Riding frame 5

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Frame 5 geometry is as follows:
29er with 19.5″ seat tube length (center to center), 69.5 degree head tube angle, 72 degree seat tube angle, 17.1″ chainstays, 24.25″ effective top tube length, 27″ front-center, 12.4″ bottom bracket height (52mm bb drop), and a 44.1″ wheelbase.

It has my 5-ish year old Fox F29 110mm suspension fork on it with 51mm offset so it has around 83mm of trail. The steerer was cut too short for this frame (i originally made this frame for Heyride who hadn’t cut his steerer yet…) so instead of a King headset, I had to buy a Crank Brothers Cobalt headset which has almost a 1/2″ less stack height than the King! So with some extra facing of the head tube (down to 115mm from 120mm in length) I was able to fit the fork with some extra room.

I took some ‘risks’ on geometry and for the most part I’m happy with how it turned out. I like higher than normal bottom bracket heights.  With all the boulders around here, i hit my pedals too much for my liking if it’s any lower than 12.25″.  The chainstays are short but not too short that i can’t fit a normal front derailleur on there (SRAM low mount top pull 2x). The chainline turned out ok, but needed to put two spacers on the driveside of the bottom bracket in order not to let the inner 26t chainring (2×10) be a tiny 1mm away from hitting the chainstay.  I need to dimple the outsides of the driveside chainstay for short-stay frames from here on out! Anything under 17.25″ probably (guessing on that)?  Also, when I rode 26″-wheeled bikes, I loved the “Genesis” geometry from Fisher so have always dug the short chainstay/long top tube/short stem thing.  But I’ve learned that with a 29er it just doesn’t work because you increase the front-center length and the wheelbase too much so that it rides too much like a cadillac and you can’t wheelie at all.  So..instead of going for the 25″ top tube like I put on frame #3, I went with a front center of 687mm making the effective top tube length only 24.25″ long. This is by far the shortest top tube bike I’ve ever had.  It rides more ‘quick’ – can wheelie drop easier, and more manuverable in tight singletrack but on rough fast descents it’s..well…harsher.  In my experience, shorter chainstays make a harsher ride and so does a shorter wheelbase…but like with everything – there are tradeoffs.  It depends on what style of riding you will be doing mostly, or what you want the bike to excel at. You can only really CHOOSE these variables with a custom frame.  The different big manufacturers do have differences in their geometry, but it’s really not that striking – for example, you can’t buy a stock hardtail frame with a 69 degree head tube angle, or with 17″ chainstays (correct me if i’m wrong anybody…).

Anyways, my first 3 hour ride went really well, nothing broke! hahah…i guess I should stop expecting that after frame 5, eh?! But seriously, i’m still amazed I am making bikes to ride.

The 2×10 is great too.  X9 shifts…OK…not great. I’d say like LX for Shimano.  It’s just not very SOLID feeling.  It shifts fine once you learn that you can’t just expect it to act like XX or eve XO or Shimano XT. Why did they do that btw? Couldn’t SRAM choose a different letter than “X”…? I’m surprised Shimano didn’t Trademark “X”.  The main difference is more plastic in SRAM parts than Shimano, and in the lower line SRAM parts they use steel instead of aluminum so they’re a bit heavier.  Top of the line uses Carbon and aluminum (XX).  But i DIG the 2×10 setup…i’ve always liked the 2x front setup – more clearance for hopping rocks and logs, no chainsuck, simpler, less stuff.  All said and done with the parts you see (Stans Olympic tubeless wheelset, Salsa moto-ace 17deg sweep bars, Moots layback post, Bontrager race-lite saddle, XT crankset, etc., it’s 26lbs.

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