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Ogden, UT
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Have any of you AER 48 users done any basic valve upgrades? Specifically this one from JBI?
https://www.ridejbi.com/jbi-suspension-wp-aer48-xact48-pro-fork-diy-kit/
Or any similar upgrade form another brand? If so, how do you like it, or not like it?
I am thinking of getting something like this, I do not want to spend $1,000 on suspension mods or do a spring conversion, this seemed like an "affordable" option to add a little comfort to the forks.
I know a lot of people don't like these forks, that's fine, I actually do not mind them. Any recommendations or user experiences or opinions are welcome and helpful, thanks!
if you have 2021 or newer aer i would go with that kit, then they are good fork, in my opinion never going to be as good as dual spring fork but not super far away anymore.
I have not used the JBI products but the overwhelming sentiment is he runs a good company with great products and support. I wouldn’t hesitate to give them a try if I were you.
I am on a 2017 year model, 350sxf. I am an average skill rider, not going to set the world on fire, thats for sure.
What differences were made from 2017 to current models?
I recently installed the JBI DIY kit in my AER forks. (FC350 forks). I am really impressed. I have ridden with them for two full days of riding on a rather rough track. The best way I can describe it is you don’t notice the forks. No harshness, no issues with bottoming, corners well, no surprises. Any thoughts I had about 6500s or KYBs are gone. It’s not often that a bike mod exceeds my expectations but this certainly has, and by quite a bit.
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Luxon 4-Post Bar Mounts
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I have a '23 XCF350 I installed the SKF Glide kit and run 260ml of engine oil in the outer tube. I run 8.5 bar for pressure and compression 14 out and rebound 10 out. They work great just did the Vet National at Glen Helen and hammered the downhills as fast as I could, the forks were impressive. That is probably $150 in that kit and oil.
great, thank you! I will look into that kit as well!
Thank you for the info, that is cool to hear. $300 mod with real improvement is encouraging
First I’ve heard of engine oil in the outer chamber. How’d you stumble upon this?
Did this back in 2017 and into my 19...I used 0w16...20 would work too. Not sure who ultimately started this, but I liked it back then with the just the SKF kit. I imagine a DIY kit from JBI or RT would be even better.
Interesting. I have heard of using ATF fluid but never engine oil. What sort of improvements did you notice?
2021 was a significant improvement in the forks. You can't really retrofit any of it to your forks either because they made small changes all over the fork. If I remember correctly even 2018 was better than 2017.
For me it seemed like it was smoother, a bit more fluid in action, better g-out action too. Didn't seem as harsh. That was the older iteration, may have been more about the SKF add on though or the combo of both. ATF isn't as heavy, I would be prone to using that on the inside or the shock. The newest gen would probably benefit the same way, but I am no pro tuner, I imagine plenty will say that it shouldn't do anything. Super easy to try with the outer though, no harm, no foul short of a bit of time swapping oil.
I should leave well enough alone, but would maybe buying a set of newer forks would see better improvement over the 2017's with the valve kit?
Also, you may be right, but I do know that the 2016 forks are very different than the 2017's, 2017 & 2018 seem to share a lot of the same parts. Maybe that is the year when big improvement was made? Or maybe there was improvement both years as well.
You might be right about 2016 vs 2017 but 2021 was a huge improvement over 2020.
16 was 4cs and regarded as one of the worst modern forks. My only experience with aer is the 23sxf and i couldn’t gel with them. Went from those to cone valves, 6500s, and now testing a kyb swap
If you do in fact have an early AER 48, it is worth noting that the air spring had significantly less negative air volume than future iterations. This does make a big difference in the forces curve, especially early in the suspension's travel.
Personally, I'm not so keen on tuning just to tune. I've done it a bunch of times and usually come out with a setup that isn't materially better. I'm more interested in first defining what I don't like about a setup, then aiming to fix that problem. This way we're approaching the problem from the right angle as opposed to just throwing stuff at the wall and hoping something sticks.
