Just wanted to share my recent fork spring swap/service experience, it might help others that have not done this and are considering it.
First off - a HUGE
thanks to MGFChapin for detailing this procedure in a clear, easy-to-follow format! I also had a few questions involving my particular situation and MGF was very helpful and offered valuable guidance. For most everyone that will be doing this procedure - just follow his outline and you will be fine.
From my experience, here are a couple points that might also help others.
1. I wanted to address the OEM spring rate to better suit my weight, so I ordered a .925kg spring kit from Traxxion Dynamics. To my surprise, the Traxxion spring (270mm) is considerably longer than the OEM spring (235mm). The Traxxion kit comes with a "buffer" to help keep the spring centered and from rubbing against the tube wall. A great concept in theory, but adds extra length to the overall assembly and also jacks with the fluid/air volume ratio inside the fork. The Traxxion kit also comes with a new spacer tube (60mm). The entire Traxxion assembly ended up about 5mm longer than the OEM assembly. This doesn't sound like much - but it really made it extremely difficult to get to the damper rod locknut-to-fork cap assembly. It took all I could do to manhandle everything into position.... and it was not fun. After a couple of emails with Traxxion about how difficult this was - they informed me that they forgot
to tell me that to use their kit, you need to remove the "bottom-out" device from the Damper Rod. Well crap...... I did not want to make a permanent modification to my Damper Rod, so I sent the Traxxion kit back.
Traxxion Dynamics kit on the right, OEM on the left:
So now that I realized that I needed to be very specific with aftermarket spring providers - I asked about the length before ordering, lol. I finally found a brand that is a 100% direct replacement for the OEM spring ... K-Tech.
I ordered the .95kg K-Tech spring set. Out of curiousity, I set up a redneck spring comparison tool to compare the OEM spring vs the .95kg K-Tech spring:
Herein lies another issue that I have found. Everyone seems to rate their springs differently. Do not assume that "X" brand's .95kg spring is the same as "Y" companie's .95kg spring. Pick a brand, and stick with that brand. Then if you need to change rates, it's easy to know that the spring you actually get will be the expected rate. For anyone that is wondering - the K-Tech .95kg spring is almost darn near equal to the 2010 D675 OEM spring rate. With 70 pounds of weight - the K-Tech spring deflected 1mm less
than the OEM 1.02kg spring. lol The difference in these springs, is that the K-Tech is a linear design and the OEM spring has a little bit of progressiveness built in.
For reference, I currently weigh 160 pounds naked / 180 with full riding gear. With the .95kg K-Tech springs, preload backed all the way out, then turned in 1 full revolution, I get 36mm of SAG. According to an email I received from Dan Kyle, you have the correct spring rate when you achieve your desired SAG with the preload adjuster 1/2 way out. So, it appears I'm really close with this .95kg - I'll ride this set-up as-is and determine if I want to add some preload. The linear-rate springs are an "unknown" to me right now so we'll see how it feels as soon as it thaws out here in the midwest, lol.
All-in-all, after coming up with the correct length spring, this is a very easy swap and service. I found a new Race-Tech spring compressor tool on Ebay for cheap, and as MGFChapin advised - I wouldn't do this job without it.