SR Suntour Durolux 29 Fork - Review
There's no shortage of burly, long-travel 29ers these days, which is why SR Suntour decided to release a big-wheel compatible version of their air-sprung Durolux fork. We first spotted the fork at the Taipei Cycle show earlier this year, but the new addition is now officially on the market, with a retail price of $800 USD. That's still not inexpensive, but it will leave a couple hundred extra dollars in your wallet compared to a top-of-the-line fork from the likes of Fox or RockShox.
SR Suntour Durolux R2C2
• 36mm stanchions
• Air-sprung
• R2C2 sealed cartridge damper
• 15x110mm thru axle
• Clearance for 29 x 2.6" tires
• Hollow forged aluminum crown, magnesium lowers
• 150, 160, or 170mm of travel
• 2,220 grams
• Price: $800 USD
• www.srsuntour-cycling.com
That cost savings does come with a weight penalty to match, and the Durolux weighed in at a slightly portly 2,220 grams on our scale, or roughly 200 grams more than a Fox 36 Float. Of course, weight isn't everything if that extra heft comes with a performance advantage, but you'll need to skip ahead to the ride impressions to see how the Durolux held up.
SR Suntour Durolux R2C2
• 36mm stanchions
• Air-sprung
• R2C2 sealed cartridge damper
• 15x110mm thru axle
• Clearance for 29 x 2.6" tires
• Hollow forged aluminum crown, magnesium lowers
• 150, 160, or 170mm of travel
• 2,220 grams
• Price: $800 USD
• www.srsuntour-cycling.com
That cost savings does come with a weight penalty to match, and the Durolux weighed in at a slightly portly 2,220 grams on our scale, or roughly 200 grams more than a Fox 36 Float. Of course, weight isn't everything if that extra heft comes with a performance advantage, but you'll need to skip ahead to the ride impressions to see how the Durolux held up.
The blue dial adjusts the fork's high-speed compression damping, and the smaller grey knob provides 17 clicks of low-speed compression adjustment.
High- and low- speed rebound are adjusted via the dials found on the bottom of the right leg.
Construction
Like its 27.5" sibling, the Durolux 29 has 36mm stanchions and uses SR Suntour's R2C2 damper, which has externally adjustable high- and low-speed compression damping, along with high- and low-speed rebound damping. It also uses a coil spring-backed internal floating piston (IFP), eschewing the bladder style dampers that have become increasingly common in favor of simplicity and ease of maintenance. The sealed damper cartridge design of the R2C2 means that it can easily be removed for service or replacement – if a shop had a replacement cartridge in stock it would only be a matter of minutes before a customer was up and running again.
Plastic spacers above the coil negative spring can be added or removed relatively easily to adjust the fork's travel in 10mm increments.
Volume spacer slide onto the underside of the air spring top cap to increase or reduce the amount of end-stroke ramp-up.
The air spring is located on the left side of the fork, where the of end-stroke ramp-up can be altered by adding or removing up to three plastic spacers. Fewer spacers creates a more linear feel, and adding more increases the amount of bottom-out resistance. It's also possible to change the Durolux's travel, and while it does involve removing the fork lowers it's still an extremely simple procedure – the same air shaft is used for all travel configuration. By adding or removing the black plastic discs that sit above the negative spring the fork can be set up with anywhere from 150mm all the way up to 170mm of travel in 10mm increments.
There are lots of forks out there that have screw holes on the back of the crown, but there's a distinct lack of fenders to go with them. SR Suntour's fender is nicely integrated and looks much better than wrapping four zip ties around an expensive fork. The one part of the fork that's a little odd are the two bolts that stick out from the middle of the lowers – it turns out they're for mounting a full fender on the European e-bike version of the fork. Apparently, e-bikes have different fender needs than regular bikes – who knew?
Although it's a little fiddly at first, with some practice operating the Q-Loc II thru axle becomes second nature. Personally, I'd like to see the option of a bolt-on thru axle added into the mix.
The Durolux can accommodate up to a 29 x 2.6" tire; the integrated fender is a nice touch.
