Yes, absolutely, you should experiment with the volume spacers to get additional travel out of the fork. If you're not sure what to do, there are definitely directions available, but in their infinite wisdom, Manitou doesn't seem to have a link to them on their Mastodon webpage. There a link to contact them, though, so I'd try that. Good luck

 

Check these out for more info;

Looking at the IVA settings on page 10 of the travel change doc it shows the 150mm is already set up to give the maximum air volume.

Also check you're running the correct pressure as shown in the set up guide.

https://manitoumtb.com/wp-content/up...vice-Guide.pdf

https://manitoumtb.com/wp-content/up...ange-Guide.pdf

https://manitoumtb.com/wp-content/up...etup-Guide.pdf

 

Thanks guys, I'll do some reading.

D

 

Just tried your links Jack and none of them work..

D

 

DOH!

Try these;

https://manitoumtb.com/wp-content/u...ntent/uploads/sites/2/2018/08/2017_RD_Mastodon-Pro_Comp-Travel-Change-Guide.pdf

https://manitoumtb.com/wp-content/u.../wp-content/uploads/sites/2/2018/08/2017-RB-Mastodon-Pro_Comp-Service-Guide.pdf

https://manitoumtb.com/wp-content/uploads/sites/2/2018/08/45-35283-Mastodon-Setup-Guide.pdf

For future info they're listed in the Bicycle > Support > Documentation page on the Manitou website

 

what are you running for pressure and what do you weigh?
If you are using the suggested pressure chart on the fork leg, you probably have too high psi.
That's where I'd start.
Another cause is too much oil in the damper...but start with letting the air out and seeing if the fork will compress all the way

 

there's a whole thread on the Mastodon here:

https://forums.mtbr.com/fat-bikes/manitou-mastodon-1039416.html

And Dougal frequents it, he should be able to help you out if others can't.

 

Thanks again guys.

Yes, I was running 92ish psi as per the chart and have now dropped it to 83psi. I also added a spacer to the IVA dealie above the seal and kept the 3 below the seal.

Fork is a little plusher now and I seem to be getting full travel now. Mid stroke is maybe a little firmer?. Still have to take it out for a rip on the trails to see what's what.

D

 

I have a 120 Mastodon. Per advice Dougal gave, I removed the o-ring on my IVA which disables the system and gives a lot more air volume. I really like the linear, coil like feel. You might hate it.

So, in addition to the several spacer configurations, you can bypass the system totally and have a very large air volume.

If you hate it, slide the o-ring back on in 2 minutes and keep playing around.

 

I have a 120 Mastodon. Per advice Dougal gave, I removed the o-ring on my IVA which disables the system and gives a lot more air volume. I really like the linear, coil like feel. You might hate it.

So, in addition to the several spacer configurations, you can bypass the system totally and have a very large air volume.

If you hate it, slide the o-ring back on in 2 minutes and keep playing around.

Similar for me too. I ended up just taking all the spacers and piston off the IVA shaft. Nice and plush and gets full travel now.

 

I’m running the IRT and appear to use all of my 120EXT. I was never a fan of the IVA, but I would do the same, remove the o-ring if I did not have the IRT. When I put one on my wife’s fatty I may just put my old Mattoc cap on, that has nothing but the cap itself. I put an IRT in that fork as well.

 

Huh... worth a try. So remove just the o ring or the o ring and the spacers?

D

 

I just slid the o-ring up and hid it under the cap. It's still in the fork, just not where it's supposed to be.

 

I had to lower my pressure below the chart recommended level to get mo'full travel. Currently set at 55 psi. I weigh ~180 geared up. Fork travel is at a 120mm.

Urmb

 

Depends on what I'm doing on my Bucksaw. If I'm taking it off 2ft drops and jumping it then I need 80/125 (IRT) or 80 with 4 spacers below piston (IVA). If I want the plushest such as when I sprained my hand mid-Mohican (26miles) (luckily I had the pump in my pack) I set it to 70/80 and avoided sending it.

 

Using all the travel is not a 'must'; especially on a bigger travel fork I think it can be too soft and not supportive enough if you use the 'full travel' metric without doing anything that would use full travel.

 

Bottomed out too much on the big hits without the IVA so I threw all the crap back in. Just lowered the air pressure a bit and now I love the feel and the lack of bottoming.

D

 

My experience with the stock IVA is that if it is in the least aggressive setting it uses most of the travel off 2 foot drops and never bottoms. But this comes at the cost of feeling some of that ramp-up over bigger roots and rocks.

 

Manitou Mastodon STD 100mm PRO. Here's what my IVA looks like. I don't know what the spacers are on the other side in the oil. I'm running about 90lbs of pressure. I weigh probably 190-200lbs with riding gear. I have been searching for how to adjust things, but coming up short on specifics for a novice. I feel like I'm bottoming out on bigger hits.