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Discussion Starter · #1 ·
I posted about this in the Mastodon thread in the fatbike forum but I don't know if many people look at that thread anymore-it's pretty old. So please forgive the crosspost but I really need some help.

I had my Mastodon serviced recently and it now doesn't get full travel. It hits a hard stop with about 4cm of stanchion showing. I did ask them to reduce travel from 120 to 100 because it made my bike too slack but I don't think that happened. The IVA stack is still in the 120mm configuration and with a shock pump attached there is nearly 140m of stanchion showing when fully extended. Maybe they made the spacer adjustment on the air spring but not on the IVA? Would that cause the travel to be limited? I'm not comfortable removing the spring without a better idea of what I'm dealing with so I can't check it myself. I'm going to call the shop that handled the overhaul (they "sent it in" for service) and see what they think but does anyone have an idea of what might be causing this? The rubber o-ring shown here is where the travel stops, even with the shock fully deflated.
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The Mastodon is made so you can change the bottom-out bumper spacers to accomodate different tyre sizes. The info for that is in the bottom of my fork descriptions here: https://www.shockcraft.co.nz/mastodon-pro-straight-steerer-80-150-mm-matte-black-manitou.html

Basically the fork is set for STD size tyres, +10mm or +20mm (EXT) radius with bottom-out bumper spacers and then you use top-out spacers to set available travel.

Available stanchion means nothing.
 

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Discussion Starter · #3 ·
The Mastodon is made so you can change the bottom-out bumper spacers to accomodate different tyre sizes. The info for that is in the bottom of my fork descriptions here: https://www.shockcraft.co.nz/mastodon-pro-straight-steerer-80-150-mm-matte-black-manitou.html

Basically the fork is set for STD size tyres, +10mm or +20mm (EXT) radius with bottom-out bumper spacers and then you use top-out spacers to set available travel.

Available stanchion means nothing.
Thanks, Dougal. It's a standard fork, not EXT, and I run 26x4-4.25" tires. So do you suppose they changed the bumper spacer to make the change in travel I requested? What I wanted was to have the spacers on the air spring and IVA swapped around to reduce fork height, to reduce the crown to axle distance to be close to what the original rigid fork was. (485mm, it's an Otso voytek) That would work, right? I don't want to lose that much travel without the benefit of reducing the A-C measurement so I suppose I should have them put the original bottom out bumper back in if that's what they changed. Let me know if that doesn't make sense or if you have other suggestions. Thanks again!
 

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Thanks, Dougal. It's a standard fork, not EXT, and I run 26x4-4.25" tires. So do you suppose they changed the bumper spacer to make the change in travel I requested? What I wanted was to have the spacers on the air spring and IVA swapped around to reduce fork height, to reduce the crown to axle distance to be close to what the original rigid fork was. (485mm, it's an Otso voytek) That would work, right? I don't want to lose that much travel without the benefit of reducing the A-C measurement so I suppose I should have them put the original bottom out bumper back in if that's what they changed. Let me know if that doesn't make sense or if you have other suggestions. Thanks again!
I don't know what they've done. But I'd want to pull the air shaft out and check. The STD and EXT are the same stanchions, just different spacer config. There is another complication when you're looking at spacer configs, the EXT150 fork has 10mm longer tubes than the other forks.

Here are your guides: https://hayesbicycle.zendesk.com/hc/en-us/articles/360036017874-Mastodon
 

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Discussion Starter · #5 · (Edited)
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