Cromo vs Aluminum

[wiredued]

I am noticing little difference between cyclocross bicycle wieghts using Cromoly/carbon forks vs Aluminum/carbon forks how can a steel alloy (atleast thats what I think it is) come so close in wieght?

 

[SpearSlinger1]

Because steel is stronger. To get the same strength from aluminum the tubes have to be thicker or larger in diameter. In other words more material. More material also tends to make for a stiffer frame.

 

[babybunny]

Because steel is stronger. To get the same strength from aluminum the tubes have to be thicker or larger in diameter. In other words more material. More material also tends to make for a stiffer frame.

So would Reynolds 520 Chromoly be better for frames than 7005 Aluminum?

 

[Fat Hack]

I am noticing little difference between cyclocross bicycle wieghts using Cromoly/carbon forks vs Aluminum/carbon forks how can a steel alloy (atleast thats what I think it is) come so close in wieght?

Yes, alu has to be "built up" to achieve reasonable strength and stiffness, and also has to be stiff because, if allowed too much flex, it will fatigue quicker.

Here are a couple of gross generalizations: average alu frames should weigh about 200g less than a comparable steel frame, but good alu frames should be at least a lb lighter. You can go crazy light with an alu frame, but there's a greater chance of a shorter life.

 

[Fat Hack]

So would Reynolds 520 Chromoly be better for frames than 7005 Aluminum?

The general consensus with the lower reynolds tubing such as 531 and 520 is that it's not stiff enough for a top quality racing bike -- it's also a little bit heavy. Racers started to prefer the stiffness of alu frames, so the "good old" steels like 531 and Columbus SLX quickly went out of of favor.

The lighter weight of alu meant that the racers could hawl a lighter bike over the big mountains in Europe.

So, 520 should be a much stronger and (usually) a more comfortable frame that should also last a lot, lot longer than a 7005 frame. I would expect a 7005 frame to weigh at least 400g less than a 520 frame.

The whole "steel vs aluminum" argument is a very long one

 

[babybunny]

The general consensus with the lower reynolds tubing such as 531 and 520 is that it's not stiff enough for a top quality racing bike -- it's also a little bit heavy. Racers started to prefer the stiffness of alu frames, so the "good old" steels like 531 and Columbus SLX quickly went out of of favor.

The lighter weight of alu meant that the racers could hawl a lighter bike over the big mountains in Europe.

So, 520 should be a much stronger and (usually) a more comfortable frame that should also last a lot, lot longer than a 7005 frame. I would expect a 7005 frame to weigh at least 400g less than a 520 frame.

The whole "steel vs aluminum" argument is a very long one

Thanks for the info! Say that you have two bikes that are exactly the same except one has a Reynold 520 frame and the other has an aluminum 7005 frame. How much cheaper do you think the Reynolds 520 frame bike should be compared to the 7005 one?

 

[SpearSlinger1]

So would Reynolds 520 Chromoly be better for frames than 7005 Aluminum?

Depends on what kind of riding you want to do and which is more important to you. Stiffer-faster, better energy transfer because there is less flex there to absorb the pedaling forces. More flex-less transfer of road vibration, less fatigue on longer rides.

The whole "steel vs aluminum" argument is a very long one

Word. Like going to a freediving forum and asking, "What the best fins?".

For whatever it's worth, if anything, I like a stiffer frame, but I also use a shock absorbing seat post.

 

[babybunny]

I feel like I'm hijacking this thread, but a quick question: I'm thinking about getting a used bike but it's going to come with a Reynolds 520 frame. Would it be easy and economic for me to sell the 520 frame and go buy something else, like a Reynolds 853 frame from a Fuji Roubaix or an AL frame?

What measurements would I have to know of?

I heard that Reynolds 520 was basically cheap generic cromoly for use on low end bikes

 

[Fat Hack]

I feel like I'm hijacking this thread

you might wanna start a thread of your own. With a name like that, you're sure to get a lot of replies

I'm thinking about getting a used bike but it's going to come with a Reynolds 520 frame. Would it be easy and economic for me to sell the 520 frame and go buy something else, like a Reynolds 853 frame from a Fuji Roubaix or an AL frame?

