| Fifty-Five | Small | Medium | Med-Large | Large | X-Large |
Head Angle |
70.5 |
71 |
71 |
71 |
71 |
Seat Angle |
73.5 |
73 |
73 |
73 |
73 |
ETT |
22.25" |
23" |
23.5" |
24.5" |
25.1" |
Chain Stays |
16.75" |
16.75" |
16.75" |
16.75" |
16.75" |
BB Height |
12" |
12" |
12" |
12" |
12" |
Wheelbase |
41.75" |
41.7" |
42" |
43" |
43.5" |
Standover |
26.5" |
27.25" |
27.25" |
29.25" |
29.6" |
| Trauco | Small | Medium | Med-Lg | Large | XL |
Head Angle |
70 |
71 |
71 |
71 |
71 |
Seat Angle |
73.5 |
73.5 |
73.5 |
73.5 |
73.5 |
ETT |
22.25" |
23" |
23.5" |
24.5" |
25.1" |
Chain Stays |
17.3" |
17.3" |
17.3" |
17.5" |
17.5" |
BB Height |
12.25" |
12.25" |
12.25" |
12.25" |
12.25" |
Wheelbase |
42.4" |
42.3" |
42.6" |
43.6" |
44.1" |
Standover |
26.5" |
27.25" |
27.25" |
29.25" |
29.6" |
| Song 29 | Medium | Med-Lg | Large | XL | |
Head Angle |
70.5 |
70.5 |
70.5 |
70.5 |
|
Seat Angle |
73.5 |
73.5 |
73.5 |
73.5 |
|
| ETT |
23" |
23.5" |
24.5" |
25.25" |
|
Chain Stays |
17.4" |
17.4" |
17.6" |
17.6" |
|
BB Height |
12.25" |
12.25" |
12.25" |
12.25" |
|
| Seat Tube | 21.75" | 21.75" | 21.75" | 21.75" | |
| Head Tube | 4" | 4" | 4.5" | 5" | |
| Song 55 | Small | Medium | Med-Lg | Large | XL |
Head Angle |
70.5 |
71 |
71 |
71 |
71 |
Seat Angle |
73.5 |
73 |
73 |
73 |
73 |
| ETT |
22.5" |
23" |
23.5" |
24.5" |
25.1" |
Chain Stays |
16.75" |
16.75" |
16.75" |
16.75" |
16.75" |
BB Height |
12" |
12" |
12" |
12" |
12" |
| Seat Tube | 20" | 20" | 20" | 20" | 21" |
| Head Tube | 3.75" | 4" | 4" | 4.5" | 5" |
Geometry
Sirens come in 5 stock sizes, but we also offer full custom geometry and sizing or we can modify any of our stock sizes to fit your needs. Most of our clients choose custom - this is the joy of hand-built!
The above geometry chart is based on a Rockshox Reba 29 set at 80mm travel with 2.2" tires.

