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2024 KTM 450 XC-F fork springs are soft. what should I go to?

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theidbreder

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Mar 3, 2020
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Hello all, first off, I just moved over to snow bikes last weekend after years of snowmobiling and now I have a new addiction! The change over is already by far the best decision I've made in a long time... Anyhow, I have a 2024 KTM 450XC-F and a 126" Mtn Top track. The rear suspension is close to perfect but my front forks are quite soft and I am having problems finding out what for spring rate to go with. I am 6' 3" and 220 lbs with gear I'd guess I'm around 240 lbs. What should I go with?

Let me know if you have any useful information and or know where to go to get the right springs.
 

needpowder

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Nice! I do not own the mountaintop kit, but have read that for most people the stock springs are fairly close. I imagine you would only have to go up a size or two on your spring rate, but you should call Alan..
 

Sheetmetalfab

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Oct 5, 2010
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……..
Mtn top bible


This is a text Allen sent me about settings and I want to share it with other mtntop riders, I am coming off a aro 3, am a older rider, 64, and like a non rowdy, stable ski, ride. I was concerned about ski lift and these settings cured the ski in the air ride. Granted I have only 3 rides, the kit feels lighter to ride……



To start with, I can tell you that the factory settings are your best all-around settings. That means it works pretty good for all of the things you're describing. I tend to raise the pressures a little bit for me because I'm large. I also tend to ride around Handling issues due to different conditions. It's just too much work to adjust all the time.



Here are some things:

1. Lower the front track shock pressure will give you more ski pressure all around but the bike will still ski lift when climbing. Normally you only do this for a lighter rider that does not have as much weight sitting on the shock. I keep my front shock at 80 psi.



2. Pulling up the limiter strap will make the front end more planted with out making it ride overly heavy on the ski. This will help keep the front down will climb better due to a shallower track angle (less trenching). The draw back will be trail riding due to less suspension travel and lack of suppleness. This is why you only want to adjust the strap for deep bottomless snow. In these conditions, you can't ski lift anyway, so you might as well make it climb the best that it can.

NOTE, do not readjust your air pressure when you pull down the strap. If you are at 80 PSI and you pull the strap down 2 holes, you will then be at about 95 psi. You have to keep this pressure when pulling up the strap to retain the amount of weight that the front track shock can hold up.



3. Frame shock needs to be calibrated to work with your weight. If it is too low of pressure, it will sack out. It will articulate the chassis in the middle, which then lowers the drive axle to the ground. That's not good for climbing.

Most guys 170 lbs and up like to keep it at no less than 150 psi. I like to run 180 psi for my weight. Rush runs 200 psi.



4. Rear track shock can affect your ski lift. 60 psi for me wheelies out of control. You mostly noticed this when the bike grabs traction. 80 psi is a good middle of the road and 90 to 100 psi will give you great climbing with improved adequate ski control.



5. EVOL chambers. This 100% control your bottoming resistance. 100 psi gives you some adequate bottoming resistance. 150 psi gives you exceptional bottoming resistance. Personally, I would keep it at 150 to 160 psi. I run 160 psi. No need to go higher. If you were to run low main chamber air pressures then going higher in the EVOL can help it from bottoming out.

Note: The Mtn.Top suspension is very bottom out resistance, naturally due to its linkage style suspension. Most of the time you do not feel it bottom out and this could be damaging to parts. That's why it's important to keep that EVOL pressure up and to also tune by looking at the zip ties. When checking your travel with a zip tie, you need to slide the zip tie down ride for five minutes and then check you cannot judge the zip tie if you've been riding all day. The compressed snow on the shock shoves the zip tie down and gives you a false reading.



6. Ski Skaggs are strictly a handling thing. Larger outer skags can definitely make heavy steering when on the trail but more positive steering in soft snow.

On the center Skag I do not notice much difference by changing the center Skag in any snow condition.

I run the factory Skags on both, which is the middle sizes. There is one bigger and there is one smaller option. Typically bigger works better for deep snow only and shorter works better for trails.

The outer Skaggs are a fickle bitch, and are the Skag you would change for different snow conditions. We have 3 multi heights outer Skags and 6 straight cut options. The ski comes with the middle size multi hight. This is what I run. If my ski does not handle perfect one day I just deal with it because I don't like changing them. Reagan, on the other hand changes his skags for the conditions. Bigger outer skags, give you a more positive feel in the deep snow. But they handle like crap on the trail. The trail likes a multi heights skags, because it creates self steer so that you don't have to turn the bars on the trail to make the corners

Like I mentioned before, in the crusty snow, like in the springtime, I don't run any outer Skag. I simply just remove them and run the plastic. This makes crusty snow feel like you're riding in 6 inches of fresh snow. The easy steering comes right back in this condition.



7. More comments:

Save this information. Comment to people on the Internet if you can. This is helpful for me. It takes me a lot of time to put a text message like this together. If this kind of information is utilized in more places than just this.

Also, we do have shock tuning information on the manual section of our website. There is rear shock, tuning, and also in frame shock tuning. If you have not seen that you should probably take a look.
 
T

theidbreder

Active member
Mar 3, 2020
66
37
18
Great information for the Mtn Top kits and 2023 or older KTM’s. Unfortunately the 2024 KTM’s went away from the air assist forks and back to spring only. Recomendations on springs and weight? I don’t want to make it too stiff in the snow but will swap season to season if needed.
 
A little different situation for me since I don't have the new XACT spring forks. I started with air and switched to a spring conversion.

What I'm currently running is a .60 equivalent spring with a very light initial valving that ramps up quickly for additional bottoming resistance. It's very plush on the initial part of the stroke and feels bottomless. I'm a little oversprung for the Mtn. Top, but by doing that I have a pretty quick rebound that helps the whole set-up feel light and lively. It has made for a very well balanced ride for me.

It's pretty easy to "over fork" a mtn top.
 

Sheetmetalfab

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Oct 5, 2010
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……..
A little different situation for me since I don't have the new XACT spring forks. I started with air and switched to a spring conversion.

What I'm currently running is a .60 equivalent spring with a very light initial valving that ramps up quickly for additional bottoming resistance. It's very plush on the initial part of the stroke and feels bottomless. I'm a little oversprung for the Mtn. Top, but by doing that I have a pretty quick rebound that helps the whole set-up feel light and lively. It has made for a very well balanced ride for me.

It's pretty easy to "over fork" a mtn top.

Good information. What springs did you go with?
His post says .60 springs?
 
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