Great Bicycle Fit
Great Bicycle Fit
Creating Great Bike Fit
By Steve Robson
Ever wonder how some people can be on their bikes for hours without them being uncomfortable. By using a number of things to help dial in bike, you too can feel far better on getting any bikes you have. These tips could help you spend more time on the road.
Having a great fitting bike is a good way to spend more time riding. Whether it be a hybrid, mountain, or road bike, modifying it by changing parts goes a long way to getting the bike you want. The changes being written about here reflect my personal ideals on how the bike fits my needs. Yours fit will be different then mine.
I still like the feel of the road bike. With the dropped handle bars, thin high pressure tires, and light weight frame, it makes for quick fun ride. In 2009, my girlfriend bought me department store road bike. The name of it is called the Vision Orion. It is a basic 14 speed road bike. The frame size was ideal for my height. It is a 20" (50 cm) frame. After having to take apart the bike to get it home, I started to do the basics fine tuning the bike into safe riding condition. Unless you are buying a bike from a bike shop that will do the first base tuning, it is up to the new owner do this. Either way you make to make sure the bike is safe.
I have also have a number of older bikes and two mountain bikes that I have adjusted to get me the same basic feel of the Vision Orion road bike has. The Orion road is my base for setting up the other bikes I own. This article deals with what I have done to get the best fit for these bikes.
At this time, the first major set-up is to set the seat height. A simple method of determining this is to measure your inseam plus 10% get the height of the seat. An example of this is by using my measurements I have used to set-up my bikes. I have an inseam measurement 30". When you multiply this number by 1.1 you get the measurement of 33". This is the seat height on my bikes. It is measured from pedal axle to the top of the seat when the crank arm set to the same angle as the seat post tube. This adjustment can be fine tuned up or down a bit at this time to get the fit you feel good about.
At this time, it is time to see if the seat that came with the bike suits your needs. If you have had older bikes and know what you are looking for, the seat original will most likely go. Once a replacement seat has been placed on to the bike, make some small adjustments allow for any small changes that will take place. At this point, there are is another small adjustment that can be easily over looked. That is the seat rail adjustment. This small feature makes a difference in the feel of how you sit in the seat. A way of setting up this adjustment make sure when the crank arm is sitting out to the front and level to the ground. Place the ball of your foot on the base of the pedal. Make sure that when your knee is properly placed, a string with a weight will fall on to ball of the foot.
The next item on the list changes on the bike are the stem. The factory equipped stem has been set-up to allow a basic fit for the rider of average size. It may or may not meet you needs. There are two basic design types for stems. The Quill design is the older style used on all older bikes. It uses a long bolt and either a locking wedge or cone nut to lock the stem into place. The newer thread less stems are now the new standard in new bike design. This system allows far easier maintenance on the bike. It uses three bolts to hold the stem into place. The tube that mounts the stem is part fork assembly. Two are on the stem itself and one is in the middle of the steering tube. The two roads bikes I own use both of these designs. The original stem that came with the Vision Orion road bike was a 110 mm long thread less type. It was replaced with aftermarket 100 mm stem.
One of the major problems with the older quill design is the fact that over time, the stem can rust on to the steerer tube. At that point, it becomes very difficult to remove the stem. I ran into this on the Kurahara road bike I picked up for free. Being around 25 years old the stem was rusted on to the steerer tube. The bike uses an alloy stem that is mounted on to a steel fork. Over time, there is a process where the two different metal types bond together. It is something like welding in the fact that two parts now bond. It took a heat torch and some liquid spray to break the bond to allow the stem to from the fork steering tube. The alloy lock nut melted so another one was found from an old donor bike to replace it. Once this operation was done, I readjusted the height of the stem height to make the height of the handle bars the same height as the Orion road bike.
The seat post on the Kurahara was a problem. The frame size on the Kurahara is 55 cm. The last owner of the bike had been around my height (5' 6" to 5' 7" tall). The seat was placed well into the frame of the bike. The frame itself is a 55 cm (22") in size. The post is made of alloy so the same problem that happened with the stem has also happened to the seat post tube. Since the post is well into the frame, the option of heating it to remove it is not there. The post itself is designed as a two part assembly. The upper section holds the seat locking clamps. There is a smaller section of tubing that holds this part into the main seat post. This is one point of micro adjusting I used to allow the seat to gain a bit of height needed to allow the two seat heights to match. With the age of the bike, rust is a problem. After using some liquid wrench, I loosened up the bolt holding the seat clamp and moved the seat forward a bit. On the Orion, the measurement from the nose of the seat to the handle bar is 20". This is matched on the Kurahara.
Small but important detail is the size of the handle bar drops. There can vary in size. The two road bikes have small differences in the sizes drop sizes. The smaller framed Orion has slightly larger end drops when compared to the Kurahara. This small detail allows for a slightly longer reach on the Orion road bike. The brake hoods are slightly farther out. Given the slightly difference measurements over the two bikes, to end result is basically to matching bikes. They share the same overall feel.
