What it is: The Auron is a 34mm (35mm for Boost versions) stanchion single crown fork made by SR Suntour. The fork provides a number of adjustments at a reasonable price. The fork, along with most other SR Suntour suspension products, can be tried for 3 weeks as part of a demo program for a refundable $100 (https://www.srsuntour.com/pages/dtyd).
Adjustment options: The fork has several adjustments, including spring rate, air volume, HSC, LSC, LSR, and negative spring rate via replaceable coil.
Thoughts:
SR Suntour isn't exactly the first manufacturer to come to mind when people are considering a high end fork. I only bought the fork because my other fork was being problematic and a friend of mine had really positive things to say about the Auron. I also got it on a 30% off deal they ran around Thanksgiving, which certainly helped.
The ordering process was super easy, you specify your bike (2017 Smuggler, in this case), riding style, and bodyweight, Suntour sends you a fork with the proper negative spring (this is important), air pressure, and volume spacers.
Note that this is a little different than what you get from PUSH or other custom tunes, they don't actually tune the damper, rather it's just the more simple adjustments, which I can't argue with given the price and workload in tuning a damper. It was really nice to have it set up as they recommended and not have to add spacers myself, although I think offering a baseline for compression/rebound would have been nice.
I'm usually about 215lbs geared up, which Suntour set up at about 105psi with 3 spacers in the fork. I did tell them that I prefer the fork ride high in it's travel for natural terrain (bottoming out your fork off a steep feature is never fun), so I think they may have added another spacer above what they normally do for that. That put me right at about 25% sag, which is a bit more than I'm used to running, but seems to be just right.
Normally, when setting up a fork, I favor things on the firm side of settings, so I approximated the rebound, then set the HSC at 3 clicks and LSC somewhere in the middle. I used my Shockwiz to provide more insight into tuning, which found I was a little on the firm side, which I was happy with.
The first thing I noticed about the fork was how smooth it is. There is almost no stiction in the fork, even the slightest movement causes it to move. This is a contrast to my other forks, which require a little bit of a push to get unstuck on the first compression. The fork remained this way the entire time I owned it, despite some fairly heavy use and little maintenance.
The second thing is the really cool axle system, which I'll cover later.
On the trail:
I have to admit, I wasn't expecting much, but I was really impressed with how well the fork performed. The front end stayed planted and I was able to ride through some sections faster and with more control than with other forks I had tried.
The small bump sensitivity was really noticeable, it soaked up small chatter really well, blowing off on bigger hits really well. Overall, it tracked very well in comparison to the other forks I ran on the same bike.
The fork also remained high in it's travel, in addition to being smooth, which I think is an important feature in forks, especially riding around Pisgah. We have a lot of drops and features that are steep and have to be rolled, if your fork bottoms out on them, then you could be looking at getting tossed off the bike.
I found the Auron stayed high in it's travel except in the most awkward circumstances, which were often my own mistake, even then it remained composed.
I will caveat this: the fork really doesn't do well below 40f, it starts to get really harsh, presumably because the oil in the damper thickens to the point it causes the fork to become noticeable firmer, resulting in effectively more compression and rebound damping. The fork will not perform as well in those circumstances, but that also approaches the point most forks exhibit the same behavior, although they tend to start showing it closer to freezing. I was able to mitigate this somewhat by adjusting the damper settings, though. Most forks have a range of temps where they perform best and the Auron clearly is above 40f.
My Shockwiz gave me a few tuning recommendations, mainly around lowering the LSC and HSC slightly. The adjustments had a clear impact on the way the fork handled, my only complaint is that the HSC setting really needs more adjustment. I found myself needing to be somewhere between 2 and 3 clicks, but with only 5, it doesn't provide a ton of adjustment range. I'd like to see more granular adjustments here.
Regarding the chassis, I weigh 215-220 geared and it was stiff as it needed to be. I couldn't feel any flex, which can be a problem for me with some forks.
