Who makes quality bikes?

[marathon marke]

However I would never buy a welded 7000 series aluminum alloy frame.

Why is that?
I'm just curious. I used to weld (TIG and MIG) for a living, but I never got involved in making frames.

 

[fasthill]

Aluminium is generally refered to a course metal. Its fatigue life is very short. It work harden's very quickly. This creates a rigid frame without much 'give'. You can bend aluminium but try and bend that back into shape and it will crack. You also have the issue of electrolysis which is worse with aluminium than it is with any other material.

The durability of aluminium is nothing compared to steel. Some of the high grade "Aircraft" alumnium that is available can eleviate soem of the problems but it is still a course grade metal.

It's pretty much an accepted opinion out there that aluminium frames are both harsh and have some fatigue issues. I think it was Gary Klein who challenged these notions in his speech (can't find that document on my computer). That's why I was interested in your opinion since you're a frame builder.

Life observations, however, do not support these notions very much though (I know, observations, in some quarters, are not very scientific even though all science is nothing more than life observations).

For example, I've been riding steel frames for most of my life, good frames too, all from established Italian builders. Then life carried me away from cycling. When I started riding again 4 years ago, I got a CF frame. It broke. I got it replaced, sold it and bought another brand, swapped the gruppo only to have a broken frame again in 4 months. I repeated this cycle 4 times and eventually gave up, bought a second hand ancient aluminium frame and now sitting wondering if I should just go and buy a steel frame.

And here are the observations - the 4 CF frames, with exactly the same gruppo and wheels, all felt the same to me even though they've come from 4 different brands (the frames themselves were in $3,000 to $5,000 bracket, retail of course). And here's the most interesting bit: when I finally put my gruppo on a $150 second hand aluminium frame made in the late 90s, again, I felt no distinguishable difference. Rough or smooth surface, uphill or downhill, these 5 bikes felt the same as far as I could tell. To be fair, the aluminium frame, because of its crit oriented geometry, is a bit more twitchy than the CF frames but other than that, it's same *** different pile. Even on 6hr rides with plenty of climbing and crap roads the alu frame wasn't a hindrance contrary to what so many people believe about alu frames.

Now to aluminium's fatigue - I understand very little about properties of metals etc but why this almost 20yo frame is still going when, if fatigue theory is true, it should've cracked by now? I know it was used all this time since it was originally bought but it just keeps going. Why's that?

Harshness - this too never convinced me much because I learned long ago your ride is as harsh as your tire pressure. Geometry too can contribute, e.g. short seatstay will give you a harsher ride than a longer one. But is it that much noticeable anyway to talk about alu frame in general as being harsh?

 

[Fiemme]

The difference between 6000 and 7000 alloys is the composition. 7000 series alloys are generally stronger than 6000, but more brittle. This creates a stiffer frame but prone to cracking.

"Avanti" aluminium does not have any where near the fatigue life of steel. I do agree that joins can be just as strong and tough though. This is why aircrafts need to inspected regularly.

Out of all the aluminium bikes I've seen the Cannondales (CAAD Frames) do seem to better than the rest. They seem to doing something right.

 

[Fiemme]

For example, I've been riding steel frames for most of my life, good frames too, all from established Italian builders. Then life carried me away from cycling. When I started riding again 4 years ago, I got a CF frame. It broke. I got it replaced, sold it and bought another brand, swapped the gruppo only to have a broken frame again in 4 months. I repeated this cycle 4 times and eventually gave up, bought a second hand ancient aluminium frame and now sitting wondering if I should just go and buy a steel frame.

Now to aluminium's fatigue - I understand very little about properties of metals etc but why this almost 20yo frame is still going when, if fatigue theory is true, it should've cracked by now? I know it was used all this time since it was originally bought but it just keeps going. Why's that?
QUOTE]

Fasthill I think you've been extremely lucky. I've been in cycling since I was 12years old and have seen to many aluminium frames crack and fail. I have also seen a lot of carbon frames fail 'Catastrophically'.

My first road bike was a 531 reynolds frame I bought from and old semi-pro. It was 12 years old when I brought it and lasted another 10years until I hit a dog. I also have an early carbon frame (Aluminium Lugs, with round carbon tubes glued and screwed to the lugs) this is over 25years old, which is now my training bike. Over the years I have had 2 aluminium frames both lasted 3 years and both cracked at the head tube and down tube join. Also a common breakage point with steel frames, but usually takes 10years. I now own 6 bikes two carbon and four steel frames one a I made myself 3 years ago and another custom built frame by a local builder in Sydney 'Kerry Hopkins' which is now 10years old and two off the shelf Colombus Aelle frames also made by Kerry Hopkins.

As everyone keeps stating the comfort and ride quality of a frame comes down to the geometery. If you are to compare three identical geometery frames made from aluminium, steel and carbon, I can guarantee which one will last the longest and give a more comfortable ride.

 

[CobbleStoner]

here are the results of lab testing on the Ritte/Russ Denny frames and the Ritte Bosberg
http://www.ritteracing.com/blog/2012/02/testing/

 

[Fiemme]

here are the results of lab testing on the Ritte/Russ Denny frames and the Ritte Bosberg
http://www.ritteracing.com/blog/2012/02/testing/

Had a look at this website and somewhat agree with what was written. However some of the images had me wondering. One image shows the down tube looking up to the head tube join. There seems to be a definate mis-alignment where the carbon down tube meets the steel down tube. Also some of the welds leave alot to be desired. I do not TIG weld but I do get involved with a lot of Race Car frame and roll cage builders who TIG weld regularly and the quality of the welds on the RITTE do not look that great. Have a look at a Baum and the welds are alot nicer and uniform.

