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Coil is the new black

Vorsprung Smashpot Coil Conversion For Fox 36 Reviewed

Words AJ Barlas
Photos AJ Barlas
Date Jul 5, 2019

Air springs have come a long way over the years and the latest options from the major players are incredible. But do they really feel like a coil yet? Vorsprung believes there’s still merit to a coil sprung fork and they developed the Smashpot to serve riders who agree. And while air springs are great, sliding a Smashpot conversion into my fork clearly demonstrated the advantages of coil over air.

You've likely heard the gospel of the spring; coil-sprung suspension has less friction making it more sensitive, has better mid-stroke support, yada yada yada. However, the lack of bottom out support because of the more linear nature of a coil spring can be a setback. Air springs progressively build pressure as they get deeper into their travel, naturally providing more support at the end of the stroke. The clever cats at Vorsprung have tried to remedy this with a speed sensitive hydraulic bottom out control valve, aiming to deliver the best of both worlds.

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Everything you need is included in the kit, except for oil.


My air sprung 2019 Fox 36 was set up perfectly. While I couldn't imagine a better feeling fork, remembering the feeling of coil sprung suspension left me curious. I was also growing tired of checking the pressure in the fork. After removing the excellent Fox Float X2 rear shock in favour of the wallet-friendly Marzocchi Bomber CR, I was keen to see how a coil fork would go.

Highlights

  • Fits Fox 36 (2015+), Fox Rhythm 36, Marzocchi Z1 (2019+) and 35mm RockShox Lyrik, Pike, Yari and Revelation
  • Works with forks between 130–180mm travel
  • Tool-free bottom out adjustability
  • Customizable hydraulic bottom out (HBO) shim stack
  • Universal cartridge. Requires only a potential new top-cap and brand-specific foot stud to fit a new fork
  • Allows 180mm of travel
  • Weight: 547g (Setup to run with a 160mm Fox 36)
  • MSRP: 420.69 CAD (Replacement Springs: 80 CAD)
Vorsprung Smashpot Coil Conversion Recommended Spring Rates

Vorsprung's coil spring rate recommendations. I fall squarely on the two that I tried based on the recommended starting point and the aggressive riding options.

Details

A few things caught me by surprise when I picked up the Smashpot kit from Vorsprung. I hadn’t ridden a coil sprung fork since around 2013 and I’d forgotten to even plan what spring rate I’d need. Thankfully Steve is always on it and after sharing my weight and how I normally run my air-sprung forks, we settled on starting with the 45 lbs/in spring. He also sent me off with a firmer 50 lbs/in spring based on where we ride and my feedback.

I chose to install the conversion kit myself and was surprised how straight-forward the process was. Vorsprung offers excellent, easy to follow instructions on their website and anyone comfortable with taking their fork apart can install this system in a little more time than a lower fork service.

There are some important steps to the installation process to ensure the kit is prepped for the right travel. Before the fork is even opened up, put together the spring assembly. Once the top out spring spacers and travel spacers have been set for the travel of your fork, heat shrink is carefully applied to the tube assembly. While the gun was heating, I applied the included heat shrink to the coil spring and then proceeded with the rest of the assembly.

There are other parts of the process to take special note of as well. When applying the heat shrink to the inner tube assembly, it must remain clear of the ports or the fork won't work as intended. The spring collar also needs to have between 8 and 10mm of thread exposed before the top cap is installed. Each of these was easy enough to get right but required extra care.

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The hydraulic bottom out. Little did I know during my initial install how familiar I would become with this little fella. We've had some good times together.

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The ports sitting beneath the spring of the completed assembly. Sometimes my O.C.D. comes in handy—there's plenty of clearance here.

The Positive

The most unique feature to the Smashpot coil conversion is the speed sensitive hydraulic bottom out. Its attempt to marry a coil with the feeling of air deeper in the stroke has been done before; Push does this with the ACS3 conversion. But something I looked forward to with a coil sprung fork was the consistency it offers. Temperature, ambient air pressure and elevation each affect how an air spring behaves but with coil—unless temperatures take an extreme change—it's no longer an issue. This remains true when using a hydraulic bottom out system rather than air like Push does.

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The speed sensitive hydraulic bottom out system is a clever solution to the problem some riders have with coil-sprung forks.


