Suntour Durolux RC2 29'er
REVIEW

SR Suntour Durolux RC2 29'er Fork Reviewed

Words Andrew Major
Photos Andrew Major
Date Aug 21, 2018

Durolux²

Putting a bunch of hours on the SR Suntour Durolux 29 wasn't at the top of my list. I had plenty of ride time on the 27" R2C2 version, including a full teardown, and it was an okay-turned-good experience when I factored in a handicap for affordability. 

Within a few rides, and after a bit of tuning, I was seeing the Durolux platform in a whole new light. The new RC2 damper is simpler to set up and feels much more fluid than R2C2 I'd ridden previously. In my experience, with three dampers over two forks, it's a huge improvement. 

With fairly open damper settings, lots of progression in the air spring, an über-stiff chassis, and smooth sliding, the simple-to-service Durolux 29'er quickly became one of the best suspension experiences I've had. 

Suntour Durolux RC2 29'er

Plenty of space for a 29x3" Plus tire means that epic mud clearance with a 29x2.4" tire.  

Cam started the test of this fork on his Yeti 5.5 and then was pulled away to another project, so my first step was to drop the lowers, lube up the seals, and lower the travel. One of my favourite features of Suntour's forks is how easy it is to drop the travel, or more accurately the axle-to-crown height, to whatever number I like. Suntour calls this a 170mm, 160mm, or 150mm fork but the truth is that if a custom 29'er dirt jumper product calls for a 100mm 29'er fork that can take a sh*t kicking just keep clipping in spacers. Adjusting travel is a 5-minute job with zero-mess. Once I added a bit of bath oil to the lowers. I ran the fork at 160mm, 150mm, and 140mm travel for this test. 

Suntour Durolux RC2 29'er

The Durolux starts as a 170mm fork and travel is easily reduced by clipping on 1cm spacers. 

Chassis Talk

I'm ambivalent to claims of increasing stiffness for stiffness' sake but when I say the Durolux 29" is the stiffest 29'er fork I've ridden - torsionally and laterally - I truly mean that as a compliment. For heavier riders pushing long travel 29'er forks two issues come up regularly. The first is creaking crown steerer units (CSUs)* and the second is unexpected harshness under certain loads in certain trail situations. An example of one of these situations would be riding fast through technical terrain that's fairly flat relative to a modern long-travel 29'er head angle where a fork feels harsh when called on to telescope. Another is braking hard in steep terrain with a fork high in its travel where suspension seems to have a large increase in stiction. 


*The CSU consists of the stanchions, crown, and steerer tube that are pressed together.

Suntour Durolux RC2 29'er

Thanks to the uppers, the Durolux is the stiffest single crown fork I've ridden. This is much more notable in a long travel 29'er platform compared to riding the 27" version. 

I was talking to James OC, who heads up motorsports service at SuspensionWerx, about this phenomenon and he was quick to theorize that the creaking CSUs that plague many forks in markets with highly technical terrain are actually a symptom of chassis flex. As the stanchions flex rearward under heavy loads, for example braking down steep descents or the front wheel smoking an object at speed, the amount of stiction as they telescope through the bushings in the fork lowers increases phenomenally. 

According to OC the solution is simple. Suck up the extra weight, make the stanchions stiffer, and improve fork performance and resiliency at the same time. It's an easy theory to test with products hitting the market like Fox Racing Shox's 36mm Marzocchi Z-1 and 36A Performance forks which have such thick stanchions they use that brands 34mm internals. The Durolux also meets this criterion. 

Suntour Durolux RC2 29'er

Sitting around 2250 grams the Durolux is a beast and a good chunk of the 200 gram gain over a compartable Lyrik is in the boxy crown and beefy stanchion tubes. 

Going back as far as 26" wheels, SR Suntour has been developing the long-travel Durolux single crown forks and as part of that process they've been tested under some mean-ass riders like James Doerfling, Garett Buehler, Ryan Berrecloth and, of course, Brett Tippie, which means there is a significant chronicle when it comes to durability. 

