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Old 07-10-08, 05:55 AM
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Goon
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Bike Geometry

A Bike mechanic friend of mine was riding my bike around, and mentioned how very nice the riding geometry was. He really liked it, and said it turned very well. He admitted to enjoying the ride.

Now, it still has flat bars, but I am changing the handlebars to something else soon (going to try flop and chop old steel drops-to-bullhorns, and trekking if that doesn't work).

What effects the "Riding Geometry." People talk about having more hand positions, but Will having trekking bars or bull horns significantly alter how the bike feels or handles?
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Old 07-10-08, 06:37 AM
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Originally Posted by cg1985
..Will having trekking bars or bull horns significantly alter how the bike feels or handles?
The key issue to how the bike will feel (as long as you're staying with the same fork) is how far forward from the steerer tube your hands end up. With a flat bar you're pretty much only getting the length of the stem. Keeping the stem but going to bullhorns will push you hands forwards(when you're on the horns) which will change the feel and to some extent the handling. Trekking bars usually offer hand positions that are both ahead and behind where a flat bar would be, so they can give you the change in both directios so to speak.
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Old 07-10-08, 06:52 AM
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Originally Posted by dabac
The key issue to how the bike will feel (as long as you're staying with the same fork) is how far forward from the steerer tube your hands end up. With a flat bar you're pretty much only getting the length of the stem. Keeping the stem but going to bullhorns will push you hands forwards(when you're on the horns) which will change the feel and to some extent the handling. Trekking bars usually offer hand positions that are both ahead and behind where a flat bar would be, so they can give you the change in both directios so to speak.
I guess if I don't like how either the trekking or the bull horns alter the bikes feel, I can always Go back to the flat bars.

If I am I going to change the Handlebars, is it a wise move to also change the stem?

I guess I won't know Until I get the new bars on and ride it around to see how it feels. If the bikes balance feels weird, I can always get a shorter stem. vOv
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Old 07-10-08, 06:59 AM
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Also, I notice on more traditional Road bikes the "crotch" bar or whatever the bar is called from the stem to the seat post, is more or less parallel to the ground, where on my Bike, it's angled ever so slightly downward.

How does this effect feel? The angle of the seat post, and the angle of the forks appear to be the same, just by eyeballing it, so what does the angle of the "cross" bar do?
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Old 07-10-08, 07:14 AM
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Originally Posted by cg1985
If I am I going to change the Handlebars, is it a wise move to also change the stem?
Depends on what you're trying to achieve with your change.
My winter commuter is a flat bar MTB-looking type of bike, and for the city riding I have to do I'm very happy with the rather upright position that bar+stem combo gives me. But as soon as there aren't any immediate braking or gear changing to be done I much prefer to ride with my hands on the bar ends.
So for the summer commuter I'll hopefully have done before the snow settles I'm planning to use bullhorns and a shorter stem, to get about the same distance between my palms and the saddle on both bikes.
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Old 07-10-08, 07:20 AM
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Originally Posted by dabac
Depends on what you're trying to achieve with your change.
My winter commuter is a flat bar MTB-looking type of bike, and for the city riding I have to do I'm very happy with the rather upright position that bar+stem combo gives me. But as soon as there aren't any immediate braking or gear changing to be done I much prefer to ride with my hands on the bar ends.
So for the summer commuter I'll hopefully have done before the snow settles I'm planning to use bullhorns and a shorter stem, to get about the same distance between my palms and the saddle on both bikes.
Mostly, I am trying to get some variety in my hand positions. Secondly, I like riding on "Hoods" but as this bike is a flat bar, I don't have that option. Thirdly, I want to have the option to get into a more aerodynamic shape comfortably.

We'll see how it works out. I am getting some old steel drops that are 22.2mm that I am going to chop into bull horns. And if I don't like that, or if it doesn't work properly, I am going to try trekking handlebars. and if all else fails I'll just throw the flat bars on there.