With the Smashpot I never need to check the air pressure and regardless of the conditions, it performed as expected. More time riding and less time faffing is always a win. Another benefit of coil over air is more traction, thanks to the more compliant, consistent nature from fewer seals and more oil. There's also less to overcome when initiating the fork's travel, making it more sensitive, especially in the first 30% of the stroke. Greater mid-stroke support is also offered thanks to the linear rate of coil springs, holding the rider up better in relation to how light it is off the top. Improved lubrication of the internals also comes into play with a larger amount of oil. This can create a better running fork and it's claimed to result in less maintenance.

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The full assembly ready for install, with the unused top out and spring spacers sitting below.

The Negative

The downside to coil over air is, of course, the weight. You'll have to decide if the extra heft is offset by performance. According to the Vorsprung website, the Smashpot conversion adds between 250-450g grams. It’s a noticeable amount, especially when first installed. But once the first ride is complete it’s quickly forgotten. During installation I weighed the individual pieces for a better idea of the differences.

  • Spring w/ top spacer and wrap: 335g
    • Spring alone: 324g
  • Top cap (FOX 36): 23g
  • Inner tube assembly (stock): 68g
    • Inner tube assembly (setup): 65g (2 x 10mm top out spring spacers for 160mm travel fork)
  • Outer tube assembly (stock): 119g
    • Outer tube assembly (setup): 105g (160mm travel)
  • Finished assembly (160mm FOX 36): 542g (547g w/ extra 50mm length of heat shrink for 36 fork – FOX Rhythm, nor RockShox forks need extra)
  • Replaced air spring assembly weight: 96g

On my scales, the Fox 36 160mm setup results in an extra 451g, without oil. My rough estimate for the weight of 110ml of 20wt oil puts me around 550g (1.21 lbs). A coil conversion isn't for the weight conscious.

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The spring accounts for most of the weight. Steve wanted something durable and when asked about ti-spring options, he noted their expense.

There's also the possibility of noise from the spring contacting the inside of the fork. I heard it rattle occasionally during the first ride with each spring and was also able to force a top out clunk when I really pushed the issue. Once everything settled in I didn't notice any noise that wasn't rubble churning up off the front wheel.

That’s it for negatives. For me, the positives far outweighed the weight gain and occasional thunk during the first ride.

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The top cap is the final piece installed to the assembly before it goes into the fork.

Time to 'Smash Everything'

I first installed the lighter 45 lbs/in spring. Instantly it felt soft, and my gut said it was too soft. Part of the difference came from how freely the front end moved. The fork had seen about 240km since its last service. It's not heaps but enough to make a difference with the lowers freshened up. I went through my usual setup process. I was able to get the shape of the bike similar to my setup with air once the damper dials were adjusted deeper into their respective settings.

With the lighter spring installed, the front end was clearly more composed compared to air. I found myself riding more aggressively with the front wheel, demanding where it went with relative ease. Pushing harder did little to unsettle the bike—it tracked superbly and trail feedback was more muted. Similar to nagging your older sibling just to get a response, I found myself driving the front wheel into things I shouldn’t have. I pushed harder into sections than I had previously only to find myself going faster than I should. It took everything in stride. Well... almost.

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When discussing the break-in period with Vorsprung, we came to the conclusion that the heat shrink was likely the cause. It had also shifted about 15mm in a few rides.

During the first ride, I experienced a mild break in and by the second outing things needed further adjusting. On average grades, the fork was working remarkably well but in steeper terrain or on sections with successive ledges, it dove too deep into its stroke. With the hydraulic bottom out set between four and five clicks out (from fully closed) it never bottomed, nor was there a harsh end to the travel used. But the fork was getting caught deep in its mid-stroke, negatively affecting my bike's shape.

I adjusted the damper dials more and repeated the process. Hitting the same sections of trail that caused the issues. I was able to achieve a setup that I was reasonably happy with. But in order to retain shape, I found myself sitting at the limits of my damper settings. And it still wasn’t quite there.

The 45 lb/in spring was pulled from the fork and replaced with the 50 lb/in option. Once everything was back in place I set my compression dials back to my base settings. The bike instantly felt better. Its shape at sag was how I prefer but during the parking lot test, it felt harsh during deep, fast compressions. After backing out the HSC compression completely and fettling with the rebound things improved. That first ride on the firmer spring was the opposite to the previous rides on the lighter option. In the first 50–60% of the stroke the fork felt sensational but beyond that it was harsh. I was now experiencing hand fatigue, and on shorter trails too.

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Externally, this adjuster knob provides control over the bottom out support provided. But sometimes you need more.