I put Brett's personal mechanic, Dave McInnes of BicycleHub fame, on the spot regarding his experience with Durolux CSUs. The CSU on one fork made a tiny bit of protest after a year-and-a-half getting Tippied but the noise was ‘barely noticeable by today’s creaky CSU standards’.

I know a few riders frustrated enough with chassis issues that they'll pedal happily carry a little extra weight. 

Tire Clearance

Once removed to give them a good twisting without the crowns and axle, the Durolux lowers don't stand out compared to other forks like the 36 or the Lyrik, suggesting the crowns are the biggest contributor to the fork's impressive stiffness The lowers do however supply an impressive amount of tire clearance. I rode this fork with both a Maxxis DHF 29x3" tire and a 29x3" Bontrager SE4 on a 40mm ID Race Face rim and there is tonnes of daylight all around. With the ease of travel adjust the Durolux is a great option for a rider looking to beastify a mid-fat bike like Trek's Full Stache. 

Suntour Durolux RC2 29'er

Ample clearance to run Plus-size 29'er rubber on a 40mm ID rim. 

Suntour Durolux RC2 29'er

The Durolux air system works well with Plus and regular rubber.  

For most of the test period, I've run more regular sized tires up front as I prefer them in the summer on the Shore when speeds get higher and trails get dustier. I've been running both a 29x2.5" DHF 3c and a 29x2.35" e13 LG1r. 

Negative Spring Swap

The internals of SR Suntour's top-end forks aren't as flashy or expensive looking as the competition but in addition to getting the job done pleasurably, they are easy to work on. And, more importantly, Suntour actively encourages customers to tackle their own service with a range of service videos

Running about 90 psi with the damper fairly open I found the Durolux was extending un-sagged which meant that the coil negative spring was being compressed in its fork-contained war with the air spring. All it takes is a socket set and some Loctite to set that right with a 10 USD negative spring upgrade. Suntour sells a softer and firmer rate on their website and the swap is as simple as dropping the lowers. 

Suntour Durolux RC2 29'er

I run 5cc of oil in each side so it's a good idea to keep the fork level for no spilly-spilly when changing travel or, in this case, the neg spring. 

Suntour Durolux RC2 29'er

In with the old and out with the new. I obviously had a bit of help with the swap but I'm sure I could handle it on my own. 

Suntour Durolux RC2 29'er

10 USD and 10 minutes of time is the input. Improved suspension performance and lower ride height for the same travel is the payoff. 

At about 185lbs I noticed an immediate improvement in the initial characteristics of the air spring in my fork. Suntour ships a medium rate spring but a light is available for riders who don't get full extension at the air pressure they need for their weight. If I had one piece of feedback, I think that Suntour should offer one heavier rate as well. I think the stiffness in a long travel 29'er platform, and performance gains from the stiffness in some situations, is going to attract some large people. 

Suntour Durolux RC2 29'er

Change volume by swapping the spacers from one side of this air piston to the other. 

Damper Improvements

The new, simpler, RC2 damper is a world of improvement over the R2C2 damper in the 27" fork I tested, here. I appreciate that the new model is an easy drop-in piece for existing forks. In addition to being simpler through ditching the external high-speed rebound adjustment, the new damper feels less restricted or more open even with the damper adjusted for more support. 

In my experience, when it comes to damping there are two kinds of animals. The first resembles forks like Fox and X-Fusion that feel quite damped when set-up properly and then open up out on the trail. The other is a fork like this Durolux or a RockShox product that generally likes to be run more open using an increased bar height and fast rebound to keep the rider in attach position. 

Suntour Durolux RC2 29'er

RC2 damper compression controls shown but this photo is actually to show how the stack height. I like to run my bars much higher on more open forks like the Durolux. 

I ran the damper on this fork very open. Out of five positions of high-speed compression (HSC), I ran the knob at one-and-a-half. From open, I had 2-4 clicks of low-speed compression (LSC). The rebound was set fast so the fork could recover and it also helps it ride a bit higher without overpressurizing the air spring or adding a pile of LSC. 

