Fork Springs Comparison (Picture)

[Cambi]

Originally Posted by deguoren

My local bike shop (and suspension specialist) quoted 985 Euros for parts and 210 Euros for labour & consumables

Do you mind sharing the address/contact?
- Am interested at getting a kit fro that price.

[deguoren]

Originally Posted by Cambi

Do you mind sharing the address/contact?
- Am interested at getting a kit fro that price.

Well its just a small bike shop in Germany http://www.twowheel.de.... If you happen to be in this country... I dont think he speaks English or does international shipping.
He would order it from the German Importer www.zupin.de I guess.

[DoWorkSon]

Originally Posted by deguoren

A German Enduro magazine compared some springs available on the market.
Öhlins (linear), Hyperpro (progresive), Wilbers (progresive)

Wilbers got the best results in their test

Also they mention a Italian supplier for catrrige kit which I didnt knew before, it MUPO
http://www.mupo.it/moduli/prodotto_e...ID=11&c=8&p=48

I just recieved an email back from Wilbers...

"Yes the Wilbers progressive fork springs for your USD fork is very popular so we keep them in stock. they have a slightly higher initial rate but still rides nice over the little bumps, then it ramps up progressively when you grab a handful of front brake to reduce nose dive. We've had excellent feedback from customers and even BMW dealers are buying them from us now. Wunderliche is also selling it under their own name (at a higher price) the springs have a great reputation.
Let me know if you'd like a set, they sell for $119.00/set. Not on our new shopping cart yet, but soon. You can buy over the phone or you can send us a Paypal and do it through email if you prefer.

Thanks for the inquiry!

Best regards,


Ted Porter

Ph: 831-438-1100 ext 113
Cell: 831-420-7776
Fax: 831-438-1104"

[DoWorkSon]

Just installed the Wilbers progressive springs with 7.5 weight oil.

Amazing difference and I just did a small ride around the town. No dirt yet. No brake dive, and bike feels planted and far more controllable. I actually have confidence in it's handling.

Total price was only about $160... That's for springs, oil, shipping. Far cheaper than most mods and great results. Plus the install is fairly easy, took me a couple of hours.

Ted at beemershop.com(us seller of wilbers) was also very helpful.

Next up should be a new rear shock.

[ride2little]

Originally Posted by DoWorkSon

Just installed the Wilbers progressive springs with 7.5 weight oil.

Amazing difference and I just did a small ride around the town. No dirt yet. No brake dive, and bike feels planted and far more controllable. I actually have confidence in it's handling.

Total price was only about $160... That's for springs, oil, shipping. Far cheaper than most mods and great results. Plus the install is fairly easy, took me a couple of hours.

Ted at beemershop.com(us seller of wilbers) was also very helpful.

Next up should be a new rear shock.

Sounds very similar to my set-up w/ HyperPro and 10w oil.

[Loutre]

Originally Posted by ride2little

Sounds very similar to my set-up w/ HyperPro and 10w oil.

now I'm hesitating between both fork springs

[deguoren]

I will go the Wilbers way.

next month.....

[Gumbeaux]

All this talk of springs has me wondering.

I had the Ohlins NIX kit put on the front by the guys at Ohlins USA, and they told me they would just use the stock springs cause they were good enough when combined with this new kit.

I am really happy with this Ohlins transformation, just a little secret that the stock springs are still in there...not sure if they still do it that way.

Anyway...I guess if you are doing springs only, it makes sense you would see a huge benefit.

[DoWorkSon]

I would think with the upgrade of the cartridges to adjustable, you would eliminate the need for new springs since you can adjust everything to your weight/riding style. So stock springs might be ok with new cartridges.

[Schai]

Ride2Little,

With oil height set at 120mm (below the top of the tube, fully compressed fork legs, and no springs), you might experience very harsh bottoming. At 75mm it will never bottom.

I put a set of Hyperpro progressive lowering springs on my F800GS. I removed enough oil to hit their spec., for my springs, of 110mm. The first time into the woods, it started bottoming really harshly, even on bumps that my KTM would totally ignore. Back home, I spent a Sunday inspecting and measuring forks.

