ATC 250SX Rear Shock Alternatives

[Flyingw]

For you guys who have the beloved SX, here is an alternative to the stock rear shock. When I built my Army trike, I bought about 3 used stock shocks for the build and none of them worked very well. One of them looked almost new but yet when I pushed the rear end down, the rebound was pretty bad so I went on a quest to find a different shock. The ES shocks look the same but the bottom eye is shorter then the SX so without some grinding on the SX swingarm, the ES shocks are not an option. The stock SX shocks are sealed so no way to rebuild them. The critical dimension on the shock is the eye to eye dimension. The SX shocks have an eye to eye dimension of 365mm or 14 3/8" with 10mm eye holes. Knowing this I started looking. Back then I was able to find a 360mm gas shock but the reservoir was a problem. In order to work, the reservoir has to at the top facing the rear but guess what? the battery box was in the way. The solution? shift the battery box back. I did this by moving the battery tray back in the side mounts meaning I took the forward mount and shifted it to the rear hole leaving the front of the battery tray unsupported. To fix this, I made a couple of aluminum brackets and riveted them to the front of the battery tray and bolts the other end of the bracket to the forward hole of the side brackets. It worked beautifully and I have been very happy with the results since.

I'm selling my Marine Corp and Sheriff trikes next weekend but I'm not happy with either of the stock rear shocks so I went looking for a set of shocks to do the same thing as my Army trike. I was able to find a set of 360mm shocks for 150.00 but they are red and gold. Totally the wrong color so again I went looking for options. The re/gold shock is the same shock I used on my Army trike but I have an OD green cover over it. On these two, I didn't want a cover but alas, no 360mm shocks in any other color. I was spying a set of black and gold shocks which for color was perfect for both BUT they were only 340mm eye to eye. I contacted the seller and asked if they could get that same shock in a 360mm length. They saif unless they but 100 each, they said no but they did offer a possible solution. The 340mm shock with a 30mm eye extension putting the length at 370mm. Almost there....

I ordered the 340mm shocks and the 30mm eyes and I got them yesterday. I removed the locking nut on the eye and screwed the 30mm eye in all the way and was still too long as the threaded shank of the eye was too long. I determined if I was to cut off the thickness of the locking nut (about 7mm) it would put me right where I needed to be so I took the 30mm eyes in to work and shaved them down 7mm on the end mill. Now with no locking nut and the eye screwed all the way in, the length is perfect 365mm or 14 3/8". Right now I'm getting ready to pull both battery trays and do the mod so I can install the new gas shocks. I will illustrate the mod while I'm doing it so if you guys ever want to do this, you know exactly what needs to be done.

The first pic is the battery box installed.

[Flyingw]

This is the modified battery box in my Army trike. Note the setback of the battery box now and you can see the gas shock reservoir between the shock and the battery box. This is what I'll end up with when completed.

[Flyingw]

This next set of pictures shows the modification as installed. It shows the two little brackets I made and attached to the battery box and how I shifted the battery tray back in the side mount brackets.

[Flyingw]

These are the 340mm shocks I'm getting ready to install.

[dougspcs]

I have been playing this game a bit with the ES to try and soften it up..my old back can only take so much pounding from the utility suspension.

A softer suspension like the 350X would be a savior..

I really don't want to mod the shock mounts in case I decide to return it to stock though.

[Flyingw]

Here's some Ebay links

340mm shock (each 2)
http://www.ebay.com/itm/170675955315?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

30mm eye extensions
http://www.ebay.com/itm/190710278033?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648

360mm red and gold shocks
http://www.ebay.com/itm/Air-Shock-Absorber-14-1-4-ATV-Quad-Go-Kart-Buggy-Motorcycle-Dirt-Bike-360mm-/170969429624?pt=Motors_ATV_Parts_Accessories&hash=item27ce927678&vxp=mtr

[Flyingw]

When I first put the gas shock on my SX, I thought it was a little stiffer than stock but after riding it now for over a year, I have come to realize its about the same and actually got a little softer over time. The compression and rebound is far better than stock. I did a side by side comparison of the gas shock and stock shock and clearly, the gas shock works much better.