The Kurahara is equipped with 175mm crank arms. This is the last of the small bike details. These are bit longer than the 170 mm crank arms used on the Orion. The bike was designed for taller riders so the longer arms are needed. After riding the bike for a bit, this is not a real big deal. I can work well with these slightly longer crank arms.
I own other bikes as well that I wanted the same feel that I have on the road bikes. I picked up an old women’s framed CCM bike in 2010. It has seen better days. The frame and structure are still very solid. The front wheel has been replaced but a slightly smaller 26 by 1 3/8th in tire/ rim combination. The original Dunlop Range (made in Canada) rear 28 by 1 1/2 inch tire is mounted on the bike. I liked the simple single speed bike and saw the possibility of having single speed cruiser. This conversion was very easy to done. I just used methods used by early pioneers of cycling. Near the turn of the century, racers did simple tricks gain speed on their bikes. The upright handle bars where turned up-side down allowing the rider to bend over more. This allowed the use of the lower back muscles to power the rider that much faster.
I used this trick on the CCM bike. The simple rotation of the bars put the handle bars into an extended length creating the same distance out as the road bikes. The height off the ground is also the same. There are a number of key geometry changes on this old bike. The steering and seat tube are set at a more relaxed angles. The length of the rear chain stay is longer by 3 inches. The wheelbase is longer giving a different ride quality. This bike bridges the days of old simple bikes in this modern era. It is great to use an old classic design today.
Mountain bikes are a different breed of bike. With slightly smaller diameter tires and lower gear ratios, they lack the quick snappy feel of the road bike. They are more comfortable to ride with more user friendly controls. I have two of these. Many riders place the stem at a higher level than the seat height. I wanted my mountain bike to have a set-up that was more like the road bike. I reversed their stems into its lowest possible positions. The stem design that is used on the mountain bikes is the thread less type. This allowed easy changes to the bikes.
The mountain bike I bought in 2001 (not shown) was modified last year to a hybrid road bike. The tires where changed from the off-road tires to a set of street slick style type. This changed the feel of the bike a smoother, road bike like ride. A set of bar ends allowed the bike to have the same distance as on the Vision Orion road bike. The seat was raised to the same height as on the road bike. These small details make the bike a great road going machine. The mountain bikes I own have dual suspension.
On the second mountain bike I found last year, I keep it as a mountain bike. The seat was raised but due to the length of seat post tube being slightly short, it was set 3/4 of an inch shorter than the road bike. The stem on the second mountain bike is only 90 mm long but it places the handle bar out at 20", the same as road bike. What all mountain bikes lack for the most part is the use of factory installed bar ends. These can be bought but I got a set for free, just like the bike. With the added bar ends, the extended reach. matches the reach of the road bike position. The handle bar is wider and opens up the chest to better breathing. The height of handle bars is level with the seat. The bar ends are slightly higher than the seat.
The bike has a feel that different then the road bike due to the tire size, gearing and weight but the riding position has a nice feel to it. When ridden off road, the bike comes into its element. The set-up of the bike is more for shorter commutes rather than long distance riding. The suspension design is not suited for road use. Much of the energy is taken away by the rear shock doing its job. Part of the problem is the fact that the shock itself worn due to age and use. Overall though, the bike is in good shape for the condition I found it in.
A folding bike I found at a local dump and rebuilt started me off about how to go about looking at bike fit. The specs for this bike really do not match the other bikes mentioned above but suited the needs for what the bike was being used for. I have included to specs for this bike along with the other talked about in the article.
Getting different types of bikes to have the same basic fit is important to me. It gets the same basic feel on all the bikes being used. By either doing simple changes without changing parts or having to buy new parts to get the bike to have its best fit, you get the best out of the machine. Having a good base to start with is the key to make these changes work. The drawings showed with this post how the different bikes measure up for Without this, any work done on something it is not really worth doing. It makes for a nice hobby to start to work on your bike to get to know it better.
Specs for the bikes
Vision Orion road bike
Handle bar section
- Distance out front- 4.3125"
- Drop height- 6"
- Bottom handle bar section- 6"
- Stem length- 100 mm
- Frame size- 50 cm
- Top tube- 21.75"
- Rear drive train section- 16.5"
- Stand over height- 30.5"
- Crank arm length- 170 mm
- Wheel Base- 39" *
Kurahara road bike
Handle bar section
- Distance out front- 4"
- Drop height- 6"
- Bottom handle bar section- 5.59"
- Stem length- 110 mm
- Frame size- 55 cm
- Top tube- 22.5"
- Rear drive train section- 16"
- Sand over height- 32.24"
- Wheel Base- 39.38"
CCM Roadster bike
Handle bar section
- Handle bar width- 18.5"
- Handle bar height (from the stem)- 34.81"
- Stem length- 1.75
- Frame Size- 19"
- Rear drive train section- 19"
- Wheel Base- 44"
Super cycle Trill DS Mountain Bike
Handle bar section
- Handle bar width- 22.25"
- Height from the ground- 36.75"
- Stem Length- 90 mm
- Stand over height- 26.5"
- Rear Drive train section- 17"
- Wheel Base- 42.5"
*- Measurement after front fork damage on bike