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Rear Shock Options, Including Budget

90687 Views 81 Replies 30 Participants Last post by  urbane
Hopefully this summary will help to group a bunch of scattered replies on the topic. Obviously, it's all JMO. :)

I found just a re-springing of the stock shock to be a very adequate economy answer to the wallowing and general lousy handling experienced on these as you start to push them, ESPECIALLY for just street use. It's NOT a Penske but is still a dramatic improvement. If you're not experiencing those wallowing problems, not pushing it a bit, or just a cruising type rider, ignore this post. ;)

I took the time honored approach that on a budget, the best bang for the buck is get the spring right. These are so soft that that approach made even more sense the more I thought about it. I took the measurements, figured the linkage ratios, drew up some cups, sourced a used spring, and proceeded. I was AMAZED with the improvement and easily recommend it to anyone who wants to improve the suspension but hasn't the money to do it "right" (translation: Penske, translation: $). ;)

I've used this on the track and will again, finding it totally rideable, but the shock absorber's weakness really shows there, cold tearing tires. Inflating a couple of extra pounds over typical track pressures will help, but not totally cure that. If you're a rider who track rides and can push that hard you could probably justify the cost of a Penske just with a season's tire wear savings alone and could realize the benefits of a nice, tuneable shock.

But if you're a street rider, possibly a novice track rider just getting into it, you won't have the tire tearing problem and will LOVE the dramatic improvement in handling if you're riding twisties even a little hard. On the street, even experienced riders won't be able to push so hard as to have the cold tear issues and will find that it's rideable at a pretty good pace, certainly FAR better than a stock set-up. Not a Penske, but not so bad. :)

It requires a spring for your weight, a set of special machined spring cups and, not necessary but highly recommended, a set of links (often called dog bones) to raise it.

The spring is a 2" X 6" series from Hypercoil and is the same spring used on Penske's shock. They are available in 50# increments. The range most likely to be used on these is 400, 450, or 500#, and for the really husky ones, maybe a 550#. New cost, about $100.

The spring cups are machined from 6061 aluminum and should cost no more than $100. I can make them for that, shipped. That price may be better depending on material costs.

The links to raise the rear and built with a minor outward step in them to clear the spring's slightly larger diameter should cost no more than $65. If you weren't raising the rear the stock links can be used but a washer should be added to each side to afford just a little more clearance. The addition of the washers then requires a longer set of bolts to maintain the engagement of the locking feature on the stock nuts. The spring will just fit between the links either with this mod or a purchased Penske, but even the slightest shift of it on the spring cups or the smallest variation in diameter will cause it to rub. Not good. The additional 1/16" per side assures clearance.

Summary: The cost for the shock mods alone is about $200.
Add the links for a truly complete package and the total is $265.

Shopping for a used spring from a racer who has had occasion to change his Penske shock's spring could be as little as $25 shipped (that's what mine cost) so you could conceivably complete the whole deal for under $200. If you have access to a machine shop and can figure out the parts, maybe way less than $200.

Next lowest cost package to my awares is a basic Works Performance shock, ordered and sprung for your weight, at about $400. That's an old price and from memory so it may be more, not likely less. It would still need the links if raising the rear was to be done so add the $65 for those to complete the package. That makes a total of about $465.

The ultimate, the Penske, sprung for your weight, is around $875. It has everything including adjustable ride height. (For those not familiar, ride height adjustment is NOT the same as spring adjustment. All of these, including your original, have spring adjustment, but not ride height.) At its lowest setting it already raises the rear 7/8" but can then be adjusted up from there. It should have washers added to the stock links to assure spring clearance and then longer bolts to assure the locking nut engagement. Those longer bolts will not be hardware store stock in that size and length so will have to be ordered from a fastener supplier. Expect between $10 at best and $20 at worst by the time you cover shipping and handling, getting that package up to just under $900.

