New Bike Build 1x vs 2x Gearing

cd03wba

Hi,

I'm not new to cycling by any stretch but would like some up to date MTB advice, as I've been concentrating on Road stuff for the last decade and appreciate that things have moved on a bit in the MTB World

I'm building up my umpteenth bike and would like to encompass as many gear inches as possible. The purpose is long distance on and off road touring or what everyone now calls "Bikepacking".

My build is based on a Ti MTB hardtail frame with either Ti forks or some lightweight 100mm suspension forks.

I like the look of the e13 9-50 Helix cassette and was simply going to use a standard 32T Sram Eagle set-up with it.

The problem is, as we all know, spinning out.

Back in the day, I used to ride an extremely lightweight SC Highball 29er with an 11-28 and a 39T for XC and found that to be limited on the flat!

But like everyone I also want the best of both worlds, in terms of being able to climb. Especially when relatively fully laden.

So my questions are... Is it possible to run a dinner plate 9T-50T, 10T-50T, 11T-52T cassette with a double front chainset?

And if so, could I use some existing Di2 hardware I have or maybe even AXS? I much prefer SRAM for MTBs but that's just through personal experience with Shimano in the past.

Or am I just better off swapping a 38T for the standard 32T when the going gets easier?

Ideally, of course, I'd like to run a double 32T / 38T and the 9T-50T which would give me a good range of 18.6" to 122.75".

steve_sordy

Yes, you can run a 2x12 set up. Here is a link to a complete groupset available on eBay.

https://www.ebay.co.uk/itm/125256385654?var=0&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338268676&toolid=10044&customid=CjwKCAjwqauVBhBGEiwAXOepkWY0wjdHDagcgXKYpwFUtD67Yz9BKaHiDZR5lTkT-HbrlcyFh3EcRRoCEuIQAvD_BwE

But you can buy the bits separately if you already have some elements.

You can also buy 2x11 and 2x10.

But why go for 2x10 when you can have 2x12? The range you can get with a 2x is enormous and if you decide that something a bit less than enormous is what you really "need" then you can save yourself a lot of the initial cost, the maintenance problems and also the cost of replacement parts.

If you intend to stay on the road, then 2x12 remains just a cost issue (purchase and replacement).

However, you will be going off road, so ground clearance and snagging will be an issue. Trust me on this, while the 12-speed is great for providing range, the mech really does scoop up vegetation and snag on rocks and roots. My first 12-speed bike (a 1x) was constantly having shifting problems caused by the mech arm getting bent; I once bent the mech hanger! In the previous many years of biking (7-speed to 10-speed), I had never bent either a mech arm or a hanger. After three trips to the LBS for realignment, I bought myself a mech hanger alignment gauge and tool, so now I can sort it myself quickly and easily.
I have since had other bikes with 1x11 (not quite as bad) and 1x12 (just as bad). On my last bike I snagged a small Pine sapling and snapped the XT mech clean in two! When my current drive train next gets to a decision point, I am seriously thinking of going back to 1x10 but with a wide range cassette.

I suspect that a 2x10 with a wide range cassette (but not quite the colossal 11-52 that you are thinking of), will give you a very good range but with none of the cost and operational problems I referred to earlier. Whatever speed and range you go for, remember that the larger the big ring on the cassette, the longer the mech arm has to be and the closer it gets to the ground. Therefore, a 29er would be a better choice of wheel than a 27.5er.

The big advantage of 1x for me is that there is now clear room for a dropper remote on the left. The activity for my fingers and thumbs is more evenly divided and the bar layout just works better.

cd03wba

Wow! That there is the insight that I need. Thank you!

I had seen a few people resorting back to 2 x 10 and 2 x 11 and when push comes to shove it's not about the number of gears, it's about the range!

That's really helpful to know about how the length of the rear derailleur could be problematic.

I must admit I've never been a fan of dinner plates on the back for that reason but seeing how most riders seem to have accepted them and longer rear derailleurs, I naturally assumed that 1 x was the way forward.

Let me ponder!

cd03wba

Interesting... Thanks for all that information.

I'm currently thinking of going back to Plan A and running a 1 X set-up 30T or 32T with a reduced "dinner plate" 11T-46T BUT taking a 38T with me and fitting that out, on the road whenever the route I'm doing is more flat or downhill...

I know that sounds finickity but the weight and cost of all the other paraphernalia versus swapping out a relatively light chainring in the morning of a ride doesn't sound too bad, if I'm honest!

Obviously, chain length could be a problem but having done that sort of thing in the past with single speeds, it could be a half-decent work around...

steve_sordy

I would recommend that you consider very carefully what range of gears you actually need. Instead of going as big as possible just in case, try to determine what gearing either end of the range will work for you. Then choose your gear set up.

If you will be using a dropper seat post with a remote on the bar, then a 1x is really worth going for. I have tried 2x with a remote on the right and the left and the less than ideal positioning of the remote was a proper faff. Not only awkward to use, but failing to actuate the remote quickly enough once caused me to have an accident. It was at that moment that I decided to take the plunge and go 1x.
I agonised for ages over range; would I be able to do those climbs, but spin out on the flat? Or would I get up to speed OK, but fail to get up that climb? Which was more important to me? I had just decided that climbing was more important when the decision was made for me by 1x12 gearing coming on to the market. 1x12 has a very similar range to a 2x10. I have never regretted the decision.... well maybe when I had to keep getting my mech and/or mech arm reset! I now have an emtb with 1x12 and I rarely use the 51T gear and the 39T only occasionally, which is why I am contemplating going to a 1x10.

But I don't do touring or bike-packing and my needs are different to yours. If you have no need for a dropper, then there is every reason to go for a 2x. The extra weight of a second ring and its lever and cable is very small compared with all the crap you will be carrying with you when bike-packing. That will be when you really need that extra gear range.

I personally could not contemplate carrying an extra ring with me just because the terrain might change. In addition to that, the chain length would have to be altered as well, so you would be adding/removing half a dozen links every time. You'd need to carry the tools to do all this as well. For what I do, that is just too much hassle.

cd03wba

Thanks both.

I was just working out the chain length needed to run say a 28T to a 50T and then what the limit would be, switching over to a 38T and the usable gears on the same length of chain aren't terrible. I'd just be losing the 36T and 50T.

OneUp and Wolf Teeth do a SRAM crankset spider that allows you to swap over the chainrings simply by undoing the four chainring bolts, so that at least wouldn't involve removing the whole crankset.