What defines a "good" frame compared to a total crap one?
 

A friend has an Al frame he's offered me. What things about a frame make it worth the build? I'm getting this for free, so no discussion about steel vs. Al vs. CF because I'm not actively looking for a frame.

What are the qualities of a good frame? Are light weight and clean welds enough since road frames pretty universally follow the diamond model? Other things worth considering? Please discuss.

It's good if it fits you for your intended riding style. If it doesn't, it's total crap.

It's not so much as the frame material but what the builder does with the material. Frame geometry afftects handling and comfort. Just by changing the seat and head tube angles, you can move from a sports car to a Cadilac feel. Change the chain stay lengths and you go from a rapidly accelerating feel to a loaded bus sensation. The frame tubes can be nade think or thing or the wall thickness can do the same thing - make the frame strong and stiff or more flexible and comfortable.

You should have bought titanium fiber. Just kidding.

Well, it depends on what you want to do. One of the qualities of good frame is stiffness, because the more flexy a frame is, the more of your effort goes into flexing the metal instead of moving the bike forward. Conversely, a really stiff bike tends to be a little bit harsh, in the sense that every crack in the road goes into your shoulders. The geometer is also pretty important; for example, you can make a bike comfy by raising the handlebars, or fast by lowering them, putting the rider in a more aerodynamic position. A short wheel base and a high bottom bracket make for a responsive ( also known as "twitchy" ) ride.

There's really a lot going on here, and it's pretty hard to say over the interwebs. Probably the first question is whether it fits you at all?

To answer the first question, I don't know yet. This frame is still sight unseen, but he tells me that the top tube measure is within a cm of my Interval's, and that's a good, if not great, fit. So, I've seen this "high bottom bracket" bit before, but when I'm just looking at a frame, how do I evaluate that? Is there an angle I can measure (maybe use the top tube as parallel to ground and measure angle from "ground" to chainstay?) or some characteristic length that suggests how high the bb would be?

Assuming I'll use standard 700c wheels, how can I look at the geometry? ie, what are "aggressive" head tube/seat tube angles and what are relaxed angles?

1. It fits
2. It's fun to ride

"So Pricey" Gucci Mane Remix

A good frame needs to be laterally stiff yet vertically compliant.

God I hate that marketing line.

How cool it looks.

And corners on rails. Is responsive but not twitchy.

Columbus tubing preferably MAX and Bianchis Superset design. IMHO nothing rides better

I think you have to go to walmart-level bikes to get a "total crap" frame now a days. Even the entry level road bikes made by the mainstream guys are pretty darn good.

Free frames are the best frames. Sometimes.

Read this:
http://www.rivbike.com/article/bicyc...rame_materials

Heavy stuff though.

I'm sure you're not biased at all.

It says Cervélo on the side.

That Rivendell dude is like the Mother of All Freds.

SOOO....what kind of frame is it.

St. Rivendell, the patron saint.

3. Fits the rider's budget

Decals, mostly.

Quality is about frame material, construction, detailing, and finish.

Geometry doesn't come into the equation, IMO, because even if tri-bike angles don't suit your mountain riding, the bike would have to assessed within its intended purpose.

So, sophisticated, big grade tubesets, labor intensive details like custom bits, bends, lugs, and complicated constuction need to be considered together, as do details like joint finish, cable routing and stops, and materials used for stops braze-ons and dropouts.

As mentioned above, getting a good frame is pretty easy, and you'd have to go out of your way to get total crap these days. However, getting a great frameset is another thing, and can be quite pricey.

You can measure frame geometry and visually inspect it, but the only way to measure stiffness, road feel, etc, is to build it up and ride it. After a few rides, you'll know if it's right for you. Fit is key. I'm currently riding a new, but cheap aluminum frame, and besides being a bit harsh on rougher patches of asphalt, it's great because it fits me. That's the most important thing. You can mess around with stem length and seat fore/aft positions only so much. Build it up and give it a ride. Gino

Sette Ximo.


Finally took a look at it. It would fit, by measure, and looks to be a good frame, but something about it that I can't identify I just don't like. So I'll pass on it. But thanks for the answers!