Road Bike Frames, Size, Symmetry and Frame Materials

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What should I know to make sure the frame of a new bicycle is right for me?

The frame is the basis of both the strength and the beauty of the bicycle. Nothing besides its paint job is superficial, and when you’re buying a new bike, you want to pay particular attention to the frame.You will want to know enough about size, symmetry, and materials to get a frame that fits you and your riding style and purpose.

focus bike frame

The design of the bicycle frame has not changed much over the years, but the materials have. The original “bike” way back in 1817, was a hobbyhorse you propelled with your feet on the ground and was made from wood. Obviously, bikes have improved!

Beginning in the mid-1800s and throughout the next century, bicycle frames were manufactured of steel. You can still find steel frame bikes around, but they are nothing in weight compared to earlier models!

The first frames were extremely heavy, with laid back angles and with a long wheel base, making for more comfortable riding on the rough roads of the time.

These frames would go nowhere, and slowly, on today’s fast roads and race conditions. Even steel bicycle frames got progressively lighter over the decades by making the tubes thinner and joining them without using lugs.

The next revolution in the manufacture of bicycle frames came when alloy tubes could be joined to each other strongly and safely to make responsive and very light frames.

The tubes had to be bigger, but they could be made in aerodynamic shapes. Alloy bicycle frames are now most people’s choice, often combined with carbon forks and in some cases carbon chain and seat stays at the back.If you don’t want to spend a couple of thousand dollars on a bike, an alloy frame is a good option.

TItanium and Carbon

If you have the money, a titanium or carbon frame would probably be your choice today. Frames made of these materials are much more expensive but if well-made will last a lifetime.

Bikes made of titanium feel almost weightless but offer you a nice, tight ride.

Mixing titanium main tubes with carbon forks and back end gives the best combination for handling and for comfort. At the moment, an all-carbon frame seems to be what everyone wants, but few can afford.

All the main frame manufacturers make bikes of these different compositions, some with lugs (Colnago, Cervelo), some without (Scott, De Rosa, Battaglin), and even some of monocoque, or single mould, construction (Giant, Trek).

Basically, you will buy the best bicycle frame you can afford. With the right components added, even the most basic frame out there today, made by a reputable manufacturer, can serve you well and happily for many years, IF it fits you well.Fit is where any frame can be all wrong for the rider, or all right.

Below is a table giving you some of the elements of buying a bike frame that fits you.The most basic element of sizing a bike frame is commonly referred to as its height; what is usually meant by this measurement is the length of the frame from the center of the bottom bracket to the top of the top tube.

Professionals most often talk about measurements in centimeters because of the European history of the sport and also because of the precision it allows.For those of you who need to translate this into inches, a conversion table is also given below.

To use this chart, you will first need to get an accurate measurement of your inseam.The easiest way to get a good measurement is to hold a book between your thighs, with its spine snugly against your crotch in the same way a bike seat will be, then have a friend make a mark on a wall at the top of the (horizontally straight) spine.

Stepping away from the wall, measure the distance to the floor.This is your inseam length.A road bike frame’s “height” is generally thought to be ideal if it is 67 percent of your inseam length.A mountain bike is ridden on a much smaller frame: as a guideline, use your road bike size and subtract 10-12 cm.

Exact size of a mountain bike is most affected by the amount of downhill riding you do.All frame sizes are affected by the unique configuration of your body, which can be accommodated by differences in frame geometry, top tube length, seat post height and/or saddle angle, handlebar width and slant, and even crank length.
The following chart is just enough to get you going.Once you have the right basic size, the best thing you can do is to test ride different bike frames to see what feels best.

Remember to apply these measurements with some leeway to take into account the factors cited above and your unique body form.If you are shorter or taller than the heights in this chart, you will have special considerations of frame size, so talk to a specialist.

Finally, check out the beauty of the frame.The paint job is perhaps the last thing you should take into consideration, but definitely the first thing you, and everyone else, is going to notice.Enjoy!!

Keep reading about Bike Frame Sizes, Geometry, Angles and All That!

SIZE GUIDELINES FOR ROAD BIKE FRAMES

YOUR INSEAM(inches)FRAME SIZE(in inches, approx.)FRAME SIZE(in cm.)TOP TUBE  (cm)(Approximate)YOUR HEIGHT(feet & inches)
28.519.349515′ 3″
2919.750515′ 4″
29.52051525′ 4.5″
3020.552535′ 5″
30.7520.953545′ 6″
31.2521.35454.55′ 7″
3221.755555′ 8″
32.522.15655.55′ 8.75″
3322.557565′  9.5″
33.7522.95856.55 ‘ 11″
34.2523.259576′

conversion:
1 inch = 2,54 cm
1 centimeter = .394 inch

frame-sizes-table_1.gif

Bicycle Frames Table


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