Winter Pain: 2014 Vassago Jabberwocky

d7000_2016_09_10-15_11_44_jpgI’ve been doing these long ride/race things for 5 years now. I’m definitely getting faster, the rides are getting easier. Winter on the trainer helped a bunch to keep fitness for spring. It is cool to see my fitness increasing, my strava segment times improving slowly.

That said my times on Strava are still far far behind my fast friends (who happen to be among the fastest locals.) Is discouraging to give it my all, sprint some segment so hard that I’m nauseous with cramped abs and still find myself 25% slower. There’s just something wrong! What can I do?


175mm X0 crank with direct mount 32 tooth chainring.

The real actionable problem is that my pace on the long races is too slow and that means I can’t make the time cutoffs for the long races I want to do. How to increase my pace?

Well, here’s my issues:

  • Years sitting on my ass not keeping fitness
  • generically fat ‘n heavy, good marbling
  • heavy bones: I’ve got wide shoulders and solid bones, I’m built like a rugby player, not a birdy type cyclist. My natural weight is 185-190. At 175 I look like a skelington.
  • not enough seat time (“no aerobic base”)

Can see that most of this is about weight and strength, and the remainder is aerobic base.


Endless 22 tooth cog on hope hub

Well, I ask my fast friends and what do they say? “Ride a single speed all winter and your legs will become stronger than you’d ever have imagined.” Huh… that’s stupid!

What the hell kind of advice is that? I can obviously emulate a single speed by just… not shifting… how can riding in one gear make my pace faster? Hmm. They’re fast though, and I’m not… so maybe they’re right? Hmm.

So I ignored the advice, did my normal “try hard” training, watched my strava times slowly improve. Thinking of winter training to come.

And then… at the Capitol Forest race I was riding along feeling sorry for myself because I’m still doing the stupid 50 since its doubtful I can make the cutoffs for the two lap 100miler…

I was PASSED by Ben Shaklee on his second lap. Now back in 2012 the 50 took me 8:30 I was passed by many fast 100 mile racers. They start at 6:30am, the 50s start at 8:30, with their two hour lead and 9 hour finish time I am passed 60-90 minutes before I finish.

Last year I finished the 50 in ~6:30 and was drinking a beer when the first 100 miler finished. So to be lapped by a 100 miler this year was pretty awesome as I finished even faster in ~6:10.

Not only did he pass me, he broke the course record by 45 minutes and with second place more than 50 minutes behind. Just stupid fast… and… he was on a FULL RIGID SINGLESPEED. Ti frame, carbon fork, he zoomed by at impossible speed and he looked like a skier as is cornered away into the trees.

Ok. I wanna be fast. Ben Shaklee is fast. Ben Shaklee rides a singlespeed. My fast friends agree. Ok. Well then I’ll get one! I talk with the fast friends, you gunna take our advice? “Um… yeah… but what gears should I ride on Grand Ridge?” “Grand Ridge… hmm… you should start with a 32:22.” Jesus! I normally ride the steep parts of grand ridge on a 26″ in a 22:28 which is ~1.5m per stroke. A 29er with 32:22 is 3m per stroke, about double the ratio I normally ride. Is it even possible to climb Grand Ridge in that ratio? Fast guy reiterates: “yeah… buy a cheap single speed with a 32:22, ride it all winter and you’ll be faster, your legs will be a lot stronger.”


Chromag Ranger Stem, Acute bars. Very stiff!

I’m thinking of converting a 26er to single speed but that means either converting my princess (the merlin on the wall), or converting the kona that lives on the trainer, and then I’d have no trainer bike… and besides, neither of those has disk brakes. Clearly the solution is to just get a new bike.


Chromag Dolomite Seatpost and Seat

Heading to San Juans s few days later I check pinkbike for singlespeeds. There’s one just across the border in Canadia. Bike isn’t a piece of shit and price seems reasonable, owner awesomely agrees to meet me near the border, the deal is done.