[Flyingw]

I know the red/gold shocks work as far as spring rate goes but these black/gold shock are unknown until I get them installed but I think they will work out just fine but I'll report later on how they work.

[dougspcs]

I like it..if it weren't for the 30mm extensions I'd say there was no chance of installing this shock on the BR.

But it just might work..

Thanks again Jim.

[Flyingw]

I'll post up later how it turns out.

[Flyingw]

Test fit on the black and gold shock revealed an interference issue. I'm going to do a little shaving on one part of the shock and see if it fits. The tongue shaped rise on the shock hits on the frame. I'm going to grind it off and see what happens. If you look at the link for the red and gold shocks, that area sits lower and doesn't interfere. If Doug was to put the red and gold shocks on an ES. I think it would fit with no issues other then possibly the battery box.

[Flyingw]

Ok, the conclusion on the black and gold shocks is...... not recommended. I ground so much off in that one area that I hit the drilled hole that links the shock to the res. I'm going to order the red/gold shocks.

[Flyingw]

That one shock is trashed!!!! Oh well. I'll put the other away for another project. The red and gold shocks are on order. I'll get the battery boxes modified so when the shocks arrive, all I have to do is install them. Win some, lose some.

[dougspcs]

On the ES the issue is the trunk box, but that could be removed and shelved in case I decide to revert to stock.

The battery is mounted to the side and clear of the shock.

BTW can these shocks be mounted inverted?

[Flyingw]

Inverted??? That my Brother is a good question. I don't see any reason why they couldn't. The only reason I haven't gone that route is I want the reservoir protected by the battery box.

[dougspcs]

Inverted??? That my Brother is a good question. I don't see any reason why they couldn't. The only reason I haven't gone that route is I want the reservoir protected by the battery box.

I figured if I inverted it and put a shock wrap around it to keep the dirt out I might be able to install it without modding..

Just didn't know if these shocks had any liquid charge in them that might obstruct the gas flowing in and out of the cannister during compression.

If it can maybe I'll buy that other black/gold shock and 30mm extension from you to help you cover some of your investment since you can only buy them in pairs..unless you have a future plan for it that is?

[Flyingw]

Here is the black and gold shock inverted. It only fits with the reservoir facing the back. On the SX, the battery box still has to be shifted back because if the shock bottoms out, the reservoir slams the bottom of the battery tray.

[Flyingw]

I figured if I inverted it and put a shock wrap around it to keep the dirt out I might be able to install it without modding..

Just didn't know if these shocks had any liquid charge in them that might obstruct the gas flowing in and out of the cannister during compression.

If it can maybe I'll buy that other black/gold shock and 30mm extension from you to help you cover some of your investment since you can only buy them in pairs..unless you have a future plan for it that is?I'd be game for that.

[Flyingw]

These shocks are charged with Nitrogen. All the Nitrogen does is keep the oil from foaming and yes they have oil in them. I know because the one I trashed has oil coming out of a pin hole.

[Flyingw]

I left the black and gold shock on the trike and set it back on its wheels...... Too soft for the SX or even the ES for that matter. The red/gold shocks are stiffer and fit nicely after the battery box mod is done. The black and gold shocks are NO GOOD!!! Don't use these shocks on the SX or ES. Maybe if the spring preload is tightened up they might but the spring rate is too soft in my opinion.

[Flyingw]

I tightened up the preload quite a bit and it helped but I still think the springs are too soft.

[dougspcs]

I tightened up the preload quite a bit and it helped but I still think the springs are too soft.

Too soft? Or bottom out soft?

I'd be ok with a cushiony ride..but if it's bottom out soft then maybe you're right to wait on your red/gold set to show..

Then if they are a winner and you're game, I'll split the pair with you.

