What it is: Manitou's aggressive 37mm stanchion fork for the enduro segment, providing 140-180mm of travel in 29 and 27.5 sizes, with HSC/LSC/LSR adjustments, IRT/main positive chamber adjustments, and hydraulic bottom out
Construction:
The fork uses 37mm stanchions, which gives it a very stout appearance:
The stanchions are said to be a considerable stiffness increase over the Fox 36 chassis and a minor improvement over the Lyrik. I don't have the instrumentation to really know if that's the case and both of those forks are very stiff, so determining if that's the case would be challenging for an average person such as myself. Being heavier, I can induce flex in some forks, but I've never had that issue with any of the aggressive forks on the market.
Similar to other Manitou forks, a reverse arch is used:
The folks at Manitou claim there is an engineering reason behind the reverse arch, however that's, again, not really something I have the expertise to know about. The arch has a bolt on fender, which is a really nice touch.
The fender is light and made of flexible material, which means it won't bind if it gets snagged, like some other bolt on models I've used. I have ridden without glasses in some pretty sloppy conditions, the fender does a great job of keeping that stuff out of your face, but it isn't a total stopgap for it either.
The fork has LSC/HSC adjustments on the damper side:
There are 4 clicks of high speed compression and 10 of low speed compression. The clicks are tangible and easily felt, not subtle like some other forks (DVO) or difficult to crank down on (Cane Creek). Yes, the colors on the knobs are reversed, but those colors are, as far as I know, arbitrary and not standardized.
There is a rebound adjuster that controls low speed rebound on the damper side, but no HSR adjuster like the GRIP2:
I don't know much about the damper architecture, it uses a bladder and has an overfill blow off. That's about the extent of my knowledge on the internals. There is a hydraulic bottom out, but unlike the Mattoc, it isn't adjustable, it's set to 30mm from bottom out. essentially, this appears to increase the high speed compression damping in the last 30mm of the stroke, where a valve closes and firms up the fork. It provides a more cushioned progression into the later part of the stroke than use of tokens, which can feel spiky or harsh at the progression point.
Interestingly, the air spring side has two fill ports: one for the positive and negative chambers and another for the IRT. The IRT is something sortof unique to Manitou (there are aftermarket mods for other forks that provide similar functionality), instead of using tokens, there is a piston in the positive chamber that presses against the primary positive chamber and acts to ease the fork into the latter part of the stroke. So you effectively have a high pressure positive chamber, providing progression and support (possibly a bit faster rebound from deep in the stroke) and a low pressure one for the initial bit of travel.
It seems complicated, but in practice it's fairly simple: When the lower primary positive chamber, which is lower pressure, equalizes pressure with the upper IRT chamber, the piston begins to move and create a singular air chamber. You essentially end up with two stages: stage 1 being the lower pressure main chamber, providing compliance for small bumps, then stage 2 occurring when the main chamber's air pressure equalizes to that of the IRT, providing a second, higher pressure air spring for later portions of the stroke.
Where this equalization occurs will depend on the pressures in the main and IRT, running a higher main and lower IRT pressure will mean it occurs sooner in the stroke, but also provide more linearity throughout the entire stroke.
One minor gripe on the construction on the spring side is the lack of a seal around the outer portion of the IRT cap:
The lack of a seal around the outside of the cap (the valve itself is sealed) can allow water and dirt into the cap. It's not a huge deal, but a bit annoying.
The lowers can be dropped using standard tools: a 14mm socket for the nuts, 8mm allen for the damper side, and 8mm socket for the air side. I've dropped the lowers twice and it's a fairly simple process, which means replacing the bath oil is easy. There are also no crush washers required, as rubber seals are used at the base of each leg.
Unlike RS and Fox, the travel change is accomplished using spacers rather than air spring assemblies, which is more in line with what DVO, Cane Creek, and others do. It's nice to be able to change up the travel without having to keep easily damaged air springs laying around, although the travel reduction does require a slotted cassette tool.
The axle is interesting, as well, and uses Manitou's Hex Lock axle system. Instead of being round and threaded in, the axle has a hex shape along with the lowers. The axle is pushed into the lowers, then tightened via captured threaded bolt on the other side:
The design is supposed to improve stiffness. I can't speak to that, but I do like that it's easy to use, quiet, and not overly complicated or mechanical like some others. you can also fairly easily replace the captured bolt if it strips or there is a problem, which is nice.
