ARO suspension setup thread

[NBD925]

Guys I need help setting up my kit.

Bike: 2017 KTM 350 XC-F
Kit: 2019 Timbersled 137 ARO (Trio, TSS/QSL)
Rider: 6’4” 255 guessing gear and cloths at 300

I have the seat on the bike level so dropped the TSS length below the Timbersled book specs to get there.

Have not drilled the new hole for the rear strut rod yet. (Drill size to be able to use the original steel insert?) (3/4 up 1/8 back?). The timbersled tech was saying to measure from the front strut bolt center and swing an arch with that original measurement 3/4 inch up and drill there keeping that distance is critical he said. Thoughts on that??? In my mine 3/4 up and 1/8 back would be wrong 1/8 forward would make more of that arch.

Thoughts on front and rear track shock spring weights for this setup??? I see allot of people doing a 250 in front on the shorter kits but I want to make this long track climb better. What setup can I do the make that happen? I always thought you would want less spring pressure in the front to get the track up on the snow.

I know I am a big guy on a 350 but that XC-F makes allot of Horsepower and I ride high in the RPM. It should climb better than it is right now. Was hoping some proper setup would help.

 

[eric82930]

I think you have the wrong terminology. The strut is the rod under your seat. The mod you want to do is drill where the rear swing arm bolts to the tunnel and the arc is measured from where it bolts to the rails so yes it will be up and back. My buddy just did it to his aro and made it have way less ski pressure. Don't worry about the seat being level. Just pick up the back of the track and see which paddles touch first when you set it down. You want the front paddles to touch first barely.

 

[eric82930]

If you aren't bottoming it out often then just try and ride it as is. Guys pay extra to get an aro that sags. It's called the s model.. Just kidding you're probably heavy enough to want bigger springs but sometimes the softer springs do help it crawl on top of the snow as it lets the rails plane out. But see how often it bottoms and don't be afraid to crank up the preload.

 

[JimBridger]

I think you have the wrong terminology. The strut is the rod under your seat. The mod you want to do is drill where the rear swing arm bolts to the tunnel and the arc is measured from where it bolts to the rails so yes it will be up and back. My buddy just did it to his aro and made it have way less ski pressure. Don't worry about the seat being level. Just pick up the back of the track and see which paddles touch first when you set it down. You want the front paddles to touch first barely.

This is for the pre 2020 kits only, right?

I just swapped my 2022 129s to a full size and put the lighter 150 lb spring in the rear and the heavier 175lb up front. (Opposite of what the factory does)

It climbs just as good as the other way around, but requires more rider input, like getting over the tank when climbing.
On the trail and in the trees, my 129 feels as agile, if not more agile than my 2018 aro 120. I haven't relocated the swingarm to the 3/4" up position on my 18 120 yet. What does this change/help most? Will this help climbing performance or just ski pressure? (Is there a thread dedicated to this mod by chance? )

Last question... has anyone ditched the rear arm on older kits to mimic the 2023 aro? If so, what's needed to do this?

 

[00Tundra]

This is for the pre 2020 kits only, right?

I just swapped my 2022 129s to a full size and put the lighter 150 lb spring in the rear and the heavier 175lb up front. (Opposite of what the factory does)

It climbs just as good as the other way around, but requires more rider input, like getting over the tank when climbing.
On the trail and in the trees, my 129 feels as agile, if not more agile than my 2018 aro 120. I haven't relocated the swingarm to the 3/4" up position on my 18 120 yet. What does this change/help most? Will this help climbing performance or just ski pressure? (Is there a thread dedicated to this mod by chance? )

Last question... has anyone ditched the rear arm on older kits to mimic the 2023 aro? If so, what's needed to do this?

What would be the benefit of ditching the rear arm?

 

[JimBridger]

What would be the benefit of ditching the rear arm?

I don't know, that's why I asked if anyone had done it. Ha. That's how the 2023 aro3 is, didn't know if there was an upgraded parts list to have the same skid as the 2023. I guess it saves 12lbs ditching it.

 

[z987k]

I have too much ski pressure, before I get into spending money, can someone explain if I want to add or remove preload from the front and rear track springs and how that effects how it rides?

2018 137 ARO.

 

[NBD925]

I also have a 2019 ARO 137, which falls into the 2018/2019 category.

I believe you have too much ski pressure because of the holes that are drilled in the wrong location on the side rails on the 2018/2019 ARO kits. 3/4 inch up is a large adjustment back there for the rear hole relocation. The correct hole location ends up effectively bringing the rear of the track up into the tunnel by about 3/4 inch. This changes allot. It changes how the bike sits and how the track is positioned in relation to the mounted bike.