With a regular tire, sag was about 23% when paired with my CCDB Coil shock but I would run more on the front of my hardtail. With the Plus sized SE4 at 17psi, I found running closer to 20% sag, with the same damper settings, made the tire and fork suspension work more seamlessly. 

The chassis provides excellent tracking and the damper and air system work in tandem for optimum traction. The Durolux damper is nowhere near as fancy as other premium-level forks but the fork is fantastic on the trail. 

Axle Analysis 

It's really easy to use, has proven durable, and simplifies production of the lowers but I just can't fall in love with the Q-Loc axle system. Some riders love a quick release but I always ride with tools and I'll gladly forfeit that extra thirty seconds to fish out a 5mm or 6mm hex when changing a tire. I already run a thru-axle out back and I get way more rear flats.

I don't think it would be hard for Suntour to offer an axle and end-nut system to work with all their high-performance Boost forks. Combine that axle system with black-on-black graphics and this fork would look so much meaner & cleaner. 

Suntour Durolux RC2 29'er

The Q-Loc QR can be run with the lever on either side. It's ergonomic to use and tightens easily. 

Suntour Durolux RC2 29'er

The end nut expands to capture the drop-outs and retracts to slide through the lowers and hub axle. 

Final Thoughts

Like every non-Manitou fork on the market, I think an adjustable hydraulic bottom out system would be a winning addition to this fork. In theory, the new RC2 damper is not as adjustable, advanced, or interesting as the previous R2C2 damper but it's easier to set-up while providing a better on-trail experience. 

It's easy to adjust air volume and adjust travel. Comparatively, every service job on the Durolux is easy and requires few, if any, specialty tools other than a flush-face socket. I'd love to see Suntour follow other brands and switch both top caps to be compatible with a Shimano cassette tool. 

Suntour Durolux RC2 29'er

The Durolux 29'er uses post mount 180mm tabs so a 7"/180mm rotor can be used with the caliper mounted directly to the fork.

At 750 USD, or just under a grand Canadian, this is still a premium fork and if I had to pick some upgrades I'd like to see the aforementioned tool-required axle system and some fresh black-on-black graphics.

Even putting the price aside, the Durolux is one of the best suspension fork experiences I've had. As of today if I was buying a long travel 29'er fork, this would be the one. The ride quality is superb. It has a solid chassis, the finish is durable, parts support is good, it's highly adjustable, and it's a big improvement over the previous model thanks to the fresh damper.

Add in the price, the reputation for creak-free CSU performance,  and the fact that it's easy to work on at home and I think the 29'er Durolux, with the new RC2 damper, is a great long-travel option for most riders. 

For more information please check the Durolux 29'er here

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Comments

Zapp
+2 Andrew Major James Vasilyev
Zapp  - Aug. 21, 2018, 7:07 a.m.

Nice option! Wish my Lyrik had that much clearance. Hate to be that guy, but are we going to see a review of the Wolf Tooth Headset?

Reply

AndrewMajor
+1 Zapp
Andrew Major  - Aug. 21, 2018, 8:03 a.m.

Hi Zapp,

I've done a first look of the Wolf Tooth headset, here, and have a lot of hours on it but I would like to take it through part of the rainy season so I can comment more fully on the oversize aluminum crown race with built-in quad seal. Thus far it has done a remarkable job of keeping crap out of the lower-bearing and crown race interface but it hasn't seen many rainy rides. 

I'm happy to answer any questions that you have.

Reply

Zapp
+1 Andrew Major
Zapp  - Aug. 21, 2018, 8:41 a.m.

Oh that sounds great! Totally understand wanting to be thorough. None of my headsets are  due for a replacement *knock-on-wood* but I've had my eye on the Wolf Tooth for when one eventually goes. Should hopefully be after the rains end.

Reply

irollones
0
Chris Makin  - July 28, 2019, 11:32 a.m.

I've taken a WT headset through a British Winter and it scored top marks. top. marks.  for keeping crap out and keeping everything running smooth

Reply

Shinook
+1 Andrew Major
Shinook  - Aug. 21, 2018, 7:14 a.m.

