Forks , Rebound/Compression .Teledraulic Cone and Shuttle.

Shelby-Right · 2025-01-10T23:05:12-0700

Are there any experts on this subject , is this basically saying that the rebound should be easier than the compression i:e "twice as many holes" ,
i have read that if the rebound is too slow you can get what is called (packing) which means forks stay down from too many bumps .
There are different ratios i know but im working on these teledraulic cone and shuttle , and ive been altering the forks to actually have some dampening, and ive got them to work , I found this on a technical site .

"The rule-of-thumb for compression damping is the ratio of rebound/compression damping needs to be around 2:1. That ratio makes it sound like compression damping is softer than rebound."
So this is saying less rebound than compression dampening correct ?

Any comments would be great . Cheers

gpzkat · 2025-01-10T23:25:34-0700

Interesting question and looking forward to those that are more knowledgeable than I am, of which the Internet is full of. I want the sharp impact jolts to be 'blown by' the valving and a slower response upwards, and to avoid pogo-ing. That impact absorption ability seems like a specific behavior in the valving, but overall yes, softer on compression is what I want and have experienced on well suspended bikes. Off road MX or enduro bikes are so eye-opening when set up right, they can just take on anything, just bounding over huge craters at speed with about a foot of travel is amazing to me. I have emulators on one of my bikes that I'm not happy with. It could be fluid level too high causing airlock, or other issues. They are fine under normal riding and braking, then when I hit a pothole, for instance, they just don't react right. Bam! To me it seems easier to compress, and slower to decompress is the way.

Shelby-Right · 2025-01-11T00:37:39-0700

gpzkat said:
Interesting question and looking forward to those that are more knowledgeable than I am, of which the Internet is full of. I want the sharp impact jolts to be 'blown by' the valving and a slower response upwards, and to avoid pogo-ing. That impact absorption ability seems like a specific behavior in the valving, but overall yes, softer on compression is what I want and have experienced on well suspended bikes. Off road MX or enduro bikes are so eye-opening when set up right, they can just take on anything, just bounding over huge craters at speed with about a foot of travel is amazing to me. I have emulators on one of my bikes that I'm not happy with. It could be fluid level too high causing airlock, or other issues. They are fine under normal riding and braking, then when I hit a pothole, for instance, they just don't react right. Bam! To me it seems easier to compress, and slower to decompress is the way.

Thanks for your reply, I have made the oil go though the holes instead of just going up the middle , nothing fancy here just want to remove the pogo , here's a pick it's all easy to go back to stock , or find more bits to go to damper rods , probably needs new forks anyway , there is some pitting !

only 76 years old . So I made a rod that comes down the fork and sits just above the top holes , in the lower holes there are 4 holes I've added a ring about 6mm wide and made the shuttle so that on compression the shuttle will slide up and block the 4 holes , on rebound it will slide down uncovering 4 half holes , so i have 2 holes for compression and 4 holes intotal for rebound ( 4 ½ holes = 2 holes) I still have the original cone in the bottom which works great at the last 30mm of travel , now my brass plug can be removed from the top , but the tube is thinner at the lower portion ., but I needed to have it bleed otherwise I had vacuum on the rebound stroke , I may have to drill another hole in the brass plug to decrease comp dampening, but it's actually not too bad now , it makes oil noises . I put 10 weight oil in and I will have to give it a try .not sure how the seals are going to go

. Cheers be kind .

Elfix · 2025-01-11T10:46:22-0700

Gpzkat-

The purpose of the emulators is to have the compression damping be reduced for a sudden hit or fast jolt. To do this the valve head opens against the control spring. You can adjust this by changing the spring or reducing the spring preload. All of the Emulators I’ve ever installed came with 4 springs of different colors to denote their specific tension.

You can also add additional drillings to the head which will soften the low speed damping.

The general problem with all damper rod forks is that the damping orifices are fixed and do not alter with fluid flow or speed- so one tends to have to balance the high/low speed damping rates to a central compromise. This leads to insufficient low speed damping and too much high speed damping- hit a pothole going slow and the fork bottoms, hit it hard and the forks barely move.

o0norton0o · 2025-01-11T11:15:26-0700

Cool project!

I think you have the 2 to 1 relationship backwards. It's twice as much rebound damping as compression damping. The reason the 2 to 1 is given as the rule of thumb is that compression damping is the response to a bump in the road. If you have a lot of compression damping then your bike's chassis is forced upward and unweights your traction and changes your lean angle and chassis stability. If you allow the wheel to travel more freely, (less compression damping) then the upward force only unweights the wheel momentarily without changing the angle and stability of the whole chassis, which allows the greater mass of the bike to remain stable.

The secondary reaction of your suspension after hitting a bump is the rebound. Rebound damping might actually slow down the extension of the wheel back to having traction very slightly, but it prevents the suspension behaving like a pogo stick from the initial compression and confines the spring reaction to it's compression, then it's extension, and it suppresses further bouncing. The increasing of rebound damping helps to restablize the suspension quickly after compression hits, which restores traction without a diminishing series of bounces.

* I adapted Showa dual circuit damping cartridges from a CBR600F4I to fit my commando following a modification laid out by Ken (who posts here). Here's a link to the best source of information about motorcycle damping that I have found. Just click from the list on the left side of the page to read about the different elements such as springs, dampers, hi/low speed damping, etc. It's very complex

Peter Verdone Designs - Suspension

Shelby-Right · 2025-01-11T12:26:23-0700

o0norton0o said:
Cool project!

I think you have the 2 to 1 relationship backwards. It's twice as much rebound damping as compression damping. The reason the 2 to 1 is given as the rule of thumb is that compression damping is the response to a bump in the road. If you have a lot of compression damping then your bike's chassis is forced upward and unweights your traction and changes your lean angle and chassis stability. If you allow the wheel to travel more freely, (less compression damping) then the upward force only unweights the wheel momentarily without changing the angle and stability of the whole chassis, which allows the greater mass of the bike to remain stable.

The secondary reaction of your suspension after hitting a bump is the rebound. Rebound damping might actually slow down the extension of the wheel back to having traction very slightly, but it prevents the suspension behaving like a pogo stick from the initial compression and confines the spring reaction to it's compression, then it's extension, and it suppresses further bouncing. The increasing of rebound damping helps to restablize the suspension quickly after compression hits, which restores traction without a diminishing series of bounces.

* I adapted Showa dual circuit damping cartridges from a CBR600F4I to fit my commando following a modification laid out by Ken (who posts here). Here's a link to the best source of information about motorcycle damping that I have found. Just click from the list on the left side of the page to read about the different elements such as springs, dampers, hi/low speed damping, etc. It's very complex

Peter Verdone Designs - Suspension

I thought the way that was written , rebound dampening first then compression dampening followed by 2:1 , anyway I can alter the shuttle design, no problem but I will try this first , I can drill another small hole or two in the brass plug which will decrease the compression dampening a bit .Without the brass plug when you jumped up and down on it the oil just goes up the middle of the stanchion tube I don't think it had and chance of going through any holes

, so they actually do something now it's not that noticeable but only slightly easier on the way up but still being oil dampened . Thanks, I appreciate any input .

Forks , Rebound/Compression .Teledraulic Cone and Shuttle.

Shelby-Right

gpzkat

Shelby-Right

Elfix

o0norton0o

Shelby-Right

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