The rate or resistance is relative.lukee said:Hi all,
Is anyone able to explain to me what the terms falling and progressive spring ratio mean, and what the benefits are of each? any feedback would be appreciated.
thanks
Lukee
That's a pretty good explanation, way more in depth than what I was going to say.derby said:The rate or resistance is relative.
In bikes and motorsports we usually call a spring that increases in resistance at a constant rate "linear".
Linear Rate Example: 1st inch of compression = 100 lbs, 2nd inch = 100+100=200 lbs, 3rd inch 100+100+100=300 lbs., etc.
Rising Rate Example: 1st inch of compression = 50 lbs, 2nd inch = 50+100=150lbs, 3rd inch 50+100+150=300 lbs., etc
Falling RateExample: 1st inch of compression = 150 lbs, 2nd inch = 150+100=250lbs, 3rd inch 150+100+50=300 lbs., etc.
Leverage from linkage will modify the rate of the spring. Around 360 degrees of rotating link leverage there are angles between two levers with a common pivot that are rising, then transition to falling, transition to rising, and falling again, and again, etc. every 45 degrees of usable range of pivoting leverage.
Combining rising and falling rates of linkage livers and springs (sometime springs are stacked with different rates) becomes more linear, with bias towards the stronger rate change at any moment. Rising plus rising becomes extremely rising, and vice-versa.
Rising rate gives a more compliant slow-speed compression (less resistance to pedal bob) and small bump compression and smooth deep travel big hit resistance. Falling rate gives less compliant slow-speed compression (more resistance to pedal bob) or small bump compression and less deep travel big hit resistance with more bottom out danger.
Damping modifies spring action rate too. Platform shocks add a short duration falling rate effect at the beginning of compression, and is better matched with more common rising rate net spring plus linkage leverage resistance.
- ray
derby said:The rate or resistance is relative.
In bikes and motorsports we usually call a spring that increases in resistance at a constant rate "linear".
Linear Rate Example: 1st inch of compression = 100 lbs, 2nd inch = 100+100=200 lbs, 3rd inch 100+100+100=300 lbs., etc.
Rising Rate Example: 1st inch of compression = 50 lbs, 2nd inch = 50+100=150lbs, 3rd inch 50+100+150=300 lbs., etc
Falling RateExample: 1st inch of compression = 150 lbs, 2nd inch = 150+100=250lbs, 3rd inch 150+100+50=300 lbs., etc.
Leverage from linkage will modify the rate of the spring. Around 360 degrees of rotating link leverage there are angles between two levers with a common pivot that are rising, then transition to falling, transition to rising, and falling again, and again, etc. every 45 degrees of usable range of pivoting leverage.
Combining rising and falling rates of linkage livers and springs (sometime springs are stacked with different rates) becomes more linear, with bias towards the stronger rate change at any moment. Rising plus rising becomes extremely rising, and vice-versa.
Rising rate gives a more compliant slow-speed compression (less resistance to pedal bob) and small bump compression and smooth deep travel big hit resistance. Falling rate gives less compliant slow-speed compression (more resistance to pedal bob) or small bump compression and less deep travel big hit resistance with more bottom out danger.
Damping modifies spring action rate too. Platform shocks add a short duration falling rate effect at the beginning of compression, and is better matched with more common rising rate net spring plus linkage leverage resistance.
- ray
ray, how do you determine the rate of a linkage again? Is the only way to use a linkage software? thanksderby said:Rising rate gives a more compliant slow-speed compression (less resistance to pedal bob) and small bump compression and smooth deep travel big hit resistance. Falling rate gives less compliant slow-speed compression (more resistance to pedal bob) or small bump compression and less deep travel big hit resistance with more bottom out danger.
Damping modifies spring action rate too. Platform shocks add a short duration falling rate effect at the beginning of compression, and is better matched with more common rising rate net spring plus linkage leverage resistance.
- ray
It is possible to determine the rate of a linkage by simply looking at it. Of course this will only give you a rough idea of the overall rate, and is often very difficult to do.BanzaiRider said:ray, how do you determine the rate of a linkage again? Is the only way to use a linkage software? thanks
I'm probably stupid but what do you look at exactly! haha I've taken out my shock a couple of times and cycled the suspension freely but I don't really see what defines the rate. Thanks.WheelieMan said:It is possible to determine the rate of a linkage by simply looking at it. Of course this will only give you a rough idea of the overall rate, and is often very difficult to do.
If you're really interested, just measure it. Start by measuring the distance across the shock eyelets so you know the position of the suspension at full extension, then remove the shock. With the shock removed, position the suspension at the previously measured full extension. From this point simply compress the suspension 0.25" at a time (measured at the wheel) and note down the corresponding shock movement. Repeat this process all the way through the travel and you'll end up with a curve of wheel movement against shock movement. The changing gradient of this curve defines whether it's linear, rising or falling rate.BanzaiRider said:I'm probably stupid but what do you look at exactly! haha I've taken out my shock a couple of times and cycled the suspension freely but I don't really see what defines the rate. Thanks.
Thanks guys (uktrailmonster, drunkle and All Mountain), this should occupy my spare time tonight!!! I'll try to figure it out and probably come back with more questions as I'm quite bad with mechanics/physics stuff...uktrailmonster said:If you're really interested, just measure it. Start by measuring the distance across the shock eyelets so you know the position of the suspension at full extension, then remove the shock. With the shock removed, position the suspension at the previously measured full extension. From this point simply compress the suspension 0.25" at a time (measured at the wheel) and note down the corresponding shock movement. Repeat this process all the way through the travel and you'll end up with a curve of wheel movement against shock movement. The changing gradient of this curve defines whether it's linear, rising or falling rate.
So what would they call it then?WheelieMan said:(PS. Some might argue that "rising rate" is not the correct term to describe the curve in the first 2/3 of the travel, but it is the word that I feel is best. The semantics of suspension terms can get extremely confusing.)
Well in my opinion, "rising rate" describes a suspension that becomes harder to compress as the bike goes through the travel. Doesn't matter if it becomes progressively harder to compress, or "regressively" harder to compress.uktrailmonster said:So what would they call it then?
specify leverage vs spring vs system...WheelieMan said:Well in my opinion, "rising rate" describes a suspension that becomes harder to compress as the bike goes through the travel. Doesn't matter if it becomes progressively harder to compress, or "regressively" harder to compress.
I'm not sure how else to describe that sort of shock rate.
It does matter, because eventually that "regressive" rate becomes falling rate. It depends on the travel of whatever bike, but since the regressive rate is a curved line, it will eventually turn downwards. So a bike could be "progressive" during the beginning of the travel, and then falling-rate near the end. It would ride kind of funny, but this is one problem that people run into when they put longer-stroke shocks on their bikes than were intended, although a couple bikes have rates regressive rates that turn into falling rates because they were simply designed this way. The VPP10 is a good example, starts off as progressive, the the curve levels off, and then it goes back down. They expect the progressiveness of the shock to offset this.WheelieMan said:Doesn't matter if it becomes progressively harder to compress, or "regressively" harder to compress.
I'm not sure how else to describe that sort of shock rate.