Size yourself for a bike without fancy gizmos

Seat Height:

In the interests of health and safety, choosing the correct frame size is absolutely essential when building or buying a bike. Frames are typically measured from the centres of the top tube. This is fine providing the top tube is horizantal but does become more complex when sizing with sloping frames. In the case of sloping frames, it would be adviseable to measure the seat tube as a gauge for choosing the correct frame size. Typically, a 52cm frame would probably measure 53cm from the centre of the bottom bracket to the top of the seat tube. I would advise 2-3 inches or 5-7 cm clearance on the standover.

As an example, Lets say the rider in this case is 5' 10" (approx 178 cm) with inside leg 32" (approx 81 cm) and a typical crank length is usually around 17cm.  As a starting point, add 7-8 cm to your inside leg and set the saddle height (from the top of the pedal to the top of the saddle) to this measurement. In our example , the red line in the image below measures 89 cm; the seat post and saddle make up the remaining 19cm.

This is the one every bike shop owner will tell you whenever you climb onto the saddle:  Place the heel of your shoe on the pedal and set the saddle height so your leg is straight at the bottom of the pedal cycle with the pelvis remaining in a horizontal position. The optimal angle of your knee should be 25-35 degrees.You can check the angle using a decorators angle tool or a rule protractor from a stationery supplier if you can get hold of one.

Seat Position:

The ideal low-cost tool for this job is a Decorators plumb bob.
With the crank in a horizantal position, the front of the knee cap should be inline with the the centre of the pedal mounting bolt as in the image below.

Stem Length:

This does not need a tool, just a simple visual check.
Unfortunately, the stem cannot be adjusted and must be replaced with one of the correct length.



When riding with hands on the hoods, look down at the front wheel hub - if it is inline with the handlebars ( invisible, hidden by the bars), the stem length is correct.


If you can see the hub and it is in front of the bars, the stem is too short.
If you can see the hub and it is behind the bars (closer to you), then the stem is too long.

Mike Leggiero

Colnago Active: Steerer tube extension.

Idiom: One man's trash is another man's treasure

Racing Bike mod #1:

Having recently purchased a 2nd user Colnago frame and fork set from Ebay, I noticed the steerer tube had been cut down to eliminate the use of spacers and as a result, the stem height could not be adjusted to suit.
Essentially, there would be insufficient material when tightening the top stem bolt causing the carbon steerer to collapse.
 The 'all carbon' forks made it impossible to machine, bond or thread. Had the steerer been constructed from alloy, I would have used the professional services of an engineering company to tig weld an extra lump of 1' 1/8" steerer tube and turned down on a lathe.
 I approached several bike shops but they were against the idea from the outset and a brand new set of forks at £400 plus wasn't an option. Firstly, I was able to beg an offcut of alloy steerer from a friendly bike shop in Ripon, North Yorkshire FOC. (Moonglu)
Secondly, I purchased an extended ITM 52mm carbon expanding nut in a bid to internally connect the carbon and alloy tube to form the extended steerer tube.

The problem being the internal diameter of the carbon steerer was 22mm and the alloy offcut was around 20.5mm - this would not allow the expanding nut to engage with the alloy tube. To overcome this problem, I called on a plumber who let me have a a small offcut of 22mm copper pipe- this was trimmed with a pipe cutter to the right size and cut along the length of the tube to allow the tube to act as a shim and allowed to expand to the correct internal diameter.

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Mike Leggiero