I guess I am just concerned when a much more experienced biker hops on and tells me how nice the geometry is, and I'm about to make a change to it. I suppose if It negatively effects the bike there is nothing stopping me from putting the flat bar back on, so I shouldn't be concerned.
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Old 07-10-08, 07:35 AM
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Originally Posted by cg1985
Also, I notice on more traditional Road bikes the "crotch" bar
Although your name is apt, and the part you're thinking of is evident, you may wish to use the phrase "top tube" on future occasions

Originally Posted by cg1985
..on my Bike, it's angled ever so slightly downward.
Well, that's fashion for you.

Originally Posted by cg1985
How does this effect feel?
Marginally, if anything at all.

Originally Posted by cg1985
The angle of the seat post, and the angle of the forks appear to be the same,
And those are far more important.
Originally Posted by cg1985
.. so what does the angle of the "cross" bar do?
I've heard a few different takes on that.

One is strictly fashion. With MTB frames getting sloping top tubes for extra clearance and agility road frames were soon to follow to provide the mfg with a common design pattern for all his models. Slap a spiffy name on it like "compact" frame and you've suddenly created a selling point out of thin air.

Another is that back in the days seat posts (and stems) were a bit flimsy, so the frame had to get to a certain height in the back to get the saddle where it needed to go w/o having too much protrusion.
But with the tube diameters and materials we're using today that's no longer a problem. A bike mfg can sort of squeeze more sizes of riders onto fewer sizes of bikes by having more adjustability in the seat posts, different stems ASO.
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Old 07-10-08, 07:37 AM
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Originally Posted by dabac
Although your name is apt, and the part you're thinking of is evident, you may wish to use the phrase "top tube" on future occasions


Well, that's fashion for you.



Marginally, if anything at all.


And those are far more important.


I've heard a few different takes on that.

One is strictly fashion. With MTB frames getting sloping top tubes for extra clearance and agility road frames were soon to follow to provide the mfg with a common design pattern for all his models. Slap a spiffy name on it like "compact" frame and you've suddenly created a selling point out of thin air.

Another is that back in the days seat posts (and stems) were a bit flimsy, so the frame had to get to a certain height in the back to get the saddle where it needed to go w/o having too much protrusion.
But with the tube diameters and materials we're using today that's no longer a problem. A bike mfg can sort of squeeze more sizes of riders onto fewer sizes of bikes by having more adjustability in the seat posts, different stems ASO.

hehe, I'll remember "Top Tube"

But this was very helpful, Thank you!
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Old 07-10-08, 08:11 AM
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Originally Posted by cg1985
Mostly, I am trying to get some variety in my hand positions.
Trekking/butterfly bars as well as the traditional drop bars are great for that.

Originally Posted by cg1985
Secondly, I like riding on "Hoods" .
Unless you're insisting on split-second access to brakes and shifters that can fairly well be simulated by adding bar ends to your flat bar.
Originally Posted by cg1985
Thirdly, I want to have the option to get into a more aerodynamic shape comfortably.
Bullhorns and trekking bars can stretch you out some more, but drops are the only ones that will - well, drop you.

Originally Posted by cg1985
I guess I am just concerned when a much more experienced biker hops on and tells me how nice the geometry is, and I'm about to make a change to it.
It's your bike and your riding experience. Do whatever you think required to improve on it. Everything suggested so far is is entirely reversible, so don't worry about it. Experiment a little, learn a little, share your experiences.
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Old 07-10-08, 08:18 AM
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Originally Posted by dabac
Trekking/butterfly bars as well as the traditional drop bars are great for that.

Unless you're insisting on split-second access to brakes and shifters that can fairly well be simulated by adding bar ends to your flat bar.
Bullhorns and trekking bars can stretch you out some more, but drops are the only ones that will - well, drop you.



It's your bike and your riding experience. Do whatever you think required to improve on it. Everything suggested so far is is entirely reversible, so don't worry about it. Experiment a little, learn a little, share your experiences.
Yea, I know the Drops are best for aero shapes, but the stretched position is also comfortable. I am hoping the bull horns will do the trick for me as far as comfort and positions available, as I am getting them for free.

I have bar ends, but the flat bars are really wide, so It's not as comfortable as I'd like, I could chop the bars down a little to make it less wide, but That's kind of a last resort Idea, because I'd have to get new Flatbars if I f'd up the chops.
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