With the fork feeling great everywhere outside the last 40% of stroke, it seemed like the perfect time to pull apart the HBO shim stack. The Smashpot's hydraulic bottom out has a tunable stack for those that don't mind getting their hands dirty (or you can send it to Vorsprung and have them do it). It's not something Vorsprung feel many will need, thanks to the external adjustability of the HBO, but it can be done if needed. Everything about the firmer spring worked well for me except where the HBO was coming into play. It was time to pull the spring assembly out again.

I wanted to make a fairly drastic change to the shim stack. It was pretty clear I needed something but I also wanted to make sure it was clearly felt. Three shims were moved to the back of the stack, leaving two at the front. Once mounted back to the bike the change was immediately noticeable. On the trail, it felt excellent and I was able to add a couple clicks of HSC back in. The fork worked really well and the bike held it’s shape no matter how hard it was pushed, or how sketchy I rode. After big compressions, the fork would show 15–20mm of travel remained and despite it feeling so good, I wanted to get more out of it. The HBO was also still completely wound out (fully open) and I wanted to use that too.

Again, the fork was torn down and the shims reordered to leave only one at the front of the stack. As with the previous stack adjustment, it was noticeable but more subtle. Once out on the trails, it was much clearer. A couple more clicks of high-speed compression were added. At this point, I wanted a bit more LSC too and added one. The hydraulic bottom out adjuster had a click added to it and it felt really good. I was left with about 5mm of travel after some larger hits but knowing there will be bigger, another was added.

Perfection.

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The stock shim stack configuration. The five shims on the right can be shifted between the spacer shim (far left) and the clamp shims in the middle. I first moved three of these across and then came back to move another one. This left just one of the main shims on the right.

While my bike, riding style, terrain etc. may not match yours, here's what I've ended up with. Interestingly my damper settings aren't too different from my air setup:

  • Bike: GeoMetron G16, size "Longest" / Fork: Fox 36 Grip2
  • Travel: 160mm
  • Spring: 50 lbs/in
  • Shim stack: One forward, four rear
  • HSC: 16 Out / LSC: 7 Out
  • HSR: 4 Out / LSR: 7 Out
  • Rider Height: 191cm
  • Rider Weight: 75kg

The current setup is everything I had hoped for. My bike is tracking remarkably and I’m able to be more demanding of the front wheel in more situations. Composure through choppy corners has greatly improved, allowing me to focus on what lays ahead rather than adjusting to keep things upright. It’s made exit speeds higher, which in turn has resulted in greater momentum over the course of a trail. Under braking, the front stands up more while still accounting for the feedback under the front wheel. But probably the most enjoyable thing is forcing my front wheel onto inside lines loose with debris that I have no business being on.

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Can we have a black top cap, please?

Verdict

Right now my bike is coil sprung front and rear and it's incredible. It’s heavy, for sure, but I prefer the gob-loads of traction, composure, and lack of faffing. And while the front weighs more than before, it actually strikes a more level balance. The adjustability of the Smashpot conversion is what really made it work for me though. I often find there's some form of compromise but with this being the weight, I was finally able to get the performance exactly how I wanted. It never does anything unexpected and feels perfectly planted but best of all, I can just grab my bike and ride confident its going to feel the same as the last ride.

More information on the Vorsprung Smashpot Coil Conversion is available on their site.

Comments

Lma
+1 AJ Barlas
Lma  - July 5, 2019, 4 a.m.

Cool findings, just got my Pike coil converted (no bottom out control) and have a similar spring rate. Good to hear you didn’t want too much extra bottom out resistance. Yet to ride mine but can’t wait!

Reply

Vikb
0
Vik Banerjee  - July 5, 2019, 6 a.m.

When I pulled down my summer bike [dual coil] from its hook this year my brain was starting to think about hunting down a shock pump and getting the suspension setup...then I remembered it's always setup the same and ready to roll. I'm not quite ready to get a #Coil4Life tattooed across my forehead, but it'll be interesting to see if I feel like spending $$ on air suspension next time I get a new ride. It does add a bit of weight to the bike, but it rides so nicely it's hard to care.

BTW - had Steve at Vorsprung service/tune my coil shock at the end of the summer. He was super nice to deal with, total professional and the tune was exactly what I had asked for.

Reply

AJ_Barlas
0
AJ Barlas  - July 5, 2019, 6:25 a.m.

The consistency is so nice and it works so damn well hey. I reckon air is good and has it’s place but for me, and especially on my longer travel bikes, coil is now preferred.

