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Comparison Test

Coil vs Air - Öhlins long term test

Words Trevor Hansen
Photos Deniz Merdano (unless noted)
Date Aug 1, 2019

Coil vs Air on Öhlins forks and shocks

I have been running air shocks and forks since 2010 on both DH bikes and trail bikes. Some of my riding bros were experimenting with coil shocks recently and a few had gone all in on coil forks and coil conversions - like the Push ACS3 and the Vorsprung Smashpot.

I decided to give coil a go because I am a firm believer in purchasing riding ability through technology, and with all the big crashes and aging I've been doing the over the past few years it was time to invest; my hope was that coils were the answer.

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Coil in the back air up front. Photo Deniz Murdano.

The coil vs air debate has been well documented and most riders declare that coil gives a more supple, plush feel that hugs the ground better while offering excellent tracking, feel and control that surpasses air. Coils are said to require less maintenance and you may even luck into the right spring weight to get the “set it and forget it” happy place. In addition, air uses more seals so friction may increase with heat build-up. Sounds like coils are perfect… except coils are heavier and they are linear by nature as opposed to air’s progressive spring rate. Air is considered more playful, allowing for a poppy feel on the trails.

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The test was performed on a 2017 Specialized Enduro S-Works 29'r. Photo Deniz Murdano.

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Coil weighing in at 33.4 lbs with pedals and a full SWAT compartment.

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Air weighing in .9 lbs less at 32.5.

Many top of the line air shocks and forks allow for ramp to be adjusted with tokens, spacers or air. Öhlins coil suspension does not allow for these adjustments and must rely solely on compression which does not offer adjustment specific to the end of stroke rate.

I have been riding Öhlins air suspension on a Specialized Enduro S-Works 29'r for the past two years and I'd been happy with the performance for the most part. I had an STX22 shock that leaked some air but this was easily dealt with by Suspensionwerx. Other than that all that was leading me to change was the greener grass of coils.

My test protocol idea was to try different combinations of air and coil for about 20 rides each then decide after all the riding which set up I preferred. The first was easy: air shock and air fork. I had been running this set up for about a year on the Enduro. That was my base.

The first deviation was a coil shock with an air fork. I started with the coil (525 lb/in) that Thomas Westfeldt, product specialist for the mtb side of Öhlins, said would be the right fit for my size (180 lbs with gear). I found it a bit too firm on a lot of the lower grade high speed trails I was riding so I swapped it out for a lighter 502 lb/in spring. This size gave me all the benefits of coil that I had been reading about: rear wheel tracking, increased traction into and out of turns as well as over roots and rocks and even better grip on steep and technical climbs. I even found it climbed better on fire roads than the air shock. However, I found that when I rode fast blown out trails with big dips, holes and drops I was not getting the support I wanted so I went back to the 525 spring which allowed me to plow through all of those elements.

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Part of the back to back runs route was a Shore classic, Pangor, filled with log rides, rock rolls and jank flow. Photo Cam McRae.

After 20 rides on the coil shock/air fork set up I went back to the STX22 air shock and converted the RXF 36 EVO to a coil. Öhlins sent me the updated fork with an air spring installed. The RXF36 EVO coil can be converted to air but it is not possible to do it the other way around. You need the little threaded washer mounted at the end of the inner leg when you run coil and air forks do not have that thread. Without that the spring will damage the inside of the inner leg. The new RXF36 m.2 trail fork will have that feature on both air and coil forks.

I enlisted Jeff Bryson, owner of Wheelthing to do the conversion. Using all his tricks from years of wrenching all across the world Jeff performed some voodoo that makes all forks feel better than new. He then completed the conversion removing the air spring and installing a white Öhlins 55 lb coil spring. It was way too stiff so after one ride of only using half the travel I swapped out the white for the blue 50 lb spring.

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Jeff in the air to coil conversion cave. Photo Cam McRae.

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Whenever Jeff plays with suspension it always feels smoother and better than ever. Photo Cam McRae.

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Just put that thing in that thing for me Jeff. Photo Cam McRae.

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Not the black pill, the white pill (55 lb/in.). Photo Cam McRae.

I liked the smooth almost buttery feel of the coil off the top into the sag point but I had a hard time enjoying the ride as I went faster and started hitting drops and steep hits. I went through the mid-stroke and found it ra too low in its travel. This is one of the downsides of coil. If there was a way of adding tokens to make it more progressive it might be an option but without a spring to suit me (52.5?) I did not see the need to carry on with the coil fork part of the test any further. I went back to Jeff and he quickly swapped out the RXF 36 EVO air, did some more of his magic and made it feel better than new. I rode another 20 rides on the air shock/air fork combo to remember the feel again. With 20 rides on a coil shock/ air fork, 20 on an air shock/air fork and 5 rides on an air shock/coil fork I needed to come to a conclusion on the air vs coil shock part of the test.