Presenting my 2014 Vassago Jabberwocky. It has several innovations that I’ve been itchin to try:

  • Singlespeed (duh)
  • 29er (woo!)
  • tubeless (woo!)
  • hardtail (eh…)
  • steel (haven’t had a steel bike since the 11th grade)


With the stuff on it, weights about 25 pounds. Probably more due to the Marzocchi 320 fork.


ZTR Crest 29er Rim, Nobby Nic 2.25 tires setup tubeless.

Before buying I read reviews of the Jabberwocky. Singlespeed is weird enough, there seems to have been a big craze around 2008, then hype of 29er, then hype of “new geometry”, all that stuff on the internet reads like bullshit. Who knows though, maybe I’m the one that’s full of shit.

One thing that does bother me is that the Jabberwocky is advertised and having nice long chainstays. What the hell? But there are proponents of long chainstays on the interwebs, say that short chainstays are a fad… hmm. I really don’t think that is right. Long chainstays suck if you are trying to manual, and they also make it harder to apply weight to the rear contact patch when climbing loose stuff? Hmm. I guess I’ll see. This isn’t a serious bike, not a bike I plan to fall in love with, its just something to impose pain on my legs for the winter. If singlespeeding becomes more serious thing for me, and this bike starts to piss me off then I’ll invest in a bike I like.

The other downside of the jabberwocky is that the frame in my size is ~5.5 pounds, but hey, that’s called being a training aid.

Finally I look up the jabberwocky on the internets, vassago page claims 17″ chainstays. That doesn’t seem so long to me, at least for a 29er that’s within 1/2″ of the very shortest chainstays. Maybe it is much ado about nothing?

Now, after owning the bike for a few weeks I have an opinion.

First, a history of the jabberwocky.


  • 2005: Original bike had a straight downtube and a non-tapered headtube. This original is from the guy that started the company, who was a bit of a crank. Here is one:


2013 (My bike)


Around 2013 some new owners took over and they updated the bike with:

  • bent downtube for better fork clearance with short headtube
  • 44mm head tube compatible with tapered forks
  • different tubing (blah, blah, r-tech, blah)
  • still uses 27.2mm seatpost

Here’s a review of the 2013:

Mine is a 2014, maybe some changes from 2013 but I can’t tell.

Something bad happened to Vassago at the end of 2014, they had to close shop for some reason involving the original guy being a jerk, or something. I don’t know the details.


Finally in 2015 the company restarted and for 2016 there is a new Vassago Jabberwocky.

This 2016 edition is the one with the 17″ chainstays… Sadly when my wheel is pushed full forward in the dropouts the chainstay (center of bb to center of rear axle) is 17.675″. With 32:22 ratio I need 49 links, the chainstay length is just over 18″.

  • Seatpost is upped to 31.6mm.
  • 29+” comatible… clearance in rear for 3″ tires…
  • compatible with derailleur??

The web site is confusing because they still advocate the “Wet Cat” geometry even though its changed a bunch.

It could be that Vassago has admitted that long chainstays actually suck, or they could be catering to the reality that the short-stay fad is too important to ignore. I do know I’d rather have the new frame than the one I have.

My Impressions of my 2014:

First, the steel frame does feel great. Very smooth and comfortable, steel feels great. There is a small amount of flex, some amount of resilience and give to the ride that is terrific when I am feeling fresh. At the end of a hard 2 hours though I am totally getting beaten to shit and the charm of stiff steel has worn off. Once off the rough trails, onto smooth gravel or pavement the bike again feels fantastic, even when tired. Bike isn’t great for our cascade’s normal unmaintained rocky loose trails.

The light Stans Crest wheels are light enough, I love snakeskin Nobby Nics. 29er with supple tubeless (lower tire pressure) gives lots of grip and great rollover.

The bike is really damn difficult to manual. I can briefly muscle the wheel up for logs and steps but it takes a bunch of force compared to a graceful and relaxed manual on my yeti asr5c.

