Reba Fork Query.
Comments
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I move to strike Brianbee's POV as irrelevant from all posts :P
I second that.
You can explain things for him but you can't understand it for him.Transition Patrol - viewtopic.php?f=10017&t=130702350 -
A damper resists motion and applies no force when there is no motion,.
Are you just making up your own definitions to support your point?
please provide a link to the dictionary or encyclopedia you have obtain the above definition from,
The oxford English doesn't include those qualifications at all0 -
Still at least Revell Rider has outed himself as being just as dumb....the negative does not dampen the positive spring, it just changes the effective spring rate of the two which act combined, there is NO damping effect at all.
A damper resists motion and applies no force when there is no motion, a spring a applies a force that is related to position but is unaffected by the speed of motion (compression or rebound), it's really not that hard to understand for those with an IQ over 80.
The negative changes the spring force exerted by the positive, the two add together to provide one single spring force, the progression in each due to the changing volume in each chamber and the effect that has on pressure (so the negative drops pressure as the fork goes into bump further while the positive pressure increase).
I've been playing with Car and RC car suspension for many years......I also have 26 years in the automotive industry and while I've never worked in the chassis team, I do work with them regularly.
Although I don't I have 26 years of experience in the automotive industry, I do resent being referred to as dumb.
I may have over simplified everything in my head and had the positive and negative chambers as an equal size and used the basic description of damping "Damping is an influence within or upon an oscillatory system that has the effect of reducing, restricting or preventing its oscillations. " At 10 to 12 last night I had the wrong end of the stick, a negative spring was an influence on the positive spring restricting its movement, rather than as you put it one spring acting together with initially a lower spring rate for improved small bump sensitivity. As they say, every day is a school day
I was aware that the negative spring rate was regressive (is that the correct way of explaining it?) due to the chamber expanding as the fork compresses. I am also aware that this happens at a far greater rate to the positive springs progression due to the differences in chamber size.
Can I just ask one thing, as your experience may be able to clear this up for me, you put "a spring a applies a force that is related to position but is unaffected by the speed of motion" How does this relate to elastomer springs as found in old suspension forks and original Minis, does hysteresis not count as damping or does an elastomer not count as a spring?
And unlike Brian, it appears I can admit where I have been wrong0 -
Elastomer springs have their own internal damping, in the same way a tyre has a spring function and a damper function, in effect it is dual function. Of course the damping amount is very small and not really much use by itself, but you also get a rebound effect from bump where the initial spring force is not the same as it would be steady state but higher which partly offsets the damping and also gives elastomer sprung systems that familiar pogo stick feeling.
Ironically when I was at Rover my last job was working on the last Classic mini and we did some work looking at the Moulton units, they were definitely a lot nicer to drive than the Rover parts, Moulton had put a lot of effort into reducing the 'rebound' effect.Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
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Moulton designed the original system, he later used his consultancy to design improved units which is what we tried, but the cost of change from the units Rover had in production was too high.Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0
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Elastomer springs would be my area of expertise. I design elastomer based suspension bushes and active engine mounts for high end cars.
Elastomer springs are very different to coil and air springs. Elastomers have inherent damping qualities which you will not get from an air or coil spring as well. They also have some other interesting characteristics which pretty much make them incomparable to air and coil springs and not compatible or comparable.
As much as I dislike agreeing with Rookie, he is unfortunately correct, dual air springs have absolutely zero damping. It would be a mathematical impossibility to create damping by combining two systems which have no damping.Transition Patrol - viewtopic.php?f=10017&t=130702350 -
Wow, didn't expect to check back and see the thread go slightly off topic.
I have serviced the forks a number of times over the years and performance of them is fine. The wear hasn't caused any issue with performace. A stone caused the scratch and then the gold coating has started to wear at that spot. Not a major scratch, nothing that will cause the wiper seal or foam ring any damage.Get a decent used 2011-13 fork and mix and match the best bits seems the best way forward to me!
Wear on the stanchions doesn't necessarily degrade performance as long as the fork is now being serviced properly (which it probably wasn't before!).
It's more that the forks are 4 years old and the wear bugs my brother. Don't ask why it just does. So the change is more of cosmetics than anything else.
Did have an issue with the air spring earlier in the year. Replacing all the o-rings sorted it.I would go for the new fork, the solo air RL is a very good fork and much more reliable.