The problem is that the frugal (a polite word for cheapa**) German engineers didn't include any parts for a bottoming cushion on the F800GS forks. Personally, I've never seen this in a fork before. Instead, they specified an oil height of 60mm. Adding the volume of the spring and fork cap, that would leave about 3mm of space for air when fully compressed. If you could bottom, that would compress the air space from about 250mm when extended to 3mm compressed, raising the pressure to about 83 atmospheres (bar) and over 1,200 psi. Given maybe 4 square inches of cross sectional area, you are looking at around 5,000 lbs. or 2,200 kg. to bottom the forks. Can't happen. The forks never bottom. Don't need cushions. Saves a few euros. Maybe someone got a bonus. The forks also get a lot stiffer just part way into the stroke. However, if you follow the Hyperpro spec, developed for best overall handling, and add another 50mm of air space, then you only have 5 atmospheres (bar) and 75 psi. You are only getting a few hundred pounds of resistance instead of a few thousand, so the forks now can bottom, flat metal to metal, and they do.

With a 110mm oil height, the bike handles smoother but sounds like a car crash when the forks bottom. Also rims bend easier (had to straighten one of those too). Riding just on highways and regular gravel roads, my guess is that it should rarely, if ever, bottom. However, go off on some trails with any speed and you'll hear the forks say "OUCH!" every few minutes.

Note:
How I got the 75mm: On my particular springs, I measured the volume of the stock spring and my Hyperpro spring. The Hyperpro springs have more coils and are larger, so they fill up about the same volume as 12mm of oil height. Stock spec is 60mm. Adding 12 mm for the larger springs gets to 72mm, which I rounded up to 75mm. With your 120mm height, If it doesn't bottom on you the way you use the bike, don't worry. However, if it does, start adding oil up from 120mm to 75mm. This is just my untrained amateur opinion.

Originally Posted by ride2little

Surely.
I removed the fork tubes (after removing the front tire, brakes and fender).

Then I popped off the fork caps, removed the old spring (the left one in the picture) and dumped out the old fork oil.

I filled the fork tube full of 10W fork oil up to 120mm below the top of the compressed fork.

Installed the new spring (the one on the right in the picture) with the tighter winds toward the top.

Then I put the fork caps back on, slid the tubes into the triple trees and re-installed the front wheel, brakes and fender.

Today's ride told me that I did the right thing. I really like the way it feels now. Much less sag, stiffer, yet not stiff, less nose dive while braking and the front tire feels more planted. Both on and off road.

[machinebuilder]

Originally Posted by DoWorkSon

I would think with the upgrade of the cartridges to adjustable, you would eliminate the need for new springs since you can adjust everything to your weight/riding style. So stock springs might be ok with new cartridges.

As I understand supension

Adjusting to the load weight (you+gear+cargo) is done with spring rates (Preload just Precompresses the spring to increase ride height)

the Damping (shock absorbing) is where things are adjusted to your riding style (compression and rebound)

going off poor memory the Theoretical Ideal is 15% compression with just the weight of the bike and 30% with rider, commonly refered to as sag. Most of this applies to both ends of the bike.

On the F8 the forks have 230mm? travel so with the riders weight they should compress about 60mm

With the Stock springs (.55kg/mm) mine sagged about 80-90mm (almost 50%). With the springs Traxxion put in (.65kg/mm) the sag was textbook on the money.

IMHO fixing the damping without fixing the spring rate will just slow down the bottoming out.

It could be Gumbeaux happens to be the weight that the stock springs work for, when I got a quote for the Ohlins they wanted to know a lot of info so the suspension would be built to my specs (weight, cargo, riding style etc).

I realize most of us aren't looking for the "ideal" setup, but just one that works well for us, and that depends on many things.

[DoWorkSon]

Wilbers suggested 70mm air gap. I believe stock is 60mm?

I was surprised that hyperpro was almost double.

[itsatdm]

The stock spring is .46kg, Ohlins .55kg, Bitubo .60kg, Hyperpro .52-.74kg, Wilburs ?

[DoWorkSon]

Originally Posted by itsatdm

The stock spring is .46kg, Ohlins .55kg, Bitubo .60kg, Hyperpro .52-.74kg, Wilburs ?

When I compared them, looked same as stock, but not certain

[Casejeep]

I have RaceTech springs .95 on order. Im hoping that the new springs and the adjustable cartridge and top cap of the xChallenge will give me a totally new feel for $300. im going to use 7.5 oil too.