs and figured I’d write about that.
All cogs are not the same. When I set up a singlespeed bike, I’m very specific (of course). I use DH chainrings, 10-speed chains, and only Chris King or Surly cogs. Each of these choices are made for a good reason. DH rings are stiff (except for e13 rings which are junk) and have plenty of structure where the chain contacts it. Only 9 or 10 speed chains should ever be used on a SS bike (I like 10 speed as they are stronger and lighter). This is due to the quality of the chains but more importantly, the inner champers on the chain plates that keep the chain running smooth as the bike and ring are flexing. The cog choice has to do with engineering and quality.
Most cheap SS cogs that show up on OEM bikes or in cheap kits are about the worst parts you could ever put on your bike and guaranteed to wreak havoc on your chain and ride. They are stamped out as cheaply as possible with what might look like a real roller chain tooth profile from an odd angle. A closer look reveals that this is pure fantasy. Often there are burrs or lack of metal in parts. Roller chains require very specific and precise profiles to carry the loads smoothly and at the least cost to the chain. Take a look at the profiles on these cheap cogs. Everything about them is wrong. A complete nightmare.
In contrast, cogs from Chris King and Surly have tooth profiles that are properly engineered and cut with care. These (or a comparable high end cog) are the only cogs that your should ever use. These are really great parts for different reasons.
I love the Chris King cogs. They are truly things of beauty from an engineering perspective. They are strong and light, but feel almost delicate in your hand. The machining is also exquisite as is to be expected. Honestly, given what they are, how well they do it, and how light they are – they aren’t that expensive.
The Surly cogs are fine. They do the job well and they are cheap. What really pisses me off about the surly cogs has to do with the engineering and weight of the cogs. For almost no extra manufacturing cost, I figure that these cogs could weigh 25% less than they do. I find it hard to believe that QBP was able design a proper tooth profile on these but completely screw up the design of the rest of the part unless they actually let somebody in the Surly marketing department have a say. It defies logic, but Surly’s marketing strategy is targeted at the stupid instead of the smart. I figure if this part was branded as Salsa it would be considerably lighter.
Size / Chris King / Surly / % heavier
17 / 36.6 gr. / 51.9 gr. / 42%
18 / 36.9 gr. / 59.2 gr. / 60%
19 / 40.3 gr. / 69.6 gr. /73 %
Also, a Chris King 20t cog weighs 43.3 gr.
The weight comparison between these two brands shows a staggering difference. Unlike almost any other type of part in cycling. Rarely can you cheap parts that weigh more than 1.5 times what the fancy part does, but you do in this case. Also, knowing what I know about manufacturing and engineering, there is literally no excuse for it. No significant cost would be added. Program a different profile in on the lathe and a tiny bit of extra time with an endmill on the mill. Not even an extra setup. $0.50 on the production side? Less?