My Auron RC2 PCS is the best fork I've owned out of Pikes, 34s, 36s and several MRP options (although I love MRP, I feel the Auron was a little smoother, both MRP forks I've owned would be a close second). I'd have one on my bike now but they don't offer reduced offset versions yet.

The only downside I can find is the weight and the fact people look at you funny when you tell them that you chose a Suntour fork for your bike. It's really a shame that Suntour's brand identity is so wrapped up in the low end products, because their high end forks are really awesome. I constantly tell people how awesome they are, but the reaction is disbelief every time purely because of the brand name. 

I also agree with the HSC tune on the RC2 damper, it's too firm IMO, and should be softened some so that riders can have the dial a little closer to the mid point with adjustment up/down. It's a minor gripe because running it between 1-2 works just fine, but especially being a heavier rider, I prefer to see it a little closer to the middle with more adjustment range.

Reply

AndrewMajor
+1 Shinook
Andrew Major  - Aug. 21, 2018, 8:09 a.m.

The weight I can easily justify, like X-Fusion they could certainly use a bit of a graphic update to help build the identity of their top-end products. If in doubt black-on-black graphics always look snazzy!

It's interesting riding the Durolux vs. the X-Fusion Trace 36 I'm on right now. The way I have the Durolux set in the parking lot is how it feels on the trail. The Trace is like a Fox fork where it will feel a little overdamped just gumby'ing around but it comes alive when actually riding the bike. Especially true of rebound damping. 

I think the HSC and LSC range of the Durolux would make sense if they translated to that Fox/X-Fusion experience but whether it comes down to air volumes, chassis, damper architecture or some combo of the three it really does feel amazing when it's run almost wide open. 

Without taking price into consideration the Durolux would certainly still be on my short list of forks to buy for myself. Once I look at the savings a Durolux and some fresh rubber and etc has traction.

Reply

davidt93
+1 Andrew Major
David Tran  - Jan. 18, 2019, 5:12 a.m.

After the review decided to place an order(18 eofy sale for 525usd) . Coming from a lyrik with luftkappe, i can honestly say that this fork rocks!!! the Initial plushness isn't the same as the lyric but it makes it up everywhere else( might do abit more tweaking). At the price i paid, i don't believe the other forks charging double are twice as good.

Reply

AndrewMajor
+1 David Tran
Andrew Major  - Jan. 18, 2019, 9:25 a.m.

If you haven’t already, drop the lowers, Slickoleum the seals heavily (excess will purge next 1-2 rides) and put 5-7ml of fork oil in each side. It will butter up that initialization quite a bit!

Enjoy!

Reply

pedalhound
+1 Andrew Major
pedalhound  - Aug. 21, 2018, 1:17 p.m.

I love my Auron too..best for I have ever owned. I have the same wish though, I run my HSC wide open, it would be nice to have more adjustment there.

Reply

AndrewMajor
0
Andrew Major  - Aug. 21, 2018, 1:20 p.m.

All I can say today is stay tuned :-)

Reply

envelo
0
envelo  - Aug. 21, 2018, 2:05 p.m.

Great in depth review of the Durolux and it's right in line with our experience as well.  

A couple other cool features that we like are the custom mini fender and the oil service holes.   Guessing the fender didn't come into play because of how dry the conditions are but rainy season and those are nice to have and look better than zip tied types.   The oil holes on the back of the lowers are great for just adding 1-2cc of oil on the foam oil wipers on occasion to make everything run smooth in between full lower service.  Also if spending a day in the bike park you can crack them open in case any air builds up in the lowers.   It's a cleaner solution than sticking a zip tie in the seals. 

There is an extra firm negative spring (SR Suntour part# FEP744) that we've mostly used to set up the 26" versions for slope/DJ use.   It takes about 140 psi to move the fork out to full travel with that spring.   Out of stock currently but we have them on order.  

Envelo has the Durolux Boost 29" for $700 USD.   If you prefer to go through a local retailer we also do dealer sales.

Reply

AndrewMajor
0
Andrew Major  - Aug. 21, 2018, 2:10 p.m.