The dual air start having problems with the air springs after a few years and start needing regular rebuild to re seat o rings.
Go for a new 2015 model, Merlin did have them under £300. At that price a new CSU makes no sense.0 -
A damper resists motion and applies no force when there is no motion,.
Are you just making up your own definitions to support your point?
please provide a link to the dictionary or encyclopedia you have obtain the above definition from,
The oxford English doesn't include those qualifications at all
Ive copied this down, as you have a bad habit of ignoring points when you have no answer
Please supply your definition of ''damping'' from an authoritative source, rather than just saying you have been messing about with cars for 3 decades0 -
RMSC already suppli d you with a reference, just because you don't understand what the whole of the engineering world understand is meant by damping, doesn't mean I have to prove to you what the whole world knows already, life is too short.Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0
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RMSC already suppli d you with a reference, just because you don't understand what the whole of the engineering world understand is meant by damping, doesn't mean I have to prove to you what the whole world knows already, life is too short.
yea, as i suspected, its just like the trespassing thread, you make WILD claims, tell me you an expert,then refuse to back it up
If that is indeed the definition of damping, give a source for it, you wont because you cant0 -
If you don't understand the principles involved, no definition is going to help you.I don't do smileys.
There is no secret ingredient - Kung Fu Panda
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Parktools0 -
So the negative and positive work together to change the spring rate through the range of movement, much like a progressive spring on a car which has unequal coils - there are 2 chambers as an air spring is a linear spring so it needs another air spring to make it progressive. It slows down not because it is being damped, but because it is progressive and spring rate increases at the higher end of the travel.
Or shall I just get my coat??0 -
RMSC already suppli d you with a reference, just because you don't understand what the whole of the engineering world understand is meant by damping, doesn't mean I have to prove to you what the whole world knows already, life is too short.
yea, as i suspected, its just like the trespassing thread, you make WILD claims, tell me you an expert,then refuse to back it up
If that is indeed the definition of damping, give a source for it, you wont because you cant
Brian,
You're close to trolling and, let's be honest, getting rather tiresome.
Both 'The Rookie' and 'RockmonkeySC' appear to have some experience & knowledge (via their work) in this area which, unless I'm mistaken, you don't.
I am not a technical expert in springs & damping theory. However, I do own several pairs of RS dual air forks and my experience of them tells me RMSC & Rookie are correct.
What's your experience of RS dual air forks?0 -
Did you read the link provided by RMSC?RMSC already suppli d you with a reference, just because you don't understand what the whole of the engineering world understand is meant by damping, doesn't mean I have to prove to you what the whole world knows already, life is too short.
yea, as i suspected, its just like the trespassing thread, you make WILD claims, tell me you an expert,then refuse to back it up
If that is indeed the definition of damping, give a source for it, you wont because you cant
http://www.brown.edu/Departments/Engineering/Courses/En4/Notes/vibrations_free_damped/vibrations_free_damped.htm For something more hi-tech.
Wild claims, no that's from you.Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
I DON'T UNDERSTAND PHYSICS SO IT'S TRUE. SPRINGS AND DAMPERS ARE THE SAME.
All of Brians posts combined in to one.Transition Patrol - viewtopic.php?f=10017&t=130702350 -
Did you read the link provided by RMSC?RMSC already suppli d you with a reference, just because you don't understand what the whole of the engineering world understand is meant by damping, doesn't mean I have to prove to you what the whole world knows already, life is too short.
yea, as i suspected, its just like the trespassing thread, you make WILD claims, tell me you an expert,then refuse to back it up
If that is indeed the definition of damping, give a source for it, you wont because you cant
http://www.brown.edu/Departments/Engineering/Courses/En4/Notes/vibrations_free_damped/vibrations_free_damped.htm For something more hi-tech.
Wild claims, no that's from you.
You have given a definition of damping, which you have made up and isnt in ant dictionary or text book. That is dishonest. You are now just flipping about, so you don't have to admit your deception0 -
I haven't been making anything up, no need as you've been doing that.