You compensate for that mis-drilled hole location by dropping the rear link or TSS shock measurement but that makes ski pressure worse. Also the front spring on the track is too soft. Stock it comes as a 150 pound. I just swapped mine to a 250 pound. I was also going to do my rear spring as well, same weight spring. That soft 150 pound front spring makes ski pressure worse as well. A long track 137 making flotation way out the back and this makes ski pressure worse.

I have noticed after dropping my TSS shock measurement below the recommended length (to get the track level on the ground) the side plastic on the bike comes close to touching the ARO kit. If the hole was drilled correctly it would increase that distance by allot.

I want climbing ability, so I have pumped my TSS to the max with air.

I think the 137 would be a good climbing setup if some of this was corrected and if you had the power to turn the long track. A 450 with about 55HP seems to come close. Although not as nimble as a shorter 129 or 120 the 137 will allow you to go a little slower in the deep. You need a “little” down pressure on the front to climb well too, so its a compromise. But this kit came with too much, it needs correcting.

Im new to this problem but this is my level of understanding on the situation. I have not had the hart to drill the new hole yet but I will probably be doing it soon.

 

[eric82930]

If you have an adjustable strut and you can get the front of the track to touch down first then there is no need to drill the holes. The only down side would be if your bike parts are hitting the kit when the tss compresses. Also the weight of your rear gas can is held higher than necessary if you don't drill the holes, it's minor but if you tip over it will take more force to pick it back up.

I think the 137s got a bad rap because the original ones didn't climb well enough to offset the sluggish cornering then the first 129 that came out was the first track with a decent paddle. It had nothing to do with the length. The Aro 137 is a fast kit with the 2.5 and climbs well.

 

[yooper01]

Well, I’m on a 16 mountain horse ST that’s been a little modified, but the theory here is pretty similar to aro suspension. I also have a 21 riot le to compare to, so here’s what I’ve done and my impression of the results.

16 MHST on a 2016 yz450f:
QS3 shocks off of an ARO LE, front and rear.
Front shock has a 300 lb spring. 1/4” preload.
Rear shock has a 150 lb spring, barely any preload.
Running an exit soft strut at 11 7/8” eye to eye. (Lots of preload with 0 sag while I’m on it.

129 Cmx track with ice age rails.
.64 front fork springs with 10w oil.

If a stock MH is a 0, and a well set up riot is 100, this is a 60 in wheelie mode.

When set to wheelie mode it is super playfull and
Rides awesome, wheelies maybe too much while climbing steep hills in powder, even with the shocks set to soft in the front and hard in the rear, I think stiffer valving on the rear may help that out.

 

[GlennRMK]

Thanks for all the info on here. I have a 19 Husky FX450, with solid strut and 2020 ARO3. Had an 18 ARO 137 for 3 years prior. I'm 6'3" abd about 210 lbs without gear for reference.

Both of these just feel super planted and I wanted more of a dirt bike feel.

I ordered a 300 lb front track spring for my ARO3. What a difference in playful feel. I wouldn't say there is a lot of difference in feel on the trail but as soon as your in powder, the front feels much lighter and I feel like I can lift the ski a lot better to get over obstacles or across creeks.

If its real steep and deep, sometimes I stiffen up the rear track shock all the way but most of the time I leave it set in the middle.

I haven't noticed a big difference in trenching or climbing. Couldn't be happier really.

 

[yooper01]

Thanks for all the info on here. I have a 19 Husky FX450, with solid strut and 2020 ARO3. Had an 18 ARO 137 for 3 years prior. I'm 6'3" abd about 210 lbs without gear for reference.

Both of these just feel super planted and I wanted more of a dirt bike feel.

I ordered a 300 lb front track spring for my ARO3. What a difference in playful feel. I wouldn't say there is a lot of difference in feel on the trail but as soon as your in powder, the front feels much lighter and I feel like I can lift the ski a lot better to get over obstacles or across creeks.

If its real steep and deep, sometimes I stiffen up the rear track shock all the way but most of the time I leave it set in the middle.

I haven't noticed a big difference in trenching or climbing. Couldn't be happier really.

Sounds very similar to my experience on the mountain horse. I am 6’2” 230 without gear.

The other thing I liked early but am questioning now is my tall riser. I run the C3 tall riser and think if i go to the mid height it might help with keeping my weight forward for climbing.


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