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Updated: May 7

Suspension101 Bladder Conversion Kit

There's a lot of hubbub about bladder conversion kits in recent years, so lets really dive into it. Bladder conversion - Yes or No?

We tested bladder conversions some years ago with Noah Kepple. With Noah, we raced and tested for GasGas, KTM, and Husqvarna until 2023. FYI, Noah just did the brand new Triumph 250 test for Cycle News because he has a better feel for suspension and bike set up than 99% of the riders in this country.

Anyhow on to the bladder tests we did.

At the time it was factory KTM.

The two race series' that we were focused on were the EnduroCross series and the Worc's series, with a hard enduro, might have been the Tennessee Knock out and the Tecate enduro thrown in.

WP supplied us with the shocks, both Oem and Trax, and I called SDI and they sent me a couple of their bladder kits for the Oem shocks as Oem shocks are preferred by most pro racers over the "Pro" components, but that is a different blog.

At the time I was seeing bladder arguments on the internet while tuners around the country are pushing bladder kits. Many are still doing so today. We also had many shocks with bladder conversions showing up for service. It was like a fever for Cow Bell on Saturday Night Live.

More Cow Bell and it's all good guys, but, I "Gotta have more Bladder".

So we set up two new OEM shocks with an identical race build we had just won the Tecate Enduro on, one with the bladder and one without.

We tested both shocks on the same bike on the same day.

At the end of the day in Noahs words. It might be a little bit more compliant in the initial hit but not enough to make me want to change. Simply too small of a change to justify converting the race bikes for compliance.

Pretty straight forward and that is that, story is over.

Or is it?

Some things that make you go, Hmmm, Ohh, Mo Money, & Doh.

  • Smaller inside reservoir diameter means less friction. The earlier year WP shocks and currently other brands still have a smaller diameter reservoir than we tested. Less surface area = less friction. Less than the current bladder shock? Could be.

  • The bladder shock holds a little bit more oil. Enough to help cooling? In this case it was only 20cc's but we are inside the shock at least once a week. We chose the bladder in this case.

  • Bladders leak nitrogen into the shock fluid within a year. Think about your bicycle tube, they leak. The bladder leaks and needs to be serviced every year even if the bike is not ridden. Ohh.

  • Bladders also most times need replacement every year due to oil degradation and wear. Mo Money, Mo Money.

  • The piston reservoirs do not seep nearly as much nitrogen, so if the bike is not ridden we would not hesitate to go a couple years without service. Not at pro level but weekend warrior level.

  • The 2024 Xact wp shock has a monster diameter reservoir. Way more friction. Doh?

  • Our standing joke in the shop. "Did you finish designing the piston kit for KYB and Showa bladder reservoirs yet?" Thing is, we may do so in the future. Talk about going against the grain! So how will that go over with bladder pushers?

Bottom Line

If you have a piston in your shock keep it!

If you have a bladder in your shock keep it!

Many DIY folks change to bladders because the new cap has a Schrader valve that they can fill with nitrogen.

A Schrader valve, drill and tap is all you need. An easy mod to do to your Oem reservoir cap.

WP Xact linkage shock is different. The reservoir diameter is larger than a Trophy Truck reservoir. This simply puts more rubber against the inside surface and increases friction, resistance and likely heat. Servicing a shock freshly bled without nitrogen in it yet. We set the piston in position by placing a rod inside the reservoir pushing the piston into place by hand.

Pushing a piston on an earlier year WP or other standard size piston reservoirs, the piston moves very easily. The reservoirs then got larger like the units pictured above and with these you have to push a lot harder to get the piston to move. This is due to friction, not fluid resistance through the base valve. The Xact piston has exponentially more resistance. It is truly hard to move.

This may be a shock that would benefit with a bladder conversion?

I foresee a test coming soon!

By the way Suspension101 already has the compliance issue solved on the Xact linkage shocks.

We invented a patent pending design that we install inside the oem shock.

It is so good we have been getting 100% positive feedback.

We put our money where our mouth is. Money back guarantee!

But we will not stop.

Suspension101 Tests incessantly, invents when necessary, because better performance is mandatory.

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