2018 Alta MXR Shock Re-Spring and Re-Valve

[MattB]

Hello everyone! I just bought a 2018 MXR and I am completely thrilled with the performance overall. However, I am a 190lb rider and I am finding the shock spring to be way too soft for motocross. It almost feels like I’m riding on a boat. I’m bottoming out on pretty much everything.

The spring that came with the 2018 MXR is a 60-260. I’m comparing the Alta with my 2018 KTM 450 SX-F which feels amazing to me.

Do you think Alta rates their stock spring setup like other manufacturers which means a rider weight of 165-185lbs? If so do you think changing the spring to 62-260 would fix the soft feeling?

Current Shock settings
High Speed compression 1.75
Low Speed compression 15 clicks
Rebound 10 clicks
Race Sag 105mm

Current fork settings
150lbs air pressure
Compression 15 clicks
Rebound 15 clicks

Thanks in advance!

Matt

 

[Fod]

Hey Matt,
I helped my buddy (fog 25) ~200lbs set his sag at 100 and static came to 30 if I recall. Bike balance was good but we went in quite a bit on the compression and rebound. Your numbers seem to be dangerous on an mx track. To get rid of that soft pogo stick ride, crank in the shock low speed 7 clicks and the rebound front and rear a good 4 or so. High speed we liked 1.5 turns. We only had about an hour of riding that day but our buddy who is a hired test rider for Suzuki (~170 lbs) took it for a few laps and was quite satisfied but could have laid down a bit quicker times with a bit stiffer setting. I also think we were running 145 psi but went in a few clicks on compression but didn't check where we started from.

 

[rayivers]

I imagine there's plenty of aftermarket springs available, but in case you need to roll your own to dial it in perfectly, Cannon Racecraft makes excellent ones to order, for a decent price (this one's a 48 x 203, $140):

http://i399.photobucket.com/albums/pp74/rayivers/Shock-Spring.jpg


Ray

 

[Philip]

Welcome to the Forum, Matt!

A 4% increase of the spring rate is very significant, so a 62 N/mm spring (is stock 60 N/mm??) should make a big difference. But first try cranking up the compression clickers -- both low-speed and high-speed.

You guys are way ahead of me on this one. I haven't had a chance to try my MXR at a jumping track yet. I weight 200 lbs. Looks like I will be running into all the same problems with the 2018 MXR like I did with the 2017 MX. Then I might have to revalve everything as well.

 

[snydes]

Yes, it’s good to know we have some members who appear to know a thing or two about suspension set up. This is my first air fork bike, that and the fact that getting to the shock spring is so stupid easy means I’ll be more apt to play with settings than I normally would.

Philip, did you find out what the deal is with your air pump?

 

[Philip]

I am new to air forks as well. But if I need a revalve, my buddy Adam from Kreft Moto will come up with something. He makes the coolest WP AER setup on the market called "Revalve Control". WP suspension is all he works on. I already gave him a heads-up.

My air pump, which did not come with the bike, will be getting to me hopefully this week.

It is a freaking blizzard here in Michigan today. Not sure when the tracks will re-open with a weather like this.

 

[Philip]

@MattB -- What is your stock 450 SX-F spring rate? I am thinking that if it is close to Alta's, which it should be, then we have a lot of options as far as suspension revalves.

 

[Fod]

No his 18 KTM linkage ratio is completely different..... his rate is probably 45 N.

 

[Philip]

Wow. According to MXA:

"The 2016 KTM 450SXF and 2016-1/2 Factory Edition came with the 48 N/m shock spring. This spring was too stiff for anyone under 180 pounds. The 2017–’18 450SXF has a more appropriate 45 N/m spring."

Alta has not got back to me on my shock stock spring rate question yet.

 

[MattB]

The number on the side of my spring is indeed 260-60 which is a really heavy spring! I’ll try messing with the clickers more soon.

On my 2018 KTM 450 it came with the 45N/mm and I changed it to the 48N/mm. But like FOD said, the linkage geometry is completely different.

On a different note..... I’m the owner of Synergy Cycke Park here in Alabama. Who would be interested in a gathering of Alta owners at my track? I also have a 4 mile trails loop that is really fun for guys that don’t ride tracks. Free for all, just come out and share your experience and information.

 

[snydes]

Nice graphics! Personally I’d love to participate in a Alta owner track day if it was reasonable for me attend. That’s great of you to put that out there. I’m in Pennsylvania, my vacation days for this year are pretty much spoken for, but if you would end up making it a reoccurring thing I’d certainly see if I could schedule it in for the next one!

Steve

 

[Fog 25]

I’ll be going out Thursday for more suspension testing and will get back with the out come.

 

[Philip]

I am taking it back. The "60" in the 60-260 is indeed the spring rate, measured in N/mm.

My 2017 MX rear spring rate is 62 N/mm, and I upgraded it to 65 N/mm. I should be able to use my old MX spring on the new MXR, if needed!

 

[Philip]

If I need a revalve, hopefully Alta will have the stiffer revalving specs ready for me again, like they had for my MX. Else, I might have to become creative.

 

[MattB]

A few pics... I know a little scuffing just means I’m using all of the suspension but it seems like I’m using it all the time. Lol

 

[snydes]

On a different note..... I’m the owner of Synergy Cycke Park here in Alabama. Who would be interested in a gathering of Alta owners at my track? I also have a 4 mile trails loop that is really fun for guys that don’t ride tracks. Free for all, just come out and share your experience and information.

That’s a good looking facility! Can you get 240v hookups installed awhile ?!

 

[MattB]

I can! I can run some 240 drops out of the shop.

You might be able to see some of the suspension softness in this video. Even on the smooth landings it’s almost soaking all the way to the bottom.

 

[snydes]

Nice! I think your dog is going to get docked a few positions for cutting the track though...

We typically do a Florida trip each winter, and also hit Highland Park or Durhamtown in Georgia along the way. I’ll see how far you are from our typical route and if it works out we will come by and do some riding!

 

[Fod]

Opps forgot to be looking at the riding, the dog was very entertaining! How many time have you come over an obstacle screaming CHARLIE!!!!!!

 

[MattB]

I just dropped the bike off at Highland Park which is only 1.5 hours from my house. They said respring and revalve is a must for me. They will have it back to me next week and I’ll report back.

Charlie only comes on the track when my wife Amy is out there. Very protective dog! Lol!!

Matt