I dig the on-the-fly shimstack-tuning.
DVO Suspension - potential new player?
- Thread starter 'size
- Start date
-
- Tags
- carbon shimz
Quoted for truth.
The oil is getting pumped in and out of it every bump, So it's getting used just like your cars radiator. How much difference it'd make, well, who knows. They have increased it's surface area by quite a bit I suppose. Looks like there's no thread for the majority of the shocks body though. With the same theory of increased surface area, for dissipating heat, it's strange they've done that.
Last edited:
The body of the shock has a curve in it for some reason (weight?) that was mentioned in the initial release articles a few months ago.
Do a full DH run and touch your reservoir at the bottom, it's pretty warm. Besides the oil heating up there's also the friction from the constant movement of the floating piston (or in the case of DVO maybe a bladder which might be cooler?)
inb4 watercooled suspension with gauges "omg my fork is overheating I need to take a break guys!!!"
The oil gets mixed around very thoroughly, it's a fairly uniform temperature throughout the shock.
That's kind of what I thought. If all that heat was mainly in the reservoir, I figure that wouldn't be too good
this is my first post, first DH bike (currently building), although i have been riding DJs and bmx for about 7-8 years (i only ride 26" bikes now)..
I am glad i saw this fork a couple of weeks ago, when i first bought my frame (currently the only part i have for my build), i wasnt sure if i wanted to go WC boxxer or a 40, now i think ill wait out for the DVO.. from what ive seen so far, i have been impressed.. they really seem to care about bringing what the people want, as well as answering peoples questions just about anywhere (comments on their site, pinkbike, and here).. also very glad to see that they are offering a murdered out edition, these guys are good listeners!
anywho, i felt compelled to make an account here cause there isnt a DVO thread over on pinkbike, i really hope their june/july release date doesnt get pushed back, as i want to atleast ride my new bike once or twice this season to get her all tuned in.
I am glad i saw this fork a couple of weeks ago, when i first bought my frame (currently the only part i have for my build), i wasnt sure if i wanted to go WC boxxer or a 40, now i think ill wait out for the DVO.. from what ive seen so far, i have been impressed.. they really seem to care about bringing what the people want, as well as answering peoples questions just about anywhere (comments on their site, pinkbike, and here).. also very glad to see that they are offering a murdered out edition, these guys are good listeners!
anywho, i felt compelled to make an account here cause there isnt a DVO thread over on pinkbike, i really hope their june/july release date doesnt get pushed back, as i want to atleast ride my new bike once or twice this season to get her all tuned in.
Wise choice for such a newbie
Also, you might as well delete your pinkbike forum account. the forums there are useless. mtbr.com can provide some helpful insight sometimes. but this is the best place to come if you want to geek out and actually learn something. you can get lost in here for days, so get to it! hahaOn a serious note, you most likely can't go wrong with DVO. that being said it would still be a gamble, new company, new product, etc etc. It might be a better option at this point to go with something more proven, but if DVO keeps all their ducks in a row their stuff will be rock solid and high performance. What frame did you get?
yeah, PB has a bunch of idiots.. i think the only reason why i keep my account is to ask the 4% on there that really ride about their setups.. i really dont ride with anyone (other than my one riding buddy), and his bike is almost identical to mine.. so it really helps with seeing what the general riding public likes and dislikes.
and i know what you mean.. i am usually a pessimistic towards something brand new like this, but i dont believe there is one thing that ive seen from them that i dont like.. they just seem to have their **** together! if what they say is true, and the pricing is around what the 40 costs, im just too intrigued by there stuff to not try it..
and i got a 2012 supreme operator frame. i was going to save up for the 2012 commie supreme v3, but i got my frame for a really good deal, while still being brand new, and it even comes with the warranty card! (we'll see when i get it!)
and i know what you mean.. i am usually a pessimistic towards something brand new like this, but i dont believe there is one thing that ive seen from them that i dont like.. they just seem to have their **** together! if what they say is true, and the pricing is around what the 40 costs, im just too intrigued by there stuff to not try it..
and i got a 2012 supreme operator frame. i was going to save up for the 2012 commie supreme v3, but i got my frame for a really good deal, while still being brand new, and it even comes with the warranty card! (we'll see when i get it!)
