Bike Frame Material

The cost of a mountain bike frame is proportionate to its material, as well as the treatment that material has received. Currently, there are five types of material used in mountain bikes - high tensile steel, chromoly steel, aluminum, titanium, and carbon fiber. Oversized diameters, heat treating, and butting are tubing material treatments that will increase the cost of a frame as well.

High tensile steel: This is a very durable alloy that’s found in lower priced mountain bikes. It offers a high carbon content which makes it less stiff than chromoly steel, so more materials are needed to make it stiff enough for bicycle frames, which will in turn make it that much heavier.

Relatively inexpensive to produce, you’ll find this material in trail bikes, city bikes, and even entry level mountain bikes. There are some bikes that come with a chromoly seat tube, while the rest is high tensile steel.

Chromoly steel: Short for steel alloy, chromoly is best described by its major additives - chromium and molybdenum. This is probably the most refined framing material, giving over 100 years of dependable service.

Depending on the type of heat treating and butting, you can find this material in bikes as low as 400 dollars all the way up to 1,500 and beyond. The chromoly steel material offers very good durability and a compliant ride characteristic.

Aluminum: For the past 15 years, aluminum has been refined in pretty much the same way as chromoly. There have been various alloys developed, as well as heat treatment, oversizing, and butting. With dual suspension bikes, aluminum is the preferred material as it’s the stiffest and most cost effective.

Aluminum is stiffer than chromoly, and therefore it will crack before chromoly. Of course, this depends on how you ride and how much abuse you give the frame. The advantages of aluminum is that the frame is very light and very stiff through oversizing or butting.

Titanium: Even thought it’s somewhat exotic, the prices for this material have come down over the last few years. Frames made of titanium remain expensive because it takes longer to weld the tubes to the frame.

Titanium is considered an alloy, normally mixed with small amounts of vanadium and aluminum to give it better weldability and ride characteristics. More compliant than chromoly, it offers better fatigue and corrosion properties.

The material you choose for your bike, all depends on where you ride and what style you use. Almost all materials will last you for years, as long as you take care of your bike and treat the frame with some respect.

Discuss : Cromoly 4031 vs Reynolds 531

This is discuss about Cromoly 4031 VS Reynold 531 from another Forum

- chromium molybdemum (sp.?) is an excellent steel alloy, and the 4130 denotes a specific forumulation of alloy (like 6061 aluminum is a specific alunimum alloy, as is 7005, etc.). Not all chromoly steel is specifically 4130, but you see it pretty often. I have a friend who is an aircraft engineer, and he says 4130 steel is usually used in aircraft when steel is needed. It's incredibly strong, and relatively lightweight. Reynolds 531 is a proprietary steel alloy of Reynolds, and it is manganese molybdemum, I believe. Reynolds claimed this to be superior to chromoly for bicycle tubing. The main thing about something like Reynolds 531 is in the way they manipulate (butting, shaping, etc.) the tubes, and there is a wide variety of 531 tubing for frame builders to choose from. In other words, a touring bike made of 531 would more than likely have a different 531 tubeset than a racing bike, etc. Reynolds has since come out with 501, 555, 753, 853, etc. All of them are steel, and all of them have their own characteristics. For a long time, 531 was their best.

- In theory, bicycle tubing could be made with 4130 steel that is similar in weight and strength to Reynolds 531. For years, 4130 tubing was standard in the American aircraft industry, just as Reynolds tubes were used in British made aircraft. However, marketing is always more important than engineering. A 4130 tube is generic, and therefore of little marketing value. So, bike makers of the '70's and '80's preferred to use tubes that could be promoted, such as those from Reynolds and Columbus.

When companies in that era used 4130, they often used straight gauge tubes of medium weight. They COULD have asked suppliers to make double-butted, thin walled 4130 tubes, but that would be pointless. Those sorts of tubes were already being supplied by Reynolds and Columbus.

So, although it is possible to make a light weight 4130 frame that is as strong as a light weight Reynolds frame, the 4130 frames that were actually buillt often weighed a pound or so more than a Reynolds frame of the same size. And, the Reynolds frames were often on top-of-the-line bikes, so they were set up with lighter, more expensive components. The 4130 frames got heavier cheaper components. In 1974, a company that was selling a 23 pound Reynolds bike might have also sold a much cheaper 28 pound 4130 bike. But, it was NOT impossible to make a 23 pound 4130 bike...just no motivation.

BIKE FRAME MATERIALS - Aluminum, Titanium, Chro-Moly...Does It Matter?

Mountain biking is one of my favorite sports. I've been mountain biking (MTB) for over 12 years. I've mostly ridden in the Northwest: Washington, Oregon, Idaho, and Montana. But I've also ridden in Florida and Texas.

