Building an Ohlins Shock

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Here is a quick way to mount the clamp toward the center of the damper.
Another way would be to make a new bracket where the damper mounts to the bottom of the lower triple clamp, est time 1 to 2 hours for that. (that would be unanodized)

 
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p400

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I have four daily rider Nortons in my neighborhood and they are all Mk3.
The Mk3 revised the front caliper to the left side and added a hole in the lower T clamp for the brake hose.
Will this Öhlins damper clear the hose?
Thanks

Mk3BottomTClamp2.jpg
 
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I have four daily rider Nortons in my neighborhood and they are all Mk3.
The Mk3 revised the front caliper to the left side and added a hole in the lower T clamp for the brake hose.
Will this Öhlins damper clear the hose?
Thanks

View attachment 17929
Without seeing what the hose looks like it is hard to know for sure.
But the spacer is less than 18mm diameter which is smaller then the machined flat it butts up to.
The dia of the spherical bearing and mount on the damper is 26 mm, this is mounted down due to the length of the spacer, so I would assume the OEM Norton brake hose is a normal diameter for a brake hose at that point there looks to be plenty of room.
Can you take a picture on the bike with the hose showing?
In the second picture another 18 mm spacer is shown to give you an idea the amount of space.

 
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p400

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Here are some pics of a Mk3 lower T clamp.
Forks straight is not a concern, forks at left fork stop might be.

Rubber plug still in place where damper is to mount.

20200731_Tclamp1.jpg
20200731_Tclamp2.jpg
20200731_Tclamp3.jpg
 

lcrken

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I just fitted a set of the HD022 shocks from Dan on my grandson's MK3, replacing the Works Performance shocks we've been using on it. They were bolt on with no problems. They are fitted in the inverted positon because they clear the chain guard that way with no problem. I also tried them in the upright orientation, just to see if that worked. I had used .250" spacers on the bottom mount with the Works shocks so the spring would clear the chain guard, and those also worked with the Ohlins, but with the spring just barely touching the chain guard. another 1/16" inch or so on the spacer would provide plenty of clearance. Unfortunately, I didn't take any pictures of it in that position. The spacers do splay the shocks out at the bottom, and that might bother some folks. We've run the bike that way with the Works shocks for several years now, and I don't think anyone has noticed that the shocks aren't perfectly vertical. I may go ahead later and flip the shock to the upright position to get a little more range of preload adjustment. But for right now, I wanted to show how it fits a MK3 with no mods needed. I'll be posting some comments on the handling after my grandson and I have put some miles on it. We have three different spring rates to try, if needed.

Left Side Rear 1200.jpg


Chain Guard Clearance1200.jpg


Right Side 1200.jpg


I couldn't resist this shot of the two Nortons together, both with Ohlins shocks.

Twin Nortons.JPG


Sorry about the glare in the picture. The sun was just going down right behind the shop.

Ken
 

gortnipper

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That is how IKONs fit, reservoir down and spring on top.

How much preload is on there now, would it work for a 200lb single rider, in sporty street mode?
 

p400

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Thank you for the post with photos.
Are you fitting Öhlins to the Lark?
Right now the Mk3 is running Öhlins 00360-06 spring set?
What are the dimensions/weight of grandson?
 
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lcrken

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Thank you for the post with photos.
Are you fitting Öhlins to the Lark?
Right now the Mk3 is running Öhlins 00360-06 spring set?
What are the dimensions/weight of grandson?
Dan set them up for what he thought would work for a 180 lb rider. Grandson is probably 10 lbs or so less than that with full gear, and 6 feet tall. I'm probably 10 lbs more with full gear. So these springs are a good starting place. The springs are the 00360-06 and have about 15 mm of preload cranked in. It looks like I have room for another 10 mm or so of preload. More than that would require me to make some spring spacers. But if it requires that much preload, we will just go to the stiffer springs. I don't really expect that. If anything, I think we might end up with the softer ones. But we really just have to try it out and see. The goal is to end up with a spring rate that works for both of us, as well as for grandson with passenger, with just different preload settings.

We will check for sag, and adjust if needed, and then do some riding.

OH yeah, the Lark. It's sitting on a shortened Buick Skylark chassis with aftermarket front A-arms and Bilstein shocks and full Wilwood brakes. I'm in the process of building a blown Stude V8 for it.

Ken
 
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lcrken

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That is how IKONs fit, reservoir down and spring on top.

How much preload is on there now, would it work for a 200lb single rider, in sporty street mode?
Currently has about 15 mm preload. I'm probably close to 200lb with full riding gear, so we're about to find out how it works.

Ken
 

p400

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What is your "bike on the ground" spring length please?

I am not interested in R or F dimensions, just spring length please.