All in all, the fork felt better than my Fox 34 and Pike, but not as good as my 36. My new bike requires a shorter offset fork and I'm a bit sad that I have to put the Auron aside, I really like the way it feels and have been really impressed with it's performance.
I've been running this fork for about 4 months and have about 650 miles on it, riding in Pisgah, DuPont, and other WNC trails. In that time, it continues to feel as great as it did the day it came out of the box.
Axle system: The Auron uses a rather innovative axle system called Q LOC. Rather than explain it and be redundant, this video shows how it works:
https://www.youtube.com/watch?v=U8IqJD34Ky0
I really like this system, not much else to say. No threads to strip, fewer weak points in the axle, super easy to use. The only concern is that if you unthread the axle too far, it can fall into pieces, so be careful with that.
Negative Spring
Unlike most other forks, the SR Suntour forks use a negative coil spring on the airspring side. The spring sits below the air piston and provides a similar function to a negative air spring in other forks: providing better sensitivity early on in the stroke and helping overcome seal friction.
Aside from reliability, I'm not certain of the benefits of running a coil there instead of air, but it does pose a few minor issues:
The coil spring is rated for specific air pressure ranges, so if you often make drastic changes in PSI or buy the fork used, you may have to open up the air side and put a new coil in (e.g. The 'soft' spring is for riders running <90 psi).
I would assume, but can't confirm, that running air pressures at the top or bottom range of what the coil is specified for may result in different performance
Use of an air based instrumentation tool, like ShockWiz, requires a bit more work to calibrate, but can be done by inflating the fork to ~35psi to overcome the negative, then running the calibration process.
Suntour provides helpful videos for servicing all of their forks. I consider these minor complaints, but they are worth considering. I much prefer the way DVO handles use of a negative coil, where you can adjust the preload on the coil without having to replace it, which permits granular adjustments for different air pressures and feel without having to open up the fork.
Comparisons:
vs Fox34 - I have a 2017 Fox 34 that I've been running on one of my bikes. The 34 is considerably lighter (~1/2lb), is slightly flexier, but I don't think it has the same feel. The 34 seems to have a fair bit more stiction than the Auron does, lacks the HSC adjustment, and I feel it tends to be a bit less consistent on the damping and doesn't stand up to it's travel as well. All in all, on the trail it's close, but I prefer the Auron. The Auron also seems a bit more firmly damped than the 34 does, providing a wider range of settings for riders of varying weights.
vs Pike - My experiences with the Pike have been overwhelmingly negative. To be fair, I haven't ridden the new (2017+) one, so my experience is a bit limited to older models, but I could never get the Pike to feel as good as my Fox forks. The damping was either too soft or too firm, with no in-between. Air volume, the same way. It's weight is attractive for a 35mm fork, but it seemed to perform very inconsistent.
vs Fox 36 - This isn't really a fair comparison, but I'll add it here anyway. My PUSH tuned 36 was incredible. It has a narrow lead on the Auron, but I'm not sure that's really fair given the purpose of the 36 vs the Auron and the custom tune on the damper. I do wish the Auron had more granular adjustments, like the 36 RC2. These forks fall into different categories, though, and offer different travel ranges, so I'm not sure it's a great comparison.
Pros:
Very smooth, stiction free throughout the time I ran it
The chassis is very stiff for a 34mm fork
Consistent damping performance
Great small bump sensitivity
Rides high in the travel with very little dive
Axle system is innovative and easy to use, once you get the hang of it
SR Suntour's support has been very good when I had questions
Cons:
Performance below 40f becomes inconsistent (moreso than other forks I've owned, everything sucks below freezing)
HSC settings should be more granular
Some complain about the axle system, it seems to be love it or hate it
The use of a negative coil that is not adjustable means that making significant changes in air pressure will require opening the air side to change out the coil, also assuming that performance may degrade with higher air pressures closer to the max rate for the negative spring