October 21, 2011

Jon’s Frame or… Trogdor the Burninator!

First, if you’re somehow not familiar with him, educate yourself on Trogdor.

How is this relevant? Well, really, it’s not. But if I had built this bike for myself (and, trust me, I wish my legs were shorter, or Jon’s were longer, so that I could just steal it from him) I would name it Trogdor. It’s crazy, it’s over the top, and it’s arguably gone way beyond any semblance of good judgement.

Here were the goals for this bike:
-29″ wheels
-Shortest possible chainstays
-Ability to run a bashguard and 1×9 or 1×10 drivetrain (no front derailleur)
-Slack/stable steering geometry
-Good standover

Well, I think we got there (apologies for the Craigslist-quality photo – it’s dark. I’ll try to get a better one in the morning.) Small painting in the background is by my good friend Chris (drop him a line and have him paint your favorite mountain!)
-27″ standover. Excessive? Probably. But great for, like, throwing tricks, or, um, unplanned dismounts on off-camber terrain. Not that I’m suggesting anything like that would happen.
-400mm effective chainstay length. Yes, that’s right. 15.75″ It will be a wheelie/manual machine, so much so that it’s arguable that it’ll be hard to keep the front wheel down when going uphill.
-83mm BB shell for 56mm chainline and clearance for a big 2.4-ish tire.
-Offset dropouts (5mm to the driveside) and 135mm spacing for a straight chainline and no-dish rear wheel.
-69 degree head tube angle, set up for a tapered steerer, 100mm travel fork. Throw a 120mm fork on there and go to 68 HTA if needed.

Are there drawbacks? Sure. Honestly, I’m still not sure if the chainline will allow smooth shifting at the very high and very low range on the cassette (Shimano designs their mountain bike components for ~425mm chainstays). The frame isn’t particularly light (it’ll probably just barely break 5 pounds when the powdercoat is on), and some folks wouldn’t like the wider q-factor on the cranks necessitated by the 83mm BB shell. Oh, and you need a freeride crank to fit, as well as a rear wheel that’s been built or re-dished to fit the offset dropouts.

But for burninating the peasants in their thatched… er, I mean ripping it up on the singletrack, this might be just right. And only Jon will ever know, since the thing is too darn small for me to steal from him.

Picture of the housing guide was just because it looked nice, and I usually don’t get them to look quite that perfect. The darn things are way thin/light/lacking in thermal mass, so they want to instantly turn into a little ball of molten metal if you throw just a little bit too much heat at them.