Going to plunk down for a used Wilburs shock...

[Khunajawdge]

My '05 has 44,000+ miles on it! I have noticed the bike doing a bit of wallowing lately and I have the stock rear preload cranked up to 10. Found a very lightly used Wilburs 640 model which allows pre-load and both high and low speed damping/compression adjustment with around 5,000 miles on it for around $500. Seems like a good deal No?

Anay input muchly appreciated.

 

[GunMD]

Assuming that the original owner had the shock built for a weight that is comparable to your own, you should be OK. In fact, not to bash Wilbers, you may want to shoot for getting one that was setup for a larger rider or a two-up setup since Wilbers have been reported to be a little soft in their spring rate.

Mine was purchased with a passenger in mind and works great while riding solo.

.02

 

[Khunajawdge]

Assuming that the original owner had the shock built for a weight that is comparable to your own, you should be OK. In fact, not to bash Wilbers, you may want to shoot for getting one that was setup for a larger rider or a two-up setup since Wilbers have been reported to be a little soft in their spring rate.
Mine was purchased with a passenger in mind and works great while riding solo.

.02

Thanks for the reply, and yes the rider is similar in size and build to me. Here is what he said;

"Parts: Everything that came with it is included... hanger bracket and

bolts for preload adjuster, bottom mount bolt (replaces stock bolt),

all documentation, original box.

Rear shock includes remote preload adjuster and variable ride height

adjuster (+/- 0.5 inch)

Rebound is set from factory at 12 clicks

Preload is set from factory at 16 mm

Spring is a "59/59 - 110-130"

further he wrote:

"I have all the original documentation and instructions with all of the

above info printed on it. My original invoice says the following,

which is how I originally requested the setup listed above:

Rider Weight: 205 lbs

Cargo Weight: 150 lbs

Riding Style: Moderate

Rider Height: -10mm"

I do weigh a little more than he does, but I don't usually carry quite that much weight as cargo!

 

[Ignacio]

IIRC, the 543 originally cost around the $500 mark...as it was an emulsion type shock. It's not the tricky technology of the Ohlins or Pensek (or even the upper end Wilbers), but definitely better than stock and rebuildable.

Just remember that they were notoriously undersprung in the Group Buy. I can't remember the conversion for the 59/59 - 110 - 130, but one may need a beefier spring to make it fully happy. You may have to invest addtional to make it yours.

 

[Khunajawdge]

I can't remember the conversion for the 59/59 - 110 - 130, but one may need a beefier spring to make it fully happy. You may have to invest addtional to make it yours.

Thanks

 

[SkooterG]

Go for it! You will not be disappointed.

Never mind what Iggy said, the 643 with the hi/lo compression damping is a top end shock and was like $900+ IIRC at the group buy prices way back when. The only option it sounds like it doesn't have is ride height adjustment. And also looks as though it's set up to lower the rear about a half inch?

It's the same shock I have and I love it. I have about 130,000+ miles on mine with only one rebuild on it. Huge difference from the stocker. And you my friend, are waaay overdue. Even if the spring is slightly off, you will still notice a huge improvement. Spring rate is only on aspect, according to my suspension guru proper compression and rebound damping settings are more important. And you can always get the spring changed, albeit at a cost.

 

[exskibum]

I'd echo what ScooterG said about the model, but also voice a caution about the -10mm height. I'm pretty sure that the shock you are considering is the same one O'Vale had on his -- he bought his used, too, but from someone heavier than he was IIRC.

Recalling from installing mine, there isn't any way of shimming or modifying anything to get that 10mm back.** I ordered mine with the adjustable height feature, and when I was playing with that to give my Muzzy pipe additional clearance, that much height difference was discernable enough in changed handling characteristics for me not to like the bike's attitude that far off (in the other -- taller -- direction). In my case, it got twitchy on the freeway. But in the case of a lower rear (esp. if the shock is undersprung), yours may be slow to turn in and react, a bitch with speed bumps, etc. Definitely check on that before taking the plunge.

