Disclaimer: The following is a procedure that I followed to swap the stock Specialized Shiv extensions with a different brand. While this has worked perfectly for me over the past year, I make no guarantee of the structural integrity of this modification. Basically, this is for informational purposes only, so perform at your own risk.
So with that out of the way, lets get started…..
Last year in early 2011, when I first took delivery of my Shiv, I loved it, except the shape of the extensions. I am not a fan of the straight s-bend extensions, especially for Ironman racing. The approach to my bike set-up is I first must be comfortable, because if I’m not comfortable I will not perform my best. So I set out to make the one change I needed to perfect my bike before my first big race of the year.
My last bike had Zipp Vuka extensions, which I really liked, so my first thought was to use those same extensions. After some investigating, I found pretty much any aftermarket extensions will work…..except Zipp (due to their non-standard diameter), so I decided to go with a set of Hed Lazy-S bend extensions. Once I had the parts here is what I did:
Step 1: Remove the existing extensions:
The first step is to heat the extensions to soften the resin and remove them from the aluminum mounting brackets. To do this, I first installed an old bolt into the mounting holes so I could grab on with pliers, and then placed them in the oven at 350F for about 12-15 minutes. When I pulled them out I was amazed at how easily the carbon extension delaminated and fell apart. It quickly disintegrated in my hand, and was completely unusable. So be sure you want to do this before you start because once you place them in the oven, you are already at the point of no return. Also, it still took a fair amount of force to remove the extensions; they don’t “just slide off”. I only heated one extension at a time, so repeat the process with both extensions.
Step 2: Prep the brackets:
The mounting brackets will still have some resin residue left on them, so we need to remove that down to bare metal to ensure good adhesion. So with a combination of sand paper and a Dremel tool with the little wire wheel installed, I removed all the remaining resin.
Oh yeah, it’s probably a good idea to wear a dust mask for this step, I figure it’s not good to breath the fine dust being sanded off. Once they were clean, I went over them with the sand paper one more time at a 45-degree angle in both directions to create a cross hatch pattern. This was a trick from my go-kart racing days to prep the surface. I’m not sure if it helps, but I figured it couldn’t hurt.
Step 3: Prep the extensions:
Now get your extensions how you want them. You only have 1 chance to epoxy them on, so you must make sure they are perfect after this step. Shorten them, adjust them, twist them, create and internal cable routing hole (I had to do this with the Heds), whatever you want, just make sure they are perfect before you get the epoxy out. The epoxy sets up in about 5-minutes, so you have to move quick once you start to apply it, so make sure you are ready. I also found the interior surface of the extensions were not smooth and had some resin build-up which prevented them from sliding completely onto the mounts. To address this, I had to sand the inside of the extensions so they would slide all the way up the mounting brackets.
Once I was sure everything lined up correctly and was perfect (for me), I mixed up the JB Weld epoxy (a standard 2-part epoxy), and slathered it all over both the mounts and inside the extensions. Then I slid the extensions on, and repeated for the other side, wiped off any excess and held them in place until the epoxy set-up about 5-10 minutes, then that was it. Bam. Done. I checked them over the course of the next couple of hours to be sure they were still where I wanted them, and they didn’t budge.
After curing for 24 hours, they were good to go. I wrapped a piece of black electrical tape around the joint, and viola! New extensions on my Shiv!