Author Topic: damper rods and progressive springs  (Read 332 times)

0 Members and 1 Guest are viewing this topic.

DAVE BRADY

  • Golden Flash
  • *****
  • Posts: 1982
    • View Profile
damper rods and progressive springs
« on: 17 May, 2022, 09:42:01 »
Hello All,

I am thinking of fitting damper rods and progressive springs to my wife's '51 Flash.  Has any one got direct 'before and after' experience of these?  Are they best fitted together or do the dampers give a good improvement on their own?

Dave.

idie

  • Golden Flash
  • *****
  • Posts: 771
    • View Profile
Re: damper rods and progressive springs
« Reply #1 on: 18 May, 2022, 09:31:29 »
i have tried the progressive fork springs in my B33 and Shooting Star and haven't really noticed any difference. I have also tried the damping rods but removed them as I found that it stiffened up the fork action. Alright if you were a hard rider, those days are gone for me. It's comfort not speed that counts now.

DAVE BRADY

  • Golden Flash
  • *****
  • Posts: 1982
    • View Profile
Re: damper rods and progressive springs
« Reply #2 on: 18 May, 2022, 10:06:35 »
Hi idie,

Thanks for the reply.  I was more interested in the damper rods as the standard springs seem to be ok.  It is more the forks topping out when there is a bumpy surface and getting a bit wallowy if a bump is hit in a corner.  As the bike has plunger back end any improvement is welcome.

Dave.

JulianS

  • Empire Star
  • *****
  • Posts: 2417
  • A10
    • View Profile
Re: damper rods and progressive springs
« Reply #3 on: 18 May, 2022, 13:24:20 »
I tried Dow type drop in dampers from several sources on my A10, including an original Dow set. I found that the action on compression was certainly stiffened up but that on full extension the forks still topped out. I presume because below the damper valve there is just oil but above there is oil and a coloumn of air.

I had the original fork bottoms machined to accept the later 1966-1968 damper and this improved the overal action including stopping the topping out, then, due to some corrosion on the mudguard mounting studs, I fitted 1968 Lightning/Spitfire forks.

EDDIE SIMPSON

  • Royal Star
  • ***
  • Posts: 230
    • View Profile
Re: damper rods and progressive springs
« Reply #4 on: 19 May, 2022, 23:32:53 »
hi dave, i found fork rebound dampers helped one of my b sa with poor handling. a b31. however the eventual problem was found to be worn swing arm bushing. since i ve gone to needle rollers and bobbins and am now happy. the stiffer front end is better than bouncing on the front springs as you potter along and any other issue like i had makes it worse.

DAVE BRADY

  • Golden Flash
  • *****
  • Posts: 1982
    • View Profile
Re: damper rods and progressive springs
« Reply #5 on: 20 May, 2022, 07:34:57 »
Hi Eddie,

Thanks for the reply.  It looks like any advantage to fitting the damper rods is going to be minimal so perhaps put that idea on the back burner.  As with worn swinging arm bushes, worn plunger bushes can cause handling problems especially as the sliders try to work independently anyway.  The plungers on this bike are in good order so, as my wife has not actually complained about the front end perhaps I am overthinking things.

Dave.

EDDIE SIMPSON

  • Royal Star
  • ***
  • Posts: 230
    • View Profile
Re: damper rods and progressive springs
« Reply #6 on: 22 May, 2022, 00:38:13 »
hi dave,
with my b31 handling issue i changed head races ,front tyre, fork springs then added rebound dampers which all helped but i saved the worst for last and swopped the swing arm bearings for needle rollers and cured.
recently on my a10 i had a horrible high speed veer to the left which i thought was wheel bearings but turned out to be an old tyre on the front wheel. it looked perfect but i suspect didnt like getting warmed up.
nothing worse than poor handling on a straight road at high speed.

BILL NELSON

  • Blue Star
  • **
  • Posts: 58
    • View Profile
Re: damper rods and progressive springs
« Reply #7 on: 30 May, 2022, 15:22:21 »
Hi Dave
My A65P banged horribly when the forks were at full extension.
The first problem found was that the expert classic car restorer had fitted short springs.
Back in the day, I had a good supply of springs from the factory. BSA made a range of grades & also supplied Triumph springs. The Triumph springs were graded between the BSA rates and were slightly stiffer than the equivalent BSA items, thereby doubling the options available.
As nobody seemed to know this, I had a set of springs wound by a Sheffield company and cut down a nylon bush, from a local bearing supplier, to length to give a very slight preload - the total cost was no more than buying springs of unknown origin. The preload prevented the clanging. Achieving the same effect would have been possible, if I had specified longer springs, but the factory had put me onto using spacers.
I never found much, if any, real benefit from Eddie Dow's dampers & even he said they were a step towards pretending a sow's ear was a silk purse.
The later Triumph shuttle forks are much better, but so far I haven't found anyone making & supplying new sliders. (working on a length of thick wall ally tube shouldn't be too big a task)

paulm

  • Blue Star
  • **
  • Posts: 89
    • View Profile
Re: damper rods and progressive springs
« Reply #8 on: 03 June, 2022, 22:43:47 »
Dave,
as you know my A10 is worked hard, i fitted both and it was a well worth upgrade

DAVE BRADY

  • Golden Flash
  • *****
  • Posts: 1982
    • View Profile
Re: damper rods and progressive springs
« Reply #9 on: 05 June, 2022, 16:16:51 »
Hi Paul,

Thanks for the reply.  Depending on funds we might still give them a try or at least wait until after the International.
I will put something in 'Wanted' section just in case there some gathering dust.

Dave.