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An epic day on Cypress Mountain being chased by the red and blue rocket Cam McRae. Photo Deniz Murdano.

For that I did a back to back test on one of our local mountains. I chose a route that had all the elements of riding I usually hit: steeps, loam, tech gnar, flow trails and a few big rock moves. I did the route on the air shock/air fork set up first, then did the exact same route on the coil shock. The coil gave me more traction which inspired more confidence to go faster and it made some of the hard moves on the route seem easier to initiate. Even though the air shock allowed me to pop small hits and double some sections of trail, the constant slipping of the back wheel had me anticipating the rear end sliding on me on most turns.

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The coil gave me excellent traction on the way up not just on the way down. Photo Deniz Murdano.

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The softer 502 I tested before settling on the 525 coil. Photo Deniz Murdano.

Ever since that test day I have been running the coil shock exclusively…sort of. I decided while writing this to give the air shock one more try. I noticed the back wheel skipping out of turns and off roots and rocks immediately. After a few minutes I got used to that and adapted my riding. I appreciated the lighter weight on the climbs but missed the extra climbing traction. I also was liking the poppy feel of it on jumps and even on trails trying to double small features. But even with the weight and pop I still longed for the plushness and confidence of the coil so it is back on the bike again.

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The infamous Pre-Reaper rock drop. Photo Deniz Murdano.

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When I told Johnny Smoke that I was riding his rock drop he sent this classic shot over. Check out his suspension dropping to flat with smooth Smoke style.

There is never a perfect solution in the world of mountain biking; nor the world in general. However, for me I am sticking with the plush, easily adjusted, progressive, stiff and smooth RXF 36 EVO air fork and the good traction, buttery, confidence inspiring feel of the TTX22 coil spring…until the crew at Spesh come out with a new Enduro; then I might have to re-evaluate everything.

For more on these products hit up Ohlins.com

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Comments

Cheez1ts
+3 THELEGENDMTB Tim Coleman Cam McRae
Garrett Thibault  - Aug. 1, 2019, 9:46 a.m.

Nice write-up Trevor and photos Deniz!

I run the opposite set-up as you, air in the back, and coil in the front. After reading AJ's detailed review, I think the reason I like my coil fork so much is because I replaced my stock damper with an Avalanche Cartridge. I don't have a problem with mid-stroke support.

Reply

IslandLife
0
IslandLife  - Aug. 1, 2019, 10:38 a.m.

This was great... for comparing the rear of the bike.  But in this day in age of the Smashpot, MRP's coil with Ramp Control and others on the market, I'd like to see a another fork air vs coil test  with come better technology involved.

Also, I'd love to hear how MRP's new progressive spring for the rear feels and if something like that might be the golden middle ground you're searching for?  Sounds like you might get what you liked from both spring weights with a progressive spring, no?

For now, for me... this confirms what I've thought and kinda tested (with friends bikes), and so far, I'm sticking with air/air.  But... I'm using MRP's Ribbon which can easily be changed to coil.  They offer 5 different spring weights to choose from and with Ramp Control, it's very tempting.  Also my bike is built to work with a coil on the rear as well... so that MRP Hazard with a progressive spring is also tempting.

The two things that worry me is: #1. the weight of going coil on both ends and: #2. losing some liveliness = are the benefits outweighed by the gains?  It's also quite an investment to fully switch (and a commitment because the fork can't go back), I worry about not liking it as much, but I've invested and committed so I wouldn't be going back anytime soon.

Ahhh... first world problems for sure, haha.

Reply

Tbone
+1 IslandLife
Trevor Hansen  - Aug. 1, 2019, 4:46 p.m.

I would love to do the test you with progressive springs. I was riding with a friend today who has an Ext coil in back $1200 CAD, Vorsprung Smashpot up front ($420 CAD) and his bike feels great; other than the 40 lb weight (he does have tire inserts too). I definitely wouldn't want that much weight even if it meant a super buttery feel.

Reply

luisgutierod
0
luisgutierod  - Aug. 1, 2019, 6:20 p.m.

en ext storia lok shock is 200 gr heavier than an X2..  mid stroke support I find its always better in coil forks..

Reply

craw
+1 Shoreboy
Cr4w  - Aug. 1, 2019, 12:16 p.m.