On the Trail
Air spring: The Durolux's beginning stroke sensitivity was excellent right out of the box, with no break-in period required. After some experimentation, I settled on 70psi in the air chamber, with one volume spacer installed for my 160-pound weight. The air spring does ramp up more quickly than I'm used to – even without any spacers there's a distinct difference between the first half of the travel and the second half. I'd rather have the progression begin a little later in the stroke, or take place more gradually, in order to make the most of the 160mm of travel.
Damper: This is where the Durolux's performance pales in comparison to similar options from RockShox or Fox. Partway through my second ride, the fork began to act erratically, delivering a harsh, almost locked-out feeling whenever a rapid succession of bumps was encountered. The first few impacts would be absorbed without any issue, but then the next impact would be incredibly jarring, and a couple of times I was afraid my hands were going to blow off the grips. In short, a far from ideal sensation.
I sent the cartridge back to SR Suntour, and they discovered that the high-speed rebound shims had started to bend, which meant that not enough oil flow was occurring during those quicker hits, in turn causing the harshness I had experienced. Not willing to write off the Durolux completely, next I installed a replacement R2C2 cartridge that SR Suntour had fitted with a higher flow rebound piston. Unfortunately, the same rebound issue occurred – the fork still couldn't keep up with multiple impacts in a row, and the erratic nature of the issue made it difficult to feel confident charging into rough sections of trail.
As a final step, I swapped to an RC2 PCS cartridge, which uses a fixed, shim-based rebound piston design. This made a significant difference, and there was a welcome return to a more consistent feel out on the trail. Except for one thing - the noise. Now, SR Suntour's forks have always been on the louder side of things, and while I'd rather have complete silence, I can handle some squelching / squishing noises. The key word there is 'some' – the noise with this cartridge was louder than anything I'd experienced before.
![Suntour Durolux 29]()
Once again, it was time for some tinkering. SR Suntour sent out a small spring, which I installed into the damping cartridge, stacking it on top of the spring that was already in place above the internal floating piston (IFP). The theory was that by altering the position of the IFP, the cavitation noise would be reduced. That did the trick, and although the fork was still louder than a Fox or RockShox, it was much more tolerable out on the trail.
With the RC2 PCS cartridge installed and the additional spring above the IFP the Durolux's manners improved significantly – the rebound issues were gone, and repeated impacts were handled without any surprises. As a whole, the performance was much more predictable, and if given the choice I would pick the RC2 PCS cartridge over the R2C2 every time. Going with that cartridge also drops the total cost down to $700, although I'd still say that the RockShox Yari or a GRIP damper equipped Fox 36 still have the edge at that pricepoint.
SR Suntour's Response: "SR Suntour would like to thank Pinkbike for their in-depth testing and honest evaluation. The R2C2 cartridge has been ridden and evolving for 2 years now under toughest conditions. It has seen multiple WC DH wins, Rampage wins, Megavalanche wins and NAET overall titles.
However, technologies on such a level can fail sometimes and we have realized it is not perfect. Its long-term performance is not meeting our goals and we are immediately seeking the reasons and will relaunch once solutions exceed those goals. We believe the RC2 PCS platform is solid and reliable, we are looking at reducing the possible noise. Customers with R2C2 forks/ cartridges please contact one of our global service centers or via Facebook or Instagram for a tuned replacement."
Pinkbike's Take:
Air spring: The Durolux's beginning stroke sensitivity was excellent right out of the box, with no break-in period required. After some experimentation, I settled on 70psi in the air chamber, with one volume spacer installed for my 160-pound weight. The air spring does ramp up more quickly than I'm used to – even without any spacers there's a distinct difference between the first half of the travel and the second half. I'd rather have the progression begin a little later in the stroke, or take place more gradually, in order to make the most of the 160mm of travel.
Damper: This is where the Durolux's performance pales in comparison to similar options from RockShox or Fox. Partway through my second ride, the fork began to act erratically, delivering a harsh, almost locked-out feeling whenever a rapid succession of bumps was encountered. The first few impacts would be absorbed without any issue, but then the next impact would be incredibly jarring, and a couple of times I was afraid my hands were going to blow off the grips. In short, a far from ideal sensation.