 

[CobbleStoner]

Had a look at this website and somewhat agree with what was written. However some of the images had me wondering. One image shows the down tube looking up to the head tube join. There seems to be a definate mis-alignment where the carbon down tube meets the steel down tube. Also some of the welds leave alot to be desired. I do not TIG weld but I do get involved with a lot of Race Car frame and roll cage builders who TIG weld regularly and the quality of the welds on the RITTE do not look that great. Have a look at a Baum and the welds are alot nicer and uniform.

interesting, I'm not an expert in welding so I wouldn't know, but Russ Denny has a pretty good reputation, and he does all the welding, as far as the mis-alignment, I'm sure that is a 2D photo thing, plenty of people have ridden that frame and rave about it, the test numbers are very good, but it has not been proven on the long term durability yet.
In theory, it should last longer than any full carbon frame

 

[Indurain]

Probably the nicest looking bike on the market at the moment. Ride and manufacteuring quality unknown. But based on feed back of the 2012 Pinarello Dogma 2's it's a dream.

 

[fasthill]

This is an old test but relevant and interesting nevertheless.

Briefly, these guys ran a frame fatigue test between steel, alu and CF (very early models) frames by applying 1,200 Newtons through 100,000 repetitive cycles. If the frame survived, it went through another 100,000 cycles with now 1,300 Newtons applied.

The first frame to crack was a De Rosa SLX (56,000 cycles), followed by Fondriest (77,000 cycles), both steel. Cannondale (CAD3) didn't crack at all nor did Principia (both alu frames). The only other frame that survived was a CF Trek.

I'm not saying alu frames are more durable than steel but at the same time it's hard to accept the notion about alu frames being inherently prone to cracking after seeing some 15-20yo alu frames still being ridden. I'm sure there would've been more of them if more people could resist the marketing spin doctors.

 

[richwagmn]

This is an old test but relevant and interesting nevertheless.

Briefly, these guys ran a frame fatigue test between steel, alu and CF (very early models) frames by applying 1,200 Newtons through 100,000 repetitive cycles. If the frame survived, it went through another 100,000 cycles with now 1,300 Newtons applied.

The first frame to crack was a De Rosa SLX (56,000 cycles), followed by Fondriest (77,000 cycles), both steel. Cannondale (CAD3) didn't crack at all nor did Principia (both alu frames). The only other frame that survived was a CF Trek.

I'm not saying alu frames are more durable than steel but at the same time it's hard to accept the notion about alu frames being inherently prone to cracking after seeing some 15-20yo alu frames still being ridden. I'm sure there would've been more of them if more people could resist the marketing spin doctors.

Aren't aircraft largely made of aluminum? And they're used for a very long time. I have a hard time believing alu is as risky a material as some people believe. If it was, I'd expect to see aircraft falling out of the sky.

 

[Bustedknuckle]

Aren't aircraft largely made of aluminum? And they're used for a very long time. I have a hard time believing alu is as risky a material as some people believe. If it was, I'd expect to see aircraft falling out of the sky.

Aluminum in aircraft is generally a higher 'number', are more purpose built, more science and engineering than any bicycle frame tube.

Flew F-4s for a 'while', had a part in the stabilator, called a stab horn, 6061 aluminum and it failed enough to lose 2-3 aircraft until they finally salvaged one, examined it and found the broken part. Grounded all until all these could be replaced with a 'better' designed aluminum piece.

Cracks in aluminum bits on aircraft is actually quite common, also flew the F-16N, also had some cracks in the rudder base, little repair and it was fine.

 

[richwagmn]

Aluminum in aircraft is generally a higher 'number', are more purpose built, more science and engineering than any bicycle frame tube.

Flew F-4s for a 'while', had a part in the stabilator, called a stab horn, 6061 aluminum and it failed enough to lose 2-3 aircraft until they finally salvaged one, examined it and found the broken part. Grounded all until all these could be replaced with a 'better' designed aluminum piece.

Cracks in aluminum bits on aircraft is actually quite common, also flew the F-16N, also had some cracks in the rudder base, little repair and it was fine.

Point taken.

When you say higher number you're meaning something like 7075? How high does it go?

 

[simo1733]

Point taken.

When you say higher number you're meaning something like 7075? How high does it go?

The numbers dont work like that.They refer to the main alloying element.
7000 series is zinc, 2000 series is copper.
Just as important is the heat treatment.Often aluminium is worked in an annealed state ( soft)and then heat treated afterwards (hard) .Bike manufactures often rely on age hardening instead of heat treatment,its easier but less effective.

 

[Fiemme]

The numbers represent a % of each composition. Do a simple wikipedia search for SAE Aluminium Grades and you may find the answer. You will also find the answers for 4130 steel and the like.

I was lead to believe that age hardening was a form of heat treatment. The heat treatment accelerated the ageing process.

 

[CobbleStoner]

here is a vid of Russ building a Muur

http://player.vimeo.com/video/43158726

 

[hfer07]

BAUM
http://www.baumcycles.com/bikes