You had me with the second paragraph.
I switched my G16 to coil in the rear and it rides much much better. For my 230lbs air shocks were just too sticky. The coil shock moves well and is super supportive in the mid stroke. I'm definitely converted.
On the front not so much. The ability to tweak fork pressure so granularly is awesome. My Helm doesn't suffer from any early stiction and has proven to be tough. I couldn't see the extra weight of a coil fork paying off for me though it's cool that there are a few options now for those that want it.

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shoreboy
0
Shoreboy  - Aug. 1, 2019, 1:12 p.m.

On a somewhat related note, how do you like your Helm?  I rode one last season, but ended up selling it as I found it far too progressive even with the entire 'volume spacer' setup removed. I did think that it would be a great fork for the heavier and more aggressive rider.

Reply

craw
0
Cr4w  - Aug. 1, 2019, 2:10 p.m.

Lucky for me I'm a heavy and more aggressive rider then! I had lots of RS damper issues and every Fox 36 I've ever had became a creaky heap within a few months so I was running out of options. So far the Helm has been awesome. My only complaint is that the HSC adjustment lever sticks out from the fork leg so it's easily bumped.

I like the look of the DVO Onyx SC as well, which I suppose is what I'll try next.

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shoreboy
0
Shoreboy  - Aug. 1, 2019, 2:13 p.m.

Are you able to run the volume spacer setup?  Do you have it on minimum or maximum? Im just interested to see how much others are able to run.  I weigh 180 and I wouldnt consider myself an aggressive rider.  Even with 35% sag and zero 'spacers' I couldnt get anywhere near full travel.  Im rolling the dice on a Lyrik Ultimate and so far it is much better for me.

Reply

Isildur
0
Isildur  - Aug. 1, 2019, 7:59 p.m.

That's pretty interesting to hear. I'm 78kg (170ish) and run the volume spacer at position 3, and run about 20mm sag. This leaves travel in reserve on most trails, but only about 15-20mm, which comes in handy when things get really rough or a big drop goes a bit front heavy.

With that said, I would consider myself an agressive rider on certain trails, and on the Ripmo the long front end really encourages weight on the fork so it does get a fair bit of bias most of the time.

Reply

craw
0
Cr4w  - Aug. 2, 2019, 9:48 a.m.

I'm at position 3 as well and life is good. I think the G16 has very different setup requirements than a steeper head angle bike.

JVP
+1 Cr4w
JVP  - Aug. 1, 2019, 2:49 p.m.

I'm on a DVO Onyx SC, can confirm, it's a great fork. It's easy to tune beginning, mid and end stroke support. Damping isn't quite Fox level refined, but it's pretty darn good, and it's a far better chassis and air spring setup. I really like the DVO 6 position LSC adjuster - very usable.

I also had problems with repeated creaky CSUs. Screw light weight forks. Maybe e-bike components will save us?

I like forks buttery off the top, more mid-stroke support, and keeping the last 10mm of travel for the worst oh-shit moments. I can do that on the DVO. Personal preference, for sure.

Reply

Heinous
0
Heinous  - Aug. 2, 2019, 7:38 p.m.

I ran the Helm, it was good and fill travel never an issue (82kg).

I recently put a DVO on my singlespeed and when I hopped back on my big bike I was really surprised how shit the 36/grip2 feels, especially in the early stroke. The DVO is just super plush with the OTT and spring for early part of travel. As soon as there’s a DVO option for 29” / 170mm I’ll be doing it.

Reply

kiksy
0
kiksy  - Aug. 5, 2019, 11:34 p.m.

I have Helm coil . I weigh 65kg. The small bump is on another level, mid stroke is great, but it REALLY ramps up towards the end. I have it set to 160mm and I think 140mm is the most I've ever used. Initially I was trying to tweak this using lighter spring and more damping, but now I love being in the knowledge that the firm is going to support me and not dive, even in the biggest "whoops" moments.

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GladePlayboy
0
Rob Gretchen  - Aug. 1, 2019, 1:53 p.m.

Your air shock testing was only with the STX22?   It would be nice to get a comparison to the latest TTX Air shock..... it might change the conclusion?    Might not.

Reply

AJ_Barlas
0
AJ Barlas  - Aug. 2, 2019, 7:25 a.m.

There will be a TTX Air review in the future. We just received it and will be comparing it to the EXT Coil on the bike it will be tested on.

Reply

JVP
0
JVP  - Aug. 1, 2019, 10:10 p.m.

