How to Measure Your Bike
Basic Notes on how to measure your bike.
. All measurements are done in Centimeters. You can blame this and Sushi on Nixon.
. For best results tires should be pumped up. Bike should be on a level surface and Vertical as it can be. The more accurate this is the more accurate your measurements will be.
. Measurements are done from Top dead center of saddle. Measure the length of the saddle and divide by 2. A saddle 27cm will be 13.5cm. If you change the saddle your numbers will change slightly.
We also use “Seated Area” as a measurement point. This can be suggestive. Think of where you actually sit on the saddle. The photo should help this.
. Measurements incorporate the use of the center of the Bottom Bracket. This is the heart of the bike. Newer cranks don’t allow you measure this easily from the drive side. Suggestion is to use Non-Drive side of bike for all measurements.
. New equipment changes the numbers, not necessarily your position, If, done correctly. If you wish to make changes to equipment please consult with us and we can advise.
The Base of your position is your Saddle. From here you and the machine interact as one. Three things make up Saddle Position. Saddle Height, Set Back and Angle. Tough to get all three at once. Rough in the height, Rough in the Setback. Get the angle correct. Confirm the height. Confirm the Setback. Make changes gently. May take 3-4 times to get it accurate.
Measure Top dead center of saddle to Dead center of Bottom Bracket / Crank Center.
We use a Long bubble level for this, and some patience. Place the level on the floor with the edge at the center of the center of the Bottom Bracket – Crank Center.
It takes a little practice to get the Bubble in the center and the edge in the center. Once this is done, carefully measure from the edge of the level to the tip of the saddle. Slide the saddle accordingly to get this number.
Use something you trust as flat. Clip Board, small cutting board, book, small cat. You can get a Level Ap on your phone that can help if you do not have a digital level. Adjust the angle as you tighten the saddle. Some posts make this easy with a front and back screw. Others are more complex.
The control of your machine is at the Handlebars. Three measurements are done here. Drop, Reach to Stem Center, Reach to Shifter Hoods.
Drop is the difference in height from Top of saddle “Seating Area”. Think of where your weight on the saddle will be. (Check Photo) To top of Handlebar. Two ways to do this. Simple way is to measure from Top of saddle to floor. And Top of Bar to floor. The difference is your drop. If the bar is higher than the saddle it’s + Positive. If the Bar is Lower than the saddle it’s – Negative.
We use a long Bubble Level. If the drop is Negative (Bar lower than saddle) Place Bubble Level on “Seating Area” of saddle. Carefully hold the level and measure down to Bar.
Adjusting this is done with spacers or stem angle. Consult with us for details.
There are two reach numbers. To the Stem and to the Shifter Hoods. The most important number is to the Shifter Hoods. If the bike has been built to you then the Reach to Stem Center is a great quick check to see if anything is off in your position. If you switch bars it can change your reach to Hoods dramatically.
You Might be seeing a theme here with “Consult us if you’re making changes”
Reach to Stem
Measure Tip of Saddle to Stem Center. Yup That easy. Unless you changed your saddle or stem. Then it can be different.
Reach to Shifter Hoods
Tip of saddle to both hood tops “Triangulated”. Move the bar gently until the measurement from Tip of saddle to Hood tops are the same.
Aero Position Notes
Seat Notes are the same as listed. What does change is our Reach and Drop positions.
Aero Drop is done to from Top “Seated Area” of saddle Top Center of aero elbow pad.
Reach to stem center remains the same but we include Reach to End of extension. Not end of Shifter. If your bars slip down this number will change. This is a quick way to check if things are off.
Aero Bar Extension – Measure Back center of Pad to end of Extension
Aero Pad Width - Rear center of pad to rear center of pad.
Aero bar Angle – measured off top center of elbow pad