Dave's Garage - Linear or Progressive Springs?
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- เผยแพร่เมื่อ 2 ธ.ค. 2022
- Ahhh, the age old question... Everyone has an opinion, but some opinions have more weight than others. Especially pro suspension engineers that do this for a living!
I was up visiting Kent at GMD Computrak and asked him to settle the debate once and for all... He is a wealth of knowledge and has probably forgotten more about this stuff than most of us will ever learn. And he has a nice, simple way of explaining things for us Muggles.
So grab a beer, watch, enjoy and LEARN.
www.gmdatl.com - ยานยนต์และพาหนะ
Excellent informative interview (thank you)!
For someone who knows pretty much nothing about suspension,this info is Tops Dave 👍👌
What you see in this video, is mirrored by any pro suspension engineer. Dave Moss, Traxxion Dynamics, Thermosman, etc...
Progressives are almost never the way, unless you don't know the weight of the rider and just want something in there so that they can "safely" ride away.
If you are trying to upgrade the forks to make them perform properly, there is zero excuse to go progressive. You have to take the forks apart anyway, you know how much you weigh... so just get the correct linear spring and do the upgrade right the first time. 🙂
🌟This is an excellent article. I'm not fitting progressive springs now I've had that explanation. Perfect guys, many, many thanks🌟
Glad it was helpful! SO many guys go progressive because "that's what I heard", rather than doing research and talking to a pro suspension guru that does it for a living. The cost difference is minimal, the effort is the same, so why not go with the much better option?
Kent be like: maybe I can get a word in at some point!😆
Yeah, I tend to do that. Haha
Great video Dave. Really useful
Thanks 👍
What he said at 3:10 - 3:45 basically poo-poos the "preload adjuster only" belief, glad I bought full kits for my 2020 INT650 and Bonneville front forks; they're not perfect but much better than just the stock progressive springs by themselves.
Excellent video about a topic that only a few riders understand and sadly one area on our bikes that gets neglected in favor of go-fast goodies / louder pipes 😂
Yeah, you can't fix an improper spring rate with more preload. You might get the sag you want, but you will bind the springs and the suspension action will be poor.
The problem is that a lot of guys don't really understand how this all works, so they don't know what to look for, or how to get things sorted, or even what questions to ask. They just hear from other guys to get progressive springs and they don't even question it.
I tried explaining this to folks, but about half the guys just "know what they know", even when what they know is wrong. haha
So I figured, don't take my word for it, listen to a guy that's been doing it for 30+ years...
... Yes, repeated again at the 7:00 mark.
My HD 2004 1200C front forks need new/different springs.
There is not much travel and it results in a rough ride.
Jeff
Thank you very informational
Agree, got myself linear
Great stuff,man! I have a 93 klx650c. I'd like to improve my fork, but only option for sale is progresive springs. Fork not adjustable. I am a heavier rider and need more stiffness. Don't know what to decide? May be small spacers and 7.5w oil(5w stock) will improve a little bit. Just drive me crazy)
There has to be a set of linear springs out there, but in a pinch, heavier progressives will at least be better than what you have...
@@SquireSCA Thanks a lot 👍
You mentioned different springs for weight . How do you reference the right ones ?
You have to determine what spring rates are in there now, and then talk to someone at Ohlins/K-Tech/Racetech and see what they suggest for your weight and riding style... They usually have a phone number or email you can send your questions to. They will almost always have a chart somewhere to reference and can get you what you need.
Would reckoned Progressive Springs foe a BMW R1250GS LC with ESA ?
Not familiar with that bike, and I am not sure how the ESA system would react with different springs? Is there a way to re-calibrate the electronics for a different spring rate?
I don't disagree with anything said here, but would add the proviso of considering older(70's) road motorcycles. With there limited damping abilities in the front forks I've found a progressive spring can works well, if properly set up for the machine in terms of preload etc. and spring rating. It seems they can give you what you need at either end of the suspension travel, a decent controlled ride over normal road ripples and bumps, while controlling much better the fork dive under hard braking. However one of the shortcomings is the lack of different spring rates available for progressive fork springs, most seem to be 35/50 rated over a whole range of motorcycle weights and do not allow for for changes in rider weight either, so while they are generally an improvement over the poor sagging OEM springs, they do not really provide any customization. I found for my Suzuki GT500 that 35/50 springs meant for the much heavier GT750 work well, even trimmed shorter to fit the forks, which leads me to believe they would be too soft for my purposes and weight on a heavier bike. So currently I'm on the fence regarding my 1978 Kawasaki KZ1000A, which I'd like to upgrade. IMO the biggest shortcoming of the progressive spring route is the lack of choice over the spring rates, as opposed to single rate springs that can be bought in just about any rate to suit the motorcycle's weight, rider weight and riding style.
I have never really had a vintage bike, so there may be additional concessions to make in those cases...
@@SquireSCA Probably a wise decision on vintage bikes ;), I have a few and there's never a lack of things that need tinkering with. The stock springs were not generally the best quality at outset and often had dubious spring rates and preload, so any sensibly thought out changes will seem amazing. Where I feel the progressive fork spring works well, assuming you can get an appropriate rate, is with the rebound damping, which in many is very poor, this seems to function better when you have the lighter weight spring rate in operation as you approach the full extension of the fork. Again the lack of spring rate choices is the Achilles heel of the progressive spring market, while they will almost certainly be a big improvement over stock on a 40+ year old motorcycle, the necessary options are not available to fine tune a suspension to suit a particular rider and machine.
Maybe Dave could shut up more and let this guy that knows stuff talk. He’s the one with the knowledge 🤦♂️
Yeah, but I wanted to make sure that certain points were mentioned and covered, for very specific debates that I tend to have with people who just think that linear springs are the answer to everything, because their uncle that rides a Harley, said so...