I sent the cartridge back to SR Suntour, and they discovered that the high-speed rebound shims had started to bend, which meant that not enough oil flow was occurring during those quicker hits, in turn causing the harshness I had experienced. Not willing to write off the Durolux completely, next I installed a replacement R2C2 cartridge that SR Suntour had fitted with a higher flow rebound piston. Unfortunately, the same rebound issue occurred – the fork still couldn't keep up with multiple impacts in a row, and the erratic nature of the issue made it difficult to feel confident charging into rough sections of trail.
As a final step, I swapped to an RC2 PCS cartridge, which uses a fixed, shim-based rebound piston design. This made a significant difference, and there was a welcome return to a more consistent feel out on the trail. Except for one thing - the noise. Now, SR Suntour's forks have always been on the louder side of things, and while I'd rather have complete silence, I can handle some squelching / squishing noises. The key word there is 'some' – the noise with this cartridge was louder than anything I'd experienced before.
Once again, it was time for some tinkering. SR Suntour sent out a small spring, which I installed into the damping cartridge, stacking it on top of the spring that was already in place above the internal floating piston (IFP). The theory was that by altering the position of the IFP, the cavitation noise would be reduced. That did the trick, and although the fork was still louder than a Fox or RockShox, it was much more tolerable out on the trail.
With the RC2 PCS cartridge installed and the additional spring above the IFP the Durolux's manners improved significantly – the rebound issues were gone, and repeated impacts were handled without any surprises. As a whole, the performance was much more predictable, and if given the choice I would pick the RC2 PCS cartridge over the R2C2 every time. Going with that cartridge also drops the total cost down to $700, although I'd still say that the RockShox Yari or a GRIP damper equipped Fox 36 still have the edge at that pricepoint.
SR Suntour's Response: "SR Suntour would like to thank Pinkbike for their in-depth testing and honest evaluation. The R2C2 cartridge has been ridden and evolving for 2 years now under toughest conditions. It has seen multiple WC DH wins, Rampage wins, Megavalanche wins and NAET overall titles.
However, technologies on such a level can fail sometimes and we have realized it is not perfect. Its long-term performance is not meeting our goals and we are immediately seeking the reasons and will relaunch once solutions exceed those goals. We believe the RC2 PCS platform is solid and reliable, we are looking at reducing the possible noise. Customers with R2C2 forks/ cartridges please contact one of our global service centers or via Facebook or Instagram for a tuned replacement."
Pinkbike's Take:
 | Unfortunately, at this point in time I can't recommend the Durolux 29 R2C2 as a viable option for riders looking to upgrade their current suspension. Its performance simply doesn't measure up to the other contenders currently on the market that weigh less and offer quieter, more consistent performance. |
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While I have not used the R2C2 damper, the RC2 I had in the past worked great, and reviews everywhere else have verified that the Durolux RC2 is a viable alternative to the top two brands. I just wish I could find more of it in my country.
I recently bought a Norco with a coiled zeron that I am quite enjoying and I also have a trek fuel ex 8 with a float 32 fit4 cartridge that I want to change the fork on... Wondering if that's still possible?
I was going to take advantage of the dytd fork trial from your website but going to wait till the snow melts first so I can give it a proper trial.
It's hard to tout a convoluted conspiracy theory about advertising money in reviews for forks when the much simpler explanation (supported by community opinion) is that the most commonly used products provide the highest value per dollar.
I do agree with you on the vast majority of riders being on the top two for a good reason, but there are financial, performance and reliability alternatives that are just simply better choices.
www.jensonusa.com/Dvo-Diamond-29-Fork
Well said sir. well said.
No mention in the reviews however.... just saying...
Few things.
1) I'm bigger than Mike at 200 pounds.
2) I too found the RC2 damper to be more to my liking than the R2C2.
3) I did not find any additional noise to the RC2 damper, though both are louder than a bladder based RS/Fox damper.