Final point, to those putting random oils in their fork, it may work but it also may create seal swell. I'm very keen on sticking with whatever the manufacturer suggests just for this reason. I've personally had seal swell occur and its a surefire way to make any suspension product feel like garbage.
YMMV.
JB knows his stuff. Go with the JBI kit, although I would still go with his 6500 kit personally but obviously you stated you aren’t interested.
Did you run the motor oil in just the air leg?
Pit Row
The AER forks are really good until you read how crap they are on the internet, or until some old dude at rhe track tells you they were so bad he threw them in the dumpster after 3 laps.
Or ride a well setup spring fork
I have done the JBI kit. What do you want to know? Ask me 20 questions and I’ll answer them all, I hope to help.
In the USA the 2017 standard models and the 2016.5 (Factory Edition) models were the first year of AER-48 forks.
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There are mainly just valving changes after that.
The next major functional change was made for 2021 models and the forks are labeled XACT rather than AER-48.
The significant change is in the pneumatic spring where the air bypasses the piston at the top of the stroke. Really, it's just a dent in the air-spring cylinder that allows some air to pass below the piston giving a softer feel from top-out through the sag point. It's an effective change and when you ride a 2016.5 - 2020 AER-48 fork back to back vs a 2021+ XACT fork you can really feel the improved spring and valving feel.
Husqvarna models are also 10mm shorter from 2021 onward.
There is a slight difference in cartridge length between AER-48 and XACT cartridges.
I haven't tried this, but I believe you can swap in the later air spring and damper cartridge if you swap over the hexagonal blue and gray rod ends to make up for the difference in cartridge length.
Top is a 2016.5 AER-48 from a 450SXF-FE, bottom is 2023 XACT from a MC350F. The difference in the rod end is about 9mm and it corresponds to an equal difference in the fork lug between years.
"Well set up spring fork" is a good point.
I know expert and masters level riders run cone valves and even after several setting changes were not happy and sold them.
So maybe either air or spring fork, or even bikes hust need to be set up well?
And maybe some riders will always blame the bike?
It’s hard to say. The biggest difference I noticed between my aer and multiple spring fork setups was front end feel in the beginning and middle of a turn. I did have them setup for me and they were better than stock. I’m not very fast but it cost me a lot to race and go to the nearest track (1.5 hours), so I may be spending more than I should on comfort.
I installed the kit in your original post. Install wasn’t bad. Worst part was getting the midvalve assembly out.
I’m afraid I don’t have a good before/after comparison because the midvalve nut on my OEM assembly backed out on its own after I bought it which resulted in horrible performance and ultimately a nasty crash.
Since I’ve had 6 months to stew on it, I decided to install the JBI kit.
I was only able to ride around the house so far but it seems much more planted. Looking forward to trying it on the track in a few months.
***edit***
Customer service has been really solid with these guys. Really recommend them. I’ll probably revolve my shock next year and order a diy kit from them.
I have gotten the newer air fork to work well with a simple revalve on my 22 mc450f. The best suspension will feel bad if the valving and/or bike setup is off.
No in both legs motor oil is heavier and slipperier seems to coat internals and stay on surfaces longer. It's all about reducing stiction including perfect alignment and torque settings on all nuts and bolts.
Engine oil?? lol, do the forks even move?
Hey, PRM, what year forks did you install them on? Thanks
This is all great info, FWIW, I spoke to JB at JBI, he was absolutely honest and helpful in his recommendations. Brief summary of what he told me is that the JBI kit will definitely improve the 2017-2020 AER forks, but that the improvements made specifically to the pneumatic spring (picture in post above) on the 2021 - current forks will take you a step even past the old set up with his upgrade, then obviously adding his upgrade will allow those forks the be even better.
Given that these aren't a popular forks, I will check to see if I can find a 2021 pair for a decent price.
Post a reply to: WP AER 48 air fork users, help/opinion wanted