Otis gets a 2×9 to 1×11 Conversion

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Otis at the Beach – 2×9 Drive Train

I got this crazy idea to upgrade the drivetrain on my legacy fat-bike Otis from a 2×9 Shimano/Microshift set-up to a Box 1×11 with a 30 Tooth Wolftooth Oval chairing and Camo/Direct Mount spider. Let me begin by saying that it’s not our intention to disparage our long-time amigo ‘the front derailleur’ or the folks that still rock a two-by propulsion system. If that’s what got you to the ho-down that’s 100% cool with us. Otis has been pimped so many times, it’s almost second nature to want to keep fresh bike bling bolted in place. Check out the parade of pimpalicious upgrades we’ve journaled over the years (linkage below).

Otis’s Story

12/25/2013 – Otis’s Introduction and Naming – https://fat-bike.com/2013/12/fatback-190-product-test-episode-1/

12/25/2014 – Otis Turns One – https://fat-bike.com/2014/12/otis-turns-one-%E2%99%A6-fatback-long-term-review/

2/5/2015 – Otis Gets Pimped – https://fat-bike.com/2015/02/otis-gets-pimped-part-one-otisgetspimped/

6/18/2015 – Otis’s Pimped Parts Review – https://fat-bike.com/2015/06/hed-rims-onyx-racing-hubs-paul-skewers-6-month-review/

1/21/2016 – Otis Turns Two – Fatback Review – The extended club version – https://fat-bike.com/2016/01/otis-turns-two-fatback-review-the-extended-club-version/

I’ve got my own set of issues that has led me down the path towards making the switch to a 1×11. The majority of the test bikes that make their way through the shop and most of the bikes in my stable (that still get ridden) do not have a front derailleur. My Krampus has a Shimano 1×10, my Fatback Corvus FLT has a Sram Gripshift 1×11 and my Asylum Cycles Hank is a singlespeed. Otis is the last hold-out with a 2×9 set-up. It’s funny that ya never forget how to shift on a singlespeed. However, I do get really rusty with the efficient operation of a 2×9 drive train while attempting to negotiate the frequent ups and downs that are one of the hallmarks of midwest singletrack. So when I get on Otis I have to think about when I should get in the granny. Another issue that I have is chain suck on longer beach rides. Otis is primarily my guest bike but also gets called up for beach rides. Once the lube gets worn or washed off, the chain starts to stick to the small chainring – aka chain suck. I hope the 1×11 will alleviate that issue.

Microshift Thumbies
Box One Trigger Shifter

Then there’s the clumsy ergonomics of the Microshift Thumb Shifters combined with Shimano Brake Levers and a set of Ergon GS2 grips. The thumbie shifter lever routinely gets in the way of my hand position with this mismatched combination of components. I love the way the Microshift thumbies shift, but changing to triggers or grip shift would cure that ergonomic problem. It’s also easier now than ever to make the conversion with Box and Sram NX 11 speed cassettes being compatible with Shimano freehubs. So all of that is what’s led me to make the switch from 2×9 to 1×11. (YMMV)

I didn’t go it alone on the conversion. I brought in Adam Blake aka Fatty Lumpkin from World of Bikes out in Iowa City for technical consultation. The first subject of the conversion that we talked about was cranks. The existing RF Next crank on my bike uses RF’s ‘Cinch’ direct mount system so it made the conversion fairly simple. I replaced the existing Raceface 2 ring spider with a Wolftooth Components Camo spider with a 30 tooth oval chainring. I also sought the advice of Rob at Raceface and Dan at Wolftooth about the conversion of the chainrings.

Raceface Cinch 2 ring spider & Wolftooth Components Camo spider with a 30 tooth oval chainring

Here’s where Adam’s knowledge kicks in – If you’re trying to convert a crank that doesn’t have a direct mount system things get a little more complicated. The most common 4 bolt fat-bike cranks have a 104 BCD and they can be fitted with a 30 tooth chainring, but not a 28. There are a number of other cranks that have different BCD bolt patterns that complicate chainring compatibility as well. Your existing chainring is in the 32-38 range and you’re going to want to run a 28-32 tooth range after the conversion. Chainrings also come in different offsets that help to optimize your chain line. Dan at Wolftooth set me up with a chainring with 3mm of offset for my 190mm set-up.

As I mentioned above, Box, Sram NX, Sun and Shimano have cassettes that are compatible with 11 speed Shimano freehubs. Some legacy bikes with 8/9/10 speed Shimano freehubs aren’t compatible. Those freehubs would work with a Shimano 1×10 drivetrain or there’s a possibility (depending on the hub brand) that you could swap over to an XD driver and run Sram 11 or 12 speed. In some cases, it will make more sense to swap over to an XD driver.

2 Ring spider removed – RF Next Crank with the new Wolftooth Camo Spider and Oval Ring installed – Box 2 Cassette and Chain

This is where having a good relationship with a bike shop is important. They can save you a lot of headaches getting you set up with the right parts. Luckily for me, my fatback hubs had a stainless steel 11 speed Shimano freehub that accepts the Box Two 11-46 11-speed cassette. I paired that up with a Box One derailleur and trigger shifter because the Box Two derailleur and shifter was out of stock. The resulting conversion shifts like butter!

I guess my only concern is the durability of the new 11-speed chain and cassette. I’ll never stop riding my fat-bike on the beach and in the lake where necessary. Will the narrower chainring tolerances inherent with 11-speed handle sand as well as 9-speed? I guess we’ll find that out somewhere down the beach amigos. We have a big Spring Beach ShinDig in the works. If you’re in the area at the end of April come and join in the fun! We have a bunch of things in the works and Surly just signed on as a sponsor. Surly might even have some demo bikes there as well as demos from Wyatt Bicycle Co. (and more). Keep your ear to the ground because we know how to throw a Rock’n Beach Party! (or Funduro)

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About Gomez 2576 Articles
Just an old cat that rides bikes, herds pixels, ropes gnomes and sometimes writes stories. I love a good story.

1 Comment

  1. Gomez! Thanks for doing this conversion. This is exactly what I want to do to my 2015 BigFoot. I eagerly await your test results and comments. Looks damn good on Otis.

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