Questions About Frames

[clunk]

I'm new to this forum and have some questions I hope I can get some help on. I'm going to buy a new bike in the next year or so and my question is about seat tube angle and head tube angle. Does more seat tube angle mean a less aggressive ride? What about head tube angle? Is there an article or website I can be pointed to that has this type of information? Also, is it better to get a shorter top tube and longer stem or longer top tube and shorter stem? What are the advantages and disadvantages? Thanks.

[CNY rider]

Welcome to the Forum!
You will get some more insightful answers later, but here goes first shot:

The angles are not about the "aggressiveness" of your ride.
They're about putting your body in the proper place with respect to your bicycle.
Your legs have to be in the right place to pedal properly and your weight has to be distributed properly for the bicycle to handle optimally.
The angles are only a small part of the much larger picture of bike design.
For most of us, we look to great designers and builders like Serotta to get those things right, and don't try to get too fancy.

And nobody cares how long your stem is. Honestly ;)

[WadePatton]

head tube angle is part of the complex equation that determines how the bike should handle, and is fairly standardized for any given discipline of cycling (road/track/tour/tri/atb).

seat tube angle is the first step in getting your hips where they need to be. production bikes use a "fits all" approach and you are expected to fit or use different seatposts to make it fit (achieve proper setback). custom-fitted and/or hand-made frames allow the builder to vary the seat tube angle for the proper placement of the rider to accentuate efficient pedaling and optimum handling.

head tube angles are directly associated with "aggressive" or twitchy or not. seat tube angles shouldn't be thought of that way. it's a point of fit.

[Lifelover]

Unless you are just interested in this stuff and want to understand it out of curiosity, it is relatively useless information. Clearly it is stuff that matters to the builder but the rider need not worry about it.

Find something that can be made to fit and that you like to look at.

[Hard Fit]

I agree with Lifelover. I think your best bet is to go to your local Serotta dealer and work closely with the fitter to get the ride you want. Leave the details to the expert.

[TAW]

Actually, these angles do have something to do with the way a bike rides. Maybe a rider may not be able to tell the difference, but a slacker head tube angle typically produces a longer front center (distance from the bottom bracket to the front wheel) which will make a bike handle differently. Colnago bikes have slacker head tube angles, and they seem more stable, but not as "agile" feeling as some others.

[cmg]

Here are 2 websites that try to answer your questions http://www.coloradocyclist.com/bikefit/ and a really elaborate explanation http://www.cyclefitcentre.com/further%20reading.htm

Bicycle fit really effect riders that are 5'-6' or less or 5'-10" or taller. Most everyone else can probably get close enough on a production bike. the goal of the seat tube angle is to put your knees over the pedal spindle with room to move forward and back, changing out the seat post gives the rider more leeway. the head tube angle controls handling, track bikes have a steep head tube angles while touring bikes have relaxed angles. there are millions of fitting sites, enjoy the research......

[c-record]

You'll find a great group of very experienced cyclists here without the unpleasant 'tude of some sites.

Great advice will be give. Tom Kellog has a nice article on some of the aspects of HT angle/rake/trail. Fun if you've got the interest.

Right. Go to you're local Serotta dealer and get it done properly from someone who knows whats up and has your best interest at heart.

[clunk]

Thanks for the helpful feedback. It's great that you are all willing to share your knowledge.