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Agreed, the bladder kit conversion is a significant improvement over the stock shock.
I’m also using the REP link and knuckle which makes the shock feel more progressive and gets rid of the harshness on square edges.
I know it’s not suspension related, but a month ago I changed the upper motor mounts on my 24 450 to the 2025 FE mounts with the hole in them- big improvement in comfort, and the vibration is gone…
You have part nnumbers for those motor mounts?
Are folks really that unhappy with their ‘23/‘24 WP forks? What is the top one or two things the KYB or 6500 improves upon?
I have a new 24 350 SXF. Only ridden once, but no initial complaints. I did just swap some lower Husky forks on to it. Once the new rear links arrive I’ll get it back out.
For me it is the lack of balance in being plush on smaller stutter bumps, square edge and smaller chatter acceleration and braking bumps while having good bottoming resistance. I find that in order to make the suspension soft enough to comfortably soak up the small stuff, it blows through the stroke and bottoms out too easy and dives too much in corners. When stiffening the fork enough to hold up from bottoming, it is too stiff and harsh in the first 1/4 of fork travel, where I want the plushness on the small chatter and square edge. I am sure a revalve is required for my weight. But for me, if I am going to spend that amount on a revlave, I might as well spend the extra and get springs.
I also have a '24 KX450 that is not yet sprung or valved for my weight, and the forks are more plush and fluid on that bike with just a bit more oil in the forks.
I do prefer the feel of the spring fork. I like the plushness and the fluidity. Also, not a huge fan of having to worry about and manage the air pressure and easily it can effect the feel of the forks.
The Shop
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
Luxon 4-Post Bar Mounts
$189.95 - $239.95
The AER fork is really good until you read how crap they are on the internet.
A46003912044C1 is the OEM part number. They are black.
https://www.ktm.com/zh-cn/parts---wear/powerparts/products.html?c1=1001…
I understand that REP is manufacturing their own version of these that are supposed to be similar to the OEM mounts, but I don't know when they will be available.
I was sure skeptical about much improvement these mounts would give to vibration and handling, but a day at Glen Helen showed me otherwise, they really do lessen vibration and the back of the bike handles square edges better than before...
They are ok until the air inside gets hot and changes the spring rate during a moto.
I've got a question i've never seen/heard addressed regarding the "increase in air pressure" on the AER forks while in use that many cite as a reason for converting.
Spring forks experience the same warming and increase in internal air pressure while in use. So, for those who have gone to a spring conversion - do you not feel the same increase in spring force in them as in the stock AER? It would stand to reason that the AER and coil spring forks are using the same spring force for a given application, so do the AER have a greater increase in overall rate during use, and if so, why?
I get that some don't care for the AER due to feel/action, but I'm curious about the ones who made the change because of the above reason.
If this has been addressed previously, I'd appreciate someone pointing me to a source.
Thanks.
when air gets hot it expands and increases in pressure in a closed container(ie fork tube)...the air in the wp airfork is your "spring rate" so as it heats up from cycling the pressure increases giving you a higher spring rate. A metal spring doesnt expand or change when heated.
No, the coil spring doesn't change rate, but the air in the spring fork also heats up and expands, thereby increasing the internal pressure and adding to the overall spring rate; that's why they have bleeder screws.
If my forks are services and aligned, I get very little air build up on fork springs. Most of the time nothing comes out when I bleed them right after a 20min session even if it's really hot outside.
On normal AER fork, it was around 2-3psi. On Cone valve AER lower chamber, it was bad due to the small volume seemed to heat up a lot. Going out for practise in the morning with 160 upper 175 lower, I'd come in and have 180 in the lower. Wasn't really working, affected the fork a lot.
Tried nitrogen in both normal AER and CV, made no difference.
In coil spring forks, the air is only the ambient pressure, neutral chamber. So a small percentage increase has very little practical impact. The AER forks also still have an outer, neutral chamber just like coil spring forks.
I AER forks, the air spring is not at ambient pressure. It is on the order of ~150 psi. So, a small percentage increase can be 2-3 psi, as said above. Which equals approximately 1 spring rate, in coil spring terms. So, it could potentially have a practical impact for faster rider in longer motos.
Last August I rode my 450 bone stock for the first time.
Set the pressure at 10.8 bar. It was over 105 at Glen Helen that day.
Post moto- 11.7 bar.
@aees
@FGR01
@Brent
Thanks guys, that's the info I was missing. For some reason I was thinking they used around 30 psi (~2 bar) but it makes sense that if they're using about 5 times that it will be noticeable since the increase would be proportional to the starting pressure (the whole P1V1/T1 = P2V2/T2 thing).
So, an increase from 10.8 to 11.7 bar is close to 10% - that's like going from slow trail riding springs to moto rates in the course of a moto - hard to miss a change like that.
I'm assuming they haven't incorporated a self-regulating feature yet to keep them close to the set pressure? Seems like someone (Rinaldi?) who was developing air-spring suspension years ago had worked that out - I would think it would be standard in current designs but it doesn't sound like it.
And FWIW, other than being moisture-free compared to regular compressed air, I've never seen (nor would I expect) a performance difference with nitrogen since it's governed by all the same gas laws.
Thanks again.
Adding more to an old thread... In what way did (do) the 6500s feel better than the KYBs to you? I am looking at options and am somewhat leaning towards the KYBs. Though I have read a few comments of folks happy with the 6500s. I was thinking KYBs from Enzo or JBI and 6500s from REP. I ride mostly on a very soft, very rough track where handling bumps is the main issue. But also have a few tracks that can be very hard and slick and want a better front end feel in the corner (not wash out...).
I have slightly better front end feel and traction with the 6500, but KYB more plush. 6500 feels more racing.
Performance wise both are ok, just different.
Pit Row
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