I recently got a second set of 120mm SIDs, this time with 15mm lowers. As a result, I thought I'd see what all the 15mm fuss is about and put the lowers from this fork onto my current fork. Here is the process in brief:
- remove front wheel;
- remove brake hose mounting bracket from fork;
- remove brake caliper and tape to handlebars to keep it out of the way;
- let all air out of the fork;
- invert bike on ground so you can get access to underside of fork;
- undo air piston nut and rebound rod retaining bolt - give them both a tap before they are completely undone to unseat the air piston and rebound rod from the lowers;
- put bike rightway up in repair stand, place oil drain pan underneath forks and slide off lowers;
- putting new lowers on is the reverse process.
Swapping to 15mm lowers - weight loss or weight gain?
The 15mm lowers for 26" wheels are 8g heavier than the 9mm lowers, but the 15mm axle is much heavier than a lightweight quick release. For my setup, using a Carbon-Ti thru-axle (37g) to replace the A2Z Titanium QR skewer (43g) and converting my hub from QR endcaps (20g) to 15mm thru (18g) the combined new 15mm setup weighed exactly the same.
9mm weights:
- lowers: 510g;
- A2Z Titanium QR skewer: 43g;
- Tune 9mm QR endcaps and axle: 20g;
Total: 573g
15mm weights:
- lowers: 518g;
- Carbon-Ti 15mm thru axle: 37g;
- Tune 15mm endcaps and axle: 18g;
Total: 573g