Regarding tire clearance, Manitou claims you can fit up to a 29x2.6 in the front at least. My Vigilante 2.5 clears the front really well, even with the fender in place, so I doubt tire clearance will be an issue.
Lastly, the cable routing is really clean:
The cable attachment point being so close to the wheel means accessing the bolt is a little tedious, but the large "clamp" of sorts that attaches it to the fork keeps the cable secure without having tiny little rubber or plastic pieces like most others have. It also won't abrade the cable as badly as some of the smaller ones would.
Setup:
Typically, I aim to start setting up by getting the air spring dialed, then the damper settings. Thankfully, Manitou provides a rough starting point for these settings:
The setup guide is a bit more rudimentary than others I've used, of which the DVO is my favorite, but it gets the job done. I started with the base settings and found it gave me ~25% sag and nice progression, but I wanted a slightly higher ride height.
I found the main chamber is very sensitive to air pressure changes, even 2-3 psi can raise the fork another 3-5% or so. As always, shock pumps vary anywhere from 1-3psi or as high as 10psi in how they read, so you can use the guide above as a baseline, but where you land may be a bit different.
I initially ran the fork at a bit higher than recommended on both the IRT and main pressures, because the recommended settings were a bit on the soft side for me, but I was also coming from the Helm, which is a fork that is really supportive and firmly damped. Over time, I started letting off the air pressure a bit in both the main and IRT, bringing me back around the recommended settings for my weight. Ultimately, at 210lbs, I found I was around 73psi on the main and 100 the IRT. If you increase the difference in the IRT and main chambers too much, the fork will start to spike a bit, feel harsher, and not track as well, so it's important for the feel of the fork to keep those in a reasonable range depending on how much progression you need.
On the damper side, I ran the fork fairly fast on the rebound, with a 75/100 split on the air spring, the adjuster was 4 clicks from closed. I do wish the setup guide had a grid similar to what MRP and DVO provide, which gives users a range of rebound settings to start with. Another article said Manitou didn't want to overload users with information, but I think the rebound setting is one place where it's real important to have a grid or chart showing a rough range to start with. My observation being that most mountain bikers don't know how to set it and end up running it too slow.
The HSC and LSC adjustments don't have a huge effect on parking lot feel. I left the HSC open and the LSC I put about 5 clicks in to start with. You likely won't feel much difference pushing on the bars, like you will with firmer forks, but the difference when you ride is definitely there.
I found on the trail, you can achieve a firmer feel with the fork by running the HSC at full closed or 1 click off from closed, providing a very GRIP2-esque feel with plenty of support, but that is more likely to be a bit on the harsh side. By leaving the HSC dial open, you can get more compliance.
It seems to be recommended for these forks that the HSC dial be used to provide more range for the LSC adjuster, so you may need to adjust LSC if you crank in the HSC, also. I've experimented with settings and found that fully closed off is a bit on the harsh, less compliant side, but still reasonably comfortable and tracks well. On the wide open front, the fork is still supportive (with the proper spring setup) and stands up to it's travel well. I think it's really hard to get these settings wrong and make the fork feel awful, but there is definitely an ideal range for different track types and certain settings on the low end may produce more dive than with other forks.
I typically find myself at full open HSC with 6-7 on the LSC adjuster or 1 click from closed on the HSC adjuster and 3-4 on the LSC adjuster, depending on what I'm riding.
The last thing to note on setup is that the fork appears to work best if you have a good balance of air pressure and damper adjustments. That seems like common sense, but a lot of the forks I've had required an excess of one or the other to perform properly. I was either full open on the compression settings with a lot of air in the air spring or the other way around. The Mezzer seems a bit more moderate, it seems to do best with a sag point around 22-23% and the damping closer to the middle rather than full open or closed. That'll obviously change depending on riding style, but I would probably start with the recommended settings and have about 5-6 clicks of LSC tuned in with the HSC adjuster closed off. If you find the fork is diving or lacks support, then add a bit of compression to the damper instead of going straight to air pressure settings. On the flip side, if you find it's harsh or not tracking well, keep some compression damping dialed in, but back off the IRT ~5 psi to start before making damper adjustments and see if that improves it or not. Personally, I found it best to keep the air spring on the softer side (the IRT in particular) with more compression damping dialed in, it provided more support while tracking well and not diving.