[Flyingw]

Here's the modified battery box. Two simple brackets riveted to the front of the box. Note the CDI tab is bent down. On the Army trike I drilled the welds and dropped it to the bottom corner but bending it over works too.

Let me get back to you on that Doug. With the preload all the way relaxed, the trike weight squats the shock about an inch. Tightening it up fixed that but I'm about 180 and when I sit on it, it squats more than I want it to but let me get it back together. I'll tighten up the preload a little more and let you know.

[jeffatc250r]

I have a set of those shocks on my 200s fatcat conversion. It seems to work well with the 2 of them. Only one would be too weak, esp on a trike. Id like to find a nice replacement for my big sped, all my nice and slow driving blew her out!
How abt newer smaller quads? Got my wheels turning now, im gonna stop by the dealership in town tomm and see if i cant sniff out a possible candidate.

[Flyingw]

Here's the modified battery boxes reinstalled. You have to pull some slack to the back on the main harness and cable going between the solenoid and starter. maybe even playing with the routing a little but there's enough there to do it. So that's it really. If I had the red and gold shocks I'd be done but those will take all about 10 minutes to install.

I agree Jeff, this particular shock is too weak. The red/gold shock is actually a buggy shock hence the stiffer spring. This was an experiment with the black/gold shock and it didn't work but no biggie. Now we know.

Doug, I'm going to tighten up the preload a little more and see how it is. Back in a few.

[Flyingw]

If you can find a 360-365mm shock with the right spring rate then it should work just fine. even a 370mm would probably work.

[Flyingw]

Here's a comparison.

Cop trike, stock shock. Measuring from the floor to the top of the grab bar....28" Sitting on it...26 1/2"

Marine trike, black/gold shock. Floor to top of grab bar.... 27 7/8" Sitting on it... 25 1/2"

Army trike, red/gold shock with a PRM grab bar.... 27 1/4" Sitting on it 26"

I can tell the black/gold shock is softer than the others so your call if you want to take a chance on it Doug.

[ps2fixer]

There is rumor that the 250x quad rear shock will work on the SX, I have an SX and the shock, but I can't seem to find it for testing :(. Of course... 250x was made 87-92, so probably no NEW shocks for them :(.

I'm watching this thread, as well as the other for findings. The 250es and sx seem to have a bit too stiff of a shock for me, but I'm only around 150lbs and I like a soft ride :). Just to point out, my old 350 warrior would sink quite a lot when sat on, and it rode great as well as landings for jumps, but it has the link setup like a 250r/tri-z

[userj8670]

Hey this is a neat thread! I will be keeping my eye on this for sure!

[Flyingw]

Going back to PS2fixer's comments about the 250X shock, yes, that is compatible but its basically the same shock as the ES/SX just sprung and valved slightly different. What my goal is to find a better shock than stock and I think I've found it with the red/gold shock. Keep in mind that the ES/SX were NOT designed for jumping. What they were designed for was working, pulling, towing and in the case of the SX, some sport riding. The red/gold shocks should be waiting for me when I get home today so they will get installed tonight.

Now, with all that said, if a person who weighs 150 or less, the black/gold shock mounted in the inverted position may be a good choice but I'm about 180 and when I sit down on it, it squats. Before I pull the shock off tonight, I'll have my wife sit on it and take a few pics and measurements just as a referance. She's about 130 so we'll see how much it squats with her on it. Right now the shock has about 5/8" preload on it as opposed to having the preload backed all the way off.

[Larry T Moore]

then you can experiment and find a shock for us..*ahem*...rubinesque riders...lol!

[Flyingw]

Well for the horizontally challenged, I think the red/gold shock is a good candidate. The shocks are here and later I'll be installing them but as I said before, I already have this shock on my Army trike and I'm happy with it. Id have to say that stiffness (hehehehehehe, he said stiffness) is a touch more than stock so a heavier rider would have a better suspension experience with this shock.

[Larry T Moore]

hhmmmmm...and whatta those run apiece?

