Hello Vital MTB Visitor,
We’re conducting a survey and would appreciate your input. Your answers will help Vital and the MTB industry better understand what riders like you want. Survey results will be used to recognize top brands. Make your voice heard!
Five lucky people will be selected at random to win a Vital MTB t-shirt.
Thanks in advance,
The Vital MTB Crew
Ah I sure do miss all the ti coil options we used to have! Obtanium, RCS (Renton Coil Springs), Ti Springs, and some others. I think you might.. with a big fat maybe… be able to order some RCS springs still.
In my opinion, EXT ones look very good and are light enough, and you need a reducer to use them on fox/canecreek/dvo which I believe is the same for a bomber.
Check out:
https://helixcoildesign.com/
Who is Alex Volokov?
https://www.pinkbike.com/news/tags/alex-volokhov/
K. So who is Alex Volokov?
Maybe this example will clarify;
If you have a PUSH SV8, and a Fox DHX, it is easier to change the base valve tune on the fully shimmed DHX, and there are many more options available, than the poppet system of the SV8.
The base valve on the DHX is comprised of 1/4" ID shims, which are very abundant and easy to source. In addition, a ring shim could be added to provide a pre-loaded setup, again with multiple levels of preload available. The number of potential base valve tunes is numerous; straight stack, preloaded stack, even a cross over stack is possible to install. Not saying that they are all good or will even work, but the options are numerous.
The SV8 base valve options are limited to what PUSH alone offers, or is willing to sell to the end user. Which seems like perhaps only one other option?
This is what is meant by a fully shimmed base valve having a greater tuning potential that an poppet valve system. A poppet valve system is limited to what the shock mfg offers, a fully shimmed system is not limited in this way. Does that make sense?
The Fox SLS 425# is a direct fit.
Other 425# options such as Super Alloy Racing and MRP will require a little adapter spacer as they have a larger ID. MRP offers the little adapters for their springs to work with your shock.
The Hypercoil springs that PUSH uses will fit, but the bulge in the middle of the coil can contact the reservoir at or near bottom out in some cases. Don't ask me how I know....😀
you touched stuff with your bulge you shouldn’t have?
"If you have a PUSH SV8, and a Fox DHX, it is easier to change the base valve tune on the fully shimmed DHX, and there are many more options available, than the poppet system of the SV8. "
The above statement is incorrect when referring to the design and architecture of the two products. It requires similar tools and time to disassemble and reassemble both products and change the base vlave tuning. When it comes to tuning, you also have a similar range of damping characteristics that can be created.
With that being said, I now understand that you're basing your statement on your ability to get parts and technical information. I think it would be less confusing had you said: "If I have a PUSH SV8, and a Fox DHX, it is easier for me to change the base valve tune on the DHX because of my ability to get the parts necessary to change from the stock tune."
Why shimmed vs shimless anyway?!?!?!? Shimmed designs have a larger manufacturing and assembly tolerance at scale. This is why they're widely used in production shocks where you need consistent results over a large volume of product. Shim-less designs have tight manufacturing and assembly tolerances and are more difficult to scale at production. Shim-less base valves, however, provide faster response, providing increased grip and have far greater fatigue life, providing more consistent damping over a long season of riding.
Ultimately, we're still back in the same place. Base valve tuning in a montube damper is for setting the range of the external adjusters, and for pressure balancing. When we use the term "revalve",or "tuning", it rarely refers to the base valve. The primary tuning is done at the damper piston, where you're able to impact the entire range of the damper's movement.
This is a basic question, but how does a poppet system work? Im familiar with orifice style dampers like what Rockshox does and shim style dampers like what Fox uses but Im just now learning there’s another way to implement damping that comes with its own performance benefits and engineering challenges.
https://www.performancetrends.com/PDFs/Ohlins-TTX-Shocks-Tech-Adjustment-Shock-Dyno-Info.pdf is a pretty good read that talks about using poppet valves in a TTX 40.
I'm not an engineer, I don't play one on TV, but I do think that sometimes people on the Internet get wound up concerning the finer points of X vs Y.
Everything has tradeoffs and various systems have benefits and limitations so at the end of the day a poor/limited implementation of a system that contains X or Y may not address or overcome those limitations.
The flip side of that coin is the limitations may not matter much or be noticeable in the vast majority of use cases.
TL;DR - there are many ways to achieve the same goal and the finer details will differ but that is ok and what makes things interesting
This 100% - peoole get too hung up on single details about a damper without inderstanding it only makes up for a tiny fraction of the performance - you can make almost any damper curve with multiple different valves but some will be easier than others, so each manufacturer will prioritise what they think achieves their specific goals. A "poppet" can be combined with a shimmed main piston to be linear or even progressive, while shims on both can be extremely digressive, there is a lot more to is than the basic valve design.
Also "poppet" gets used a blanket term for any kind of shimless valve when really there are several designs which perform quite different when you actually dyno them. But people see a valve on a spring and just assume it will perform a certain way.
Yes, that is what I was getting at in terms of shim stack vs spring backed "something".
Easier for anyone other than the company that produces the shock to change and modify, and typically with more options available.