Cheers!

The fender is very clean (no zip-ties, ties in nicely with fork) but could certainly be longer. As you state, I haven't had much call to use it but I will be looking at a few small fenders when the rain comes back and should definitely talk about this one at the same time (thank you)

I hadn't considered the need to burp air out of the fork (not an issue I've come across) and never took advantage of the oil holes as it is so easy to drop the lowers on this fork and clean out the seals at the same time. SR Suntour's QSP is a great design philosophy. 

Great to know re. the extra firm spring! Thanks!

Reply

davidt93
0
David Tran  - Dec. 25, 2018, 12:27 a.m.

This comment has been removed.

Losifer
0
Carlos Matutes  - April 10, 2019, 1 p.m.

Sorry for reviving an old review, but I just want to clarify your negative spring replacement. The way I read it, you replaced the stock “medium” spring for a “heavy” spring?

Reply

AndrewMajor
+1 Carlos Matutes
Andrew Major  - April 10, 2019, 1:18 p.m.

Hi Carlos,

No stress. Yes, I went from the stock ‘medium’ spring up one rate. There is an extra-firm option as well.

Reply

Losifer
0
Carlos Matutes  - April 10, 2019, 2:53 p.m.

Thanks for the quick reply! Considering a Durolux on my Chromag Rootdown- any qualms about running one on a hardtail?

Reply

AndrewMajor
0
Andrew Major  - April 10, 2019, 5:03 p.m.

No qualms at all. I've ridden the Durolux at a range of travels from 140mm to 170mm on FS bikes and hardtails, including 170mm on my Honzo ST with a -2° Works angleset. It's a great, very tunable, fork.

Reply

Verbl_Kint
+1 Andrew Major
Kent Saga  - April 12, 2019, 10:04 a.m.

Just bought a 29 RC2 for the princely sum of US$380. I haven't taken it out on the trails yet but I did do a road test at a nearby university. When going down some stairs it makes a really loud squeaky noise. Is this normal? How do I remove it?

Also, anything I need to do on the fork before I take it to the local DH track? 

I weigh 140 lbs kitted up, in case that info is needed. Should I order the lighter spring?

Reply

AndrewMajor
+1 Kent Saga
Andrew Major  - April 16, 2019, 12:04 p.m.

Hi Kent,

Depending on the amount of sag you intend to run I’d guess the stock neg Spring is perfect. They’re really inexpensive though, so no reason not to try both.

Do you have the R2C2 or the RC2 PCS damper?

Does the sound happen in all damper settings (rebound + compression)?

If the sound’s consistent then I’d assume the fork’s just been sitting a long time and drop the lowers (super quick job) and lube it up with Slickokeum.

If it’s an R2C2 fork and the noise changes based on damper settings I’d talk to your nearest service centre (envelo, SuspensionWerx, etc). If you read my last R2C2 review, I encountered a similar issue. 

Hope that helps!

Reply

Verbl_Kint
0
Kent Saga  - July 26, 2019, 12:37 a.m.

Checking back in after a couple of months. 

I have the RC2 PCS damper.  The squeaking was just on the rebound settings.  The faster the rebound, the louder the squeak.  I was basically the laughing stock of my buddies for an entire day at the DH track. It sounded like I was pounding a mouse to death at the rock garden. 

I had it warrantied that evening (thanks, Decimal Cycles!) and the replacement still had a bit of a squeak but not as scandalously loud as the first one, and only on the fastest 4-5 clicks of rebound. 

Outside of the noise, this is a great fork.  I was essentially thinking this to be something to tide me by until the Lyrik Ultimate arrived.  The Ultimate has been here a month now and I'm still hesitant to upgrade.  One adjective that I could describe this fork is sure-footed, it will allow you to go where you want it to go.  It is as close as it gets to riding a dual crown 170mm fork.  After you get the settings dialed, you will hardly notice that it's there.  This is absolutely great value for US$380 (the Lyrik is about US$1000 here). 

Will do a lower leg service in August and will also reduce the travel to 160mm to see how that works out.