[Flyingw]

Well crap!!!!! I put the shocks on the Sheriff trike and it doesn't even perform like the one on my Army trike. Very little rebound so I tightened up the preload and that helped. I checked the charge in the res and very little Nitrogen so I recharged to 120psi. I also turned the end eye out so eye to eye was 14 3/8". Much better but still not the rebound Army trike has. I dunno..... maybe its ok but using Army as the example, not the same. I'm not sure where to go from here. One shock was worse than the other.

[Flyingw]

Oh ya, and something is draining the battery on Sheriff trike. Last week I want to go start it and the starter barely turned. I pulled both batteries and charged them up and when I installed them, I switched batteries so that's two batteries its drained in a weeks time. I wonder if a bad regulator/rectifier could cause this?

[ps2fixer]

Oh ya, and something is draining the battery on Sheriff trike. Last week I want to go start it and the starter barely turned. I pulled both batteries and charged them up and when I installed them, I switched batteries so that's two batteries its drained in a weeks time. I wonder if a bad regulator/rectifier could cause this?

You could use the automotive diag methods to find what is causing the drain. Hook up an ampmeter (or multi meater on the 10A inline mode) between the battery positive and the 3 wheeler positive wire. Check what the draw is on it with every thing off. There is no computer or anything, so it should be really close to 0, cars are allowed upto something like 0.015 amps or maybe it was 0.15 amps, something like that. If you have a high reading, unplug what you think is drawing the power, and see if the draw is effected.

Good luck on the electrical issue hunt!

[Flyingw]

ya the book says to do that on the neg side and I did. My Army and Marine trikes were showing .070 - .080 millivolts but the sheriff trike between .170 - .210 millivolts. The reading on the other two trikes was consistent with everything plugged in or disconnected but on Sheriff trike, the reading dropped off to about .080 millivolts with the ignition switch disconnected and back up when reconnected. For the sake of selling these this weekend (Sheriff and Marine), I cannibalized the ignition switch off Army trike and installed it on Sheriff trike. If Army trikes battery drains in the next week, I'll know for sure.

[Dave Little]

Great post Jim.

Anybody wanna go half with me on a set of the red/gold shocks? They're still here on Ebay:
http://www.ebay.com/itm/170969429624?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
So your share would be $62.25 + shipping from NH

[Flyingw]

I bought a set of these to use one of them on the Sheriff trike and they turned out to be too soft as compared to the stock shock. The one I bought a few years ago for my Army trike is perfect so it must have been a fluke.

[Dave Little]

I kinda figured that reading the thread, because you didn't mention having to add nitrogen to the first red/gold shock purchased. Now after adding nitrogen to the second one you got you mentioned it helped along with adding preload...is that still the case that the second is now comparable to the first or has
performance diminished with time in the saddle? I'm also a heavier rider than you at 240lbs with all my crap on. I'm in the middle of converting to a TRX swinger and since I have to fabricate a lower shock mount I might as well upgrade so the added leverage will, all other things remaining equal will make the shock seem softer still. Thoughts?

[Flyingw]

Its hard to say. The trike has been in the hands of the Sheriff I sold it to and he says he likes the softer ride but he's about 225 so I can't answer that. Mine hasn't changed since I installed it. I like it. Its a tad softer than stock but not too soft. I still have another up in the attic.

[Flyingw]

I looked at this one. It has a 400lb spring rate but it would take a suspension guy to run the formula to determine is its compatible to the stock shock. It would help to know what spring rate the stock shock has.

http://www.ebay.com/itm/ATV-Rear-Shock-Absorber-Suspension-360mm-400lb-Genuine-Kazuma-110-150-250cc-ATV-/161184296787?pt=Motors_ATV_Parts_Accessories&hash=item2587552f53&vxp=mtr

[barnett468]

I looked at this one. It has a 400lb spring rate but it would take a suspension guy to run the formula to determine is its compatible to the stock shock. It would help to know what spring rate the stock shock has.

http://www.ebay.com/itm/ATV-Rear-Shock-Absorber-Suspension-360mm-400lb-Genuine-Kazuma-110-150-250cc-ATV-/161184296787?pt=Motors_ATV_Parts_Accessories&hash=item2587552f53&vxp=mtrHi Flyingw;

That spring is a "dual rate" [progressive wound] spring. Therefore it has a dual rating. They are only listing one rating so there is no way to tell exactly what it is.

