May 19, 2010

Troy’s free ride 29er hardtail/44mm headtube

Warning, this one is long. Tony, you don’t *officially* get the first bike built with the new True Temper 44mm head tube stock, but you and Troy’s bikes will be going to the powdercoater at the same time – so I guess you can race to see who can assemble and ride the quickest or something. Someday, you’ll be able to tell your grandchildren how you pioneered this awesome new technology – or they’ll laugh at you because you’re riding the future equivalent of biopace. We’ll see.

First off, I had to actually buy a new holesaw. Crazy! I regularly get several hundred cuts from a Lennox saw, so I can’t even remember the last time I bought one. For the builders out there, a 46mm saw works great, since they tend to cut a tiny bit oversize anyway (the head tube is 46.5mm OD).

Don Ferris has a time machine, I think, because the Anvil main tube mitering fixture that I bought in 2005 has a phase adapter that fits almost perfectly! Nice work, Terminator. Seriously, I was psyched not to have to spend a bunch of lathe time making one – though I did have to clean a LOT of dust off of this sucker.

Here’s the downtube tacked in. Note that I’ve welded the top portion, because the toptube will be compound mitered here and hence I have to weld it in advance. Otherwise… well, bad noises, weak joint, not fun for anyone. Troy’s going to be slaying Pisgah (or, well, riding there) on this bike, so it needs to be non-fragile.

Whole head tube/toptube/downtube assembly, tacked. Some folks have said this head tube will look weird. I can’t say I think it’s that weird (those are a 38mm and 32mm downtube and toptube, respectively) and I’ll take the mega-stiff front fork over looks any day. But that’s just me.

Here we’re all welded up. Again, I think it looks fine. Plus, how much do you stare at your head tube when riding? Not the head tube for the coffee shop bike parking crowd (Martin, Charlie – I’m looking at you guys…) but pretty rad if you want a stiff solid front end.

Here’s the front triangle welded up, in the fixture. Yes, the seat tube looks weird and huge. That’s for a good reason – Troy’s running a Joplin post, which needs a 31.6 ID. That means 1.375″x.065″ tubing, turned down on the lathe to slip fit into a 1.375″x.035″ seat tube, then welded together. Light? No. Functional when the trail gets steep? Yes.

Yes, this frame has 17″ (~430mm) effective chainstays, and it will fit a WTB dissent with decent clearance everywhere. All hail the wondrous Shimano direct mount front derailleur! Troy should be able to wheelie and manual until he either goes off the trail (as Hassan and I usually do) or gets on the cover of Dirt Rag. Actually, strike that. Mountain Flyer is the new Dirt Rag. Dirt Rag is the new Bicycling. Bicycling is the new crap tabloid you can’t help staring at in the checkout line.

Going backwards, here’s the seat cluster showing (if you look carefully) the welded-in shim/plug that will allow the 31.6 Joplin post to work. This solution is kinda heavy, but I’m hoping to talk True Temper into making some 30.9 or 31.6 compatible seat tubes sometime soon. We’ll see how that goes – they have been really cool about getting stuff done for me over the last 5 years or so.

Final shot. Again, beefy, not light, built to huck yourself off idiotic stuff in Pisgah and survive, even on days when you’re not feeling heroic.