Experienced road cyclists will know their ideal saddle height like the back of their hand. They can tell the difference even with a 1mm change in saddle height in either direction.
In this article, I’ll discuss the factors that affect the saddle height and the steps to take to compensate for the change.
What is saddle height?
Saddle height is the distance along the seat tube from the center of the bottom bracket to the top of the saddle, usually measured in millimeters (mm).
What are the factors that affect saddle height?
Saddle height is not something you set and forget even after a professional bike fit. The outcome of the bike fit is a result of all the inputs and parameters used during the bike fit session.
Change any of them, and your saddle height will be affected.
Saddle stack height
The saddle stack is the distance from the bottom of the rail to the top of the saddle. Every saddle model has a slight difference in saddle stack in the range of up to 10mm.
Tip : If the saddle stack increases after changing to a new saddle, you’ll need to lower your seat post to compensate for it, and vice versa.
Pedal + cleat stack height
The pedal stack height is the distance between the pedal axle’s center to the pedal’s top. Manufacturers usually quote the stack height as the total (pedal + cleat).
Each pedal system (Shimano, Look, or Speedplay) has a different stack height. Top-of-the-line pedals have lower stack height, making them more efficient (less rocking when pedaling) and stable.
| Pedal model | Stack height |
|---|---|
| Shimano Dura Ace R9100 | 14.6mm |
| Shimano Ultegra R8000 | 14.6mm |
| Shimano 105 R7000 | 16.5mm |
| Look KEO Blade | 14.8mm |
| Look KEO Classic | 17.8mm |
| Look KEO 2 Max | 17.3mm |
| Speedplay (3-hole) | 11.5mm |
| Speedplay (4-hole) | 8.5mm |
| Time (all models) | 13.5mm |
Tip : If you’re swapping to a pedal with a lower stack height, you’ll need to lower your saddle height to compensate accordingly, and vice versa.
Shoe stack height
Cycling shoes’ stack height specifications are hard to come by and are not mentioned by most manufacturers. Unknown to many, the cycling shoes’ stack height varies.
Top-of-the-line cycling shoes tend to have lower stack height, placing the ball of the foot closer to the pedals for efficiency and stability.
Here are some of the popular cycling shoes’ stack heights:
| Shoe model | Stack height |
|---|---|
| Shimano S-Phyre RC-902 | 4.9mm |
| Shimano RC-702 | 5.5mm |
| Shimano RC-504 | 6.5mm |
| Specialized S-Works 7 | 5.0mm |
| Fizik Infinito R1 | 8.7mm |
Tip : If you’re upgrading from low/mid-tier to top-of-the-line cycling shoes with a lower stack height, you’ll need to lower your saddle height and vice versa.
Crankarm length
The majority of road bikes today are factory fitted with either 170mm or 172.5mm crankarms, depending on the frame size. Frame sizes up to 52cm are usually supplied with 170mm, and anything above 54mm is usually fitted with 172.5mm crankarms.
Some cyclists, especially those below 5’8”, usually use a longer crankarm (170mm, 172.5mm) to their ideal length of 165mm or 167.5mm. Hence, the rise in popularity of shorter crankarm length.
For example, if you moved from 172.5mm to 165mm crankarm length, you’ll need to increase your saddle height by 7.5mm to maintain the same hip angle (top of the pedal stroke) and knee extension angle (bottom of the pedal stroke).
Otherwise, you’ll have a higher hip angle but a lower knee extension angle. For many cyclists, the ideal saddle height compensation lies somewhere in between. From my experience, it takes several rides to dial in the new saddle height.
The opposite applies if you’re moving from a shorter to a longer crankarm length.
Seat post offset
A seat post offset is the distance between the center of the seat post to the center of the clamp. Seat posts offset can range from 0 to 35mm. The majority of road bikes today are specced with offset from 5mm to 25mm. Generally, the larger frame sizes will use larger seat post offsets and vice versa.
If you’re swapping your seat post with a different offset value, you’ll need to compensate with your saddle height.
Tip : As a rule of thumb, you’ll need to drop your saddle height about 3mm for every 10mm of seat post offset and vice versa.
It’s not uncommon for smaller riders (5’8” and below) to move to a 0mm offset (straight) seatpost. For example, moving from a 10mm to 0mm offset would require the rider to increase the saddle height by 3mm, with all things being equal.
Bib shorts and chamois
It’s not uncommon for cyclists to own and wear bib shorts from various brands.
Each brand and model uses different chamois types, hence the difference in thickness. If you’re one of the lucky ones, all your chamois will be of similar thickness. Otherwise, you might feel a slightly different sensation each time you ride.
I prefer to keep things consistent by having my bibs from the same brand, Castelli.
Alex Lee is the founder and editor-at-large of Mr. Mamil. Coming from a professional engineering background, he breaks down technical cycling nuances into an easy-to-understand and digestible format here.
He has been riding road bikes actively for the past 12 years and started racing competitively in the senior category during the summer recently.