So, there you go. A good list of the options... for the rear. ;D If you're going to do the rear you should really consider doing the front, too. The best handling is when you keep the front and rear working similar. With a spring change at the rear that will be at least a one third increase for anybody but the lightest rider (the stock rear is 300#) and it will underscore the front's soft springing. :(

At the front expect to spend $150 for parts to do the springs alone. That would include the springs, fork oil, and a little for miscellaneous. Add another $150 for cartridge emulators and you'll have all of the parts for the front, as good as it gets. No high dollar Penske options here, thank goodness. ;) The works for $300, the minimum for $150, or maybe shop the racers again for used.

Additional Notes:
This list is from my experience with my bike over about 10,000 miles riding as modded, riding it on both street and track, about equal amounts of each. (I use it coaching novice sometimes.) The total list of mods is:

1. re-sprung rear.
2. links to raise rear (started at 7/8", now at 1 1/2").
3. re-sprung front.
4. cartridge emulators front.
5. front raised 1/2" by sliding tubes in triple tree clamps.
6. radial tires.
7. lowered stock bars (approx. 2") using old 600 risers.
8. carburetor pilot screws out 2 1/2 turns.
9. EBC front brake pads.
10. EBC floating front rotor. (Just installed, warped two stockers beyond hope.) :(

That's the TOTAL list. And in that configuration it can be ridden quite fast without doing scary things. :) If I were racing it or running against my lap timer at track days, going for the track record, ;) I'd certainly want a Penske. If one comes my way at a steal, I'll buy it and put it in. Other than that, I'm content with the bike as it is.
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querie on the suspension situation... im looking to eventually upgrade my entire suspesion system, however it will not be simultaneous... would i be able to upgrade the front forks with some race techs and wait a while to put in the rear shock without sacrificing handling?
This is in reference to my post here:

http://www.ex-500.com/index.php/topic,2699.0/topicseen.html

To sum up my question at my other post. If a spring is truly linear then as long as the bike is not bottomed out then an additional X kgs on the spring should always compress the spring Y mm according to the spring rate. As long as there is *some* (could just barely be zero) free sag then the weight of the bike itself overcomes the preload. Adding additional weight from the rider should only make the bike lower an amount related to the additional force, and the rate of the spring. The preload should not have any affect at that point.

I put together the attached Excel spreadsheet to better understand and illustrate my point. Here is a screen shot of the spreadsheet.



So graphically you can see that as long as there is some free sag (the magenta line), then the Static Sag (bright green line) only depends on the additional weight of the rider and the spring rate. Am I missing something here? How can you both recomend that there be some free sag, while at the same time suggest that it's possible to adjust the static sag through the preload.

Eric


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That's a fatal assumption Eric, The rear suspension on many bikes has a progression too, and will change the amount of movement per unit of load per it's ratios.

FOG
Ahh ok. So is it that the springs aren't really linear, or that the leverage of the other suspension components make the suspension behave in a non-linear fashion?

I can see how all the joints in the rear suspension would introduce a lot more variables in addition to the spring rate, but the front suspension is pretty much just sitting directly on the spring.

Force on front suspension = Force on the wheel / COS(Rank angle)
You didn't signify the you were referring to the front only. Even there some variability is avaliable with a progressivlly wound spring. These have several coils on one end wound in a tighter spacing, This causes them to stack (coil bind) first thus shortening the remainder and creating a stiffer spring in the process.

FOG
Oh well I was refering to either the front or the back, since most tutorials I've read on setting sag describe the process the same for both the front and the back. Well other then the actual adjustment made (spacers vs collar). Do we have linear springs, or progressive springs. I thought the SonicSprings I bought and the stock rear spring were both linear. Are you saying that these "linear" springs behave somewhat as a progressive spring because the coils will still begin to lock at the ends.
No not at all. You are correct just not difinitave enough. If your going to teach you must learn your subject well. There are linier springs (most are) then there are Progressives, and a whole bunch of other variables too.

FOG
I have found very little information on performing a shock swap on the ex-500. Is this a bad idea?

I am new to the realm of the ninja. My SV shock swaps out perfectly with a ZX shock which is much better than the stock SV shock.

