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SR Suntour Auron Fork

Vital Rating: (Very Good)
SR Suntour Auron Fork 2014 SR Suntour Auron Fork
C70_2014_sr_suntour_auron_fork C70_2014_sr_suntour_auron_fork C70_2014_sr_suntour_auron_fork C70_2014_sr_suntour_auron_fork
Vital MTB Retail Partners:
Chain Reaction Bicycles Jenson U.S.A. Competitive Cyclist Backcountry

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Vital Review

“Tested: 2014 SR Suntour Auron RC2 Fork”

Review by Evan Turpen // Photos by Dave Trumpore

Last year I had the opportunity to test my first ever SR Suntour suspension product in the form of the 32mm Epicon-X1 trail/XC fork. The fork showed a lot of promise, especially at its $599 price point, and it left me pondering the potential for future SR Suntour products as more time and energy was put into development.

When I first heard of the 34mm Auron fork I was excited to give it a try. At 150-160mm of travel it suits the bikes I enjoy riding most these days - they're much closer to their downhill ancestors than XC. Because of this I personally prefer high and low-speed compression adjustments over pre-set compression or lock-out adjustments on my fork. I feel that these downhill oriented dampers really help eek out the most performance from a bike when pushed hard, and the new Auron, with its RC2 damper, seemed like it might just do the trick. Well, after two months on all types of terrain and in all kinds of conditions it's time for you to find out how I got along with this sub 4.5-pound, $700 fork during our time together.

2014 Auron RC2 Fork Highlights

  • 27.5-inch wheel size
  • 34mm stanchions
  • 150/160mm travel (adjusted internally)
  • External rebound, low-speed compression, high-speed compression and air pressure adjustments
  • Internal travel and air volume adjustments
  • QSP (Quick Service Product) sealed hydraulic cartridge damper
  • Progressive air spring system
  • Magnesium lowers
  • Forged hollow alloy crown
  • Alloy tapered steerer 1 1/2 to 1 1/8-inch
  • Integrated brake cable guide
  • 15mm Q-LOC2 axle
  • Disc post mount for 160mm rotors
  • Weight: 2018 grams / 4.45-pounds (27.5-inch 160mm option, full-length tapered steerer with 15mm axle)
  • Available in black or white
  • MSRP $700 (RC2 Model)

Setup And Initial Impressions

Installing the Auron on my Santa Cruz Bronson was no different than any other fork I’ve installed in the past except for two small details. First off, the integrated front brake cable guide which utilizes a mount like what you’d find on an external cable routed frame. You can simply use a zip tie or the included fancy looking cable clamp that snaps into place to secure your hose. This is a nice feature, and although it's not as fancy as other forks, it's simple and effective and absolutely bombproof with no tiny threads to strip out or proprietary cable guides to lose.

The second detail worth noting was the steerer tube. I work as a mechanic at a high-end bike shop and we cut steerer tubes quite often. Never have I experienced a steerer tube this difficult to cut through! I had to check the hack saw blade to make sure it wasn’t worn out, and it turns out it had just been replaced recently. It was pretty confidence inspiring knowing that the steerer tube isn’t made out of sub-par materials. No corners cut here!

After the fork was installed it took me a little while exploring air pressure and adjustment knobs before finding a ballpark setting to start my test. The RC2 Auron uses a single schrader air valve to adjust air pressure on the top of the left side of the fork. On the top of the right side are two knobs that independently adjust both high and low-speed compression. Last, but not least, is the rebound knob located on the bottom of the right side of the fork. All adjustment knobs turn fluidly and have clearly defined clicks. Although not audibly loud, they can be distinctly felt while turning the knobs. The rebound and high/low-speed compression adjustments are very effective and have a broad range making it easy to dial in the fork for different rider weights and riding styles.

On The Trail

First impressions of this fork are that it is light, stiff, and has a very controlled feeling. Weight wise, the fork weighed in at 4.45-pounds with an uncut steerer. That shaved nearly a quarter of a pound off the front of my bike compared to the 2014 Fox Float CTD 160mm travel fork it replaced. Not bad.

Stiffness and steering is best in class for a 34mm fork with a 15mm axle in my opinion. I'm not sure what SR Suntour did to achieve this, but the front end always felt precise and I never found myself wishing for a 20mm axle. Suntour should also be commended on the execution of the Q-LOC 2 quick release system which in addition to being solid is also very fast and easy to use.

The RC2 damper does a great job of offering simple and effective adjustments to its behavior on high- and low-speed impact events respectively. I did however find myself backing off the high-speed compression adjuster much more than I would with other similar dampers. Early in the test period I found myself all the way out on the high-speed compression adjuster yet still wishing for a more forgiving ride over choppy fast terrain. On really big hits I also noticed that I was only using about 85% of the available travel which I suspected was caused by the air volume reducer creating a too progressive spring rate.

After much experimentation I eventually settled on 5psi less air pressure with approximately half of the 35mm foam air volume spacer removed. This allowed for more sensitivity off the top, decent mid-stroke support, and just enough ramp at the end to cushion the hardest of impacts. With the air spring working as well as possible I was now able to focus solely on how the fork handles the trail.

The action of the fork is smooth, but not entirely buttery. There is some stiction, which I feel might be coming from the bushings. The high/low compression and rebound adjustments are very effective, but I feel like the base tuning is off (excluding rebound). With fully closed low-speed compression and almost fully open high speed compression (2 out of a total of 12 clicks) I still found myself wishing for more low to mid-speed support with more forgiving action at really high-speed and high-frequency bumps. This is something that SR Suntour could perhaps achieve with shimstack tuning, high-speed compression spring adjustment, or the addition of a mid-valve.