Last edited:
just wanted to share some actual test footage from the NW Cup.
CG Testing DVO In PA on Vimeo
CG Testing DVO In PA on Vimeo
given the low viscosity index of the oil prescribed by the shock and fork manufactures, i wonder how well the temperature is intended to be controlled. typically, a low visco index oils tend to exhibit large swings in viscosity for any given temperature changed when compared with oils having a higher visco index. An SAE 5w/7.5w oil, which is typical of oils used in forks and shocks, only confirms to that SAE number at about 100 degrees celcius. Does the fork/shock oil ever reach that temperature, and just how much of a performance advantage/disadvantage are we experiencing with the oil at a generally lower temperature? Which comes back to my initial thought: to what degree is the temperature of the oil in a shock/fork controlled by the design of the fork or shock? Anyone have typical operating temperature values, or rather, target operating temperature values?
I can't imagine that they rise much beyond environment temperature. If a shock would exceed that significantly you could feel the heat on the surface.
Manufacturers that know what they are doing will not be prescribing low VI fluids for low volume applications (i.e. rear shocks and low volume fork cartridges). I'm not sure where you are getting that information from.
While a design that aids heat dissipation can help, low volume / high heat applications should use a suitable oil. There are plenty of high VI fluids available on the market, and good oils will specify a cSt at 40*C and 100*C which together can be used to calculate the VI. It's worth noting that higher viscosity oils will tend towards lower VI values, which makes sense given that oils in general will decrease in viscosity with increased temperature - thus it is easier to maintain viscosity in an oil that has a lower initial viscosity.
The negative effects of using an inadequate oil will be easy to spot in colder climates, and/or on longer runs - this will manifest itself in the form of excessive damping at the start of a run, with less (and perhaps insufficient) damping towards the end.
They do rise well beyond environment temperature, and you can indeed feel the heat on the surface of the shock. Feel the piggyback reservoir or main shock body at the end of a reasonable length run. Hydraulic damping is the conversion of kinetic energy into heat energy.
Of course they will go well above ambient, if the damper is working it is going to make heat, you can't have friction and not make heat. My brand new(very NOS) $100 Swinger is all out of damping about 1km in to my local DH track and when I ran an Elka it wouldn't feel nice until it warmed up.
I have got a heat gun so I guess I could look like the world's biggest nerd and use it after a run to check temps.
You'd imagine a machined anodised fork would cool better than one covered in paint, not sure how much difference it would make though.
I have got a heat gun so I guess I could look like the world's biggest nerd and use it after a run to check temps.
You'd imagine a machined anodised fork would cool better than one covered in paint, not sure how much difference it would make though.
It's all true, at the end of a run down Ft.Bill my shock always gets a bit 'interesting', Byrceland going OTB a few years ago was a good example (of tiredness + no rebound left)
I remember having a chat with Craig at Avy about this years ago. Iirc he designed DHS shocks to get up to around 350F. Pretty sure I could've burnt myself on mine.
People don't seem to understand that a damper is a brake system- all that energy has to go somewhere
I remember having a chat with Craig at Avy about this years ago. Iirc he designed DHS shocks to get up to around 350F. Pretty sure I could've burnt myself on mine.
People don't seem to understand that a damper is a brake system- all that energy has to go somewhere
It depends on the run's lenght. Apart from racing nobody is going full tilt >5 mins every run. Realistically more like way below the 5 minutes mark.
It's more of an issue to some smaller air shocks with less amount of oil and material that they really 'heat' up.
Otherwise Marcelo would have melted his shock in this vid:
It's more of an issue to some smaller air shocks with less amount of oil and material that they really 'heat' up.
Otherwise Marcelo would have melted his shock in this vid:
Last edited:
No, the simple fact that heat is generated does not depend on the run length, nor does it require going 'full tilt'.
As I said (and as re-iterated by a few others), hydraulic damping is simply a conversion of kinetic energy into heat energy. If there is damping, there is heat generated. No one is suggesting a shock is going to melt, however with any reasonable amount of riding, oil temperature will rise well above ambient - which is why most manufacturers will spec a high-VI fluid for rear shocks and other low volume dampers.