Reply

Cheez1ts
0
Garrett Thibault  - July 5, 2019, 7:41 a.m.

I have the hydraulic bottom out in my avalanche damper cartridge in my pike. Unfortunately I ordered the push coil conversion before the avalanche cartridge or I could have done away with any addition to the spring side entirely and just gotten a cheaper spring kit from the uk brand. 

The pike is perfect. 

I don’t have a hydraulic bottom out in the avalanche damper cartridge in my boxxer. I also don’t have anything but a spring in the spring side. I do wish I had the adjustability of the pike (or your fox) in the boxxer. I have the fork a bit overspring to compensate for the linearity, which means I had to overspring the back to keep the shape which isn’t ideal.

Reply

AJ_Barlas
0
AJ Barlas  - July 5, 2019, 8:26 a.m.

I often forget about Avalanche. Years ago they were a go-to for conversions but they seem less prominent now. That doesn't mean they're any less knowledgable or good; ya just don't see them around much. 

How are you finding the conversions otherwise? Still the top quality they used to provide I take it?

Reply

Cheez1ts
+3 Andrew Major JVP AJ Barlas
Garrett Thibault  - July 5, 2019, 9:16 a.m.

Avalanche is great. Definitely feels like it’s a small operation still. They took the time to call me and explain their damper and the push conversion kit that I already had and double checked that I still wanted to go through with my Avalnche order with the hydraulic bottom out and the damping cardridge at all. Seems like the service hasn’t changed since my dad ordered the cartridge for his boxxer many moons ago. 

The industry hasn’t really been good for buying something nice and holding onto it forever recently. It’s not cheap to buy an Avalanche cartridge knowing that it will at best be shipped back to be modified to fit your next fork. Fortunately the boxxers didn’t change much from 26” to 27.5, but I’m 27.5 160mm pike for life on at least one bike in my stable now. 

At this point I’m of the mindset that I’m just going to run boxxers lowered to whatever height I need on any aggressive bike I own going forward. I had success lowering one, they don’t creak, they’re cheap used, I can still get a new, long straight 1 1/8 steertube for them, and I can get them in any wheelsize. What more could I ask for?

Reply

JVP
+3 AJ Barlas Tjaard Breeuwer Andrew Major
JVP  - July 5, 2019, 6:32 p.m.

You might be ahead of the curve. I think 160-180mm dual crown forks might become a trend, as current trail/enduro bikes with 64* head angles are awful hard on single crowns.

Reply

Xorrox
0
Brad_xyz  - July 10, 2019, 7:32 a.m.

Yes this is also what I'm starting to think.  I love my Fox 36 with the Grip 2 damper but running it at 170mm with a 29er wheel I really feel it lets me down in the crown and steerer stiffness specification.  Coincidentally my head angle is right around 64 degrees :) I'd be very temped to try a MRP Bartlett but have found 0 reviews online for them and am pretty concerned about breaking my frame at the head tube as I'm already way over forked after going from a stock 27.5" , 160 mm fork to my current 29" 170 mm.  Also I am not a light guy so my experience may not be typical.

Reply

LoamtoHome
+2 Pete Roggeman AJ Barlas
Jerry Willows  - July 5, 2019, 8:57 a.m.

Great article AJ !  I've got a Smashpot on my SJ EVO at 160 with 50 lb spring.  I have the HBO 2 clicks from fully closed so she doesn't bottom.  Think I'm going to put it at 170mm and less HBO and see how it feels.  Maybe a 55 lb in the future to make it feel as good as the EXT rear.

Reply

AJ_Barlas
+1 Jerry Willows
AJ Barlas  - July 5, 2019, 11:39 a.m.

Thanks Jerry. Looking forward to seeing how this measures up to the EXT on my new bike, which I hope to have built very soon.

Reply

blackfly
0
Peter Leeds  - July 5, 2019, 5:09 p.m.

Know of any shops locally that carry it?  I have the exact fork and stroke as you and I have been a Marzocchi (of old) fan for years; decades, actually.  This looks like something I would look into.  In lbs, what is your weight for reference to the spring rate?  I am 200 so if you use 50......

Reply

LoamtoHome
+1 AJ Barlas
Jerry Willows  - July 5, 2019, 10:40 p.m.

Everything is on the website

Reply

BigDukeSix
0
BigDukeSix  - July 5, 2019, 2:47 p.m.

Great article!

Sent my Fork to Push for the conversion. 

