WP AER Fork

Design analysis and potential upgrades for the WP AER Fork. Looking at spring conversion kits, revalving and replacement cartridges.
‪@dalsoggiorace6135‬ ‪@KTM‬‪@HusqvarnaMotorcyclesOfficial‬

[@lachlanmassie5691]

Really enjoying these videos Terry. You're a wealth of knowledge and obviously passionate about suspension.

[@davebuckmanbuchanan1237]

Fancy seeing you here haha

[@shocktreatment5495]

Thanks Lachlan

[@jamesklauzner6938]

Another great and educational video, thank you Terry.

[@DENIS0209]

very useful information your explanation and passion in doing this is really amazing!

[@shocktreatment5495]

Thanks a lot!

[@postmortemspasm]

Awesome stuff once again. Thank you. I would love to see you do the xplor pds shock

[@shocktreatment5495]

I will put it on the to do list

[@gladeamatoren7106]

So intresting to see n listen at an expert, Thank you so much Terry😀 But please, can you film a bit closer 🙏🏻

[@shocktreatment5495]

I generally do this on a Sunday when no one else is in the shop. I'll take note for future reference.

[@AceOfSpadesPRO01]

I just switched to a 2022 tc250 from a 2018 yz250 and am pleasantly surprised with the WP air forks they’re a lot better than I was expecting especially coming from KYB sss forks

[@shocktreatment5495]

Some people really like the Air Fork. It just seems to gel with their particular style etc. They are not for everyone but its these differences that keep things interesting.

[@bikesbeersbeats]

Got to agree, I have the 2022 250 xcf and when you get the air pressure right for the conditions its a great fork.

[@strifex-suspension-works]

Hello and thank you for another amazing vidoe explaining the ins & outs of this fork, sharing your knowledge and experience. I think I understood everything you said in this video, Terry, apart from the "rebate" on the rebound piston - can you, please, elaborate on that and explain what is it, how it looks, etc. I tried searching internet to understand how that "rebate" looks on the "compression" side of the rebound piston but couldn't find anything so cannot understand how to make the "upgrade". P.S. I'm from Baltic States, Europe. Cheers and thank your for all these videos. Really hope you'll have motivation, time and resources to keep us blessing with such valuable info.

[@shocktreatment5495]

Most rebound pistons have a small rebate on the Midvalve side. If the piston has 6mm id shims on the rebound side it will usually have a rebate that is appr 1mm deep and 8mm od on the midvalve side. This allows for a secondary compression stack to be assembled assisting the base valve and providing additional stroke control. Usually this stack is allowed to move away from the piston a set amount when flow is intiated before resistive force accumulates. This breakaway distance is referred to as "Float". Float is incredibly beneficial. The AER fork uses a fixed stack that has no float which hampers ideal action.

[@joelballard4955]

I took some of your advice. I experimented yesterday with changing the fork oil on the spring side out with a high end synthetic motor oil. 2023 ktm250sxf. I actually felt like it stayed more consistent and less sticky. I ended up going in a bit on compression which i normally don’t do because of the stickiness that I feel sometimes. 🤙🏻🤙🏻

[@shocktreatment5495]

Friction acts like a secondary damper but also contributes a lot to harshness due to the nature of "Static friction". When you reduce friction it allows the fork to move more freely. This is why you may need to add compression damping to control the new found "freedom" of movement.

[@joelballard4955]

@@shocktreatment5495 when you are talking about drilling a 1mm hole in the piston, can you show details. Im actually pretty happy with the 2023 WP xact fork. After 8.9 hours. It feels pretty dang good. It’s way better than any of the previous WP aer/xact forks.

[@shocktreatment5495]

@@joelballard4955 Its just a hole in the side of one of the ports. Check out our facebook page. There is a shot of a bleed hole in a valve story a few posts back.

[@jcbenson01]

Out of curiosity, what type and weight did you go with?

[@joelballard4955]

@@jcbenson01 I put 5w40 in the spring leg. It actually feels like the suspension stays smoother. I had to go in on compression which tells me it’s moving freely.

[@bwhaskell]

Excellent overview of the aer48 and how it can be improved. Adding a significant amount of float in the midvalve using RaceTechs goldvalve drastically improved the plushness feel of this fork on my Alta MXR for motocross. Without float in the midvalve comp stack, due to the seal drag from the air spring, the fork made the front end feel vague at slow velocities. Adding float fixed that, and a stiff stack really ramps up damping quickly after that. That motor oil in the spring leg tip is interested. What weight would you recommend? Thinnest possible synthetic motor oil?

[@shocktreatment5495]

Keep it light. Its really only for lubrication and has no damping duties. Weight shouldn't really be a factor but I would stick to 5 or 10 wt

[@JB-th4bx]

The gold valve transformed the AERs on my '18. The best money I ever spent on that bike. I wish I would've done it sooner.