Their info below is incomplete and therefore inaccurate etc.

"Pounds per Square Inch (spring rating) 400 lb/in"

[Flyingw]

ya that is confusing.

[barnett468]

It would help to know what spring rate the stock shock has.
No prob, EASY deal [maybe].

If your spring is straight wound [single rate] like the 85' model, you can do the following:

Find a hydraulic press.

Place a weight scale on the press table.

Place the spring on the scale.

Wrap a tie down through the spring and to the press so if it flies out it will not kill you.

Put on some safety glasses. [If I didn't say that someone would yell at me I know it, lol].

Compress the spring lightly until you get around 20 lbs of pressure on the scale.

Reset scale to 0.

Measure the height of the spring. If you compress it until you get an even number it will be easier to measure.

Compress the spring 3”.

Divide the weight on the scale by 3 and that is your spring rate.

[barnett468]

To calculate compressed spring rate of straight wound spring.

Measure the extended length of the shock from the center of each eye.

Compress the shock until it just touches the bumper.

Measure the length.

Measure the length of the bumper and divide by 3.

Take that number and multiply it by 2.

Take that number and subtract it from the compressed length of the shock. This will be your approximate fully compressed length [within 1/4"].

Measure the length of the spring.

Subtract the total compressed length of the shock from the length of the spring.

Multiply the spring rate by that number.


EXAMPLE

Spring free length 12” minus shock total compressed length of 8” = 4” X spring rate of 300 lbs. per in = 1200 lbs. when shock is fully compressed.

[barnett468]

Hello Flyingw;


As you may know, if you have a dual rate spring that is 400 lbs. on the high rate for example, it could be anything on the lighter rate such as, 150, 200 or 250 etc..

Also, if you have two equal rate and equal length springs like 150/400 lb. from different mfg’s etc., one might have 2 inches of 150 lb. spring rate while the other might have 3 inches of 150 lb spring rate.

The one with the longer light spring rate will have a smoother transition from the light rate to the stiff rate. This is because the longer light rate spring provides a wider “transition” phase than the other. It will also transition to the heavy rate at a later time in the travel.

We tested one dual rate spring on the 85 T3 prototype that had such a big difference in spring rates on a dual rate spring, and such a short light spring, that it felt like a rock when it hit the transition phase.

If the free length and compressed length of both springs is the same, the one with the longer light spring rate will have less compressed rate than the other. It will also get stiffer later in the travel as mentioned.

Now, if one adds any type of progressive ratio suspension to the equation, it complicates calculating the "curve" of the spring rate much more.

The easiest way I know of to determine the installed [with shock extended], and compressed rate of any dual rate spring is simply to compress the spring to those distances using the method I described previously.

[ps2fixer]

I kinda figured that reading the thread, because you didn't mention having to add nitrogen to the first red/gold shock purchased. Now after adding nitrogen to the second one you got you mentioned it helped along with adding preload...is that still the case that the second is now comparable to the first or has
performance diminished with time in the saddle? I'm also a heavier rider than you at 240lbs with all my crap on. I'm in the middle of converting to a TRX swinger and since I have to fabricate a lower shock mount I might as well upgrade so the added leverage will, all other things remaining equal will make the shock seem softer still. Thoughts?

You have a lot of options when your making your own mount, besides being able to change the length of shock within reason, also the point at which it is mounted to the swing arm. Every inch out will effect how soft the shock feels due to the changes in leverage from the pivit point of the swing arm (great old days of math class lol). In theory if you liked your old suspension and want it to act similar, you would want to keep the location at the same ratio from the pivit point as the OEM swing arm. Here is a quick example, I don't have the measurements at hand.

