Monday, January 23, 2012

"Weekend" Project

This is something I've been dabbling with on and off for months and months, but this weekend, I decided I'd finally finish it. Of course, the "weekend" ended up including a decent amount of Monday, but it's finally (almost) done - my geeked-out FS racer-boy frame.

Yes, I know that as recently as a few years ago I was getting outsprinted at the line on my super-core rigid singlespeed (damn you, Mitch!) Then I graduated to a suspension fork. Lame. Finally, I raced 24 hours of Moab on a full suspension bike that I inherited after DHL did it's best to destroy it... and loved it. The transition to oldness and lameness (let's not forget: slowness) had begun.

And that process culminates here, in my attempt to build/buy back some of the extra weight around my middle. As usual, it probably won't work, but what the heck.

Another reason for building this was that I had an old "superlight" Ventana rear end lying around that it had become clear nobody was ever going to buy from me. So I figured what the heck... I'll do a super light FS bike, and use my new tube bender to make a sweet bent seat tube.

So, here she is. First, geometry:
-69 HTA, effective 73 STA
-60cm/23.2" effective toptube
-48.2cm/19" seat tube, curved like buttah!
-335mm/13.2" unsprung BB height - yes, low
-100mm travel front/rear
-43.3cm/17" chainstays
-108.6cm/42.7" wheelbase (!!!)
-150mm head tube
-1x only right now, I might add a direct mount for a front derailleur at some point (or not, we'll see).

And the kicker... 2625g, or 5.8# (edit: now 2600g/5.7# with machined-down rockers) with the shock and all the hardware. That's by far the lightest FS bike I've ever built - and it's not even small. Nothing crazy with the tubing, either - the seat tube is Supertherm, and the TT and DT are 8/5/8 OX platinum. Should be durable enough for everday riding, albeit not for a huge rider or big hucking craziness.

The geometry is weird, I know. I went super short, and super slack. And the standover, for most people, would be kinda sucky. But for leggy me, it's fine. I did a similar geometry on my 2011 hardtail and loved it - so why not do it with a dualie? Could I easily sell it to someone if I don't like it? Well, no. But that wasn't a major concern.

Before you flip out and email me wanting this frame, or one like it (perhaps with less kooky geometry) keep a couple of things in mind:
-As far as I know, Ventana won't do these superlight rear ends anymore. So add 200g or so for that - meaning that a medium-ish frame would be in the 6.2# range right off the bat.
-Most people would probably want a bigger head tube for a tapered steerer - which will also add some weight. I used a 1mm wall 36mm OD OX platinum tube here, partially because I was geeking out about weight, and partially because I already have a fork to fit and am not fat enough (yet) to feel that I need a tapered steerer.

Here's a quick shot of the bike built up (24.5# with my old junky parts) that I snapped quickly before heading inside to cook up a batch of green chile stew. Ride report soon, assuming the weather holds.


sdl said...

Looks and sounds fun! Careful with that lighting and all those cool shadows! You accidentally took a good picture of the bike!

Walt said...

Doh! I need to learn to use photoshop to, um, crapify it...

Anonymous said...

where can you test a bike like that in the colorado winter? didn't you just tell us to stay off the trails?

Walt said...

We've got dry weather for the last 3 weeks... and now, some dry trails (ok, the lamest ones...)

So, good point. I won't be riding anything muddy, don't worry!

ssportsman said...

I look forward to seeing some gnarrr riding pictures :)

NickS said...

Another new bike? Soon you will have mor WW BIkes than me!

onlyontwo said...

That turned out great.

I'm curious to hear your thoughts on how that geo works out. Looks like perfect numbers for Midwest.


Anonymous said...

Damn. Just when I felt hard-core on my WW rigid singlespeed you gotta go and do something like this.

BigHank53 said...

How much weight will the powdercoat add? I'm guessing two, two and a half ounces?

Walt said...

Hey Hank -

I'd guess 50g or so. But it's hard to say for sure, powdercoats vary a lot.

Anonymous said...

Can you tell my why bike companies can make a short chainstay FS bike? I love it when they brag about short chainstays and there like 17.6 or 17.5 when I have seen several small builders make 17" ones. Love the bike Im really digging the steel front/Ventana rear these days

Walt said...

Hey DiscoDave -

It's just not necessary to sell the bikes to 99% of the riding public, many of whom size their new ride by standing over it. People who read this blog care, but y'all are like a tiny fraction of a niche in the overall mountain bike market. So most big companies just go the easy route - and most riders, who couldn't manual off a curb, don't notice.