4) I ran the fork in a shorter travel configuration (one reason I found the air spring to be a bit more linear than he did)
5) I found the fork, specifically in the RC2 configuration, to be a very viable competitor to the Fox Elite GRIP damper, and at $100 less.
6) The service ports are a nice touch.
7) The chassis is stiffer than just about anything out there.
Had I only reviewed the original R2C2 damper, I would have similar thoughts overall. But the updated damper was good for those with a propensity for a firmer ride and the RC2 a diamond in the rough.
Just wanted to chime in as this review should be taken with a grain of salt (as should mine!)
Before you send a product out, surely make sure it at least works as it should - how did no other test riders spot this or is it a tolerance issue? Either way, maybe dyno the fork before sending it to review, what a way to ruin a new product launch.
How can this review be so negative and another one on Vital just a few days ago very positive?
www.vitalmtb.com/product/guide/Forks,33/SR-Suntour/Durolux-29-R2C2-PCS,21252#product-reviews/2946
1) Mike tended to focus on the fact the R2C2 wasn't up to his liking, and the RC2 was noisy. I focused on the fact I found the RC2 to work splendidly, even though I too found the original R2C2 to be a bit underwhelming and the updated damper to remain a bit on the firm side.
2) I'm heavier than Mike.
3) I could care less about a noisy damper. (though I did note it)
I understand why Mike has a negative feeling toward the fork, its kind of confusing to review multiple configurations at once, especially when early configrations miss the mark. I suppose I just chose to focus on the positive, what the consumer will receive (which isn't what I was originally on) and also note who something might be for and why.
At $700 there is nothing at this pricepoint that performs as well. The Fox 36 Elite GRIP fork has a better air spring, but its also $100 more and doesn't have service ports - a nice touch.
I can objectively say I put down some of my fastest times all year on the SR Suntour Durolox 29" 150mm RC2. YMMV. Its a good fork at a good price. Sounds like they are putting the other damper back on the drawing board.
What I think is that in this case, PB just put the focus on the negative issues of the Durolux, a fork that really like every person who had the opportunity to test.
And I may be nitpicking here.. but I would be seriously surprised if that noise really comes from "cavitation".
I was one of the first having issues with guides, Told SRAM they were locking on, got told and I quote 'learn how to brake'
Now as soon as a magazine or website report the same issue they sing like canaries and admit all. If only the big companies treated the punters like they do the media hacks we would be doing alright
For these money i could have used fox 36 kashima in exellent condition or bos deville :/
SR Suntour's Response: "SR Suntour would like to thank Pinkbike for their in-depth testing and honest evaluation. The R2C2 cartridge has been ridden and evolving for 2 years now under toughest conditions. It has seen multiple WC DH wins, Rampage wins, Megavalanche wins and NAET overall titles.
However, technologies on such a level can fail sometimes and we have realized it is not perfect. Its long-term performance is not meeting our goals and we are immediately seeking the reasons and will relaunch once solutions exceed those goals. We believe the RC2 PCS platform is solid and reliable, we are looking at reducing the possible noise. Customers with R2C2 forks/ cartridges please contact one of our global service centers or via Facebook or Instagram for a tuned replacement."
really mean i should contact my local support and then i will get a new cartridge?!
For 36 float is way heavier then 2000 grams.
The pike I had was 200 grams heavier than “official weight”
MRP, DVO and Formula weight as much as they claim.
When Suntour hears of this, they decide to go back to the drawing board and pull the fork off the market(if I read it right).
If this is true, my questions in this:
Doesn't Suntour [extensively] test their products BEFORE they release them to the public?
If they don't, they've gotta long career of equipping Walmart/Toys-R-Us bikes to look forward to-and NOTHING more.
If they do, then the conclusion one reaches is that Suntour(like SRAM) feels that it'd be more beneficial(for THEM) to just 'deal' with problems on an 'individual' basis as they pop up, i.e. sell a crap fork, then let the customer deal with their warranty process.
This is why I don't buy SRAM products.
I cant seem to remember who has won a World Cup in the last 2 years on a Suntour Fork?
I am 103kg/227lbs. Got my Durolux 650b R2C2 180mm on my free ride bike.
1 year of use and no problems.