Moving to 1x drivetrain

I’ve used Planet X XLS bike for about 5 years and can say that is an amazing bike – I treat it not only as cyclocross, but also as road bike and gravel, depending on used tires. I started a few MTB races on this bike, I made my longest ride on this bike, I started using tubeless, tested a lot of different configurations… and changed a lot of things regularly. In the original specification, it was a 2x10s bike, but I changed it to 2x11s and now it is a 1x11s bike. I would like to write why I decided to move from 2×11 to 1x and why it is the best choice in my opinion. 

Top pull frame horror

The problem is that this frame uses top pull cable routing. It’s because a cyclocross frame should be easy to carry during a race, when we have to run up the stairs with the bike on the shoulder. Idea is very fine and can help a lot, but it generates a lot of issues, because most road front derailleurs use bottom pull and are not compatible with top pull approach. Modern cyclocross bikes with 2x have internal cable routing that allows carrying the bike easily and still uses bottom pull. I really do not know why Planet X could not resolve this issue in a similar way a few years ago: frame has internal cable routing, but only partially and on top tube. Nevermind. They decided to use something different – special roller, which can change routing from top to bottom pull. Is mounted on the seat tube, below the front derailleur. 

In theory, everything is fine with it: cable is rotated and can engage the derailleur from the good side. In practise, there are some issues. First of all, it complicates all the system and there is another element that can break, during training or during race. Second, it is sensitive to… dirt and mud! Really! They decided to use uch solution on cyclocross bikes, that should be designed for bad conditions, to a lot of mud. I had several situations, especially in winters, when mud clogged roller and front derailleur didn’t work correctly. Third and the latest one: it changes route, but also cable angle and in many cases, there are a lot of problems to align shifter and derailleur: it may require a lot of force to change front gear, trimming may not work or both of them at the same time. Really, it’s not a good option. 

GRX 1x crankset
GRX 1x crankset

Old CX70 for rescue!

No solution? Fortunately, there is one, good option: Shimano CX70 front derailleur. It’s 10s front mech, but compatible with 11s. Designed for CX and has a version for top pull routing. With such a derailleur, it’s possible to completely avoid using any rollers and simplify drivetrain. It also helps to deal with mud and dirt, and has no problems with trimming. It’s a great option and only availability may be an issue: this derailleur is not available in most shops right now. I’ve used it for about 2 years and can really recommend it for all bikes with top pull routing. In my case: it worked fine, but I still looked for something else, something easier, cleaner, prettier. And 1x drivetrain is the best option for me and my cyclocross bike.

1x configuration

What I use now? It’s GRX RX810 42T crankset and 105 R7000 11-32T cassette with Ultegra RX800 rear derailleur. I use such a drivetrain with amazing Gravelkings AC 700x35c tires I reviewed on a blog a few months ago. Why such option? I tried the GRX 48/31T crankset and I think it isn’t a good option: yeah, it has very wide gearing, but in practise, is hard to use for example in gravel and cyclocross. We can use it with narrow cassettes like 11-28T, 11-30T or 11-32T, but it doesn’t help – small difference between cogs means too small speed differences during gravel riding. It was not comfortable for me. Also, such a crankset required a GRX front derailleur and using the roller I mentioned before… it didn’t work well and the trimming was awful. I decided, it’s such a bad option and only wasting time and money.

Ultegra RX800 in 1x
Ultegra RX800 in 1x

1x is simple, clean and light

Then I switched to 1x and now everything is pretty simple. I didn’t decide to use the GRX 1x rear derailleur, because it isn’t necessary. In theory, Ultegra RX800 can support a max 11-34T cassette. In practise, it supports 11-40T or even 11-42T without issues: we need only to adjust B-screw correctly. Also, as you can see, I do not use such a wide cassette. Why? Because I want to use this bike as a cyclocross bike and there are not enough hills in my area – my strength is more than enough to ride pretty well with a narrower cassette like 11-32T, even on mud and sand. I do not need a roller right now, switching gears is simpler, because I use only one shifter. Also, the whole drivetrain is much simpler to clean after a ride, because of only one front ring and without front derailleur. What about max possible speed? Using a 42×11 option with tires like the mentioned Gravelkings AC is more than enough for me and I do not see any issues. Bike is also a bit lighter right now.

What next? Probably nothing more. I was wondering about using Shimano HG700/HG800 11-34T cassette for better cogs difference, but they are not available now or completely overpriced so… I will stay with good 11-32T. Everything works like a charm, so… just ride, ride and ride! If you wander about the drivetrain on your CX or gravel bike – think about 1x. Maybe it will be a good choice also for you? Of course it all depends on the area, our strength and requirements, but if it isn’t something like a road plus bike, probably 1x will be more than enough.