BiSaddle ShapeShifter Installation Instructions

Please read the instructions thoroughly before attempting to install or ride your BiSaddle. If in doubt, please consult a professional bike fitter for assistance. We do not prescribe saddle height or your overall position, as this is best left to your personal needs or the advice of your fitter. 

This instruction sheet is intended to replicate the body position from your old saddle when installing BiSaddle for the first time. Note that BiSaddle is NOSE-LESS, meaning that it we have completely removed the front ~3 inches compared to a traditional saddle. If you’re comparing the width of your old seat to a BiSaddle, it is best to lay one saddle on the other with the widest point of both seats matching up to get an “apples to apples” comparison.


Every BiSaddle ShapeShifter leaves our factory with a neutral position that works well for a variety of people (approximately 53mm front width, 145mm rear width). If you’re new to BiSaddle and not sure what you want or need, try this setting first. If you have experience with another saddle and know of specific measurements that you’d like, feel free to adjust to those settings.

In general, most people prefer a rear width of the saddle that’s equal or slightly greater (1- 4cm) than their sit bones for comfort and support. Many bicycle shops can measure your sit bones, or you can do it at home with a piece of cardboard (see our Sit Bone attachment at the end of this document). Rear width adjustment range: 130 – 185mm.  

The front width of your BiSaddle is largely up to personal preference. A wider front typically results in better blood flow and/or reduction of genital numbness. If it’s too wide, however, it can cause rubbing or chafing of your inner thighs. We suggest that you set the front of the seat as wide as possible without chafing. You can check the width of your saddle using a tape measure or Vernier caliper. Front width adjustment range: 40-75mm.

To adjust your BiSaddle width, simply loosen (but don’t remove) the bottom bolts using the suppled Allen wrench. Adjust the seating pads to your desired width, and begin to tighten the bolts slowly. We encourage you to double check that both sides are adjusted equally several times before fully tightening the bolts (unless you have a specific issue and prefer an asymmetric saddle). MAX bolt toque is 25 inch/lb or 2.8NM.


STEP 1: Before removing your old saddle, be sure to record two measurements: 1) the height (measured from the top of the saddle to the ground, or the center of the bottom bracket):

And 2) the distance from the widest point of the saddle to the center of the stem clamp (or another fixed object at the front of the bike):

Write these two measurements down and remove your old saddle. Before installing your BiSaddle, ensure that your seat post is in good, safe condition, and is free of any grease on the clamp area that contacts the saddle rails. Follow all manufacturers’ instructions and bolt torque specifications.

STEP 2: Install the BiSaddle and lightly tighten your seatpost bolts, while still allowing for some movement and adjustments (do NOT sit on the saddle or ride the bike yet).

To set the fore-aft adjustment, replicate your old measurement from the widest point of the saddle to the center of the stem clamp:

To set the height, simply replicate the height you measured on your old saddle. 

You may also want to adjust the tilt of the saddle top. We suggest starting with the top of the saddle flat, or slightly tilted downwards.


Bring any necessary wrenches on your first few rides, as some small tweaks may be necessary to get the position 100% dialed in. Often times a small adjustment in height, tilt, or fore-aft can make a big difference in comfort. Also feel free to experiment with the saddle width, always making sure to carefully adjust it and properly tighten the bolts before riding again. Please feel free to call us for any further assistance and HAVE FUN!


Your BiSaddle ShapeShifter includes two sets of angled wedges. These can be installed between the base of the saddle and the two seating pads, to change the shape of the saddle top – making it either more flat, or more rounded across the top.

There are no absolute rules that dictate who should use wedges. In general, people with good flexibility and forward hip rotation tend to prefer a flatter saddle. People who aren’t as flexible and/or to struggle with saddle sores tend to prefer a more rounded saddle. We suggest you start with no wedges, and add them if you run in to a specific problem.


To install the wedges, you must remove the four bolts from the bottom of the saddle. Note that the REAR bolts are slightly longer than the front bolts.

Lay the wedges under each seating pad, ensuring that it is properly aligned. The raised bumps should be facing towards the underside of the seating pad.

In order to use the wedges, you must move the original rear bolts to the front position, and use the extra-long bolts supplied with the wedges in the rear position. The original short front bolts will not be used. 

Reassemble the saddle using the longer bolts (with washers), adjust as-needed, and tighten the bolts (MAX torque 25 inch/lbs or 2.8NM).

Your BiSaddle ShapeShifter Wedge Installation- (Advanced)

The BiSaddle ShapeShifter has optional saddle flattening wedges and angle increasing wedge for fine-tuning saddle fit. It is recommended this be done by a professional fitter. 

This video shows the following:

  • How to remove saddle surfaces from the frame
  • How to install the the nut brace and nuts
  • How to install anti-vibration coating to titanium screws
  • How to install the wedges
  • How to install the longer titanium screws and washers to secure the surface/wedge 
  • How to tighten and loosen the titanium screws using cross drilled holes


Obtaining a width measurement for your sit bones (ischial tuberosities) can be useful for establishing a rear saddle width. Most bicycle shops have tools to measure your sit bones, but you can also do it at home using very simple tools and just a few minutes of your time.

STEP 2: Use a dark colored crayon to rub across the top of the cardboard (using the side of the crayon) – this will reveal your sit bone indentations.

STEP 3: Use a ruler or tape measure to determine the distance (in millimeters) between the center of the sit bones. Most people add 1-4cm (10 – 40mm) to this width to set the rear saddle width.