Front Suspension Setup

I've reached that point where I'm ready to put the right bits into the FJR's front end to get the spring and damper rates where I'm happiest with them. Geared up, I'm close to 300# and the front is mushy and weak. I'll need stiffer springs and hope that higher viscosity oil will give me the right damping range for the setup and driving type I prefer so I don't have to revalve. Does anyone know a good website for helping me think through these details? I'm very proficient with car setup and I understand bike dynamics quite well but I've not gone through this drill for a bike yet for the first time. Some guidance will be helpful.

Cheers,

W2

Klaus Huenecke gave this to me a few years ago ...a presentation he did .....

I've posted it on my server

This might be a tad elementary for your level, but if you skim through, you might pick up some good info.

It's one of the better laid out overviews in my opinion.

note this is before the Klaus/Wilbers drama so those references etc should be ignored (other than for nostalgia)

go here: Motorcycle Suspension(clicky)

BTW, .pdf format, feel free to right-click and download if you want it permanent.

Very good link RJ, saved it to, will study later.

W2, just redone mine with the Traxxion springs set up with their innovative inserts really stiffened the front. Stayed with 10wt oil and I tell you, it is a ton firmer than before.

Still using the same settings as before the upgrade.....sure the oil was dirty-weak, but there is a huge difference than when I bought the bike.

I only weigh 280 with gear.

FJR-RemingtonRider said:

Very good link RJ, saved it to, will study later.
W2, just redone mine with the Traxxion springs set up with their innovative inserts really stiffened the front. Stayed with 10wt oil and I tell you, it is a ton firmer than before.

Still using the same settings as before the upgrade.....sure the oil was dirty-weak, but there is a huge difference than when I bought the bike.

I only weigh 280 with gear.

Click to expand...

I also own a Wilbers re-buildable rear shock. Along with it's purchase, I obtained a set of Progressive front springs. Rear is done and works trick! Front still needs to be pulled due to my own procrastination. When I put in the new Progressives, I'll change the fork oil to at least 10, but I'm not going for an aftermarket front fork re-manufacture with new parts, just re-seal the OEM fronts and put the stock stuff back in. We weigh 300+ when fully loaded.

Oil content is critical in these MC front leg transfusions FYI.

.. just some of my CO2!

RenoJohn said:

Klaus Huenecke gave this to me a few years ago ...a presentation he did .....I've posted it on my server

Click to expand...

Thanks John. Some useful information in this.

W2

I'll add this tidbit...

IMO, You must be very careful with spring rate calculations on Sport-Touring bikes. Most of the formulas used will recommend excessively harsh/heavy springs for riders 300 lbs. and up. Again, IMO, anything above a 1.05 front spring on an FJR, and you begin to seriously compromise comfort for long rides.

A 1.05 is well above the roughly .85 stock springs and would be my recommendation for a rider of 300-plus pounds. Beyond that, I'd make my changes with oil and valving if necessary.

HaulinAshe said:

I'll add this tidbit...

Click to expand...

Thanks Ashe...I've read many of your posts on this technical topic and am impressed with your knowledge. I'll keep your advice close at hand.

Is the comfort issue just due to the excessive forces (it's the spectrum really...g^2/hz...but let's keep it simple) delivered up through the front to the rider over long periods? Kinda like setting your car up for track day then loathing the long drive to the track? You know what I mean...when every lane change has you spitting fillings onto the floorboards.

Or is it something else?

Curious,

W2

Wee Willy said:

Is the comfort issue just due to the excessive forces (it's the spectrum really...g^2/hz...but let's keep it simple) delivered up through the front to the rider over long periods? Kinda like setting your car up for track day then loathing the long drive to the track? You know what I mean...when every lane change has you spitting fillings onto the floorboards.
Or is it something else?

Click to expand...

Exactly. You never get anything for nothing. So if you setup the bike to do a much better job of absorbing the big and fast and hard stuff, you give up some of that ability to absorb the small, yet annoying repetitive motions. It's mostly about hitting the best compromise or balance for your weight and riding style.

HaulinAshe said:

Exactly. You never get anything for nothing. So if you setup the bike to do a much better job of absorbing the big and fast and hard stuff, you give up some of that ability to absorb the small, yet annoying repetitive motions. It's mostly about hitting the best compromise or balance for your weight and riding style.

Click to expand...

Understand exactly. So here's my plan. I want to get the springs into the front that allow the "right" preload with sag and hit the damping side of the equation with viscosity first then valving only if I really can't find Nirvana. What I am looking for is a good site that allows me to get close to the right numbers. I have a Matlab dynamic model of the bike under development that I'll use for final analyses. Spring rate first...

W2