My current multi purpose bike features some unusual component combinations that may be of interest to other bike builders. It is a fairly techy build, so warning: this post may cause eye twitches and other assorted muscle spasms in retro grouches. You have been warned.
The frame is an Airborne Carpe Diem, circa 2004. And since I have new parts on an old(ish) frame, I choose to call it my steampunk project. It is a bit of a stretch, I know, but it is my bike and I can call it whatever I like.
Airborne has since been acquired and is now making completely different bikes. But back then they were all about affordable titanium. The Carpe Diem is a light touring/cyclocross frame. It predates the current wave of adventure/gravel bikes. It does cannot handle a very wide rear tire, which keeps it out of those categories, as well as the fact that is it not suspension corrected so you can’t put your favorite RockShox on the front. Besides having an awesome name, the frame has some interesting design choices. For example, the rear dropouts have 132.5mm spacing, which is just plain showing off one of the great traits of titanium. To be specific, road bikes have 130mm spacing. Mountain bikes back then were all 135mm. Nothing was, is, or ever will be 132.5mm. But titanium can handle being pulled wider or squished in by 2.5mm. Not so much with other materials. So the Carpe Diem can be fitted with either road or mountain wheels without having to modify the dropouts or use spacers, etc.. The frame also has IS disk mount tabs in addition to canti/v-brake mounts. So a road bike/disc brake combo was possible with this frame way back in 2004, a little ahead of its time, don’t you think? The frame also features some nice tube shaping at the junctions, nice looking welds, etc. Some Lynskey/Moots/Seven/Litespeed owners are quick to point out that Airborne had some quality issues with some bike’s welds, and by all accounts it looks like they did, but I think by now it is safe to say my frame has proven to be one of the good ones.
I have been waiting for road integrated shifter/brake levers for hydraulic brakes to come into existence so I could install them on this bike. After a decade of waiting, Shimano’s RS685 were among the first available and I snatched up a set soon after they came out. I got mine as a “pull off” set and they came paired with BR-M447 calipers – a bit of a mismatch because the levers are Ultegra level, while the calipers are probably more like Alivio. But they are totally compatible. My white babies have awesome stopping power nonetheless. I had Avid BB7s on the front before getting these. These deliver more stopping power with less effort and great feel and modulation.
But hydros for a touring bike? Yup. “Aren’t you afraid they will fail and leave you stranded?” Nope. When was the last time you heard about hydro lines bursting or whatever? About as often as you hear of brake cables snapping. I bled these myself and they are super easy to work on. It is just a new skill you need to develop.
My lust for hydro drop bar brakes created a chain reaction of updates because I needed to go 11 speed to get them. That was a problem. Shimano 9 speed road and mountain bike components are highly compatible. You can pair 9 speed road or mountain triple cranksets with road or mountain cassettes with road or mountain rear derailleurs and road or mountain shifters. It is touring bike building nirvana. (Front derailleur compatibility aside). But Shimano got away from this with 10 and 11 speed. So it was SRAM to the rescue. Many of its road and mountain 10 speed components are compatible. But road hydro did not hit the scene until 11 speed, and neither SRAM nor Shimano road and mountain groups are compatible with 11 speed.
But wait, it gets worse! Road hydro shifters are currently only available as 2x, i.e. no 3×11 road groups are out yet. So no 3×11 crankset either. There are 3×10 cranksets that would work fine if the shifters ever come into existence. This unfortunate situation is happening at the same time touring/gravel/bikepacking bikes are growing in popularity. For those kinds of bikes you want wide range gearing that you can only get by mixing road and mountain components. My fearless prediction is that this situation will be fixed with 12 speed and maybe later with 11 speed. All we really need is long cage 11 speed road rear derailleurs.
But for now the solution to this is 2 parts:
- An adapter known as the Shiftmate from a company called Jtek. Several other companies now make equivalents. It changes the cable pull ratio of the shifters to allow 11 speed road shifters to throw 11 speed mountain bike rear derailleurs.
- A great big honking pie plate sized cassette. This delivers a wide gear range with a double crankset. I use an 11/42T Sunrace cassette. Paired with and 34/50T compact road crankset, it has about the same low gear ratio as a 24T chainring paired with a 34T large cog on a 9 speed mountain bike cassette.
I actually like this gearing/drivetrain BETTER than a triple combos. 2x shifting is simpler and better than 3x. You have the option of even wider range cassettes. There are 11-46T Shimano cassettes and 10-50 SRAM cassettes. Some of those are marketed as 1x cassettes, and you may have to modify your rear derailleur to get them to work. Mostly by installing a longer B tension bolt. A few notes about my specific set up:
- The 50T chainring and 42T granny cog combo takes a full uncut 116 link chain to wrap around it. If you decided to use a bigger cassette or crankset you will need 2 chains. Recumbent riders are used to this, so it is not totally weird, but be aware of it.
- The drivetrain is quiet and shifts everywhere surprisingly quickly
- Setting up the Shiftmate is a little fussy. You need to set it up so that the flat section of the adapter does not rotate so far that the cable crosses it again. If you set one up you will see what I mean. AND if you ever release all of the tension on the cable you may have to carefully position the adapter wheel again. But probably not.
Overall this makes for a beefy feeling road/tourer in spite of the relatively lightweight build. The big Salsa Cowchipper bars contribute to the big feel vs. a road bike. It can handle a heavy load with no problem. Compared to full touring frames it handles a little twitchy. Compared to a road bike build it feels like a tank. It can handle light off road duty with cyclocross tires. While it may not be as flexible as the latest round of adventure bikes on the market, it is still my indestructible, unstoppable, post apocalyptic, steampunk urban guerrilla bike.