The long chainstays make it a bitch to weight the rear tire. I have to be really careful to avoid loose rocks when climbing and even so the rear wheel tends to slide out in steep sections. My first ride on grand ridge I had to lower the rear tire pressure to 20 to keep from washing out. Now I ride with 22lbs in the rear, a bit more in the front.

I really wish the chainstays were shorter, hate having to hang back off the bars to increase rear tire grip while suffering out of saddle. Ab workout.

How does it feel?

Well, first thing. It is a novel bitch. Rides that were simple become challenging again. I’ve been focusing on doing hill intervals so searching out 10-15% grades to ride up. Been a brutal week and my legs are really damn sore.

I am spending a lot of time standing and it seems to be making my back happy.

I am not faster on any strava segments, but not disasterously slow either.

The speed on those segments does not reflect the effort being emitted. Seriously, seriously painful rides and they show up as “decent” when I look at my segment history. I’m probably in the best biking shape of my life too, so with my yeti I’d probably beat those times right now…

Rigid Fork?

I’m sort of tempted to go Full Ben Shaklee and get a rigid fork. The cheap marzocchi weighs more than 4 pounds… The Niner Carbon forks are on closeout right now for $175 (down from original price of $500) they have the perfect offset for this bike, that would cut 3 pounds from the front of bike, it might make it easier to manual? The downside is… lack of suspension. As an experiment I rode for a bit with the fork locked out. Well. I scared myself silly. I can’t manual well and nearly went over the bars, can’t balance on the rear wheel when climbing steeps, so have trouble getting the front tire up over steps. Yeah, I suck, could be I just need to be a better rider. Right now normal riding on this thing is a series of desperate muscle-strain emergencies. For the rough terrain I usually ride the rigid fork seems like a difficult choice, especially right now when I can’t manual reliably. I guess I’ll wait until I’m better at manualling this thing, then reconsider if I can rock a rigid fork.

Some Chainstay Math:

Did the math to figure out min chain length given, gears, desired chain tension and min chainstay length.


Rf: Big Ring Radius
Rr: Small Ring Radius
CSL: Chain Stay Length
Segment X: The length of chain from one ring to another. There’s an ‘X’ on the top and and ‘X’ on the bottom.

First need to find length of chain that isn’t on ring or cog.


Pretty cool! In this picture focus on the triange on the top side of the parallelogram.

Given that there are two teeth per inch, the radius of cog given # of teeth is:

teeth/2 = 2*Pi*r

Ring Radius = teeth/(2*2*Pi)= teeth/(4*Pi)

“Segment X” is the length of chain between the two gears, in pic above it is the ‘adjacent’ edge of that upper triangle. We know its a right triangle because tangent of circle is perpendicular to the radius ray.

Since it is a right triangle we can solve with Pythagoras, one side is CSL, another size is “Fr – Rr”, so length of “Segment X” is:



Correctly tensioned single speed chain needs 20mm of up/down motion. This means a single segment of x can move upwards by 10 mm. How much longer must chain be so that chain can move upward 10mm (10/25.4)”?

Below S means upward slack, so half of the total desired chain motion.


Given my 32:22 ratio the big radius is: 2.56 inches, the small radius is 1.75 inches, min chainstay length on bike is 17.675″ and desired upward slack of 10mm (20mm total) I compute that I need 48.90338″ of chain. Since chain only comes in 1/2″ pieces (if you use a half-link, otherwise it can only be adjusted in 1″ pieces), that means I need 49 full links of chain. Half link won’t help. With my ratio there’s no way to get to the min of 17.675, I’m stuck at 17.72″ and that difference won’t be detectable by mortals like myself.





About esc

I'm a programmer in the Seattle area. Mostly work on compilers but also on optimization. Currently focused on gpu stuff...
This entry was posted in Bicycle, Jabberwocky, math, Singlespeed, Uncategorized. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s