How to Fill Out a Swingarm Geometry Form

Please, please, please, pretty please use a metric tape measure. It makes it A LOT EASIER for both of us.

Filling out this form properly allows us to precisely calculate Leverage Ratios to figure out Spring Rates and Damping Curves.

If you are being directed to fill out a Swingarm Geometry Form follow these instructions. Note - It is much easier do do this with two people but you can do it by yourself (put the bike on a stand and block the front wheel so the bike is horizontal).

 

 A - Swingarm Pivot to the Ground
 
Note - measure to the center of all bolts and pivot points.
 

 

 B - Rear Axle to the Ground
 
This one along with "A" tells us what vertical is.

 

 C - Swingarm Pivot to Upper Shock Mount

 

D - Swingarm Pivot to Lower Shock Mount
 
This particular bike has a choice of three lower shock mounting positions. In this case it is important to pick the one you are going to use and be consistent.

 

 E - Shock Length Fully Extended

 

 F - Swingarm Length (with the axle in the center of the chain adjustment range.)

 

 G - Distance from Swingarm Centerline to Lower Shock Mount
 
This is not a critical measurement. Just get it as close as you can.

 

 H - Shock Length Collapsed - this should be backed off to provide tire to fender clearance of about 13mm (1/2").
 
You can put a block (i.e. anything that is 13mm thick) between the tire and fender at the closest point of contact.

 

 I - Upper Eyelet Mount Diameter

 

 J - Upper Eyelet Mount Width

 

 K - Lower Eyelet Mount Width

 

 L - Lower Eyelet M

 

 Vertical Wheel Travel reference number - Fully Extended
 
To measure Travel.

 

 Vertical Wheel Travel reference number - Fully Collapsed
 
Subtract Collapsed from Extended and subtract Tire-to-Fender-Clearance desired (or just block the tire away from the fender and subtract collapsed from extended).
 
Example:
        
EXTENDED  470
COLLAPSED-310
TIRE CLEARANCE  -13
TRAVEL=147
 
If your racing organization has a limitation on maximum travel please let us know.

 

Be sure to completely fill out the rest of the form then;
 
Scan and email it to sales@racetech.com
 
     or
 
Fax it to 951.279.7171