ARO suspension setup thread

[CB-BLR]

I recently bought a 2017 rmx450z w a 2018 aro-20le. I noticed the previous owner drilled new holes in the tunnel to mount the rear suspension about an inch higher. What effect would this cause to the suspension characteristics? Should i put it back to stock?

Short answer: Relocating the holes to that location was the correct thing to do for that year.

 

[rippintare]

Perfect. I can sleep now.


Sent from my iPhone using Tapatalk

 

[aka Mr Floyd]

Short answer: Relocating the holes to that location was the correct thing to do for that year.

OK, I'll bite. What was the long answer?
Seems this would lighten pressure at the rear of the track. Did they change this geometry in later model ARO's?
I picked up a 2019ARO for next season and a friend rides a 2018, wondering if this is a mod we should look into.

Thanks for any info!

 

[eric82930]

My guess is they didn't have an adjustable strut rod and drilling holes is cheaper than buying a new strut.

 

[CB-BLR]

Medium answer: The hole as placed in the 2017 and 2018 sleds was not drilled in the location that the engineers directed in their final draft of the aro side track frames...and for some reason it did not make it correctly into production...this was remedied for the 2020 aro's. proper location should br approximately 3/4 of an inch up from where it was drilled...to achieve the intended geometry. I used to have the exact measurements...but can't find them...but 3/4" up works. This supposedly helps reduce some of the ski pressure. I never rode mine before modifying it.

 

[hillclimber147]

Medium answer: The hole as placed in the 2017 and 2018 sleds was not drilled in the location that the engineers directed in their final draft of the aro side track frames...and for some reason it did not make it correctly into production...this was remedied for the 2020 aro's. proper location should br approximately 3/4 of an inch up from where it was drilled...to achieve the intended geometry. I used to have the exact measurements...but can't find them...but 3/4" up works. This supposedly helps reduce some of the ski pressure. I never rode mine before modifying it.

Does the shock mount higher on the 2020 137's as well? This is the first i've heard of this change.

 

[CB-BLR]

Does the shock mount higher on the 2020 137's as well? This is the first i've heard of this change.

I do not know. I do know that I had to move it on my 2019. This was confirmed by several sources.
Chris

 

[schwany31]

Interesting information about moving the hole location up roughly 3/4 inch, i have not heard that before. (Now added to the summer to-do list)

Anymore information out there regarding flipping the chain slider and moving the kit forward?

 

[300mxc_dave]

There was a thread on here last winter about flipping the chain slider, gearing different, and moving the kit forward on the ARO kits. I have a 2019 ARO 120le on my '17 250sx I ran last winter for my first snowbike season. From what I remember the thread said to go to a 15 tooth counter shaft sproc on the bike then swap the drive sprocket to a 18t and flip the chain case gears top to bottom.
This is supposed to free up a bit of rolling resistance by not forcing the drive chain down under the slider and move the whole skid forward a bit. I ran a 14 tooth counter sproc with the stock ARO gears all winter and the 250 smoker pulled it no problem even in 3 feet of fresh powder here on the north coast of BC. I ordered the 15 and 18t sprockets late in the season but did'nt do the mod yet. I will when I build the snowbike again in a few more months here.

I am curious about this mod to move the suspension skid up in the tunnel on the '18-19 ARO's it sounds like. Mine was a demo kit from a dealer that had one season on it when I got it but must have been set up decent 'cause it worked well in deep snow for me. It gets on top of the deep powder and floats very good it seems like to me. I would not say it trenches at all. I did shorten the TSS by a good 1/4" or more from the TS's recommended spec for the 250sx to lessen the ski pressure a bit. After reading this and other threads though I am curious about the skid shock springs and pre-load and if they are stock or not.

 

[cbc76am]

Riot without chain rub block

Here's Catsledman's post on the mod, you'll need a mill or a machinist to pull it off. The chain angle sucks, but this is extreme for a fit unless you are a metal worker. I went up in spring rate on the front shock on the ARO LE as well and got far better transfer from it. The Riot is a whole different story for spring rates but also benefits from longer springs with less pre-load at slightly increased rates. I'm also running a TKI belt drive now on the secondary which is a nice reduction in vibration and chain drag.

I'd love to do Catsledman's mod to get the forward chain block out and shorten the track to frame distance to the absolute minimum... I just can't get myself to apply that much modification to the kit.

 

[300mxc_dave]

Thanks for that link cbc76am. I am going to try this 15/18 gearing / removing chain rub block on my ARO LE kit as it sounds alot more simple than on a Riot. I will also look into what the spring rates are on my shocks and go stiffer on the front one if still stock.

 

[VictorV]

Pre season tuning.

So I received coil over 200, 225 and 250 from BLACK MAGIC.
Checked them for rate.
It is not quite exact...)
200 lbs TAG gave 175 lbs in measure method.
225 lbs TAG - 211 lbs measured
250 lbs TAG - 238 lbs measured

Could be measure method fluctuations, but I triple checked.

165 lbs is my personal weight.

For receiveing RIOT feel on my 120 LE ARO I decided to put 225 TAG (211 real) spring as front, and 150 (from factory front) at rear.
My concern is:
A.150 at rear would hold suspension from bottoming, or should I leave it as 175?

B. May be put 250 TAG (238 real) at front, and do not worry about stiffenes.

 

[cbc76am]

The aro holds up pretty well in stiff dampening setting. The rear should be fine. Unlike the riot the aro suspension is mostly independent of each other, so the change in front won't really effect the rear.

 

[VictorV]

The aro holds up pretty well in stiff dampening setting. The rear should be fine. Unlike the riot the aro suspension is mostly independent of each other, so the change in front won't really effect the rear.

cbc76am, thanks.
So 250 front, 150 rear is fine?

 

[cbc76am]

I think so. I weight 170 and wasn't bottoming with the clickers on firm on mine unless I was really pushing it. I've had that kit on a 17 ktm 450 and a 2000 cr500... My preload is cranked down pretty hard, stepping up a spring and running less preload is always a better route.

 

[BigAir]

cbc76am, thanks.
So 250 front, 150 rear is fine?

Any chance to test and give an update on what you found you liked on ARO spring rates?

 

[cbc76am]

It was terrible in the riot... Aro just needs to be matched to your weight on the timbersled tubing guide. Back to stock with more preload for now. It was bottomless, but too stiff on hard pack.

 

[900 Cat]

I have a 2018 aro LE and 2017 MH LE. To confirm, the relocation of the rear shock mounting hole applies to the the 2017 MH as well?

Thanks in advance.

 

[CB-BLR]

I have no info on the MH stuff... It just applied to the 18 and 19 Aro's. They fixed it by 2020.


Sent from my iPhone using Tapatalk

 

[Val00hansen]

Does any know the center to center length of the shocks on a 2018 Aro 120?