[@christophervillarreal8565]

I’ve been racing with the stock AER forks and they work phenomenally the manual makes it extremely easy to adjust the forks accordingly to get a more than comfortable feel on the bike. The best part about air as the spring is you don’t need to rebuild the entire fork leg if you gain or lose a few pounds you just add or let out some air in fact just the clickers alone make significant and noticeable changes on the bike enough to keep everything relatively close to what the manuals recommend. From over shooting 100ft jumps to casing them I’ve never had an issue with my AER forks and they feel perfectly comfortable. I’ve ridden Yamahas and Hondas long before ktms and I prefer the ktms all day even if the forks aren’t as “plushy” feeling once you’re moving faster everything has to get stiffer anyways so depending on the type of riding you’re doing that plush factor is essentially subjective. I prefer reliability and ease of adjustment and Ktm nails it.

[@shocktreatment5495]

There are people like yourself who really like the air forks. But the reality is the majority do not. Several air forks have been converted to springs and to this day I have yet to hear a single person say that the spring change was a backward step. Mind you....the only people who are doing the conversion are the ones who have lost faith in the Air System.

[@christophervillarreal8565]

@@shocktreatment5495 again I’ve ridden them all and yes the kyb is superior comfort wise and the Honda also feels great but to say the air forks are not good or uncomfortable is an absolute joke they again just are too lazy to learn how to properly tune them and to spend the ridiculous amount of money to convert them is idiotic they might as well get another brand instead of making a perfectly good 12k bike into a slightly better 15k bike.

[@shocktreatment5495]

@@christophervillarreal8565 Once again Christopher.....some people do like them. Most don't....Some people don't like meat....most do...There is a very good reason every other manufacturer went away from air...as will KTM given time. Their new fork on the EXCs anihilates it.

[@christophervillarreal8565]

@@shocktreatment5495 not if it increases the price of their models by 3k 😂

[@shocktreatment5495]

@@christophervillarreal8565 AAHH....they already have them as standard on the EXCs and....it didn't

[@double-oseven5725]

Hi Terry, in wanting to stick with and work with the air fork to keep weight down for extreme enduro, can I ask what is an approx price to do all your recommended mods on the late model AER forks?

[@Andy-co6pn]

Hi Terry, if i change to a single spring conversion do i need to change the valving in the damping side right away , or is there enough low speed adjustment range to get a workable setup?

[@shocktreatment5495]

You don't have to change everything at once. You can do it in sections if you wish. The springs are always the first thing you should address as they also have a major effect on the dynamic geometry of the bike. Once you have the correct spring you may be completely happy with the bike. Particularly if your damping requirement falls with in the working range of the stock adjusters. If not you can always get the valving done at a later date.

[@racesla]

Hey Terry what weight motor oil would you recommend? Thanks.

[@shocktreatment5495]

The oil weight is not critical as it is not contributing to damping but I would keep it light 5 - 10.

[@enduro-parts-aus]

Are these forks always going to create a more harsher feel due to only having one leg for dampening ?

[@enduro-parts-aus]

Also how do you determine spring preload? Do you set sag in the front similar to the rear as a base setting ?

[@briansalty6299]

Why not put motor oil in the outer of both legs. It shouldn't effect damping because damping us controlled by fork oil in the cartridge. Am I correct? Great video!

[@shocktreatment5495]

Hey Brian You are sort of right. The oil in the inner chamber is largely separate from the oil in the outer but there is a small exchange every time the bottom out cone is engaged. As the lower portion of the cartridge enters the bottom out cone, the oil in the cone comes under extremely high pressure and a small quantity will be forced past the seal and enter the cartridge. So some contamination will occur but how much will depend on how often you find yourself in the lower reaches of travel. If you were chasing the additional benefits of the slipprier oil, you could try installing it, but should consider servicing your forks regularly enough to ensure it never poses a problem.....

[@jamesdungan6198]

I had mine fail on a brand new gas gas on first ride, is that common, what can I do to improve my safety?

[@shocktreatment5495]

You can convert to a spring if you wish. Greater reliability as well as performance.

[@nigelpitsch5946]

Nicely done Terry !! There nasty forks std wp not the company it ince was

[@shocktreatment5495]

Cheers Nige

[@igortbp]

Could you help me understand? I'm from Brazil and I don't speak English, I'm using a translator... When you say adding oil to the cartridge, would it be on the outside or inside the pneumatic cartridge?

[@shocktreatment5495]

Outside of the cartridge

[@igortbp]

@@shocktreatment5495 I noticed in the video that you say something about 1 mm, is it a hole in the valve or lowering the valve by 1 mm?

[@myronstambaugh761]

Who are you (corporately speaking) and how do I shop your spring conversion leg?

[@shocktreatment5495]

Our Company is called Shock Treatment. (Sydney) You can either call or email and we can post one out to you.

[@thomasyork8211]

motor oil is slicker . whar weight motor oil would that be

[@shocktreatment5495]

Weight for weight. Swap a 5wt fork oil with a 5wt motor oil. Just simply dipping your finger into the oil and rubbing it against your thumb will immediately highlight the difference.