Note you are the only person now claiming black is white, as clearly you won't ever be convinced and are set on being uneducated, I'll leave you to it.Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
Come on Brian, at least I have the good grace to admit when I was wrong and attempt to learn from my mistakes.So the negative and positive work together to change the spring rate through the range of movement, much like a progressive spring on a car which has unequal coils - there are 2 chambers as an air spring is a linear spring so it needs another air spring to make it progressive. It slows down not because it is being damped, but because it is progressive and spring rate increases at the higher end of the travel.
Or shall I just get my coat??
My understanding of an air spring (and I am willing to be proved otherwise) is that it is progressive by it's nature. Coil springs can be made linear or progress due to their winding, but with an air spring their progression can be tailored by the volume of the air chamber. This is why companies like Fox do larger volume air cans for rear shocks, Trek used to use the DRCV rear shock on their trail and all mountain bikes (a second air chamber opens part the way through the stroke to increase the volume, changing the progression curve) and Rock Shox and Fox offer inserts for the air chambers of their shocks and forks so you can ramp up the progression towards the end of the stroke.
The negative air spring is there to change the initial spring rate in a suspension fork and because of the small size of the negative air chamber the further you compress a fork (expanding the negative air chamber), the less it has an effect on the spring rate of the positive air chamber. The compression of the fork is not slowed because of the progression of the spring, that would be the damper acting on the spring. As The Rookie explained to me "a spring a applies a force that is related to position but is unaffected by the speed of motion" so an undampened fork will still compress the same amount over the same bump as a correctly dampened fork but it will do so with less control.0 -
I posted a link to a page with a very straightforward description of damping.
A damper will slow and control motion. This can be done through various means including viscous fluid forced through orifices, mass damping or in elastomers by stretching and breaking chemical bonds. A damper works by converting energy from motion to another type of energy.
An air spring does none of this so cannot have any damping. Dual air is a method of changing spring characteristics.Transition Patrol - viewtopic.php?f=10017&t=130702350 -
I posted a link to a page with a very straightforward description of damping.
A damper will slow and control motion. This can be done through various means including viscous fluid forced through orifices, mass damping or in elastomers by stretching and breaking chemical bonds. A damper works by converting energy from motion to another type of energy.
An air spring does none of this so cannot have any damping. Dual air is a method of changing spring characteristics.
That says including, so its not an exclusive list of types of damping
AND an air spring DOES convert motion to another form of energy, So it would seem to count anyway ?0 -
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By your definition then, everything in a suspension fork can be considered a damper? Friction from the bushes. DAMPER! Drag from the wiper seals. DAMPER1! The stone caught between your fork brace and stanchion. DAMPER!!
I havent given a definition, Its other peoples definitions that seem to include those aliments. And thats hardly my fault !0 -
By your definition then, everything in a suspension fork can be considered a damper? Friction from the bushes. DAMPER! Drag from the wiper seals. DAMPER1! The stone caught between your fork brace and stanchion. DAMPER!!
To a certain extent, yes. But just not controlled.
An air spring is absolutely not a damper. It converts motion to potential energy and straight back to motion.Transition Patrol - viewtopic.php?f=10017&t=130702350 -
You put -AND an air spring DOES convert motion to another form of energy, So it would seem to count anyway ?
Friction between a seal or a bush may generate heat, a stone between brace and stanchion would create sound. All 3 examples I gave convert motion into another form of energy. They count.0 -
To a certain extent, yes. But just not controlled.
An air spring is absolutely not a damper. It converts motion to potential energy and straight back to motion.
My comment was not aimed at your post explaining about dampers, it was to highlight the stupidity of Brains comment about motion within an air spring converting the motion to another form of energy. I'm going to assume he means heat energy, which in an air spring changes the spring rate (and the reason why they were never originally popular on downhill bikes)0 -
I always thought anyone could learn anything. Now I'm convinced I was wrong. Some people are just thick.Transition Patrol - viewtopic.php?f=10017&t=130702350
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Quite frankly this has been a lost cause from the start. I suggest abandoning this senseless squabbling and returning to our lives.Current fleet
2015 Transition Scout
2012 Nukeproof Scalp
2016 Genesis Latitude
2012 Transition Double
2012 Transition Trail or Park
2006 Trek SL1000
2017 Fly Proton
???? Create Polo Bike0 -
I always thought anyone could learn anything. Now I'm convinced I was wrong. Some people are just thick.
I sincerely hope that was not aimed in my direction.0 -