For me, finding the right bike is a very important process. It's much like choosing a car except more important in many ways, especially if you compete. Your bike will go through a lot with you (like a good pair of shoes for a runner) and it's important to find the right qualities so the experiences are efficient and fun.

A very basic consideration when looking at a bike is - "What's the price?" That is often the first question people have, especially beginners who don't necessarily know much about bikes. One of the major contributors to the overall price of a bike is the frame material. Other factors include suspension and components among other things.

It is important that the buyer - you - has a good idea of what the bike is going to be used for. If you're just riding with the kids on the weekend you can pass buy the titanium and carbon fiber frames and look at a low cost cro-moly bike. But if you've been training and you're looking for a bike you can race with then you have to take a closer look. Be honest with yourself though because bikes can cost a lot of money. The most expensive bike I've owned was a 2001 Specialized FSR Enduro Comp which I bought for $1,699. High-end bikes can easily break the $4,000 mark.

This review will probably be the most helpful for those that are budding MTB competitors.

============================================================

Frame material affects several characteristics of a bike. They are stiffness, weight, and strength. So it's important to get a proper mix of stiffness, weight, and strength that's is appropriate for your biking activities. Though most inexperienced riders won't really be able to tell a difference, with the exception of weight, until they've been riding for a while.

There are two major types of MTB racing - downhill and cross-country (XCR). Obviously, weight is not much of a factor for downhill racers where as weight is very, very important for cross-country racers. Other types of racing include dual slalom and trials.

There really is no "perfect" material though I think some might disagree with me. With that in mind, lets take a look at the different frame materials available...


Chro-Moly

Chro-moly is a fancy name for steel. Steel is heavy. But, steel is stiff. A frame made with chro-moly will usually have small tubes. To help reduce weight many steel frames have thin walled tubes. But remember, the thinner the tube walls are the less stiffness you'll have. If you're a heavy rider you'll want a thicker tube wall to support your weight. Reynolds 853 is usually considered the best type of steel for bike frames because it gains strength as it cools after the welding process. All steel has the same inherent stiffness.

Positives:
* Very Strong
* Stiff Ride
* Durable
* Cheap

Negatives:
* Heavy
* Prone To Rusting


Aluminum

Aluminum is one of the most common frame materials because it is light and fairly affordable. Aluminum provides the rider with a very stiff ride. Aluminum frames have large diameter tubes that help improve strength and stiffness. This material is often used for unique frame shapes.

Positives:
* Light
* Stiff
* Inexpensive
* Rust-Proof

Negatives:
* Less Strength Than Steel
* Can Break Under Heavy Use
* Difficult To Repair
* Thin Walled Tubes Dent Easy


Carbon Fiber

Carbon fiber frames are very strong and stiff. They are made by braiding fibers of carbon and affixing them with a very strong glue (epoxy). These kind of frames allow for unique frame shapes because they can be molded to the proper shape much easier than metal alloys. Carbon fiber can crack so watch out for that.

Positives:
* Great Strength
* Great Stiffness
* Very Light
* No Rust

Negatives:
* Expensive
* Prone To Breakage


Titanium

In my opinion, titanium is one of the best materials for any frame. It combines a great balance of lightness, strength, durability, and stiffness. The best alloys of titanium are as strong as the best alloys of steel frames. For a stiffer titanium frame look for larger tubes. Titanium frames usually come in two alloys:
- 3Al/2.5V alloy (3% aluminum / 2.5% vanadium)
- 6Al/4V (6% aluminum / 4% vanadium)

The 6Al/4V is stronger but more expensive.

Positives:
* Super Light
* Very Strong
* Rust Proof
* Great For Large Riders

Negatives:
* Very Expensive
* Somewhat Flexible (compared to steel)


Butt My Frame Sucka! - When looking at aluminum frames and some large diameter tubed steel and titanium frames you'll want to make sure that the tubes are butted. This increases strength and it's important.

What's Up With Flex? - Flex is when there is lateral movement in the frame. This most often happens with the tire but can also come from the seatpost. But there can also be flex in the frame itself. That is why stiffness is important. Be sure to ask about the flex characteristics of the bike you're looking at. Flex can steal power from your pedal stroke and, especially with full suspension bikes, is detrimental when riding uphill (crosscountry racing for example).

Ooh, It's So Stiff! - You sick-o I know what you were thinking! Stiffness refers to how much the frame itself absorbs vibrations and bumps in the surface you are riding on. Aluminum is notorious for offering a very unforgiving ride. Steel frames are known for being absorbant.

Who Designed This? - In addition to the frame material, what determines a lot as far as stiffness, flex, strength, and even weight is the design of the frame. I would recommend reading some reviews in MTB magazines. Also, since you're on Epinions check out some of the reviews. Frame design is very important.


