Singlespeed & Fixed Gear - How much does frame geometry matter?

I'm not talking about a huge difference, just a slight one.

Excuse me if I dont use the proper cycling terms... but I've decided I want a fixed gear bike. While looking at Framesets I've found a few that I like, however the one I'd rather get (because of price) has a slightly different geometry, and I dont know how much it will effect the bike as a whole.

Here's the main two I'm looking at:

The Eighth Inch Scrambler V3- http://www.eighthinch.com/scrambler_frame.html

and the Mission Valencia- https://www.missionbicycle.com/frame

Now, I THINK I would prefer the top tube to be flat or slightly sloped downward for a LITTLE bit more aggressive geometry, however the Scrambler frame seems to have an almost upward sloped top tube... it's so slight that it's hard to tell in many of the pictures. and the Valencia looks to be slightly sloped downwards... So, do you all think that it matters for the price difference?? Would I really even notice much of a change with the different geometry?

What do you all think?? and if you have suggestions for other fixie framesets around the same price range I'm all ears, but I've read a ton of old forums on the topic of cheap fixed gear framesets, so if you have a suggestion please include some reasoning to help me decide.

thanks alot!! I appreciate any help.

Define "aggressive geometry".

I hear it used a lot, but what exactly is "aggressive"?

downward sloped toptube as opposed to upward sloped toptube. I included that in my post.

Aggressive refers to short stays and steep headtube and seattube. It has nothing to do with the angle of the top tube.

Downward slopping top tube does not necessary translate to aggressive geometry; upward slopping top tube, or compact geometry, can also be "aggressive".

You could achieve downward slopping top tube simply by buying a new fork with different length and/or add 650c wheels. The handling will be very jittery and shaky, though.

Neither of the frames are very aggressive, if you want the downward slopping look, get the Affinity Lo Pro.

It depends on all kinds of factors: riding style, aesthetics and the bike build.

Oh, thanks. As I also said in my post I dont know what alot of cycling terms mean. (although I thought I knew that one haha)

So, would you consider the Scrambler any less aggressive than the Valencia?

Downward slopping top tube does not necessary translate to aggressive geometry; upward slopping top tube, or compact geometry, can also be "aggressive".

You could achieve downward slopping top tube simply by buying a new fork with different length and/or add 650c wheels. The handling will be very jittery and shaky, though.

Neither of the frames are very aggressive, if you want the downward slopping look, get the Affinity Lo Pro.

Thanks!
I'll check it out

Comparing the dimension on the 55 scrambler and the 56 valencia(just those two cause Im lazy some times). The scrambler is slightly mor aggressive. Since there is a lot of confusion of what aggressive means, do you know how they handle differently(theoretically, there is such little difference between the two)?

Do you mean aggressive handling vs. less aggressive handling?

Correct me if I'm wrong, but doesn't an aggressive geometry give you quicker handling, more nimble a little less 'stable' ect.??

I should point out that Scrambler's forks are 30mm in rake, which will affect how the bike will steer.

I should point out that Scrambler's forks are 30mm in rake, which will affect how the bike will steer.

How exactly would that affect it?? And I apologize if I sound clueless... but I am. apparently even more so that I thought. haha

If I am correct, the less the rake, the more the trail, the more stable the bike it is at speed but will not be very lively at low speed.

David Moulton have a very cohesive article on fork rake and trail.
http://davesbikeblog.squarespace.com/blog/2007/5/4/trail-fork-rake-and-a-little-bit-of-history.html

More to read about how a bike handles by David Moutlon.
http://davesbikeblog.blogspot.com/2006/06/squirrelly_30.html

If I am correct, the less the rake, the more the trail, the more stable the bike it is at speed but will not be very lively at low speed.

David Moulton have a very cohesive article on fork rake and trail.
http://davesbikeblog.squarespace.com/blog/2007/5/4/trail-fork-rake-and-a-little-bit-of-history.html

More to read about how a bike handles by David Moutlon.
http://davesbikeblog.blogspot.com/2006/06/squirrelly_30.html

Thanks! I'll read both of those. I seriously appreciate it.

Urban Velo also did a nice easy-to-understand geometry guide in Issue #3 (http://www.urbanvelo.org/issue3/urbanvelo3_p44-45.html).


....David Moulton have a very cohesive article.........

http://farm1.static.flickr.com/22/29172942_f2de3d5bf4.jpg
:D

I know, my English sucks... :(


Very unpleasant picture to look at.

Cool disc "Break" picture

My Lo pro has fairly slack angles considering the aggressive look. I believe the headtube angle is 72-73 with a 43mm rake fork.

If you don't know what makes a frame "aggressive" then it isn't something you should be worried about when buying your bike. Pick something in your favorite color.

If you don't know what makes a frame "aggressive" then it isn't something you should be worried about when buying your bike. Pick something in your favorite color.

+1, "aggressive" isn't always the best for the street anyways and it wont even matter if you bike around the park all day. Get the one that looks the best.