Coil shocks have the potential to blow away air shocks... if the bike co’s make super progressive linkages available. 30 - 40% progressive or whatever it takes to ramp up like an air shock stuffed full of bottom out tokens on most enduro bikes. How progressive is the Enduro in this test?

Reply

luisgutierod
0
luisgutierod  - Aug. 2, 2019, 6:58 a.m.

hydraulic bottom out control does the trick as well.. and overall progressivity can be obtained  with different shapes of LR curves, bear that in mind.. cheers

Reply

Tbone
0
Trevor Hansen  - Aug. 2, 2019, 7:45 a.m.

How progressive? Other than saying that the 2017 Enduro is slightly less progressive than the 2018 I'm not sure I can quantify that. I agree that bottom out control would be great but this test was simply a comparison of Ohlins STX22 vs TTX22 matched with RFX36 EVO air vs RFX36 EVO coil.

Reply

IslandLife
0
IslandLife  - Aug. 2, 2019, 10:06 a.m.

Like the new Yeti SB165.... has a 27.5% leverage ratio and comes stock with coil vs the SB150 at 15%.

Reply

Vikb
+1 Cr4w
Vik Banerjee  - Aug. 2, 2019, 7:55 a.m.

When I got a new bike last year I spec'd coil front/rear [MRP Ribbon + RS Super Deluxe Coil]. Last dual coil bike I had was back in '99 or so. I'm quite happy with the results. It does take a moment to get used to the different feel and learn how to setup the suspension after a long stretch with only air forks/shocks. 

After swapping the lighter then the heavier springs around my weight range into my shock I settled on the stiffer spring and the shock damper run wide open. The bike sits high in its travel and has a lot of support, but the spring still moves very easily off the top and I get great traction. 

My fork is running the lighter of the two springs for my weight and it's working well. That fork does have a bottom out control adjustment which is nice. I did get the next stiffer spring for my fork. I'm curious how that will feel. Might be too stiff, but I'll give it a go when I open up the fork for the next service.

I service my coil suspension the same amount as I do my air suspension, but it is nice to never have to break out the shock pump or have the spring rate set wrong for a ride.

The weight hit is something 1.5lbs. I notice it when I lift my bike off the rack, but on the trail it disappears from my mind immediately. My bike is setup on the burly side of things to tackle any trail I have the skills/balls to ride down. I could see myself building up a light short travel bike and wanting to have air suspension to keep the weight down.

It's great we have so many excellent suspension options these days.

Reply

velocipedestrian
0
Velocipedestrian  - Aug. 2, 2019, 11:04 p.m.

I'm in a similar boat testing a 450 & 500lb spring in an old DHX 5. But I've found the 450 with near full LSC is still kind of mushy (though not bottoming - it could just be my impression of coils famous plushness). While the 500 is great for traction and mid stroke but with the LSC full open it only uses 2/3 travel and feels uncontrolled.

Still more testing to do, but I put the CCDBA back on for my last ride to recheck my benchmark, and it's great. Less supple off the top sure, but in every other way better. I'd love to be comparing with a CCDBcoil for apples, but they don't come up cheap second hand often. 

Still loving the RS firm (blue) spring in the OG 26" MiCo lyrik up front.

Reply

Vincent66
0
Vincent66  - Aug. 4, 2019, 8:49 a.m.

I am riding my durolux with a CRC cartridge and a coil conversion kit.

http://www.crconception.com/CARTRIDGE-SPRING-KIT/

CRC has been producing coil conversion kits for a long time. He might have been the first to propose a coil conversion for pikes, almost 10 years ago.

Check the original before buying the followers ...

I'm considering switching to coil in the rear too : FAST Fenix looks sick !

http://www.fast-suspensionshop.com

Reply

jdw103
0
Jason West  - Aug. 4, 2019, 11:43 a.m.

My 2019 Sensor is a heavy bike, 33.6 pounds. The Marz cr coil shock i have for it adds easily 3+ pounds. Would custom tuning reduce the weight of the spring needed? Im 240 and i need like a 650-700 spring and its just so heavy to an already porker of a bike. The Rock Shox air shock it came with is just okay but much lighter. So if i send the coil shock to Avy could they tune it so i can use a lighter weight spring?

Reply

velocipedestrian
+1 Jason West
Velocipedestrian  - Aug. 4, 2019, 6:23 p.m.

No, the required spring force is a result of your weight + the frame leverage rate. Custom super firm compression will just slow down the shaft speed, not stop it getting to the bottom of the stroke.

Reply

Vincent66
0
Vincent66  - Aug. 4, 2019, 7:47 p.m.

No. The spring depends on your weight.

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