Some examples of shocks, springs, etc. to illustrate some of the factors involved when making rear suspension mods:
Specs on shocks pictured above, bottom to top, by length:
TW200--- Non-adjustable. Eye-to-eye length, 13 3/16". Main shaft diameter,12mm. Travel to bumpstop, 1 3/16". Spring installed height, 7 1/4". Spring free length, 7 1/2". Progressive spring. Wire diameter 12mm (approx.), Bottom eye 12mm, unbushed,no seals. Top eye 12mm, rubber bushing, phenolic seals.
Comments: Adds no ride height. Adequate for most riders. Progressive spring a problem over the rough stuff as the "hit" comes too early in the stroke, causing "pogo-ing" and loss of control. Could easily be rectified with a proper spring. Least amount of factory-limited travel.
BANSHEE---Rear ATV shock. Reservoir type.Preload, rebound, compression adjustable. Eye-to-eye length, 13 7/8". Main shaft diameter, 14mm. Trvel to bumpstop, 2 3/4"(*) Spring installed height, 9" (midpoint of preload). Spring free length, 9 1/2". Straight-wound spring (non-progressive). Wire size, 10mm. Bottom eye, 12mm, Heim type. Top eye, 12mm, Heim type.
Comments: Bolt-on. Increases curb height (unloaded)but actually decreases ride height once loaded. . Sealed side plates and Heim-type bushings, both ends. Spring is spaghetti, intended for use with a linkage. Shock must be installed upside down to fit TW. Must be shimmed to center it in TW mounts. Close clearances beneath reservoir, may require some grinding to clear swingarm mounts. Hands down the best starting point of the 3 in terms of quality and adjustability for the experimenter. Needs a real spring. Nearly twice the available factory-limited travel compared to stock shock.
BLASTER---Rear ATV shock. Shaft-mounted jam nut style preload adjustment only. Eye-to-eye length, 15". Main shaft diameter, 12mm. Travel to bumpstop 1 7/8"(*) Progressive spring. Spring installed height, 9 1/4". Spring free length, 9 3/4". Wire size, 11mm. Bottom eye, 12mm, rubber bushing, no seals. Top eye, 14mm, rubber bushing, no seals.
Comments: Nosebleed suspension height increase. May cause interference between rear brake rod and passenger pegs. Drastically affects trail, may require taller front end, depending on intended use. Upper bushing requires sleeving to use TW mounting bolt. Despite its length, factory-limited travel only midway between stock shock and Banshee. Potentially the best ride quality across the board of the 3 (in stock form) due to spring design, but this spring may be too soft intitially when used with restricted travel.
I'll edit as we go, with a better pic, etc. If someone has the same info on the R6 or some other shock or spring that they've used, pass it along. Try to include what was required to install it.
Newbies need to understand that a 2" longer shock does not result in a 2" taller bike. Rather, it results in a 5"-6" taller bike, but only in the rear. This shortens your wheelbase and brings your front forks more nearly vertical, which among other things can result in twitchy handling and poor impact absorption up front. Everthang affects some other thang.
Myth of Long Travel, 101:
Same 3 shocks, springs removed and arranged by available travel. TW left, Blaster center, Banshee right.
The shiny part of the rod determines travel. Travel is limited by the rubber "snubbers" or bumpstops on the top part of the shaft.
Before you get all gah-gah over the Banshee shock on the basis of travel, you need to realize that you can't use all that travel on a TW. Ideally you would use a new snubber on it to limit it to just slightly more travel than stock. Otherwise you would shred your tire on your subframe (or worse) in a hard hit. The only shock of these 3 that can possibly use most of its available travel when mounted on a TW is the Blaster, due to its length. But then you'd have to deal with an extra 5 inches of seat height in the bargain. Everthang affects some other thang.
Springs explained, sorta:
Top view of the 3 springs, arranged by wire diameter.
Banshee left, Blaster center, TW right. roughly 10, 11 and 12mm's, respectively. It's kinda hard to tell the differences in the pic. Generally speaking, the fatter the wire, the stiffer the spring, and all things being equal a short spring will be stiffer than a longer one. Therefore the TW spring, being both shorter and of thicker wire is hugely stiffer than the other two. Therefore you would think that the Blaster shock would be the next stiffest of the 3. But not neccessarily so...
Side view, same 3 springs. The Banshee is a straight-wound spring. All the coils are an equal distance apart. That means that it has a mostly linear action as it compresses. In other words if it's too weak it will probably remain too weak throughout its stroke, and if it's too stiff that will also be somewhat linear. Get it just right and you're golden.
The Blaster is a PROGRESSIVE-WOUND spring. That means that the coils which are closest together are weaker than the ones that are wider apart. These coils will compress first, giving you a plush ride initially, then the bigger coils will kick in as your suspension compresses. This spring is actually weaker than the Banshee spring until you get into the "meat" of the coils, even though it's made of thicker wire.
The TW spring works the same way. The transisition occurs more abruptly between "off" and "on", but it gets it all done within the range of wheel travel of a stock TW. The longer spring might run out of wheel travel before it reaches the sweet spot, unless you could preload it, as with the Banshee shock body, and even then it might not have enough room. So a straight rate spring might be the best soluion here.
None of this applies to using the Blaster spring on the Blaster body. It has plenty of room to use most of the spring, but there's that seat height thing again.
I'll edit as we go, with a better pic, etc. If someone has the same info on the R6 or some other shock or spring that they've used, pass it along. Try to include what was required to install it.
Newbies need to understand that a 2" longer shock does not result in a 2" taller bike. Rather, it results in a 5"-6" taller bike, but only in the rear. This shortens your wheelbase and brings your front forks more nearly vertical, which among other things can result in twitchy handling and poor impact absorption up front. Everthang affects some other thang.
Comments are mine, and need not appear in the sticky. These are shocks I have personally fitted to a TW without modifying the shocks in any way. They're intended to inform and promote thought BEFORE you make that eBay purchase.
Suspension mods iz serious. If it ain't broke for you, don't fix it, or at least be honest with yourself about your skill level and understanding of the subject and postpone any mods until you're a little better informed.
Better still, wait til Gizmow puts his thread together. There should be enough step-by-step info to complete a safe mod and be aware of the downside, if any.
Gizmow and others have come up with solutions that work, and there are many more possible combinations that none of us have yet looked into.
I hope this info was helpful.
