How I Plan to Set up 1x11 on My Scott Scale 970 3x10 XC Bike and Why

10
Jun
2016

While there is nothing wrong with 3x10 system, the 1x11 are getting more and more popular. Why? 1x11 provides a wide range of gear ratios, you have only one shifter, no repeating gears, less weight and much cleaner looks.

The math- is it really worth it?

I did fast gear ratio calculations for my current set up which is 11-36 cassette with 22-30-40 chain rings. With green I have marked my 2 favourite gears I use when pedalling full speed, last gear has too big ratio and is useful for me only on straight and long descents on the tarmac or really hard sprinting. As it goes for climbing, I don't really use first gear, it is too slow and I lose balance because of lack of speed or rear wheel looses traction, 28t seems like the sweet spot with its 0.79 ratio.

22 30 40
11 2.00 2.73 3.64
13 1.69 2.31 3.08
15 1.47 2.00 2.67
17 1.29 1.76 2.35
19 1.16 1.58 2.11
21 1.05 1.43 1.90
24 0.92 1.25 1.67
28 0.79 1.07 1.43
32 0.69 0.94 1.25
36 0.61 0.83 1.11

Next table has 1x setup ratios. On the first row, I have chain ring sizes that are most popular choices with 1x setup, on the first column, I have cassette gears, with yellow I marked different cassette configurations for largest gear- M8000 cassette comes in 3 configurations 11-40, 11-42 and 11-46.

So 34t chain ring provides almost the same 3.08 ratio I use mostly and 11-42 cassette will provide 0.81 ratio for climbing. 36t chain ring is available only from other manufacturers like raceface or one-up. while 11-46 cassette and 36t chain ring look very good on paper- large ratio for descents and sprints and 0.78 for climbing, for starting I chose 34t and 11-42 cassette, because I'm afraid that 3.27 and 2.77 gear ratios won't suit me. Anyways I can always swap chain rings, they are not that expensive, it even could be a great idea to have a chain with 2 quick links and 2 chain rings, 36t for fast and plain courses, 34t for more technical and slower courses with a lot of ascents.

30 32 34 36
11 2.73 2.91 3.09 3.27
13 2.31 2.46 2.62 2.77
15 2.00 2.13 2.27 2.40
17 1.76 1.88 2.00 2.12
19 1.58 1.68 1.79 1.89
21 1.43 1.52 1.62 1.71
24 1.25 1.33 1.42 1.50
27 1.11 1.19 1.26 1.33
31 0.97 1.03 1.10 1.16
35 0.86 0.91 0.97 1.03
40 0.75 0.80 0.85 0.90
42 0.71 0.76 0.81 0.86
46 0.65 0.70 0.74 0.78

What I will need to convert to 1x11?

1) Cassette

The cassette is the easiest part, 11 speed Shimano cassette is compatible with 10-speed Shimano cassette, I only need to choose which configuration suits me best and swap cassettes on my rear wheel. Judging from gears how I use on my 3x10 set up, 11-42 cassette is the best choice for me.

2) Chain

Nothing really to add here, just 10-speed chain is not compatible with 11-speed cassette and I need to get HG-X11 chain instead of HG-X I have currently.

3) Rear Derailleur

This one is a bit tricky. M8000 rear derailleur comes in 2 sizes, medium and long. Long is meant to be used with 11-46 cassette and 2/3x set ups, it will work with 1x11, but chain dropping might be an issue, but if you ever think about changing back to 2x11 or 3x11 set up, buying long version derailleur might save some money.

4) Gear Lever

New derailleur with more gears means new gear levers. In my case, any 11 speed Shimano gear levers will fit. I choose Deore XT M8000, to match all groupset.

Chain Ring, Opportunity to Save Money

I have Shimano FC-M523 Octalink Crankset which has 3 chainrings. My bottom bracket is octalink system, where spindle is integrated in bottom bracket.

Option one is to buy M8000 bottom bracket and XT 1x cranks. Price is about 100$ for cranks, 40$ for chain ring and 20$ for bottom bracket, 160$ in total.

Option two is to buy only 96mm 34t chain ring for 50$, shorter chain ring bolts for 10$. Remove all chain rings from current cranks and replace 2nd chain ring with the 1x ring.

Conclusion

In total this upgrade cost me about 300$, 350 if I will replace cranks. Benefits are lower weight, less shifting, cleaner looks, less cables. Probable issues could be chain dropping and increased maintenance costs. Chain ring will be replaced more often and cassette are more expensive, but In my opinion it is worth it. Almost the same gear ratios with a lot of bonuses.