Riding:
The summary of the ride review is that this fork feels awesome: It has great mid stroke support, it is stiff, it tracks well, and the adjustments have meaningful impact.
The fork tracks over small bumps better than any other fork I've used, loose rocks that would once cause the front end to wander slightly are now absorbed and the bike tracks effortlessly over them. When approaching corners, I can push the bike wider into the entrance of the corner even when it's rougher, allowing a better setup for the corner.
With the front weighted, the fork seems to stand up to it's travel well and not dive. That said, with the initial settings and the damper mostly open, I did encounter a small amount of dive in a mud pit I hit wrong. The dive was my fault, but other forks have held up fine to similar mistakes. After increasing the main pressure a few PSI and adding some compression damping, I haven't had a repeat, despite making the same error. These types of incidents didn't really exist with the Helm or GRIP2, mostly regardless of setup, so it is definitely possible to set the fork up too soft and induce dive, but proper configuration should prevent those types of incidents. As I said earlier, I think the key here is to avoid rushing to add air pressure and find a balance between damping and air spring adjustments.
On bigger features, the fork blows off really well and progresses nicely into the end stroke. My initial settings were too soft and I experienced this effect, hitting the hydraulic bottom out causes a noticeable increase in force required to compress the fork at speed during the last bit of travel, but provides a smoother, less spiky feel to the end stroke than tokens.
I don't really have any complaints, which makes it hard to write a review on. When your suspension works well, it feels buttery and the bike balanced, it's easier to point out discrepancies in the fork feel than it is to cover everything it does well. In this case, I have little to gripe about on fork feel and can recommend this fork to anyone looking for a fork in the same category.
Differences in review experiences:
The elephant in the room on this fork is going to be a predominately negative review on a popular mountain biking website. I can't really speak to specifics of what was going on with the fork they tested, however my experiences are completely different.
I found the Mezzer to be one of the smoothest, most compliant forks I've used, which is a direct contrast to what the review states. Setting up the IRT is a bit more involved, I'll give them that, but not much more so than other offerings with multiple pressure or air side adjustments (e.g. DVO OTT).
As for bushing slop, I have a minor amount, but it seems to go away when the fork is compressed. I suppose this could be something that exists in varying degrees on other forks and may influence fork feel, but I can't say that it does in my case.
So who would I recommend this to?
Anyone looking for a highly adjustable, aggressive fork in the travel ranges provided. It's reasonable weight and can be adjusted for most any rider and riding style.
If you want a fork with a very firm feel right off the bat, then the GRIP2 or Helm would be a better choice. You can get a similar feel from the Mezzer, but the Mezzer's damper tune isn't going to be as firm as others stock.
Comparisons:
vs. Fox 36 GRIP2 : The GRIP2 is Fox's current flagship damper and provides a much wider range of damper adjustments, the HSC/LSC adjusters have more clicks and the damper provides HSR, which the Mezzer lacks. The 36 GRIP2 feels different than the Mezzer, though, and has more of a race feel, which seems typical for forks with firmer compression. The GRIP2 felt really similar to my Helm, it was smooth and composed, but not as compliant as the Mezzer. The GRIP2 felt like it'd be harder to get that compliant feel out of without custom tuning, but also less prone to catastrophic misconfiguration (e.g. dangerous levels of dive). You can get a very firm feel out of the Mezzer, but you can't get the same level of compliance out of the GRIP2. I think most aggressive riders would be well suited to either, but riders looking for more compliance would definitely be better with the Mezzer. I like the feel of both forks, but the Mezzer is stiffer and provides more tuning options for feel, despite having less adjustment range.
Pros:
Good useful travel range of 140-180
Stiff, burly chassis
Useful adjustments and wide adjustment range
Hydraulic bottom out provides a more progressive, cushioned end stroke support feel than tokens
Tracks very well on rough terrain
Easy to work on with mostly standard tools (slotted cassette tool excluded)
Manitou support is great to deal with
Supportive mid and end stroke prevents harsh bottom outs and dive
Easy to use axle system
Cable management is the cleanest and most secure of any fork I've used
Cons:
The fork developed bushing slop after a few rides. The slop goes away after a few mm of compression and isn't really noticeable when on the bike, but it's there at full extension. Apparently it's more severe for some users and posts online indicate Hayes is working towards a solution
Price is a bit high for a boutique brand fork
Slotted cassette tool to do travel changes may be a little difficult to come by