As I said (and as re-iterated by a few others), hydraulic damping is simply a conversion of kinetic energy into heat energy. If there is damping, there is heat generated. No one is suggesting a shock is going to melt, however with any reasonable amount of riding, oil temperature will rise well above ambient - which is why most manufacturers will spec a high-VI fluid for rear shocks and other low volume dampers.
If I do a run on my hometrail which is about 3-5 mins max and touch my shock I can't feel any difference. In theory it will get warmer but practically I never experienced an overheated shock. Only some old manitou swinger I suspected that it had a inconsistent feel on the rebound sometimes but then it had spv and felt funny in general.
Don't get too excited on this or someone will put a fan on his shock.
Last edited:
oh well, if it doesn't happen to your shock on your home trail the rest of us are obviously just plain wrong
he rides a tues, he paid for advanced engineering.
I'm going to tape shimano ice tech pads to my shock. Then I'll be set!
Seriously though, there are people who have been in DH for a while and never felt their shock warm up on a run? Try South Mountain or some other "jackhammer" run. It definitely takes way more than 3-5 minutes to get down, and all the time you are hitting bowling ball sized rocks. On the other hand, "flow" trails or very short trails may not cause it to heat up at all. All of this is perfectly normal. Now, actually affecting the damping and causing loss of damping? I haven't used any crappy shocks for a few years, but there are factors outside of that which we can't necessarily control, such as the leverage ratio and terrain. These are independent of the shock.
Last edited:
Then either your home trail is flat, or you are too slow to make the shock work.
Go put your hand on the reservoir of a dirt bike rear shock after a half hour moto, and tell me what happens.
Basically any mountain bike shock can fade on a long enough run. Whether it be 5 minutes, 10 minutes, 20 minutes, or higher, it'll happen. These things work on displacing about 10cc of fluid through a couple tiny ports to generate the damping force required to act against 300-1500# of accumulated spring force throughout the travel (rebound damping coeffecient is generally a ****load higher than compression on most vehicles since it's working against the spring force, not with it). The fluid is going to shear and give off heat on every cycle.
Totally off topic, but that video is nuts. There has to be a screw loose in people's heads who go that fast haha. Turning curvy trails into straight lines...
And my air shock on my trail bike warms up quite a bit. At the beginning of a ride it'll suck, then it gets warmed up and is good for a bit and then followed by it getting too warm and sucking again. But thats an air shock so completely different from a coil shock I assume?
friction and heat do not discriminate!
that was a seasons worth of abuse in 13 minutes
my forearms exploded
no shiit i was arm pumped just watchin as well LOL
I really hope the DVO guys aren't following this thread anymore, how did it get to 43 pages? Crazy stuff!
I've measured significant temperature rises through the piggyback bridge, reservoir and shock body on a variety of shocks over even a 2 minute run. I've got a temperature logger that I used previously to measure temperature rise in brakes over a short DH run. If you like, I'll mount it on an RC4 for a few runs this weekend and post the results? I've seen shock bridges get to 60ºC in previous experiments so I'd expect to be able to replicate something similar pretty easily.
16, nub
lelwhat?
I never said that it doesn't heat up. Just that it doesn't heat up significantly enough for most riders. I'm not enough of a nerd to take along a temperature logger but when I worked on my shocks in the alps it never felt like it was 60°C warm. I mean it feels really hot if you put your arm in water which is that heated.
I mean if you say 'short' - what is that compared to marcelos run?
Fair point. I think the VI of most oils does tend to vary a fair bit even in the limited temperature range you see. I think it is a misconception to assume that the temperature rise in a shock will directly correspond with the length of a run. Firstly, the oil will provide less damping as it gets hotter and less viscous. This means it will eventually plateau as thermal energy produced vs energy radiated in concerned. Also, the rate of radiation will increase as the differential between the internal temperature and external temperature increases.
I think all these problems are further exacerbated by air shocks which restrict the air flow over the damper body.
Very true. We can cycle a shock or fork for just a few minute and notice temps rise up in a matter of seconds.