**EDITED to note that Hycle mentions (below) an ability to change links to restore some height, which seems worth looking into.

 

[03silverbullet]

You will probably need a stiffer spring which will be easy to get, but the big problem is that the ride height is lowered 10 mm. Trust me, that will make a huge difference in the way the bike handles and in a negative way.

 

[HYCLE]

Hi George, I bought a used wilbers shock that was shorter to lower the bike 30mm. Then I bought rising links from ebay that brought it back up.

I played with the preload adjustment until I had the shock at the right height for my wieght. This had the spring compressed so much that the suspension topped out when I got off the bike, Not Good. I also was draging the center stand if I hit a bump in a corner. The stock spring was just too soft for 2up riding at my weight.

I now have a 750 pound spring on it. I was able to back the preload off almost all the way. I do have the hydraulic preload adjuster and can preload it 10mm more if I like.

This combination works good for Terri and I with all the luggage. Which is a load of about 500 to 550 pounds.

It also works with just my 250 pounds on it.

I still feel it could use fine tuning. I plan on having it rebuilt and valved for the heavier load.

I was very lucky to buy the used shock for less than $300 and a used spring for about $60 dollars.

 

[dcarver]

Wow, KJ..

After reading all these posts, I'm not sure how I would decide.

I will say that you set an agressive pace when the mood strikes... and need all the travel you can muster.

Unless you can get the ride back to normal height or even a bit higher (I've found I really like more front tire loading by raising the rear), I think I would pass.

Then again, I'm no suspension guru, so my opinion is only worth about .0002!

 

[Khunajawdge]

Again, thanks guys for ALL the comments! Now a couple of questions ??

- Before I pull off the old stocker (if/before I pull it off), how do I check the current ride height? I measure from where to where?

Oh, and HCycle or ?

- What markings were on your springs (the original and the new 750 lb. one?

- These say 59/59 110/130. What does that number convert to in terms of spring weight?

 

[MCRIDER007]

Thanks for the reply, and yes the rider is similar in size and build to me. Here is what he said;
"Parts: Everything that came with it is included... hanger bracket and

bolts for preload adjuster, bottom mount bolt (replaces stock bolt),

all documentation, original box.

Rear shock includes remote preload adjuster and variable ride height

adjuster (+/- 0.5 inch)

Rebound is set from factory at 12 clicks

Preload is set from factory at 16 mm

Spring is a "59/59 - 110-130"

further he wrote:

"I have all the original documentation and instructions with all of the

above info printed on it. My original invoice says the following,

which is how I originally requested the setup listed above:

Rider Weight: 205 lbs

Cargo Weight: 150 lbs

Riding Style: Moderate

Rider Height: -10mm"

To answer your question, the "110" is the spring weight and that converts to about a 615 lb spring, which should be sufficient for your weight. Wilbers uses lighter springs and more preload than a Penske so comparing their respective spring rates can be bit misleading. The real question is whether the "110" is really a 110 or something lighter.

I would be concerned about the "-10mm" rider height but if the shock has a variable ride height adjuster as advertised then you are covered, in fact they may have used the ride ride adjuster to lower the ride height in which case you would just need to set it back in the middle position.

 

[HYCLE]

Oh, and HCycle or ?
- What markings were on your springs (the original and the new 750 lb. one?

- These say 59/59 110/130. What does that number convert to in terms of spring weight?

The original wilbers spring was marked 59/59 105/150.

My measuerment found the diameter of the spring is 59mm at both ends.

This spring measures aprox. 150mm freelength.

This spring is from a shock that was designed to lower the bike 30mm and has the hydraulic preload adjuster.

The preload adjuster takes up space on the shock body where a longer spring could be installed.

My guess is the 105 on the spring is the metric spring rate.

This is based on the Eibach motorsports catalog.

The listing of a 6 inch long spring rated at 600 pounds per inch is equal to 105 newtons per mm.