Summary:

If you're doing cross-country (XCR) riding you'll want to get the lightest possible bike that has the least amount of flex. For downhill riders, focus on suspension travel, strength, and durability. Light frames and components are important for both, but even more so for XCR. I like aluminum a lot but I would love to be able to afford titanium! There are some nice carbon fiber bikes out there too!

My FSR Comp has an aluminum frame. My complaint about it is there's way too much flex in the rear swing arm for it to be a good XCR bike. The rear swing arm is the part attached to your rear tire, rear suspension, and bike frame.


Good Mountain Bike Companies:
* Specialized
* GT
* Trek
* Barracuda

And many more...


Final Say:

Be sure to research your purchase carefully!

Also, be sure you know what you and the bike will be doing, then focus on your price range. Obviously, try to get the best mix of quality components, suspension (if desired), and frame material. Other than that - have fun and enjoy your new ride!


The Bottom Line Does It Really Matter? Oh Yeah!

Bike Frame Materials: Spending Your Gold on Common Metals

Frame construction begins with tube selection. The most common bicycle frame tubes are steel, aluminum and titanium. Carbon fiber reinforced frames can also be considered for lightweight, rigid and expensive frames although I've never shopped for one so I won't comment. Here's a link that might help:

http://sheldonbrown.com/gloss_ca-m.html#carbon

The examples I provide below are for mountain bikes. The principles apply to road bike frames but my experience really stems from over ten years of mountain biking and being on the market for four bikes.

STEEL
Steel used to be the standard in bike frame manufacture. It is cheap, plentiful, easy to weld, roll and cast. Steel is bendable, thus can be repaired easier than more brittle metals. Steel can be manipulated to get a desired hardness by heat treatment, tempering and annealing. Steel has a unique "springy" feel when used in bicycle frames. It absorbs vibrations from shock better than other metals. Steel's ability to absorb vibration energy will also sap a small amount of energy from each pedal stroke. Steel is not as responsive as some of the stiffer metals. Steel will react slowly with the oxygen in the air and corrode, or rust if not coated or painted. Some people coat their frames internally as well as externally to add life to their bike frames. Steel is an alloy of iron and carbon and other metals such as chromium molybdenum (chromo, chromoly, chro-moly) and vanadium.

To maximize steel's characteristics to get the strength and lightness desired for a bicycle, a builder has to buy expensive steel tubes and spend a lot of time manipulating them. Butting, bending and gusseting need to be performed to put material where it's needed most and cut back on material in other areas to maintain lightness. The craftsmanship of quality, steel bike building will always remain an art and will always be expensive. A complete bike with hand crafted steel frame, weighing around 24lbs usually starts around $1500. You may be able to find a new frame (no parts) for under $500.

Bike manufacturers are not buying steel from steel manufacturers, like Columbus, Reynolds, Tange and True Temper in bulk anymore. It is difficult to find a complete bike with a quality steel frame in the $500 range now. Production line steel bikes tend to be very heavy, in the 28lbs, and over range, for a complete bike. Weight is a subjective matter however. Who cares if your frame is heavy if you're bombing down hills or free riding? You may want a steel frame for durability, shock absorption characteristics and peace of mind.

ALUMINUM
Although not long ago it was steel, aluminum is the most common tube used in bike frame manufacture. It is plentiful, recyclable, does not rust or corrode like steel, and has a highest strength to weight ratio compared to titanium and steel at the same price. Aluminum weighs less than one-third as much as steel and is just as strong. Aluminum tubes can be thinner than steel of the same strength, thus lighter, and maintain the same amount of rigidity. To maintain the structural integrity and lateral stiffness of the tube, aluminum tubes are generally oversized. Aluminum has very little of the springiness of steel yet yields a responsive, "pedal to the metal" kind of ride. Newer, expensive aluminum alloys, such as Easton's Scandium tubes, are supposed to have the best of both worlds, the lightness and corrosion resistance of aluminum and the liveliness of steel.

Scandium is definitely a step forward in the world of aluminum construction for bikes. Scandium frames however can cost as much as titanium frames and are not practical for the average rider. For off-road bikes, the use of light, rigid aluminum may be just perfect for use with dual suspension bikes. Although the additional parts involved with suspension add a lot of extra weight, suspension adds shock absorption and comfort missing in aluminum frames.

More highly engineered aluminum frames are butted (similarly to steel) to reduce weight and induce a more springy ride quality. A major manufacturer of performance specification aluminum tubes is Easton, well known in baseball and softball for their bats. Easton and other manipulated tubes and frames are generally more expensive and can be found on new bikes for over $1000. A bike in this range should weigh about 26lb or less. Very high end aluminum frames can weigh as little as 3lbs and yield a complete bike under 22lbs, including racing parts and a lightweight suspension fork. A lot of manufacturers choose to buy generic aluminum tubes because it is usually cheaper and they can stick their own label on it.