What measurements would I have to know of?

I heard that Reynolds 520 was basically cheap generic cromoly for use on low end bikes

Here's a couple of online bike-fit calculators:
http://www.wrenchscience.com/WS1/Secure/Fitting/Height.asp
http://www.competitivecyclist.com/za/CCY?PAGE=FIT_CALCULATOR&sex=M&units=cm
You've gotta make sure you really get the inseam measurement correct -- it's easier if someone helps you.

I don't think you'll get very much for a used 520 frame -- they usually are much less than 853 frames, so you'd probably be better off keeping it for a spare.

This is my simplified "aluminum vs steel" debate:

Steel is usually more comfortable to ride, much easier to repair if broken, stronger, and should last much, much longer than alu, provided you don't let it rust. But.....steel can often be not stiff enough, is almost always a bit heavier, and some of the older and cheaper ones can feel a cumbersome to ride compared to new aluminum bikes (that's a subjective comment).

Aluminum is usually lighter and stiffer, will not rust, but can be very hard to repair if broken (depending partly on the thickness of the damaged area). It can sometimes be a bit too stiff and uncmfortable. If you are heavyish, and/or punish the bike like a bike racer does, it will probably not last anywhere near as long as a good steel frame.

 

[wiredued]

Thanks for the help I guess 7005 is considered crazy light then. Where does Reynolds 631 Cromoly rank against 520 the Jamis Nova is using 631 on the main tubes?

The general consensus with the lower reynolds tubing such as 531 and 520 is that it's not stiff enough for a top quality racing bike -- it's also a little bit heavy. Racers started to prefer the stiffness of alu frames, so the "good old" steels like 531 and Columbus SLX quickly went out of of favor.

The lighter weight of alu meant that the racers could hawl a lighter bike over the big mountains in Europe.

So, 520 should be a much stronger and (usually) a more comfortable frame that should also last a lot, lot longer than a 7005 frame. I would expect a 7005 frame to weigh at least 400g less than a 520 frame.

The whole "steel vs aluminum" argument is a very long one

 

[Fat Hack]

Thanks for the help I guess 7005 is considered crazy light then. Where does Reynolds 631 Cromoly rank against 520 the Jamis Nova is using 631 on the main tubes?

I wouldn't say 7005 is crazy light, unless you are over 200lbs -- it depends on the builder.

631 is definitely considered a good step up from 531, and a much bigger step up from 520.

check out the Reynolds site: (click on "tubing"..)
https://vault2.secured-url.com/reynolds/english.html

 

[f1rchifi]

Does anyone have feedback on the Prestige line of cromo tubes? How about the Tange Infinity?

Thanks

 

[Fat Hack]

Does anyone have feedback on the Prestige line of cromo tubes? How about the Tange Infinity?

Thanks

Jeez, I didn't think they still made that.

There's many other steels around.

I have a Columbus Foco frame that is great.

http://www.ceeway.com/Columbus-Tubing.htm
http://www.dedacciai.com/
http://www.reynolds-cycle.com/
http://www.truetemper.com/performance_tubing/about.html

 

[boudreaux]

Thanks for the info! Say that you have two bikes that are exactly the same except one has a Reynold 520 frame and the other has an aluminum 7005 frame. How much cheaper do you think the Reynolds 520 frame bike should be compared to the 7005 one?

A total impossibility, due to differences in material properties. Frames of different materials are never made identically.

 

[boudreaux]

The general consensus with the lower reynolds tubing such as 531 and 520 is that it's not stiff enough for a top quality racing bike --

BS! You need to check youngs modulus.All steel alloys are equally stiff. Tubing stiffness as used in a frame is a playoff between diameter and thickness,with diameter being more important,especially with respect to weight.The advantage of the stronger alloys is that you can build a frame that is light and stiff.