The listing of a 6 inch long spring reted at 750 pounds per inch is equal to 130 newtons per mm.

Hope this helps.

Mike

 

[exskibum]

Oh, and HCycle or ?
- What markings were on your springs (the original and the new 750 lb. one?

- These say 59/59 110/130. What does that number convert to in terms of spring weight?

The original wilbers spring was marked 59/59 105/150.

My measuerment found the diameter of the spring is 59mm at both ends.

This spring measures aprox. 150mm freelength.

This spring is from a shock that was designed to lower the bike 30mm and has the hydraulic preload adjuster.

The preload adjuster takes up space on the shock body where a longer spring could be installed.

My guess is the 105 on the spring is the metric spring rate.

This is based on the Eibach motorsports catalog.

The listing of a 6 inch long spring rated at 600 pounds per inch is equal to 105 newtons per mm.

The listing of a 6 inch long spring reted at 750 pounds per inch is equal to 130 newtons per mm.

Hope this helps.

Mike

So, Mike -- what is the spring weight for 110 newtons per mm (the one already installed on the shock)?

 

[HYCLE]

So, Mike -- what is the spring weight for 110 newtons per mm (the one already installed on the shock)?

I think that was answered above by MCRider007, 615 pounds equals 110 newtons per mm.

I would also add you should try to go with the lightest spring possible. The control should be done in the shock.

I also have a longer 900 pound spring that I would never install. It was an impulse buy, before I did any research.

Mike

 

[zorkler]

You could buy a new penske for about 750 new .

 

[exskibum]

So, Mike -- what is the spring weight for 110 newtons per mm (the one already installed on the shock)?

I think that was answered above by MCRider007, 615 pounds equals 110 newtons per mm.

Doh! But now that I've asked, I'm scratching my head, because . . .

By doing some quick interpolation and assuming there isn't some progressive or log function, something doesn't fit. If your two figures are correct, then whether done by interpolation or by using ratios, 110 newton meters per mm must equal roughly 630 pounds (between 628 and 635). No?

 

[HYCLE]

By doing some quick interpolation and assuming there isn't some progressive or log function, something doesn't fit. If your two figures are correct, then whether done by interpolation or by using ratios, 110 newton meters per mm must equal roughly 630 pounds (between 628 and 635). No?

Damn your not only good looking but smart too.

Here is the chart I found in the Eibach Catalog.

The Physics and math will have to be explained by someone else.

Part number Length Dia. Force

mm in mm in n/mm lbs/in

0120.060.0050 120 4.75 60 2.36 50 285

0120.060.0060 120 4.75 60 2.36 60 342

0120.060.0070 120 4.75 60 2.36 70 400

0120.060.0080 120 4.75 60 2.36 80 457

0120.060.0090 120 4.75 60 2.36 90 514

0120.060.0100 120 4.75 60 2.36 100 571

0120.060.0120 120 4.75 60 2.36 120 685

0120.060.0140 120 4.75 60 2.36 140 799

0120.060.0160 120 4.75 60 2.36 160 913

0120.060.0180 120 4.75 60 2.36 180 1,027

0160.060.0080 160 6.30 60 2.36 80 457

0160.060.0090 160 6.30 60 2.36 90 514

0160.060.0100 160 6.30 60 2.36 100 571

0160.060.0120 160 6.30 60 2.36 120 685

0160.060.0140 160 6.30 60 2.36 140 799

0160.060.0160 160 6.30 60 2.36 160 913

0160.060.0180 160 6.30 60 2.36 180 1,027

0160.060.0200 160 6.30 60 2.36 200 1,142

0160.060.0220 160 6.30 60 2.36 220 1,256

0160.060.0240 160 6.30 60 2.36 240 1,370

0160.060.0260 160 6.30 60 2.36 260 1,484

0160.060.0280 160 6.30 60 2.36 280 1,598

 

[dcarver]

I'd explain all this to ya'll but I ain't no Einstein!