In the $300-500 range you can find aluminum bikes with straight unadulterated tubes. You will get a lighter bike in this price range, in comparison to steel, although heavy, less expensive parts and the overbuilt aluminum frame will keep you from getting the most out of aluminum characteristics for your money. Any buyer should feel secure that any bike in this price range is a much better value today, than was available 10 or even, 5 years ago. A mountain bike in this price range will be 28lbs or under.

Generally speaking, aluminum frames cannot be repaired. Aluminum tends to shear upon breakage and can not be re-welded or patched due to the initial heat-treatment of the frame. Oversized, stiff, thin wall tubing will dent easier than smaller diameter tubes. It is good to know that most frames are warranted to the original owner, for up to 5 years or for the life of the frame under "normal" use.

TITANIUM
Titanium is the least available metal and is the generally the most expensive. It has a very high strength to weight ratio and has the natural springiness of steel. Titanium, in its usable alloy form, does not corrode. Titanium, also used in the aerospace industry, could easily be the perfect tube for bike building. Unfortunately, titanium tubes are expensive and they are expensive to work with. Titanium need to be welded in a special gas environment (argon, I believe it is) so that when heated, it does not react with gases in the air. Prohibitive costs of titanium have seemed to stifle the use and development of titanium in the cycling world.

Sandvick is one supplier of performance specific titanium tubes. Strength, rigidity and lightness is engineered into a variety of tubes. Before Sandvick, and even now, manufacturers have been buying generic tubes that meet the bike builders' specifications.

Although impossibly difficult to break, titanium is also difficult to repair. As with aluminum frames, there are some parts on the frame, such as the derailleur hanger that are made to be replaceable via small bolts. Titanium frames can last several lifetimes if the minimum maintenance precautions are observed. Titanium is tough and highly scratch resistant. Frames are usually left raw, and unpainted, as they are not very porous and do not hold paint well.

Complete titanium frame bikes with suspension fork usually weigh-in similarly to aluminum, around 22lbs. Titanium, of course, will provide a supple, lively ride, unlike aluminum. Titanium frames alone cost around $1000. A complete bike starts at $2000.

Some builders are using rear suspension shocks with no mechanical parts on titanium frames. The rear triangle is designed to flex to provide up to 2" of travel. Titanium is springy and does not fatigue like steel. This results in a very comfortable frame with little added weight from suspension parts.

CONCLUSION
Most frames, no matter what material, especially production line frames, are overbuilt and heavier than they need to be. This is good because they will tend to last under heavy use but it is bad because the full advantage of using performance tubing diminishes as layers of durability pile-on. It is cheaper for the manufacturer to overbuild the bike frames the first time around rather than provide replacements for frail frames in the long run.

Frame material is definitely an important factor in selecting a mountain bike. Unfortunately, the bicycle industry has already decided in favor of aluminum by providing the largest selection of aluminum frames. It is very difficult to find an intermediate level steel frame on which one can grow and develop riding skills. Fortunately, aluminum quality is now fairly diverse and getting more comfortable. It is also good that there are new ways of controlling shock and vibration via suspension parts. If you can afford titanium, it is a good investment, considering that they last two lifetimes. Oddly enough, I have noticed that titanium resale value is only marginally better than some steel or most aluminum. Used bikes (check Ebay) go for about 50% off their sticker price after 1 year and depreciate in value about 15% every year after that. Titanium may only depreciate 40% after the first year and only 10% every year after that.

You will want to start with a good frame and replace parts with upgrades as you go. Most manufacturers will outfit one or two models in their line with a premium frame with cheaper parts. That's the one you should get as a new rider. For example, Gary Fisher makes one frame for their high end "professional" series bikes. There are however, 4 models or so, that use this same frame. If you are on a budget, the one to get is the least expensive of the 4 because you will be getting the same frame that is used on the top model, costing almost twice as much. The parts are replaceable. The frame is the heart and soul of the bike. Of course, you want to figure out your budget and then you want to squeeze as much value as you can in there. You'll be better off riding now and inevitably replacing parts as you wear them out rather than sitting on your money. It's probably best to stop worrying about frame material and focus on frame fit and feel. Ride your friend's bike, ride my bike, ride the bikes on the showroom floor and get out there and ride.

Cromoly Crashed

Before
Rocky mountain Greatest Cromoly Bikes



After

Rocky Mountain Blizzard

Rocky Mountain Blizzard 08
The Greatest Cromoly with Thai style Decorate.