Why Single-speed Mountain Bikes are Crazy Fun – Build & Ride

On the metaphorical bike selection screen,
I never seem to choose my old hardtail anymore. Don’t get me wrong, my Sync’r Pro is quite
capable, it has good parts on it, and it fits my riding style perfectly. It’s just overshadowed now by fancier, higher
end bikes. It’s time for a change. Today, I’m going to reconfigure my sync’r
with different parts and radical changes that emphasize fun, and bad ideas. I want to ride this bike in jeans and a hoodie,
with no particular place to go. So I polled my YouTube audience about making
the Sync’r a single speed, and less than a third of respondents thought that was a
good idea. That confirmed that this was in fact, a terrible
idea. So I proceeded to remove my drivetrain and
set up a wheel for single speed. I removed the 11 speed cassette from this
Raceface wheel, and used this conversion kit to install a 16 tooth cog. For a rear tire I used this fast rolling WTB
trail boss, which was all I could find on Christmas eve. It wasn’t my first choice, but it ended
up working out. With a Maxxis Minion DHF up front, I’d have
the best of both worlds. There was only one problem—the rear wheel
was the wrong width. So, the Sync’r would be getting this carbon
wheelset instead—I’m fine with that. Switching the tire over wasn’t messy in
the least. To convert any bike to singlespeed you need
a way of putting tension on the chain to keep it from popping off. I ordered this bottom bracket mounted mounted
chain tensioner for this very purpose. It was the wrong size. On Sunday, on Christmas eve. In an act of desperation I tried to get the
tension right without it. I call this a unicorn gear, and I didn’t
do it intentionally. The spacing and cog sizes just worked out
perfectly with no tensioner at all. This almost never happens, and so I knew it
was meant to be. Look at how pure and simple it looks without
a chain tensioner! Time to throw a 150mm fork on this beast. That would make the geometry even slacker,
and more aggressive. I also installed these Box carbon handlebars,
and some other goodies. Just a few finishing touches, and my belligerent
hardtail was ready to do its dirt. Time for a weigh in. 25.5 pounds, or 11.5 kilograms. Not bad for a nearly indestructible bike. Except that most mishaps occur on the work
stand. I had overtightened a brake lever and put
a pretty big dent in my carbon bar, and had to replace it. Bummer. I should have used a torque wrench, but I
was excited. Feast your eyes on what is, for now, my new
favorite bike. I named it the murder machine because it looks
evil and brooding. Against the advice of my instagram followers
I left the dropper post on it. It just fits so perfectly and doesn’t add
that much complexity. This is my bike and I’m doing things my
way. How do you know someone rides singlespeed? Oh they’ll tell you. Singlespeeders are a passionate bunch, but
even they have trouble explaining why you would choose to eliminate all but one gear. But on a singlespeed you never need to worry
about being in the right gear—because you’re never in the right gear. Suck it up though and you can still climb
just about anything. Well maybe you can, not me. I guess that’s what getting stronger is
for. And hiking, there’s always hiking. Okay so the Murder Machine is not the best
for climbing, but I like this gear ratio because it allows me to sprint predictably without
getting caught in too low a gear. Let me demonstrate. With a smaller rear tire, a carbon rim, and
most notably the loss of the cassette, the rear feels noticeably easier to throw around. And how a bike feels can have a profound influence
on how you ride it. It can also influence where you ride it. Another lesser known benefit of single speed
is the ability to ride backwards without the risk of the drivetrain binding up—for what
it’s worth. Could I do most of these things on an 11 speed? Of course! But there’s always a chance of busting a
derailleur hanger. Having fewer gears, less chain, less on your
bars, less on your mind, and less to break, can have a big effect on your mentality. I’m well aware that these changes can make
a bike less capable, but I don’t care. It’s fun. So why are single speeders so passionate? You may never know until you get on one. All I know is that I can’t stop riding the
murder machine. It makes me feel like a kid again without
a worry in the world. If I could only have one bike it would most
definitely not be this one. It would be my 11 speed full suspension trail
bike. But while that bike is great for almost everything,
the Murder Machine fills a long standing void in my stable. It’s for days when I’m trying something
new, learning, or just acting on bad ideas. I think we’ll be seeing a lot more of it. Thanks for riding with me today, and I’ll
see you next time.

About the author


  1. Is it a dirt jumper? Err not exactly. A DJ would have 26” wheels, slightly different geometry, slotted dropouts, and a shorter, stiffer fork. To me, this is more versatile than a DJ—and with all the great parts!

  2. This is literally the perfect solution for taller guys wanting a dirt jump/ street bike! No wonder chain reaction gave me such an odd response when I asked about buying a nukeproof scout and running it single speed! Thanks for clearing this up man

  3. i love single speed but climbing is super hard on the knees….. some mtb riders who started on bmx think all the gears are for melvins

  4. You look to be quite a good rider in your videos. Definitely makes me inspired to get back out and ride my bicycle & to continue to learn new abilities on it.

