The 1x11 Enduro Racing Drive Train Journey Part I

The 1x11 Enduro Racing Drive Train Journey

Part I

1x9 and 1x10 drive trains have been very popular for years with the downhill, enduro, and all mountain riders who need ultimate chain retention over rough demanding terrain.  Very fit cross country racers have also been enjoying the efficiency, reduction in weight, and improved reliability provided by these 1x drive train set ups.

The advent of the super wide range rear cassette (10-42 tooth), most notably the Sram XX1 and XO1 groups, has made running a single front chain ring as versatile as a good 2x drive train.  Riders and racers can now have the necessary low range gearing necessary for spinning up steep long climbs as well as a proper high range for accelerating up to common top speeds encountered on dirt.  Tuning of how low and how high a gear range is just a matter of changing the front chain ring size to suit local riding areas, fitness levels, or race courses. 

 

In an attempt to gain potential performance advantages and simplify my drive train I have began a journey away from my proven 2x drive train to a simpler and lighter 1x setup without compromise for enduro racing.  The test mule for this experiment began with my 2012 Santa Cruz Nomad and will be completed in stages as finances allow procurement of components.

Scouring the internet I discovered that this was not going to be a cheap endeavor but did find a way to eliminate some of the expenses by using my existing X0 crank set and purchasing one of the 1 piece single chain rings available aftermarket instead of purchasing either the XX1 or XO1 crank set.  This is worth a $350 saving right out of the gate.

  

I ultimately chose to purchase a 30t GXP chain ring from Wolf Tooth Components www.wolftoothcycling.com out of Minneapolis, MN for $78 (Free shipping).  It arrived promptly within the same week I placed the order.

I decided to start with the 30t because I will still be using my Shimano XT 9sp rear cassette with an 11-34t spread in the near term.  Given the nature of the enduro races I compete in the 30x34t low gear is sufficient to sprint up a race stage climb and if the transfer stage climbs get too steep I plan on just walking briskly while pushing the bike.  I did make a compromise on the high gear and dropping from a 36t big ring to a 30t cut my top speed at 100 rpm cadence by 4mph.  However when the 10-42 11 speed cassette eventually gets installed I will regain the same gear spread as my original 2x9 set up that has been working well for enduro racing (and trail riding).

With the Wolf Tooth GXP chain ring in my possession and the last Oregon Enduro Series Race only a week away I decided to go for it and ditch the Shimano XT double front derailleur, Sram X0 9 speed trigger shifter, and MRP 2X chain guide that has been in use with perfect reliability over the past year.

FYI - I entered this race in 10^th place overall in the Sport Men 40+ class for the series and some quick math indicated the only way I would move up was if all the top competitors stayed home.  Even if I suffered some minor mechanical issues I would still retain that 10^th place finish.

 

Installation was a breeze;  remove front derailleur, remove shifter, remove chain, pull crank, remove three small bolts that hold the chain ring spider on the drive side crank arm, clean away dirt build up, bolt the Wolf Tooth GXP chain ring on, reinstall the crank, and size a new chain to proper length.  With a repair stand and the proper tools at the ready it took 30 minutes to complete the swap.

You may have noticed that I am using a 9 Speed chain and did not install a chain guide or a bash guard with the Wolf Tooth GXP chain ring.  This was due to several reasons; I did not have a chain guide or bash guard compatible with the single ring, I wanted to test the chain retention abilities of the wide-narrow tooth profile with a 9 speed chain, and I thought the 30t provided adequate ground clearance to not risk damage to teeth or chain.

Note:  Wolf Tooth states on their web site “No front chain-guide is required provided you have a clutch-type rear derailleur”.  Since I do not have a clutch type derailleur (yet) I was prepared to experience a few dropped chains while racing on enduro courses that also serve dual purpose as downhill race courses. 

 

For the weight weenies out there, removing the front derailleur, shifter, spider, chain rings, and chain guide eliminated a pound from my bike.

With 2 days before my trip to Mt. Hood Oregon I went on a trail ride and was immediately struck by how much quieter, smoother, and even more efficient pedaling felt.  Over the next two hours I tried my best to shake the chain off that Wolf Tooth chain ring by bashing into, jumping off, and generally seeking out any trail feature that would induce a dropped chain.  While my local trails are not even close to a proper enduro or downhill trail the initial ride was a success.

Upon arrival at Mt. Hood we set off to ride the downhill race course at Ski Bowl West in an absolute deluge.  Slipping down the muddy rocky slopes a few times and sessioning a small gap jump did not induce any chain retention issues and the 30x34 gear combination seemed low enough for climbing back up the access roads at the ski resort with a little effort.

On day 2 we pre rode the 3 stages at Sandy Ridge and the 4^th stage that started above the timberline on Mt. Hood and descended 4 miles down some seriously fast, loose, and rocky trails.  The conditions were still wet and muddy all day and no chain retention issues came about and the 30x11 high gear seemed adequate give the conditions we were riding in. 

Day 3 and the Enduro race begin.  After careening down steep chutes, negotiating multiple rock gardens made up of basket ball to beach ball sized rocks, and one crash in a high speed muddy corner I finished stage one with the chain in place.  Stage two was a fast flow trail with one serious rock garden and many jumps but still no dropped chain.  Stage 3 finally succeeded in providing a dropped chain while spun out in the 30x11 gear and encountering a particularly rough section of trail the chain fell off the inside and came to rest on the bottom bracket shell.  I eventually stopped before a short climb and quickly placed the chain back on and finished the stage without incident.

Day 4 Stage 4 conditions were perfect hero dirt and I found myself sprinting out of corners in the 30x11t combination for the first couple of miles before plummeting down a mile long steep, loose rock garden that succeeded in throwing the chain off the inside again.   Once again, I pulled off course before a short climb and quickly put the chain back on and finished the stage.  It was at this point I realized that when running in the smallest rear cogs the non “clutch” derailleur was providing very little chain tension and that contributed to the chain dropping on what truly was down hill bike level terrain.  Stage 5 was held on the downhill course and very little pedaling was required so I just shifted to the middle rear cog at the start and had no chain retention problems on a trail that seriously taxed the capabilities of my 160mm travel bike.

Marc Garoutte