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Blog - PSFII


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49mm Showa TAC and PSFII back to back comparison.

MX-TECH recently purchased a new CRF250 for testing. We just had a chance to test the Showa 49mm. TAC on the Honda CRF250, and draw a comparison on the PSFII that comes on the CRF450 an Air fork shot-out on the same bike on the same day with different riders and controlled track.
The 49mm TAC on the CRF250 features one less volume to pressurize and this is a good thing. The TAC runs a much higher pressure than the PSF and the amount of time it takes to pressure the fork is ridiculous. Showa uses a very small hole to feed the chambers so the pressure spikes and settles even from the low volume (high pressure pump.) I’m pretty sure it’s a safety feature.
The very first thing you notice is the massive stiction created in the seals of the air cartridge. The fork just does not like to move unless you really load it up. On the track it’s not so bad if the dirt is soft but I know from experience that the harder the surface gets the worse the friction impacts things. Yes the fork is harsh under a packing load as the air spring really ramps up, in the 60% + stage of the travel. Overall with the smaller engine displacement and light overall chassis the TAC is better on the CRF250 than it is on the KXF, and RMZ.
I was really curious to actually ride the PSFII on the same bike and day. I’ve done several conversions in house taking the PSF II guts and making an open chamber SFF fork. The performance of the PSFII was horrible compared to the Showa TAC. From bouncy and loose, to very vague in the middle. They did have very nice movement (Low stiction) as we rode parking lot to the track.
I have to say the PSFII as delivered on the CRF450 is the worst fork I can remember riding for a long time. So I think the TAC wins in all categories but friction.