January 24, 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.