Plunger suspension ride height adjustment

[paul.jameson]

There is certainly some variation in the springs Ariel fitted. The late Ralph Hawkins did some work on this which I do not have to hand but which may well have been published at some stage in Cheval. Its worth a search to see. Failing that, I think son Rob might well know as he carefully selected the appropriate springs for the KH he built - ex Ralph but noted as ridden by Chris Read.

[nevhunter]

It's a while since I had a "hands on" experience of the Anstey device ( I only have one bike with it fitted ),but the rebound spring length and strength will affect ride height as well as the major one, will it not? It would be worthwhile also to ensure both sides are set up the same seeing it's capable of some antics when it's not right. Nev

[robjameson]

We have Dave Owen to thank for the plunger springs in Chris Read’s KH. He supplied them to me at an LDR, I believe they cost me a bottle of chateauneuf du pape.

From what I recall, they were the heavier gauge springs, as the lighter gauge ones I took out of the bike were completely knackered, and had been bearing on the shrouds for some time. I may still have them.

My recommendation would be to use the strongest springs available.

[pauldridge]

Thanks for all the expertise on this subject. I've ordered the heavier gauge springs from Draganfly (apparently the only version they carry), and will report my results when they arrive.

[john.whiting]

Winding springs isnt all that difficult................a crowd named Chessel Springs used to roll up railway springs on an old lathe by hand ,after hand forging the feathered ends.........nothing exotic,just a large torch heating the rod orange as it went onto a mandrel in the lathe....The end of the rod was guided by hand.........Ive always wondered how the Indians roll the double coned girder fork springs......you cant use an inside mandrel,so they must roll them by eye.

[david.anderson]

Below are pictures of the anstey on my VHA. The bike is sitting on the ground and has minimal static sag. My 4 and other anstey plungers all have the same ride height and are all fitted with the .296 wire springs.
My 4 was initially fitted with .312 sidecar springs and I found the ride to be on a par with a rigid frame bike. Not for me. While I am 62kg, much of my riding is 2 up so with my wife there is a total of 115kg. My bike has never bottomed on the roughest roads that I have been on, although I do have friction dampers fitted. The mudguard height on my bikes is such that I doubt that it would be possible for the tyre to hit the mudguard before hitting the suspension bump stops.
I have never found any standard springs that have sagged as much as yours and would think that the springs may not be original but may be substitutes, or shortened.
David

[johann.patek]

I dismantled the rear end today and my springs corresponded with the gauge of 0.312" but the length was only 154mm against the Drag listed length of 164mm. So I made up spacers of 12mm thickness. 10mm to get the correct length plus 2mm extra to improve stiffness and keep the tire off the guard. Need more outside temperature to test it.

[adrian.hannam]

I have just replaced the springs on my KH with Draganfly ones. I measured the old ones wire size to be 0.300" and the new 0.311". The old ones were 18mm shorter. Result is approx 2" higher lift measured at the mudguard unladen with the tyre on the floor. I wasn't unhappy with the old ones until I fitted a sidecar. With a passenger, over bumps the brake lever would bind up on the mudguard stay. The new ones are very stiff.

[roger.fellows]

Interesting, they're wound the opposite way. Is the pair to each wound the same way?

[adrian.hannam]

You are very observant Roger, I will check the old ones and report back later. I won't be checking the new ones tho. I remember assembling the old ones without a special tool, but I had to make one up for the new ones.