For reference, I'm about 140 lbs, riding a Kona Process 153 mullet build (using a 29r frame). 

Spring rate: 70 psi with only 1 volume spacer

Damping (clicks): Rebound is 14/25, HSC is 2/5, LSC is 4/17

Reply

eduguy
+1 Shinook
eduguy  - July 4, 2019, 10:57 p.m.

I just bought one of these except in the 27.5 version and I'm trying to figure out how to swap the negative air spring, as the stock one is too strong for me. Your review didn't go too in depth into the process, so I'm wondering how exactly you did it. I watched the SR Suntour video, but I still have a few questions. What exactly is securing the springs onto the rod? I'm guessing something needs to be removed before you can swap the springs. Also, in the official video, they use a vice to clamp the rod down. Is that necessary, in your experience?

Thanks in advance!

Reply

Shinook
0
Shinook  - July 25, 2019, 10:19 a.m.

SR Suntour has great support, I'd shoot them an email and I'm sure they'll get any questions you have answered.

Reply

Shinook
+1 Andrew Major
Shinook  - July 25, 2019, 10:19 a.m.

As I stated in a previous comment, I've got experience with the Auron, but not the Durolux. I'm looking for a new fork for my Sentinel and debating between this, the GRIP2 36 PE, and soon-to-be released Mezzer. I'm on a Helm currently.

I'm curious if you've had a chance to compare the Durolux RC2 to the GRIP2 or the other forks (Helm, Mezzer)? I've heard such good feedback about the GRIP2, but yet to ride one, although being a heavier rider on more aggressive terrain, the chassis stiffness of the Durolux is tempting. 

My main concern is the a2c on the Durolux is ~10mm longer than the 36, which is going to slack the bike out some (although Fox's spec sheet says +-5mm, so maybe it's not as big of a difference). I also know that with my Auron, I ended up running closer to 25% sag vs the 20% I typically run with Fox, so it may balance out some. I had such a good experience with my Auron that it's tempting to try out. Sadly, their demo program doesn't have the 29 Durolux or the reduced offsets :(

Reply

AndrewMajor
+1 Shinook
Andrew Major  - July 25, 2019, 6:50 p.m.

I think one important factor to consider is where the extra 1cm of a2c comes from on the Durolux which is larger the steerer tube overlap at the crown. Considering how many different forks are having issues with the crown-steerer interface I think this is a worthwhile tradeoff given my experiences with the Durolux chassis. 

A fresh GRIP2 fork feels wicked. Personally, I much prefer the FIT-RC2 (or FIT-4) forks for a couple of reasons. 

1) It's much faster and easier to do a basic lower service and you only have to capture and recycle <30ml of oil in the process.  A home mechanic can get 1-2 basic services out of a set of the SKF seals without touching the damper or air system before the fork is due for a 100hr service. 

2) The sealed damper in the FIT (Bladder) system - also true of Charger, X-Fusion HLR, Suntour - isn't cycling bath oil so there's no breakdown caused by contaminants or contact with internal surfaces. Ride a GRIP fork and a FIT fork for 50 hours and then dump the damper fluid from both into a container and you'll see what I mean. It's a give and take and given I don't service my stuff super regularly I'd personally go FIT if I was buying a Fox fork. 

Hope that's helpful!

Reply

Shinook
0
Shinook  - July 25, 2019, 8:12 p.m.

Thanks for the reply!

The ingestion of bath oil in the GRIP dampers has been a bit puzzling to me, it seems like a really bad idea esp. considering how filthy most of the bath oil in my lowers typically is. I do a pretty good job of servicing it, but it still ends up with a lot of debris. I've heard a lot of really good things on the way the fork feels, though, and I've yet to ride one.

I am not completely opposed to the weight or a2c. It seems like my Auron seemed to do best ~25% sag and my current fork is closer to 20, by the time I add that 5%, the fork will be sitting lower anyway. 

I guess I'm trying to get more of a ride feel comparison between the Durolux, GRIP2, and the Helm currently on my bike. Any insights as to the on the trail feel between those three?

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