The Tuesday Tune Ep 9 - Single Tube and Twin Tube shocks
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- čas přidán 2. 01. 2017
- Pretty well all the shocks currently on the market in the mountain bike world are one of three basic forms:
1. Inline/Monotube, eg Fox's Float RP23/CTD/DPS series, Rockshox's Monarch RT3 or X-Fusion O2
2. Single-tube (with separate or piggyback reservoir), eg DVO Jade, Fox RC4, BOS Stoy, Ohlins STX
3. Twin-tube (again with separate or piggyback reservoir), eg Cane Creek Double Barrel series (including the Inline), Ohlins TTX, Fox DHX2 and Float X2
The major defining difference between inline/monotube shocks and the single-tube type, as we're discussing them here, is that monotube shocks only have a single damper piston, and the IFP charge is the only thing providing pressure to force oil through the piston in compression. We won't be discussing those today. Single-tube types with a base valve (a second compression circuit usually mounted in the reservoir bridge, and which is usually the external compression adjustment) are a common configuration for mountain bike shocks. Twin-tube dampers are often visually similar to the single-tube dampers (CCDB Inlines being a notable exception) in terms of layout, but there are some differences.
This week on the Tuesday Tune, we're looking at what some of those differences are, where the twin tube concept came from and how the different layouts tend to behave as they currently exist.
Great video, i learn so much from your vid to become the best setup for my vivid r2c 5.1
Most of my experience is with monotube dampers in motorsport but I ride as well. With regards to hysteresis in twin tube dampers, my understanding is that the high amounts of external adjustment create higher levels of hysteresis as the adjusters are having to move further. A monotube design shimed so the adjusters are close to closed with much of the bleed achieved with notched shims or fixed orifices would give less hysteresis. How would the twin tube design be configured to reduce hysteresis? I was recently having a conversation with an ex Penske engineer about Ohlins having significantly higher levels of hysteresis but he was likely to be bias!
I love your videos. That's the comparison I've searched for. My RC4 with custom shim stack runs great, but everyone says the new fox dampers were way better.
Awesome stuff! I have learnt so much through your videos, now need to make sense of it all. Suspension is very interesting and the more I find out the more I want to know. Any good book around to look at? Been getting some theoretical info from the suspension suppliers, but was wondering if there are suspension specific books.
Keep the videos coming!
Search for the "Shock Absorber Handbook" by John C. Dixon on google. It is aimed at a motorsport and automotive applications but is very interesting.
What about shocks that have reversed layout compared to what you've shown here, as in the reservoir flow comes through the damper shaft? Like DPX2 or Mara Pro for example, those 2 have separate pathways for the compression and rebound in there as well, twin tube alike.
Another great video. Why is it only the rebound that has the digressive damping curve in the twin tube design and not the compression also?
The compression does too, but there's a lot more consensus on digressive compression damping working well - nobody ever runs progressive compression damping in the same way they might with rebound.
What's the impact of running with high IPS pressure? Should we just use the recommended IPS pressure?
what shock type is recommended for a progressive frame like a evil wreckoning?
Can you do something like this where you go in depth on the mechanics of a particular shock design except check one the DVO Topaz and compare how it functions to something like a Fox Float. The DVO uses a bladder so I would really intersted on the mechanics of it compared to other shock designs and what potential advantages or disadvantages it has. I've used a Fox DPS, Rockshox Deluxe RT3, Deluxe Select+, and my DVO Topaz. The Topaz so far feels miles better than any of those I mentioned. I guess some of that is the upgrade from inline/monotube shocks to a Single-Tube with piggyback.
The dpx2 is twin tube but i know you said the rebound has a massive effect on the compression in a fb post.
It seems to suffer serious aeration issues too.
Any notes on this shock from your experience
happy hair cut day!
digressive rebound curve, why is it bad? (or can be bad)
As far as I understand, a digressive rebound curve means that the rate of rebound damping will decrease throughout the travel of the shock. Imagine you've cased a drop at high speed and bottom your shock out- your shock will rebound quicker to start and then slow down towards full extension of your shock, potentially bucking you over the bars.
@@ilovemileycyrusok digressive/progressive damping relates to shaft speed and not position in the stroke. A progressive would have more damping force at high speed (casing a jump or a square edge impact like a root) and less damping at low speed (rollers). Generally we want digressive damping because square edge hits are usually short (roots, rocks) so it’s good to let the wheel move fast. But g-outs can be long and slow and cause bottoming with too little low speed damping.
For rebound, I would thing digressive is bad because your wheel will already rebound quicker when there is no load (leaving the ground) versus when rider weight is present (rebounding after landing a jump). So digressive would exacerbate those movements.
What? as far as I know in Motorsport mono tube is preferred
In the automotive world, monotube shocks usually refer to sealed dampers and twin tube ones (other than the TTX type like Ohlins makes, which are sealed) are emulsion dampers, which are cheap garbage. Nobody makes emulsion dampers for MTB rear shocks, and likewise nobody in any serious motorsport is using an emulsion damper.
@@VorsprungSuspension What exactly is an emulsion damper? Is it like when the oil and the gas charge (or air) isn't physically separated with like an IFP or bladder? Basically the Motion Control in a RS Yari would be an emulsion damper right? Or wrong?
Nice video. However, with your mention of twin tubes having a performance benefit in road racing, I disagree. Interesting video on the subject: czcams.com/video/ErAhHjR6mFo/video.html
The term "twin tube" when used with passenger vehicles refers to emulsion dampers which are total POS's compared to anything we're discussing - if you tip them upside down they stop working The monotubes are a sealed unit more like a Fox Float CTD. In that video they're talking about upgrading from absolute garbage to the worst thing the MTB industry actually uses. The term twin tube in the context of mountain bikes or actual race cars is a totally different thing.
Right I get you. I had assumed that some of the more reputable companies twin tubes were more like a ttx, but it seems I was wrong. There are a lot of very expensive (but garbage) dampers out there for the automotive market it seems.
Haha...float dhx2 that use twin tube is most cavitated rearshock depend single tube 🤦♂️🤦♂️
You're mistaking aeration for cavitation. They are not the same thing.