20200829_123917.jpg
 
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It is also interesting that you can look at these two bikes in the pictures above, and see the shock angles are completely different.
The red bike may also have a different length swingers.
These factors would require some differences in the shocks, most likely different springs, as the leverage is different, possible different damping as well.
On all of the twin shock designs, the leverage on the shocks is far less the most mono shock designs. This allow us to use far lighter spring rates, and even when we are changing the spring rates for different weight riders the damper changes if they are needed are very small. Usually the standard damping can cover 2 to 4 spring rate changes without the damping needing any change.
Most mono shock designs use a linkage, for two reasons, the first is to make the shock travel (stroke) shorter, this reduces the length of the shock, making it easier to package in todays motorcycles.
the second is that with a linkage you can design it to be either digressive, very rare to see this, linear, or progressive.
Progressive is what all sport bikes use. Usually a 3% to 5% progressive rate, works the best for solo riding. As well as track use.
When twin shocks are mounted straight up and down, as they are on the red bike pictured above, they are linear.
When the twin shocks are mounted an angle as on the Black Commando above, they are progressive.
As British bikes advanced, you can see they all started doing this, meaning mounting the shocks at an angle, making them progressive.

There are also Linear and Progressive springs. like most choices, they both have advantages and disadvantages.

But first what is linear, it means as the shock or spring is compressed, it produces the same movement or rate increase for each mm or if you prefer inch of movement.
Example: a 22 Nmm spring, or spring mounted on a shock, that is linear, as is the Stock Norton spring produces 22 nmm of resistance for each mm of compression, so the first 1 mm of shock movement produce 22 Nmm of resistance, and the last 22 mm produce 22mm of resistance, Linear.

This on a graph, appears as a straight flat line, as you can see in the spring chart I posted earlier.

Progressive:
With a progressive design the amount of movement of the shock stroke is changed, as it is moving thru its stroke, the further it is in its stroke, the more the shock movement is increased. the amount of change is based on the angle the shock is mounted at or the design of the shock linkage.

This means the shock is moving more at the end of its travel than it was at the beginning( for a given movement of the rear axle !) so even if the spring on the shock is linear, because the shock is moving more, it is compressing the spring more, so there is more spring resistance. If you compress a 22 nmm spring one mm at the beginning of the shock travel you will get 22 Nmm of resistance, but at the end of the shock travel, if you are compressing it 1 mm PLUS another 5% you will get 22 Nmm of resistance plus another 5% of 22 Nmm of resistance.

on a graph, this looks like a line at an increasing angle.

I will post some graphs.
 

p400

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What does this information tell you??
Just a start point for a bare Mk3 roadster with fresh -06 springs.
I thought it might be a little shorter than 181mm for this app.

Is this particular set of HD022 emulsion or decarbon?
 
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Just a start point for a bare Mk3 roadster with fresh -06 springs.
I thought it might be a little shorter than 181mm for this app.

Is this particular set of HD022 emulsion or decarbon?
The HD022 is an emulsion type shock.
Any of the 3 styles of shocks Ohlins makes for the HD this shock was made for will fit the Norton as well.
The HD022 is the least expensive and has no external damping adjustments, which is what Ken wanted to try. (me too)

All Ohlins shocks can be revalved to different specs.

What is your weight? And what shock are you using?

We have tried these shocks with a few different weights. I might be able to help with a starting point .

The softer springs with more preload with usually offer a better Ride than a stiffer spring with less preload.

The range of the springs using preload is quite large. As they are designed to have a passenger added, using only preload to correct for the 100 to 200 lbs weight change that is put mostly on the rear shocks.
Generally speaking 1 turn of preload is used for each 25 lbs of additional load (weight).

The normal starting point for a spring is measuring the Rider Sag, the Static sag (Bike Weight Only, no rider) is a used as a check number to confirm that you are not using a spring that is too light or too stiff, and making it meet the correct sag number by using to much or too little spring preload.

On most road bikes, the rear wheel travel, Not shock travel, is 130 mm, for that 130 mm rear wheel travel we set the rider sag at 30 mm. The static sag numbers we look for are 5 to 15 mm, after setting the rider sag. We never try to get the correct static sag number instead of the correct rider sag number, the reason is simple, you cannot ride the bike without sitting on it.
 
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lcrken

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Didn't get a chance to ride the bike today, but did have a friend come by so I could check the sag.

Static sag is 6 mm.
Rider sag, with 195 lb rider, is 25.5 mm.
That's measured in the traditional way, not the Race Tech way, which tries to average out the effect of friction.

That's on the short end of the range I normally look for on a street bike, more like what I might use on a race bike, but with helmet and riding gear on, the weight will be a bit more, so I think it's fine for a starting point. Probably a little stiff for the grandson. If so, we'll try the softer spring.

Ken
 

p400

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we'll try the softer spring. Ken
What is the Öhlins number on the softer spring?

How firm are you on the 6mm/25.5mm of static/rider sag with a 00360-06 spring/HD022 with 10mm of preload on Mk3 roadster?
 

lcrken

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What is the Öhlins number on the softer spring?

How firm are you on the 6mm/25.5mm of static/rider sag with a 00360-06 spring/HD022 with 10mm of preload on Mk3 roadster?
The other springs (softer and heavier) are 00360-5 and 00360-7.

I don't understand what you mean by "how firm are you...," Those are the numbers we got when we measured it on the bike, which is a lightly modified MK3. Can you be more specific in your question?

Ken
 
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