  5. i like how seth even puts up a poll and totally does the opposite like "ok ill put a single speed" yet nobody was mad at him for not following the poll.

  6. Many years ago, after an epic failed attempt at riding an Alfine 11 speed internally geared up on my trail bike, and before I simply converted that bike to a 1×9, I went about a month in the summer of '11 or '12 with my Maverick ML8 set up as a singlespeed with the same 2:1 gear ratio (but with large 26" tires).

    It was kind of fun. The back was so light, I could easily pop the back wheel up and over or on to anything on the trail. And surprisingly I rarely had to push the bike, I could make most things with that ratio. And it wasn't too terrible riding on the street with those gears either. I had to use a baby derailer style two wheeled tensioner to eat up all the chain slack since it was a full suspension.

    So all in all it was a very interesting, and not super terrible month. Single speed for general use is definitely not worth what you lose by having all the gears, in my opinion. But it was fun to try.

    I also have a dirt jumper I use in parks, it is a much smaller hardtail, also singlespeed, but with a much lower gear ratio. That bike is kind of awful on the trail. So harsh, so hard to pedal, just overall bad geometry. But it's real fun on ramps!

    Speaking of parks, the park in this video looks real nice! Better than any municipal skate parks I've ever ridden!

  7. Nice project for people with too much spare time left…but wait…1.4Mio. followers – now we know why….

  8. Just done this to my only bike and it worked without chain tension device. tight fit though. 28t front- 16 rear love it
    did some bunny hops first and it has not come off.

  9. Hello I'm from Brazil. I have a Gios 26 hoop with manitou stance 120/150 mm suspension, I use nine speed Sram gearshift, very short to take some fast track, and go down some stairs.

  10. I only ride in the street, commuting to every place I go by bike. She recently got a new crankset and when I was going back home the chain snapped. I wasn't giving it hell, but it was a year and a half old, so yeah. Since I didn't replace anything except the crankset up to that point I decided to follow your instructions, and I'm still waiting for the kit to arrive.

    Oh, and I was basically riding singlespeed already, because my gear cable also snapped and just shortened it and stuck it in place in one gear, so shedding all the weight from the cassette, putting a more resilient chain and repurposing my derraileur to a chain tensioner might be the best thing I could do, so thanks Seth!

  11. CAN SOMEONE TELL HOW I CAN TURN THIS LANGUAGE ENGLISH TO FINNISH AUTOMATIC OFF?????????!?!??!?!?! because the (i dont know en to finnish) is not correct NEVER I MEAN ITS VERY F**KED UP

  12. honestly, swapout the tires for something with a less aggressive tread, throw on a larger chainring, and lop a couple inches off the bars, and you have what is basically a two wheeled urban assault vehicle that would crush city riding

  13. Just finished a race out in the badlands, and my buddy took 3rd on a single-speed! Made me reconsider my perspective on single-speeders 😉

  14. Yeah I basically have a hardtail that I'm afraid to break because I couldn't replace the parts. It's pretty much the cotton candy machine. Getting too old to, "act out on bad ideas". It is the nicest bike I've ever owned through. Get old, and replace your exuberance with nice things I guess, seems to be the way. Freaking laughed, and felt you when all the kids came to the skate park, and you had to leave, all the kids were asking if I was a policeman last time.

  15. I had a single speed for almost 10 years. Only recently converted back to 2/9 so I can climb again without suffering. Needless to say I got pretty strong on single so climbing with a 2/9 is a piece of cake now 😀 Though it was fun and easy using a single speed, it was a pain in the ass that I couldn't climb or travel fast and I have only this bike, so it is really not the best for a main bike.

  16. I can’t imagine how tiring it is getting each and every shot because he’d have to
    stop, set the camera up, go back, hit the spot, go back, grab the camera and then carry on

  17. I was a bike messenger in SF during the 80's and rode on a one speed with a basket and kick back break. I rode up Lombard the wrong way with a 44-14 gear ratio.

  18. Why Singelspeeds are awesome? Simplicity and challenge! I once rode up a small mountain of roughly 500m (1500ft) on a single-speed road bike geared for 30 km/h (18,6 mph). I nearly puked and had to stop twice, BUT I DIDN'T HIKE… That was one of the most challenging and and rewarding things I've done on a bike so far.

    On top of that, that singlespeed was a stupid fast, easy to maintain and unbelievably cheap commuting bike. And it rides like a dream!

  19. I don’t use a change tensioner or different sprockets I just put a single speed chain on gear 7 at the back and the middle ring on the front

  20. For about 5 months I stayed with my aunt in Ashville and I used to ride at food lion skatepark, it gives me nostalgia watching you ride the park even if it was only 6 months ago
    Edit: it's also very cool to see you ride on the same park that I rode on

  21. I just love this video. After 5 years off of MTB because of this video tomorow I m gonna buy one so I can enjoy riding mountain bikes again! Thanks Seth love this channel!

Leave a Reply

Your email address will not be published. Required fields are marked *