Coach's Column with Andy Applegate: Pros & Cons of the MTB Drivetrain Options - What is Best for You
Question: I'm putting together my new race
bike for next season, with so many drivetrain options what are the pros and
cons of the different setups, i.e. 3x9 vs. 2x10 v. 1x11? Is certain
gearing more appropriate for certain focus i.e. endurance, short xc, etc.?
question. The drivetrain options available now are numerous and could be a
little confusing. Let’s try to look at it from a rider or coach perspective.
First, we can most likely omit the 3x9 option for a new bike. Going forward,
high end 3x9 gruppos will soon be discontinued. While you will probably be able
to get parts for 3x9 for years to come. New groups will be hard to find and
most will be in the lesser quality component ranges.
leaves us with 2x10 or 1x11 as choices. Both are certainly viable options and
work really well. However, it seems like we have had a glimpse of the future of
MTB gearing this year and it looks like the front derailleur will be going the
way of the dinosaur.
we go any further, think carefully about the demands of the terrain you are
most often riding and what your goal events require. Competing mostly on fast
Midwest singletrack? Or will you be doing more steep or long climbs? Do you
require a very small "granny gear” for climbing or do you need a big gear to
pedal at high speed? Keep in mind that with 2x10 (and even more so with 3x9)
there is a lot of gear "redundancy”. In other words, you don’t really have 20
discrete, different gears, as many are repeated. Several of the small ring/
small cog gear combinations come very close to matching some of the big ring,
big cog combos.
let’s consider the "hardest” and "easiest” gearing on a couple different set
ups. I guess this requires a little bit of a definition of gear "development”.
Gear development is the distance your bike will travel with one full revolution
of the cranks in a particular gear combination. The further the bike travels
(bigger gear development) the "harder” the gear. We don’t really need to talk
in specific numbers to make comparisons here though, we really just need to
know which combinations are bigger and which are smaller. Let’s look at some
are some easiest gear possibilities first (these numbers assume a 29in wheel
and a 2.0 tire)
2x10 set ups
gear = 1.6 meters development
gear = 1.5 meters development
1x11 set ups
1.8 = meters development
= 1.7 meters development
= 1.6 meters development
3x9 set up
= 1.5 meters gear development
you can see there is not as much difference on the low end as you might expect.
Depending on what size ring you choose, you can get easy gearing with 1 or 2
ring set ups. You can even get the same easy gear as a normal 3x9 set up
(22x34) with a 24 tooth ring on a 2x10 (24x36).
let’s have a look at the opposite end of the spectrum:
= 8.1 meters
= 7.8 meters
= 7.7 meters
= 7.3 meters
= 6.8 meters
= 8.7 meters
we are really seeing some differences. This is where the real compromise needs
to be made when you are going with a 1x11 over a 2x10 or even 3x9. The question
is: how big of a gear do you really need? Again, it comes down to the terrain
you will be riding most. For easy gears you really can go with either set up,
but you might need to swap rings from some stock offerings to get what you
need. For the high end, with a single ring you are going to lose some
development, but how often are you spun out in your hardest gear on the MTB?
For most of us it is not very often, however if you are riding a lot of flat
dirt roads and the like this is a consideration.
and cons of a 2x10 set up:
the plus side, you get both high and low gearing without compromise, there is a
greater variety of price point options, most wheels are equipped to handle 2x10
the negative side, you still have to deal with the front derailleur and shifter
and generally the system will be a little heavier
and cons of a 1x11 set up:
the plus side, no more front shifter and derailleur to worry about setting up!
System is generally lighter. In wet and muddy conditions the single ring setup
could be less problematic than multiple chain rings and a derailleur.
the negative side, available options are still limited and quite expensive,
compromise needs to be made on gearing particularly on the high end. Wheels may
need to be adapted to take the 11 cog cassette. Wider range cassette means
bigger jumps between gears.
is a lot of good news on the way. There are a few companies making adapters to
fit a 42 tooth cog on a 10 speed cassette so you can run a 1x10 with a gear
spread similar to the 1x11 systems. I would also expect the 11 speed technology
to trickle down to less expensive groups.
2x10 or 1x11 will work very well across a variety of MTB disciplines (xc,
endurance etc.) but be sure to look closely at the gearing you will end up
with. Pay specific attention to the high and low gears and the compromise that
you may be making. There are plenty of online gear calculators to easily do
this. In general, for most off road applications I would pay more attention to
being sure you have the easier gear you need to get up hills even if it means a
trade off in the high end. Keep in mind that if you are racing shorter XC type
events you may be able to get away with a harder gear combination. Crushing a
slightly bigger gear than comfortable up a short climb in a 2 hour or less race
is not much of a drawback. On the other hand if you are targeting longer
races, having the easier gear to get up a climb after you have been on the bike
for many hours could be the difference between having a great day or struggling
just to finish.
nice thing is that we have all these choices available and even more
Applegate is a Pro level coach with Carmichael Training Systems. He has over 20
years of racing experience and has been coaching cyclists full time since 2001.
His passion is endurance mountain bike racing. You can find out more about Andy
and his training programs at www.trainright.com