This pic was from last weekend, and more white stuff has since dropped (and is continuing to drop). Local riding season may very well be over, and that means time for suspension projects! There is a lot in the works, including another coil shock test and comparison.
The Battle of the Bombers
The Marzocchi Bomber CR (and previously the Fox Vanilla RC) has gained quite a following due to the solid architecture and ability to modify it to suit a wide spectrum of end users. It utilizes a light weight and compact chassis, has a large 27mm main piston, is still available in imperial and metric sizing, and is simple to service. The stock Bomber CR is also inexpensive at $300 retail (when not on sale). A fully custom “tuned for you” CR is less than most off the shelf products offered by various suspension manufacturers, in some cases half the cost.
Avalanche Downhill Racing possibly deserves credit for first working with this platform in depth. The “Avy tuned” Bomber CR has a near legendary status being a coveted product for close to 10 years, typically with a 3+ month wait time for builds. I have had four Avy Bombers over the years ranging from cross country to DH use, all of them have been quite good.
Seeing as there are currently more options than ever for this platform, it seems like a beneficial and educational exercise to compare some of the best. SWS will be testing the following Bomber CR options in 205mm x 65mm configuration:
Avalanche Downhill Racing (East Coast USA)
Fluid Focus (West Coast USA)
Shockcraft (New Zealand)
The basics of each build will be covered, not divulging actual shim stacks or anything, but focusing more on the differences in modification and approach each company uses. These differences are broad, even with IFP pressures ranging from 150psi to 300psi (stock configuration).
As usual, BYB data acquisition and Free Lap chip timing will be used. There are also multiple bikes this time; a Transition Spire mullet build with Cascade link and 180mm of rear travel, as well as a Norco Sight high pivot with 160mm of rear travel.
The Avalanche and Fluid Focus shocks have both seen a full season of use, they will be torn down for a refresh and all three shocks will be built up using Fluid Focus 45a bottom out bumpers for consistency. The Avalanche shock will also have the shortened reservoir removed and replaced with one of stock length as well. All three chassis will be identical.
******************************************************************************************************************************************************************
This project is brought to you in conjunction with The Shimmed Base Valve, the clear choice for options and tunability. 😁
Awesome, can't wait to hear. Having owned all three, they're all unique and fantastic in their own ways.
Is the last picture showing the infamous Bomber shaft coating wear?
Fortunately no, just some reflection on that one.
Wow dude, what a comparison you are putting together. Can hardly wait.
PS. I do have an Avy Bomber and it's impressive.
Hey @Suns_PSD , looks like you relocated. Have you made it to Spider Mountain yet?
An attempt was made to get out there last winter, but it didn't pan out. Hoping to make it happen this time and looking for some feedback on the trails and facility. Lift access would be great for some test sessions.
I know you are well versed in chunky, steep trails. 😊
Had a few hiccups with getting all the parts landed for the Bomber CR builds, but finally have everything in the shop and ready to go.
Here's a little preview of three different takes on the same size piston. The differences are quite pronounced, looking forward to comparing performance.
Avalanche Suspension uses the stock piston, but may modify port sizes. I'll verify when that shock is pulled apart.
That Fluid Focus piston is actually a PUSH piston that we used to sell them as part of our DXH Factory Tuning Kit. I've seen that piston offered by a couple of independent suspension tuners that we used to sell to. Once we stopped offering those types of products, a number of tuners took the parts to local machine shops and had them reverse-engineered because they already had all of the valve codes to go with them.
Interesting that it's still floating around. How many different iterations of the DHX Factory Tune piston did PUSH make?
The FF piston is similar, but not a direct copy of this one;
Wow, that's an old pic that you shared! Total blast from the past.
To answer your question, we probably have a total of 5 piston designs that were used over the years in our Factory Tuning Systems.
Here are a couple of evolutions that made it into our ELEVENSIX rear shocks. The 3-port design used a pretty aggressive 2 degree dish on the rebound face. The 4 port reduced that to a minimum dish and adjusted the flow rate based on a change in clamp shim diameter.
What's old is new again.
Also found this piece of cinema. You should bring back that hair style @PUSH Industries . 😀
https://www.vitalmtb.com/videos/features/PUSH-Factory-MX-Tune-for-DHX,2…
Yeah, that was 2009/2010. The hair, the glasses.....we were just kids back then with big ideas. Funny seeing Eric Neeley running CAM simulations in that large empty office! Eric is a brilliant engineer who's been doing a lot of creative things at Rock Shox over the last decade.
Curious how Shockcraft goes because the owner talks a big game but I have yet to see rider reports beyond blue flow trails with a couple rocks in the middle.
Dougal is the albatross around shock craft’s neck, much like Elon is to Tesla. Could be great, but so many people refuse to bother dealing with, or supporting him, based on his behaviour.
He knows his shit very well but is kind of lacking in interaction skills on forums. He gives good support on email. I have his improved rebound piston for Mezzer Pro, and it really made stuff better. His philosophy is based on frequency, and it is difficult to explain to people not familiar with that. But the results are very good.
Post a reply to: Coil Shock Shootout