Say the stock swing arm is 30 inches long from center of the pivit point and the center of the rear axle, and the center of the shot mount bolt hole is 8 inches from the pivit point, the ratio would be 26.66% out from the pivit point. Say the TRX is 4 inches longer, so 34 inches length would give your mounting point at about 9.07 inches from the pivit point. This isn't a perfect way to figure where to make the mounting point, but atleast gives you a good idea. If you want it softer, say "10%" softer, my logic says you could multiply the raito by 10% and get your new ratio (26.66 * 1.1 = 29.33%). Just remember, not only does it effect how soft it rides, but also effects travel distance on the shock vs swing arm, farther out makes you loose distance unless your shock is also longer... makes everything extra complicated lol.

Just to point out, I don't specialize in math/suspenion or anything like that, so my math could be way off, but in my head the logic is right.

[sledcrazyinCT]

Did anyone buy one of the Kazuma dual rate shocks? It makes sense to avoid a remote reservoir even though the battery box mod is straightforward, but losing the tool box on a big red too much of a trade off.

Next time a see one of these junk china chassis on craigslist local I might have to talk them into selling the shock cheap

[Flyingw]

I don't know enough about shocks to speak intelligently about how they work so I defer to guys like Barnett and PS2fixer. I just want to know what shock we could buy and put on our SXs that gives much the same ride. A little softer would be nice. The Chinese shock I put on my SX works pretty good and makes for a nicer ride but as I said, that shock is a fluke. I do know the length is critical for the SX so that's a factor to consider.

[ps2fixer]

I actually don't know much about shocks :), just put forward some math or physics into the logic.

From my understanding, the actual shock its self is what softens the ride, and the spring is the load ability and load range the shock can handle. With a serviceable shock where you can change the fluid, I think they work about like the front forks where you can put in thinner oil for a softer ride, and thicker for a stiffer ride. For a direct bolton interchange, besides the shocks referenced in this thread, I don't really know of any with out buying/risking it not working.

[GSUwhiskers]

Sooooooo, there isn't an aftermarket shock that can be bolted straight onto the SX?

[dreux13]

Ok...my '86 SX shock just s*** the bed. Does anyone have any updates on this to simply get a shock that may even be comparable to stock? If I had a choice of buying used shocks on eBay 'hoping' I get a good one and using a Chinese one that is known to be close, I'd be happy.

Hoping someone has some info on what has worked and thanks Jim for bringing the conversation this far!

Here are a few I'm looking at...also, do any of the other trike shocks work?
http://www.ebay.com/itm/221496765351
http://www.ebay.com/itm/291096911242
http://www.ebay.com/itm/221409252497

-Dreux

[dreux13]

Ok...my '86 SX shock just s*** the bed. Does anyone have any updates on this to simply get a shock that may even be comparable to stock? If I had a choice of buying used shocks on eBay 'hoping' I get a good one and using a Chinese one that is known to be close, I'd be happy.

Hoping someone has some info on what has worked and thanks Jim for bringing the conversation this far!

Here are a few I'm looking at...also, do any of the other trike shocks work?
http://www.ebay.com/itm/221496765351
http://www.ebay.com/itm/291096911242
http://www.ebay.com/itm/221409252497

-Dreux


In doing more research, it appears a 300ex 97- present may work. I used this works fitmgnt guide as a reference with some google searches. Looks like works still makes them for the SX if you're willing to spend a ton of money!
http://www.worksperformance.com/pdf/app_guide/atv.pdf

[Flyingw]

The SX shock is 365mm eye to eye with 10mm eyes. I have a Chinese shock on my SX and I love it but this one I have was an anomaly. I bought another just like it and put it on another SX and it was way too soft. Also, the gas res needs to be on top facing to the rear putting the battery box in the way so I had to move my battery box back. What I have works well but it took some work. I tried a 340mm shock with eye extenders getting me to 360mm but it to was too soft.