I’m at the low end of the spring rate and I ride 90% bike park so it works, but it’s stiff.  I’d need to drop 17 lbs to be at the other end of the lighter spring rate. Seems Vorsprung has a larger choice of spring rates.  Love to find out if they fit my Push set up. 

May have to pick up one of these setups next year.

Reply

AJ_Barlas
0
AJ Barlas  - July 6, 2019, 8:54 a.m.

Hey Duke. Going by the table above with my weight you’re looking at the 60lbs/in spring. Check it out at the top.

Reply

BigDukeSix
0
BigDukeSix  - July 6, 2019, 9:12 a.m.

Thanks, yeah I’m at 230 lbs. 

What is the likelihood Vorsprung springs would work in the push set up. 

Clearly they have to be a similar diameter. I’d love to have a more useable fork. 

Thanks again.

Reply

Vorsprung-Suspension
+1 AJ Barlas
Steve Mathews  - July 8, 2019, 11:31 a.m.

Smashpot springs are longer than the Push springs, they aren't cross compatible.

Reply

NickB
0
nick bitar  - July 6, 2019, 4:16 p.m.

I’ve got a Cane Creek coil Helm on my SJ Evo and am pretty chuffed with it. I looked at conversions for my Lyrik but it was cheaper to sell my old fork and buy a whole new one. Any idea how they compare? Conversion vs off the shelf mrp or Cane Creek? The CC is the only one with the sexy Cherry Bomb coloured crowns though!

Reply

Heinous
+3 luisgutierod Velocipedestrian AJ Barlas
Heinous  - July 8, 2019, 3:44 a.m.

It’s always interesting how progression in components cascades until major stuff can’t keep up - tyres, geo, brakes, wheels, and rear shocks, and suddenly you notice your fork needs a coil conversion...

The first time I thought my 36 couldn’t keep up was when I put a Push coil in the back. I’m reluctant to drop the coin on a Smash Pot, so might try a Luftkappe first.

Reply

luisgutierod
+1 AJ Barlas
luisgutierod  - July 9, 2019, 3:22 a.m.

I have not tried DVO forks, (I have used lyric, MRP coil, Pike, Fox 36 rc2, etc).. the only thing keeping up with an EXT storia is a FOX 36+push coil conversion.. even with the FIT4 damper, which is not the best, the fork is transformed completely.. nothing can compare to the way coil behaves... luftkappe, MRP ramps, nothing.. This Smashpot its a winner for sure..

Reply

andrewbikeguide
0
AndrewR  - July 10, 2019, 10:05 a.m.

@Heinous I have a Luftkappe in my 2018 36 K FIT RC2 29 x 160 mm (I also have one in my 36 K FIT4 150mm) and they really make a difference. Having had an Eleven-six as my most recent coil/ non air spring experience I would say that there is still something about a coil that air misses but the Luftkappe is a significant improvement (sensitivity, traction and holding mid travel when you need it) over the standard issue. Worth the $. If in doubt call Steve Matthews and chat through what you think is missing from your set up and what you are aiming to achieve with any changes.

Reply

DemonMike
0
mike  - July 8, 2019, 11:55 a.m.

Do you have anything else done to the fork in the other leg??

Reply

BigDukeSix
0
BigDukeSix  - July 8, 2019, 12:22 p.m.

Asking me mike?

Reply

AJ_Barlas
+1 mike
AJ Barlas  - July 9, 2019, 12:38 p.m.

Mike, if you're asking me. No. I asked Steve about changing the damper tune to accommodate a coil versus the original air and he said that the overall spring rate is roughly comparable whether air or coil. Throwing in a bit of LSC balances it out well.

Reply

dan_l
0
dan_l  - July 11, 2019, 5:26 p.m.

I have a smashpot for a pike. It is a very high quality kit and you get a lot for your money. After a couple months of running it you could go back to air if you want, not scratches on the inside of the stanchion. This setup excels in the color months when it is 40 deg F and lower.

For me, the weight was a killer. I had this on a 2016 pike with a charger 1 damper. It added a healthy 1.1 pounds to the front end of the bike. It was tiring to pull up into a manual with it. On the east coast of the USA we have lots of log that you need to bunny hop over and it was taking too much energy.

I went to a 2018 pike with the charger 2.0 and debonair spring. This setup is better nearly everywhere. The coil may be slightly better in the rough stuff but it is hard to tell. IMO if you want "coil feel" with your air spring, without adding more than a pound to the front of the bike, try a cush core.

Reply

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