JUNE 22, 2006
By Danny Brault
Photos by Allison Kennedy
The Victim: 2006 KTM 250 SX-F
The Product: Pro Tech suspension
Contact: (514) 828-5058 (Montreal), (519) 268-1140 (London), (902) 832-3155 and protechsusp.com (Nova Scotia), (604) 533-4426 (Vancouver)
About Pro Tech:
Lee Tinkler and Andy White began the Pro Tech suspension company 20 years ago. After first working with Dale Rathwell, a well-known figure in road racing, who had worked with Harley Davidson and Yoshimura Suzuki in the States, Tinkler and White bought the suspension company from him. One of Pro Tech’s first big-name clients was Jean-Sébastien Roy, and Tinkler says they’ve been tuning suspension for him since his 80 days up until a few years ago. Even though Honda and KTM are the most popular brands Pro Tech works on, they are able to tune any brand of suspension—Kayaba, Showa or WP. Pro Tech is currently helping the KTM Canada Factory MX team, Guy Giroux in off-road racing and several local racers.
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Pro Tech's Lee Tinkler was our factory suspension expert for the day. Tinkler took the time to make changes before, after --and even during practice.
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Back in April, we race tested the 2006 KTM 250 SX-F at the Auburn Hills Spring Classic. And while the bike handled well, had tons of power and over-rev, the suspension was too harsh for my 140 pound frame and prevented me from really pushing it through the sharp-edged braking bumps and accelerating bumps in the rutted corners. Fortunately, after reading the bike test, Lee Tinkler contacted us and asked if we were interested in trying the 250 SX-F complete with revalved Pro Tech forks and shock, just like the original test—in race conditions. With the Ste-Julie national close to the Pro Tech shop, and our crew heading to the event, we decided to perform the test in the MX2 class. Our only concern was whether I felt comfortable racing the KTM in national conditions, but after spending nearly a month on the orange rocket, it didn’t take much persuasion.
Practice:
When we arrived at the track on Saturday morning, Tinkler had a set of forks and shock ready to bolt onto our test bike. I must admit: I felt like I was getting the factory treatment carrying this set of suspension through the pits, with golden titanium-nitrate coatings on the fork and shock shafts.
After bolting on the forks and shock, I rode back over to the KTM Canada pit to have Tinkler check my sag before practice. With the sag sat at 105mm (Tinkler says 105 to 110mm of sag on a KTM 250 SX-F is ideal, but it does change between track conditions and rider preference), I hit the Ste-Julie track for my first practice session. Just riding down to the starting gate, the forks and shock felt much softer. Now Tinkler didn’t actually change the stock springs, but did revalve the forks and shock, coated the fork and shock tubes with titanium-nitrate as mentioned earlier and replaced the bladder cap on the shock.
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The revalved forks and shock from Pro Tech were most noticable through rutted corners with acceleration bumps and over braking chop down the Ste-Julie hills. Everything just felt plusher and it didn't transmit so much energy to the rider. |
“I softened the valving on it,” begins Tinkler. “The fork has this problem, it gets too hard and just blows through the travel and that’s the same thing with the shock. The shock doesn’t want to sit and squat and it just doesn’t get any traction to the ground through the corners and it stays too high in its travel and just wallows around.”
Tinkler basically took my complaints—which seem to be common, he says, with the 250 SX-F—and made things plusher for the smaller, sharp chop that was causing me difficulties at Auburn Hills. (Click here for the initial KTM 250 SX-F race test.)
As for the titanium-nitrate coating, it is designed to make the forks more fluid and plush over the small bumps and through the initial movement. Tinkler adds that the coating makes the tubing stronger and helps resist dings or scratches from roost or rocks.
In my first practice session, it was difficult to give a solid analysis of the suspension because it was early in the program and the track really hadn’t roughed up too much. However, I did feel the bike dove into the tight-rutted corners without as much effort from the rider and the forks seemed to settle more when braking down the steep hills, instead of wandering like they did at Auburn.
Since the track wasn’t worked up enough and I couldn’t give too much feedback, Tinkler asked me to pay attention to how it was working in the second practice and to find him on the side of the track if I needed any adjustments.
Now that a few hundred more bikes had ridden over the Ste-Julie track, which is clay-based with a few loamy sections—very similar to Walton—the corners were filled with ruts, and sharp braking bumps could be found heading into every corner. It didn’t take me long to notice the suspension was working much better than stock because I wasn’t noticing anything. Even over the fast down hill sections, with braking chop and long ruts, the Pro Tech suspended KTM allowed me to charge as deep into my braking markers as possible, without blowing through the rut or getting kicked up over the bumps. The rear end really seemed to stick to the ground and the front end no longer had that harsh feeling I experienced at Auburn. With two laps to go in practice, I caught a glimpse of Tinkler watching from the backside of the track, so I stopped just to make a couple of clicker adjustments. We softened the compression and slowed down the rebound on the forks by two clicks each.
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The Ste-Julie track features a few big single-jumps onto flat landings, but with the Pro Tech suspension, our 250 SX-F never bogged, bottomed or sputtered. |
Race Tested:
I felt pretty confident heading into my qualifier. At Auburn, I had pulled a great start on the 250 SX-F and now that the suspension was equally as impressive as the motor, I really believed I had one of the better bikes on the line. I picked the gate to the left side of the doghouse (just as I had at Auburn). When the board went sideways, I dropped my head and focused on the pin. With my peripheral vision, I could see into the doghouse and when I saw the guy go to kick down the gate, I dropped the clutch and came off the line with a great jump. For a minute I thought I might get the holeshot, but about halfway down the start straight, the really fast guys pulled up on the inside. (Actually, I already have a good job, so I didn’t want to steal a ride from any of the factory boys.) From what I heard, I rounded the first corner about seventh, which wasn’t too bad. After about two laps, I was running just outside the top-10 when I dropped in a rut and stalled the bike. I got going as quick as I could, but it was too late and I was well out of qualifying position.
In the LCQ, I figured I could get another good start—maybe even the holeshot because most of the faster guys had made it in. Unfortunately, my math was wrong—as always—and I came around the first corner mid-pack. From there, things didn’t get much better and I finished just outside the top-10.
The Verdict:
After racing the 250 SX-F for the first time at Auburn with the stock suspension, I loved the bike but I knew that the suspension needed some adjustments for my weight.
After bolting on the Pro Tech goodies with the excellent and knowledgable assistance from Lee Tinkler, I wouldn’t hesitate to race the 250 SX-F. The biggest complaint I had regarding the stock suspension was harshness. Over the sharp edged braking bumps that are close together, the bike would kick and bounce me all over the track. (Although it did work well over the further-spaced, rolling bumps at Gopher Dunes.)
But when I installed the revalved Pro Tech suspension in Ste-Julie, which features much the same track consistency as Auburn, I found myself more comfortable and willing to really to push it deep into the corners. The front end didn’t push through the ruts or berms, the rear end tracked straighter and remained on the ground and the bike seemed to duck into the tight 180 corners without any effort from the rider. When you’re able to get the suspension working as well as the motor on the KTM 250 SX-F, it’s a lethal combination.
Thanks to Lee Tinkler and Andy White at Pro Tech for their help with the suspension test, as well as Florian Burguet and KTM for allowing us to race the 250 SX-F—twice, even with this assistant editor’s history of crushing pipes like soup cans.