[dreux13]

The SX shock is 365mm eye to eye with 10mm eyes. I have a Chinese shock on my SX and I love it but this one I have was an anomaly. I bought another just like it and put it on another SX and it was way too soft. Also, the gas res needs to be on top facing to the rear putting the battery box in the way so I had to move my battery box back. What I have works well but it took some work. I tried a 340mm shock with eye extenders getting me to 360mm but it to was too soft.


Thanks Jim...I've been following the thread and am aware of your freak one-off shock! I have a lead on a used 300ex shock locally for 45 and based on research, all I need to do is make a special bushing to make the 12mm holes 10mm. Based on reviews, this should give me a as close to oem as possible.

[dreux13]

Just an update. I went to pick up the 300ex shock and the guy had them in a bin.....lots of different shocks and I'm pretty sure that the one I got isn't from a 300ex since it was only 14" eye to eye with 10mm eyes. The shock fit, but the SX sagged immediately! The guy is looking for another shock in his inventory.

While he's doing that, I came up with some alternative options that should match up to the SX. I'm 98% sure that a 300ex shock will fit once I actually get one. I read that the blaster shock will fit a 300ex and I also stumbled on the Suzuki ozark rear shock which is the same dimensions as the SX.

So many options! I'll post an update once I get something to try.

[jeswinehart]

Having recently done a 300EX quad to trike conversion I wanted to post up how a 2004 300EX stock shock mounted looked + measured at.
The trike is strapped down but not in the way it pulls on suspension. I have had 300EX shocks on my 84/85 Tecates and it is a nice upgrade,,,, not perfect but a heck of a lot better then any stock Tecate shock in fine condition IMO.
These pics are center to center bolt hole with normal machine weight on the shock.
Hopefully this will be of some aid since this conversion is the result of me giving up on a better suspension for my 85 Bigred so hopefully there will be something to gain for those wanting to apply to the 250ES Bigred since they share many parts. I have had SX's in the past and again IMO, they are a tick better suspension wise then the ES Bigred, still has to be a stock bolt on improvement w/o spending several hundreds of dollars for a custom shock.
Definitely following this thread, very interesting this topic got kicked back into the spotlight !

john

[dreux13]

Having recently done a 300EX quad to trike conversion I wanted to post up how a 2004 300EX stock shock mounted looked + measured at.
The trike is strapped down but not in the way it pulls on suspension. I have had 300EX shocks on my 84/85 Tecates and it is a nice upgrade,,,, not perfect but a heck of a lot better then any stock Tecate shock in fine condition IMO.
These pics are center to center bolt hole with normal machine weight on the shock.
Hopefully this will be of some aid since this conversion is the result of me giving up on a better suspension for my 85 Bigred so hopefully there will be something to gain for those wanting to apply to the 250ES Bigred since they share many parts. I have had SX's in the past and again IMO, they are a tick better suspension wise then the ES Bigred, still has to be a stock bolt on improvement w/o spending several hundreds of dollars for a custom shock.
Definitely following this thread, very interesting this topic got kicked back into the spotlight !

john

Thanks for the pics John....man that thing is looking sweet!

[Flyingw]

That shock looks promising

[dreux13]

So I now have a choice.....

A. Purchase a 300EX shock off of our favorite auction site for roughly $50

or

B. Purchase a 2001 Raptor Shock for $100. The Raptor shock is a direct Bolt-on to the 300ex and therefore should work on the SX. It has to be a 2001 because that is the only year where they had a remote res on it. My feeling is the raptor shock has 3 adjustment points (preload, compression, and something else) which may be helpful in tuning it for the SX. It may also just end up being too stiff. Also, with all of those parts, it has more potential to fail over time assuming the one I receive is good.

Thoughts?

[GSUwhiskers]

I wish I could choose one and you choose the other and we see which works better, but I'm too strapped at the moment for experimentation. I'm really glad you have taken such initiative though. So have you absolutely verified that a 300ex shock will fit a 250SX? I saw you mention having to fab some bushings?