Why aren't there many threads on shock swaps? I planned on holding a ZX shock up to my girlfriend's EX500 just to see if it would fit with minor modification.. I realize that lowering links, washers to space out the bones, and some modifications to the shock would be necessary..
Most of the newer shocks won't physically fit in the space afforded. That's mentioned earlier in this thread. A few specific models are mentioned but almost all newer bike shocks are too big to fit through the opening in the swingarm. :( I went through this, too. No luck, gave up and came up with the spring change outlined here and further advanced with the discovery of the ProShocks spring that's a closer fit and doesn't require machined spring cups. :)
Thanks for the speedy reply. I get you now.. It's not the clearance for the reservoir to mount.. It just won't slide up through the swingarm.. Could it be 'dropped in' from the top? I know that would be intensive but just wondering if there are mechanical limitations
The big diameter is the problem fitting through the swingarm. There are some middle or later 90's that aren't as big diameter but they have the reservoir issue. For the money and unless you're really pushing the bike hard at the track, the spring alone will do the job.

I've done it and have ridden it at the track, even used it for a part of a season coaching. And the track problem isn't even how bad the bike handles but how it tears up tires when really pushing it in track conditions. You can't do that to it on the street even if you're riding regularly like a person with a deathwish. Just can't ride it hard enough to have the tire issues on the street. In fact, most beginner track riders won't have the severe issues. They only show up in severe track duty.

Look at the Pro-Shocks spring thread for the details. It will cost you less than $100 for everything. There are set-up details, bench pre-loads, and all, ready to drop in and go.
I saw on delkevic's website that they are now offering a GPZ-500 shock.
G
Tulok said:
I saw on delkevic's website that they are now offering a GPZ-500 shock.
Aren't those like $90? I believe those are an OEM replacement shock and not a performance upgrade.
Here's a link to a thread about rear springs (Pro-Shocks) that evolved after this thread was created. They don't require the special machined cups for the Hypercoil/ Penske spring described in the thread making them a drop in piece. Makes it less than $100 bucks. Also has remarks from several users about the efficacy of the whole endeavor. 8)

http://www.ex-500.com/index.php/topic,4423.0.html
Just installed a heavier rear spring(from pro-shocks for only 50 dollars plus shipping), heavier fork springs and installed fog bones, can actually feel a difference now, doesnt dive as hard when i brake, bike also sits higher from the fog bones, feels alot better turning now and being 250 with gear on, the old stuff was way soft, only problem with putting the fogbones on is that the center stand barely holds the bike up now, will probably have to put a 2x4 under it to lift the bike up high enough. One question though, on the 2nd gens, is there allready a spacer installed with the spring in the front, i was under the impression the past while that it was only a spring in there stock, but im guessing not
Stock has a thin walled steel tube spacer at the top, directly under the cap. Approximately 4-5" long.... if I remember correctly. (It ain't 2" and it ain't a foot.) ;)

Check the front and rear static and free sag settings after completion to confirm that the front spacer and rear adjustments are correct. Refer to the posts if necessary. 8)
dad said:
Here's a link to a thread about rear springs (Pro-Shocks) that evolved after this thread was created. They don't require the special machined cups for the Hypercoil/ Penske spring described in the thread making them a drop in piece. Makes it less than $100 bucks. Also has remarks from several users about the efficacy of the whole endeavor. 8)
Dad, can you post the link. I'm trying to determine what size (length & diameter) as well as spring weight I need to order.
twowheels said:
dad said:
Here's a link to a thread about rear springs (Pro-Shocks) that evolved after this thread was created. They don't require the special machined cups for the Hypercoil/ Penske spring described in the thread making them a drop in piece. Makes it less than $100 bucks. Also has remarks from several users about the efficacy of the whole endeavor. 8)
Dad, can you post the link. I'm trying to determine what size (length & diameter) as well as spring weight I need to order.
Oops. :-[ http://www.ex-500.com/index.php/topic,4423.0.html Added it above, too. :)
if anyone has a website where i can buy the springs can you email it to me at philip.hall [at] eagles [dot] usm [dot] edu
MavT said:
if anyone has a website where i can buy the springs can you email it to me at philip.hall [at] eagles [dot] usm [dot] edu
go to the post that DAD has above... it's right at the beginning of that one.
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