When it comes to suspension, most riders are enamored with the dream of owning A-kit suspension. For most, this is because of the trick coatings, billet parts, and larger part sizes; which we're sure will make us that extra bit faster on the track. The rude awakening is that suspension still needs to be set up properly, and individual parts don't always make the difference to the public. For instance, Race Tech's 19mm shock shaft kit was originally produced with top Supercross and Arenacross riders in mind. But in this situation, they have found an application in which this kit could make the difference for the average Joe.
Race Tech 19mm Shock Shaft Kit:
- Eight clicks per revolution rebound adjuster allows for fine-tuning.
- Built in rebound separator valve.
- Around 40% stronger than stock 16mm shock shafts.
- Spring top out provides less harshness and a freer initial movement
- Made in the USA.
- MSRP: $999.99.
At 19mm, the larger shock shaft kit will stand out solely by size and its black anodized clevis. The majority of late model bikes utilize a 16mm shock shaft, such as the 2015 Honda CRF450R we had Race Tech's kit installed in. The reason we tested this in the CRF450R, is the added value by gaining a rebound adjuster in the clevis. For 2015, Honda's KYB shock came with a new shock adjuster design that housed high and low-speed compression along with the rebound at the top of the shock, so the rebound adjuster at the bottom of the shaft in the clevis was eliminated. There can be a bit of a problem with this, as the new rebound adjuster in the top of the shock seems to be a bit more high-speed based, and doesn't offer the same feel when adjusted as the older shaft-based version.
You can either purchase the shaft kit outright and install it yourself, or have Race Tech do the dirty work and even add it to a revalve, as we did. At $1000, it does include more than just the shaft; this kit comes with its own shock bumper kit, top out seal casing, and a built-in rebound separator (this part's a bit more crucial in Supercross settings). The rebound separator can create a much more progressive compression feel without an ill affect to the rebound.
On the Track
To give this kit the best comparison possible, I met up with Rob Brown from Race Tech out at one of our local tracks so I could start the day with a standard setting, then move to the 19mm shaft kit with just a short break to switch out the components. Once we had the shaft installed and I was back on the track, the first feature that stood out was the increased damping feel. I felt that the shock was more speed-sensitive, basically becoming more progressive as it pushed through the stroke, but without becoming harsh.
Beyond that, the 19mm shaft kit also added more tuning options. Not just because of the added rebound adjuster, but the extra "charge" that the larger shaft pushes through the adjuster as it goes through the stroke. To put it simply, it made the rebound and compression adjusters at the top of the shock more affective. Instead of needing to turn high-speed compression five clicks to gain the change I was looking for, I was able to find around the same adjustment with three clicks once the 19mm shaft kit was installed.
As for the rebound adjuster, the CRF450R's stock one seems to act as more of a high-speed adjuster. This adds its own unique type of adjustment, but also means it doesn't always solve the problems that you may have used rebound to fix before. With the re-addition of the shaft-based rebound adjuster, I also was able to make some more adjustments that suited low-speed situations. This adjuster acts as I'm used to with any other shock, so I found myself using it much more than the one located on the top of the shock.
In the Supercross world, it's rare but not impossible to actually bend stock shock shafts. For the general public this isn't as much of a worry, but the 19mm kit should eliminate any thought you have of this ever happening. In the durability department, there's nothing negative to report. The casing hasn't leaked and the shaft rebound adjuster clicks and spins as it should.
The Last Word
At $1000, Race Tech's 19mm shaft kit is a tough pill to swallow. Yes, it did add a performance advantage to our 2015 CRF450R, but by itself it's as much as having an entire suspension job done. In the world of large hits, big whoops, and massive rhythms, the 19mm kit seems to be a bit more worth its weight. But for the general consumer who is just looking to add shaft rebound adjustment back to their 2015 CRF450R, you're probably better off checking out one of Race Tech's clevis kits to get that effect. If you're looking to get that extra bit of adjustment due to the larger shaft charge and that more progressive feeling, this kit can do just that.
Outside of the pricing, I couldn't find a negative to Race Tech's 19mm Shock Shaft Kit, but that alone brings the rating down a bit in my eyes.
Vital MX Rating
Check out RaceTech.com for a list of applications and to check out their other suspension options.
About the Test Rider
Michael Lindsay- is a born-and-raised moto freak and gearhead from the heart of motocross in Southern California. First swinging a leg over a bike at the age of five, he immediately caught the racing bug, spending nearly every weekend behind a gate…and a lot of time on the couch while injured. While swinging back and forth between moto and the off-road scene, giving him a wide range of experience on the bike. Of course, all of this led to one thing: Lindsay loves working on his bikes almost as much as he loves talking about them. When he’s not in the Vital MX forum or writing his latest product review, you can find him out at the track taking dirt naps, snapping some pictures, or drooling over the latest parts for his bike. With an outspoken personality, gearhead background, and as Vital MX’s guru for product, Michael is here to share his unbiased opinion.
Review and Photos by Michael Lindsay