[dreux13]

If you search deep in the bowels of the site, you find some interesting stuff!

In the last post of this thread, we have proof of someone running a 2001 raptor rear in an SX, but he claims in other threads that it's a little too stiff even at the softest settings. I'm 100% positive that the raptor shock is a direct bolt on to a 300ex and 99% sure that the 300ex will bolt in to the SX too.

The question now is in what will give the best ride. I do heavy trail riding, usually on rocky logging roads at higher speeds and want soft, but not bottoming out/dangerous soft

http://www.3wheelerworld.com/showthread.php/134881-Beefier-rear-suspension-for-250es?highlight=Raptor+shock

[GSUwhiskers]

So what kind of riding is ideal for a stiff shock?

[dreux13]

More track, whoops, jumping type stuff which I've gotten too old for, although a stiffer setup can absorb some of the rocky terrain at higher speeds though.

[dreux13]

So I spent a little extra for a crispy clean 2008 300ex shock on eBay and it fit great with two spacer washers and some reducer bushings! I won't know how well it works until my first real trail ride, but it looks and feels very promising.

The original shock was mounted with the adjustment on the bottom and the 300ex shocks seem to be mounted with adjustment on the top, so I mounted it that way. Not sure if it was correct or not, so I'm open to feedback!

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[HoustonAE2]

So I spent a little extra for a crispy clean 2008 300ex shock on eBay and it fit great with two spacer washers and some reducer bushings! I won't know how well it works until my first real trail ride, but it looks and feels very promising.

The original shock was mounted with the adjustment on the bottom and the 300ex shocks seem to be mounted with adjustment on the top, so I mounted it that way. Not sure if it was correct or not, so I'm open to feedback!

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200529
200530

How did it ride? I am looking to do this to my SX as well and will spend the extra cash for a clear newer 300ex shock but am fearful that the ride quality will not be worth it...

[dreux13]

I finally got a chance to ride it with the 300ex shock and it rode great! It was on a light track up at the New England trike fest at Backwoods. While the back end feels stiff to just push down on the grab bar, it soaks up everything when actually riding! Definitely a needed upgrade!

[ps2fixer]

It fit great with two spacer washers and some reducer bushings!


Were the washers and bushings a standard size, or did you have to machine your own?

Glad the ride report came back good. The spring looks heavier, and compressed more, but it is progressive. Did you noticed your stock shock was adjusted to the stiffest setting?

[dreux13]

Were the washers and bushings a standard size, or did you have to machine your own?

Glad the ride report came back good. The spring looks heavier, and compressed more, but it is progressive. Did you noticed your stock shock was adjusted to the stiffest setting?

For once, I didn't need to do any machining! I simply bought the 12mm to 10mm reducers found here.

http://www.dimecitycycles.com/12mm-od-by-10mm-id-shock-mount-reducer-bushing-adapters.html

The washers were simply spare washers I had in my parts bin.

The stock shock was on its stiffest setting as well. Between the 200x forks, the 300ex shock, and my pro taper bars, this thing is so nice to ride!

[ps2fixer]

Thanks for the link and info, I'm tossing the idea around, but probably should look into getting new bearings first since it seems the swing arm bearings are pretty shot on my machine.

[Jmoozy27]

Has anyone tried the 300ex shock on an 85 Big Red?

[Keepah Rolln]

I'll have to take a look at one of my sx's i bought a few years ago. It has a red shock on it. It might be a ex shock...

[Dezlemke]

http://uploads.tapatalk-cdn.com/20160422/bfe6927fcd797da0856e95388de958fa.jpg
Side by side comparison of a 01 raptor 660 shock and a 250sx shock.
Sadly the raptor shock doesnt just bolt on. Theres some clearance issues for the top mount

Sent from my SM-G920P using Tapatalk

[oldskool83]

use a stock 300ex one. It will be way better