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Custom Geometry Question


isitafox

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I'm looking at getting a steel frame made up to ride in comps next year but I'm struggling a bit with geometry. Looking ideally at something along the lines of an echo 24 but I really don't want a stupid length mod stem on. I'm not great with geo but would changing the head angle be the way to go to get away with something shorter or would it mess up the whole feel of the bike?

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Not really, I think it's just that kind of bike, don't really know anything about 24" tgs geo, but whenever I've seen that frame, it's had a big lanky stem on it, no head angle change will solve it.

Slacker head angle will bring the bars marginally closer to you but then you piss up the front wheel handling.

Steeper will just give you even more reach.

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what he's getting at is that if you use a steeper head angle, you can then use a shorter stem (which looks better) while keeping the same reach. The only issue would be getting the correct bar height as the shorter the stem, the lower is usually is.

You could use a longer head tube and headset spacers to get the same bar height as a mod stem though, also a lower bb would mean the bars wouldn't have to be as high but you will sacrifice rear wheel control.

I've always wondered why trials bike have slack head angles and super long stems, why not make the head angle steeper, lengthen the reach and use a shorter stem? If your hands end up in the same position then the head angle won't feel any steeper for roll downs, but it will feel nicer when turning.

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I think Ali is spot on there.

I will add that I've just got a zoot after riding mod and stock for many years (not even sure anymore) and I was expecting it to be fairly poor on back wheel in order to gain me some more bunnyhopability etc.

This is not the case at all, it seems to be just as easy on back wheel as any other bike I've had. But also seems to pop into manuals+bunnyhops fairly easily :o

You might want to take a look at the geo for some inspiration

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Used to have a zoot so I know what your getting at though I have an Inspired so not really that fussed about keeping it streety.

Ali's getting me, think I could maybe go to a 73° head angle and increase the headtube slightly to make it a bit more dave friendly. Was considering also maybe knocking 5-10mm off the BB height but I don't know if that is a good idea or not yet.

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All I will say is learn absolutely every aspect of geometry & the effect it has, even stuff that won't apply so much to your frame.

It's pretty disappointing to get a frame through the post after weeks of waiting & planning only to find you didn't know as much as you thought you did & didn't research properly and have a frame that's perfectly made to your misguided specification!

I've learned my lessons now.

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Yeah I hear you with that, by changing the head angle I could pretty comfortably get the reach to something like my old pure but like I said I want to ask some questions to a few riders who are a bit more in the know before I do anything permanent.

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Right, I've got a design made up which to me looks about right. Works out with the reach being 665 which is the same as a 26" pure which is what I was after, and I'm pretty certain that the tweak of the headtube means with a Trialtech high rise stock stem the centre of the stem clamp with about 20mm of stackers will be almost identical to that of a standard Echo 24 running a Trialtech 150 x 35 mod stem and no stackers which from what I've seen seems to be the standard setup used.

Does this sound like a manageable setup/geo or am I dreaming?!

post-24247-0-57953900-1350513156_thumb.j

Also the geo I'm working from is based on what is listed on Tartybikes assuming they mean the 2009 version of the Urban forks which were 402 A-C and 45mm offset

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