Currently, the bike has a Tiagra 2x10. I would like to swap out to some combo of GRX 11spd 1x. I have done some swapping of drivetrains on mountain bikes before, but it seems a little more complicated on a road/gravel bike due to the integrated shifting/braking....
Here are some of the issues I'm wondering about:
1. I am pretty sure one Shimano's 11spd cassettes would be compatible with the current driver body on my rear wheel- can anyone confirm?
2. I am assuming I would need 11spd shifters- Would I need to upgrade the brakes (currently TRP Spyre mechanical disc) as well to have a Shimano shifter compatible with the 11spd drivetrain?
There are probably some issues I'm missing- thanks for any help anyone can offer!
I used to swap out cassettes from 11 speed to 8 speed when moving wheels between my bikes, until I realized that if I put an 11 speed chain on my old 8speed bike, I could just leave the 11 speed cassette on the wheel (with friction shifters). Moral of the story - most all chains (except 1/8 inch) have the same size internally (i.e. same tooth size), its the external dimensions that change.
I'm curious as to why you want 1x? It doesn't have any strong advantages (unless you are building a FS MTB and can't use a front detailer). I went out of my way for 2x because I need both range and tight gearing. That and the wear and tear when you go below 14t gets kinda high. My 2x is simpler, lighter, and more versatile. But if you don't have the need to both grind up steep hills and still ride a paceline at 30mph++, 1x is fine.
You can use the same brakes as long as the GRX is also mechanical, I assume there's a mechanical option. New wheels should be good for 10 or 11 speed. If there is a spacer behind your 10 speed cassette then all is well. If not, it's still not a big deal. Some 11 speed cassettes will fit anyway or you get a new freehub body. I agree with Chas though, for me 1x is not an upgrade for gravel. I'm actually doing the opposite of you at the moment, I'm converting an 11 speed 1x to a 10 speed 2x.
I'm curious as to why you want 1x? It doesn't have any strong advantages (unless you are building a FS MTB and can't use a front detailer). I went out of my way for 2x because I need both range and tight gearing. That and the wear and tear when you go below 14t gets kinda high. My 2x is simpler, lighter, and more versatile. But if you don't have the need to both grind up steep hills and still ride a paceline at 30mph++, 1x is fine.
Really? 1x has no strong advantages? I guess there are a lot of idiots out there (a lot of top pros too) running 1x and idiot manufacturers marketing 1x bikes with no benefit. Next time just say “here’s why I prefer 2x”.
1. Yes it is pretty much guaranteed to work if it is 11-36T or higher, 9-42T and 10-42T will not work without switching to an XD freehub 2. Yes you will need an 11 speed shifter. The cheapest way is to add a Microshift 11 speed bar end shifter and keep your Tiagra brake levers and Spyres. Ideally you would upgrade both shifters to hydraulic GRX.
This is going to be a relatively expensive process on a mid-level bike, and I'm not even sure that it's an "upgrade" to go from 2x to 1x.
To answer one of your Qs: Shimano disc brakes are hydraulic, and your current shifters won't work with them - which is partly why this will be such an expensive process. Those shifters are pricey.
GRX is available for hydraulic brakes only. If I was going to this much trouble, I'd take the opportunity to convert to hydraulic. I recently converted from 105 to GRX (both 2x11) to make this change. If you want to stick with cable discs, you may be able to find 105 options. Shimano 11speed road cassette and hubs are wider than the hub that fits Shimano 10 speed (road or mtb) and 11 speed road. Some people have reported problems putting a 11 speed road cassette on the other hub. I've had the reverse problem and had to put a 1.85mm spacer to fit a 11 speed mtb cassette on an 11 speed road hub. However, if you are going to 1x11 you will probably want to use a mtb cassette to get the range so you should be OK. Obviously you'll need to change the crankset too so will need to check whether it will require a change of bottom bracket.
Want to switch (maybe upgrade was the wrong term?) to 1x for simplicity, familiarity (came to gravel from an MTB background), ease of maintenance. Most of the riding and racing I do involves large components of super rough USFS roads and I've lost the chain multiple times, which I think a 1x system would help address.
Yes, I realize my bike is midrange and this swap will be expensive, but I love the frame and am willing to spend the $$/do the labor myself.
I have moved more to looking at SRAM's Apex 1 system- my wife runs this on her Warbird and she/I both love it. Especially since it's set up to work with mech disc system. My biggest question now is if the crankset will fit in the current bottom bracket- any insight? Thinking of just pulling my wife's off and seeing for myself...
