MXA PRODUCT TEST: MX-Tech KTM 450SXF WP Shock Mod

June 3, 2009
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WHAT IS IT? A complete revalve of the WP rear shock on the KTM 450SXF.

WHAT’S IT COST? $450.00 valving, $149.00 spring, $599.00 total.

CONTACT? www.mx-tech.com or (877) 850-5114.

WHAT’S IT DO? When the 2009 KTM 450SXF finished second overall in the 2009 MXA 450 shootout this season, the main reason that it didn’t win was the stock rear shock. MXA test riders have struggled with the WP shock since the moment that KTM introduced its no-link suspension system. And, whenever we are stymied by the shock, we have turned to MX-Tech’s Jeremy Wilkey for help. Amazingly, Wilkey may be one of the few men in America with a handle on getting KTM suspension to work. Jeremy is also quick to point out that while it is easy to blame the lack of a rising rate linkage for KTM’s shock problems, the real problems lie in bad valving, poor spring choices and basic setup flaws on the part of WP in Holland.

And so it was with the 2009 KTM 450SXF, which is why we sent a WP rear shock to MX-Tech to find out what solutions they had for our traditional complaints about G-out issues, off-throttle looseness and blowing through the stroke.

MX-Tech installed their proprietary Platform valve, rebound jet system, in-house metering needle and WP (PDS #7) progressive-rate spring and sent the shock back to us.

WHAT STANDS OUT? Here’s a list of things that stand out with MX-Tech’s KTM 450SXF shock mods.

(1) Technology. Jeremy Wilkey is part Gyro Gearloose and part Brainiac when it comes to shock absorbers. It seems that he has never seen a shock absorber that he couldn’t build a retinue of unique and different parts for. As a rule, MX-Tech starts from scratch with the stock WP shock. Thanks to an engineering background, MX-Tech designs their own internal parts (and that includes their own pistons, needles, valve stacks and orifices). What helps MX-Tech, apart from a lot of KTM experience on the National circuit, is the fact that they genuinely understand both KTM’s no-link approach and the Ohlins-licensed PDS technology used in the WP shock. Attitude mixed with intelligence goes a long way towards solving problems.

(2) Performance. Love it. Every test rider was sent out on four KTM shocks (stocker with a 7.6kg/mm spring, Ohlins TTX-44 with a 7.5 spring, Showa works shock with a 7.5 spring and the MX-Tech shock with a progressive-rate spring that starts around 7.0kg/mm and peaks above 9.0kg/mm). When all the testing and racing was done (over a four-week period), every test rider was asked to pick the best shock. They all chose the MX-Tech shock. It was by far the supplest and most stable of the four shocks. It didn’t suffer from the wild arc swings that KTM’s shocks seem subject to. It resisted low-speed/high-load G-outs. It absorbed every bump and whoop with amazing grace. It is without a doubt the best KTM rear suspension we have tested (which is exactly what we said about the last KTM shock that MX-Tech revalved for us back in 2006).

(3) Theory. MX-Tech’s workmanship is steeped in lots of techno-talk, but we asked Jeremy to explain, in layman’s terms, what he did to make our KTM 450SXF shock feel so much better. His answer? “I went back to the original PDS shock that came on the first no-link KTMs and borrowed the technology that KTM has gone away from. I tweaked the pieces, but basically returned to day one and started from there.”

WHAT’S THE SQUAWK? MX-Tech doesn’t just throw some new shims in a shock and call it a day; they virtually reengineer it. That kind of effort costs beaucoup bucks.


If the stock 2009 KTM 450SXF had come with this shock, it probably would have won the 2009 MXA 450 Shootout. It improves the Katoom that much.


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