View Full Version : progressive fork springs....
ducatilover
17th March 2006, 10:18
where would i get some racetech or progressive fork springs for my bros650? and what are gold valve emulators? and are they worth having? :rockon:
cowpoos
17th March 2006, 10:26
where would i get some racetech or progressive fork springs for my bros650? and what are gold valve emulators? and are they worth having? :rockon:
you don't want progresive springs for a road bike [good for dirt bikes] you want linier rate springs....
and any form of cartiridge emulator is well worth having in a conventional fork.. ring robert taylor at hawera motorcycles 06 2784160 for all suspension questions
ducatilover
17th March 2006, 10:28
you don't want progresive springs for a road bike [good for dirt bikes] you want linier rate springs....
and any form of cartiridge emulator is well worth having in a conventional fork.. ring robert taylor at hawera motorcycles 06 2784160 for all suspension questions
why not progressive springs? dont they stiffen towards the end of their travel?
thanks for the number:Punk:
cowpoos
17th March 2006, 10:37
why not progressive springs? dont they stiffen towards the end of their travel?
thanks for the number:Punk:
yes they do and thats the problem with them...you want your suspension to be softer at the end of the travel...the opposite to what most people will tell you...road bike suspension should be digressive never progresive...
pritch
17th March 2006, 11:47
As I understand it, when you fit your Ohlins, WP, whatever forksprings they are constant rate. You throw the oe (progressive?) springs in the can.
Pixie
17th March 2006, 11:54
yes they do and thats the problem with them...you want your suspension to be softer at the end of the travel...the opposite to what most people will tell you...road bike suspension should be digressive never progresive...
correction Mr Poos
Dr Bob advocates linear springs and digressive (should be regressive) damping.
I'd like to see a regressive spring..... it would be a wonder to behold and would defy the laws of physics.
The Stranger
17th March 2006, 12:06
The ones that Robert Taylor supplied for my bike are constant rate and far superior to the original progressive rate springs.
Best value mod you can make, for a few hundred dollars I can carry a lot more speed in the corner.
cowpoos
17th March 2006, 12:49
correction Mr Poos
Dr Bob advocates linear springs and digressive (should be regressive) damping.
I'd like to see a regressive spring..... it would be a wonder to behold and would defy the laws of physics.
I said "should be" and I also said linear springs are the go....a re-read would be in order lad!! and yes you can make a spring digresive/regresive by using linkages on the rear shock of the bike...as all race teams do and most mordern bikes do...
cowpoos
17th March 2006, 12:51
constant rate and far superior to the original progressive rate springs.
.
constant rate is linear.... :yes:
Lou Girardin
17th March 2006, 15:17
How did this get from fork springs to shocks?
BTW linear rate is best. Progressive springs were fine in theory, never seemed to work properly.
jonbuoy
17th March 2006, 15:24
Econohonda got me some for the VTR, Hyperpro ones You can find out what value to use from the Hyperpro website then get them to order them in. I find them miles better than the standard VTR ones, has made a huge difference to the front end. Not sure how different Linear ones would feel in comparison. I'm sure there must be a reason to go to all the trouble of making them progressive , the original showa ones were progressive too.
Paul in NZ
17th March 2006, 15:43
Meh! Both my bikes have progressive suspension.
In fact, when they were made suspension was considered a pretty progressive step, especially at both ends!
Paul N
(put it this way, the triumph is a competition model so it comes from the factory with sidecar springs)
Paulus
17th March 2006, 18:39
Gold valve cartridge emulators are only for those that don't already have a bending shim stack type damper. In a normal orifice type damper there are fixed size holes for the damper oil to flow through. These ports will only flow at certain rate causing them to lock or spike on big (speed) hits. In a bending shim system the bigger (faster) the hit the more the shims will bend and so the more damper oil they will flow. You can also put them together in ways to give yourself differing damping characteristics. They are a speed sensitive damping system.
The Gold emualtors use a spring loaded poppet valve to partially emulate the characteristics of a bending shim system. You usually have to enlarge your old damper holes so that they are no longer providing the damping control.
This is a bit of a simplification but hopefully it will help with the understanding. I seem to remember that there was a good article on Penske's website if you want to see how bending shim stack dampers function.
Also the air spring effect at the end of your forks stroke will make them progressive at the end anyhow.
Jackrat
17th March 2006, 20:21
why not progressive springs? dont they stiffen towards the end of their travel?
thanks for the number:Punk:
Yes I put Progressives in my XS and they improved the front end responce and allround handling out of sight,they acted on the whole feel of the front end not just the final part of the travel all though that was better than I'd even hoped for.They are probably the cheapest and easiest up grade you can do.They work really well and can be bought for any bike.
ducatilover
17th March 2006, 20:22
i'll have to talk to the mechanic doing the work on the forks, but from what has been sdaid i'll get some valve emulators and some lineir rate springs:cool:
so i take it i can change the damping rate if i have gold valve emulators?:2thumbsup
Pixie
17th March 2006, 20:39
I said "should be" and I also said linear springs are the go....a re-read would be in order lad!! and yes you can make a spring digresive/regresive by using linkages on the rear shock of the bike...as all race teams do and most mordern bikes do...
Aahh,but that wouldn't be the spring,then,would it?
cowpoos
17th March 2006, 20:44
Aahh,but that wouldn't be the spring,then,would it?
well yes you are completely right about that if we want to get right down to the knitty gritty.... lol
Pixie
17th March 2006, 20:47
Actually, I really wanted to see a regressive spring.
That would prove Einstein confused and I could build a wormhole to the twisty galaxy
Paulus
17th March 2006, 21:06
i'll have to talk to the mechanic doing the work on the forks, but from what has been sdaid i'll get some valve emulators and some lineir rate springs:cool:
so i take it i can change the damping rate if i have gold valve emulators?:2thumbsup
I believe they are tuneable but you'd have to strip your forks each time to do it.
BTW a good manual on modern shim type shocks (and forks) can be found here:
http://www.penskeshocks.com/8900%20Motorcycle%20Manual.pdf
It's a big file though.
WINJA
17th March 2006, 21:14
i put progessive springs in a few bikes now mainly my older bikes and i thought they made the bike a little better all round , allround being two up , tank bag , touring or scratching.progressive springs would be better than fucked springs in any case , theyre not great for racing or if your finding that last bit of cornering performance
ducatilover
19th March 2006, 15:48
i put progessive springs in a few bikes now mainly my older bikes and i thought they made the bike a little better all round , allround being two up , tank bag , touring or scratching.progressive springs would be better than fucked springs in any case , theyre not great for racing or if your finding that last bit of cornering performance
i wont be having any touring gear or pillions. and the current springs are fairly fucked:confused:
terbang
19th March 2006, 16:06
Used to fit Progressive to my old girls and they were fine. Had a 1200 bandit that didn't give many front end options and after a lot of mucking about with sorting out spring suitability I settled for Eibach (http://www.eibach.com/) springs front and rear, gold valves in the front and a Gixxer 1000 rear shock.
ducatilover
19th March 2006, 16:19
if this helps i will be riding her hard through corners and the roads around my area are susceptible to corrugations :puke: :crybaby: .... it wont get used much on track though [unlees you include the rimutaka hill] im really small [ 5/9 55kg] but i do tend to ride faster than i should. i know i'll get valve emulators and some aftermarket springs. just what springs:cool:
cowpoos
19th March 2006, 19:55
ring robert my lil friend....he's NZ's top suspension tuner for bikes...or even PM shaun....ask him
ducatilover
19th March 2006, 20:50
i'll get to it soon:niceone:
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