To sum up my ride impressions, this fork is without a doubt targeted more at the aggressive rider who pushes hard and isn’t necessarily looking for the most forgiving and plush ride. Small bumps are at times felt through the bars more than I‘d like, most likely caused by the slight amount of stiction at the top of the stroke. Medium to large hits are where this fork shines. With proper setup the fork won’t let you down in rough, steep, and gnarly sections, but it won’t blow you away either. It simply gets the job done in a controlled manner without complaints.

Things That Could Be Improved

RC2 Damper: No matter what I did, it never felt like I could make the damper function exactly the way I prefer. I’d like to see the damper re-tuned with increased low to mid-speed compression yet drastically decreased high-speed compression. Basically I felt it could benefit from more support with less harshness when things get really fast and rough. Less rebound noise would be nice as well since it could be loud at times, especially when getting airborne.

Seals: Although much improved over the Epicon fork I tested in the past, the seals still seem to weep lubrication a little more than I’d like to see.

Air Spring: The air spring’s negative coil springs can occasionally be heard rubbing/binding slightly as the fork is compressed and extended. I personally would like to see a more refined air spring straight out of the box that is quieter and doesn’t require air volume spacer adjustments to get a proper feel, at least initially.

Air Volume Adjustment: The air volume adjustment comes in the form of a removable/cuttable yellow foam spacer under the top cap. Once you remove material from the spacer, there is no way of putting it back. It would be nice to see a system that allows for infinite adjustability through multiple removable spacers like on Suntour's RUX downhill fork. If not this, then at least ship the Auron with a few foam air volume spacers of different lengths to cover the adjustment range.

Tire Clearance: Although never an issue during the test, the clearance between the arch and tire is pretty tight. This could definitely be an issue if your riding conditions include sticky mud.

Long Term Durability

The Auron is definitely in it for the long haul. Our fork performed flawlessly with no degrading of its performance throughout the test period. In fact, the fork only seemed to get better the more it was ridden and as things broke in. No creaky crowns here! Although more time is needed to know for sure, all signs point towards a fork that will last as long as you need it to given proper maintenance and care is taken along the way.

On that note, with a stated 300-hour service life, the damping cartridge should rarely need to be serviced. The lowers, however, need to be cleaned and lubricated at 50 hours or less. Luckily this is a relatively easy 10-20 minute job. Because it's a sealed cartridge system, there is not a lot of messy oil to deal with during the quick cleaning process. The fork has felt wipers that hold oil for lubrication of the lowers/stanchions, and it's easy enough to clean them and dunk them in fresh oil before re-assembling the fork. Note that you can also add 20-30cc of synthetic oil in the lowers for additional lubrication if you so desire, which can improve how smooth the fork feels. Suntour has a helpful series of tech videos to help walk you through servicing your fork should you be up for a little DIY action.

What's The Bottom Line?

The Auron is a stiff and light 150-160mm travel trail/enduro fork that gets the job done. It’s not flashy, it’s not awe inspiring, but it wont let you down. With small changes here and there, mostly to the RC2 damper, SR Suntour could have a real winner on their hands. At the moment this would not be my pick of the crop if I was looking for the absolute best performing suspension on the market, but at $700 it is a very viable option and it will offer great value for money for many riders seeking a reliable and highly adjustable option. We'd also add that SR Suntour just recently hired Eric Carter to work on product development, and we look forward to seeing where his influence will take their products in the near future.

Check out EC giving the Suntour Auron a hard time in the video above.

For more info visitwww.srsuntour-cycling.com.


About The Reviewer

Evan Turpen has been racing mountain bikes for over 12 years. He raced downhill as a pro for the last 8 years with his career highlight being selected to represent the U.S. in the 2006 World Championships. More recently he can be found competing in enduro races and having a blast with it. His first ever enduro event being the 2012 Trans-Provence 7-day adventure race through France. He is an aggressive yet smooth rider who loves to flick the bike around to put it on the fastest line or to smooth out the rough sections. Fast flowy trails and long technical descents (Garbanzo style) are his favorite. Whistler and Santa Cruz are his two most favorite places to ride, but he can have fun wherever he goes. With an extensive knowledge of the mountain bike industry and its technologies, Evan is able to take all things in to perspective during a review. He has helped design, develop, and test products for multiple major mountain bike companies and has an attention to detail well above most. When he's not out ripping around on a bike he helps run the recently introduced California Enduro Series and is also in charge of the bike park at China Peak Mountain Resort.

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Vital MTB Retail Partners:
Chain Reaction Bicycles Jenson U.S.A. Competitive Cyclist Backcountry

Specifications

Riding Type Trail
Travel 150mm, 160mm
Spring Type Air Spring Cartridge
Damping RC2 Low and High Speed Compression and Rebound Adjust Cartridge
External Adjustments Progressive Air System with Preload Adjust
Crown Single, Alloy
Axle 15mm Q-LOC Through / Disc Only Design
Brake Mounts Disc: Post Mount Type for 160mm Direct Mount
Steer Tube Diameter 1.5" to 1-1/8" Tapered
Steer Tube Construction AL7050 CTS
Stanchion Diameter 34mm
Colors Black or White
Weight

4 lb 2.3 oz (1.9 kg)

Miscellaneous For 27.5" Wheel Size // Fork Length: 550mm // 15mm QLOC Axle Included (AX9- QLC15-110)
Price $700.00
More Info SR Suntour Website
Vital MTB Retail Partners:
Chain Reaction Bicycles Jenson U.S.A. Competitive Cyclist Backcountry