Suspension upgrade

[jgcable]

I read numerous threads on this site and 250r forum regarding suspension upgrades for the 1986-2007 Ninja 250r and I think I am more confused than when I started. I want to upgrade both on my 2003. It only has 4100 miles on it but its spongy all around and I prefer a stiffer ride. I weigh 190 and I will only be riding 1-up. I would be considered a "spirited" rider. I am not knee dragging but I am not loafing either. I would rather have a sporty stiff ride that handles good rather than a comfy ride (which it has now).

I am thinking about the following and I would like opinions..

Rear suspension...

#1. New Gen 250 or 300 rear shock.
#2. Used EX500 rear shock

Front suspension... (I know emulators are the best but I don't want to spend that much money)

#1. New EX500 springs and 15wt fork oil
#2. New Sonic Springs and the appropriate weight fork oil
#3. Stock springs, make my own pvc spacers and 15wt fork oil
#4. Progressive springs and the appropriate weight fork oil.

[cuong-nutz]

Option 1 for rear and option 2 for front. I cannot comment too much about the rear shock but the newgen is a whole lot better than your current one.

Stock fork springs are not rated high and for your suspension to do its job, the spring has to match the weight of the rider. From there, you can adjust the viscosity of the fork oil to 'tune' your dampening.

Stay away from progressive springs. They will sag unevenly and cannot be 'tuned' properly.
Option 3 isn't good because stock spring will not support you properly a s you will be bottoming out the forks.

Read the FAQ at sonic springs so you can understand sag and preload.

[alex.s]

i'd get a rear shock that has adjustable damping instead of a newgen or 500

[jgcable]

I went on the Sonic website and based on my specs I need to order part #
10S-080 which are .80 weight springs. I think I am going to order those. Only $79.95 for the pair (I suppose its for the pair)

So.. I pretty much know what I am ordering for the front suspension.

Regarding the rear.... I am leaning towards the drop in new gen 250r or 300 shock although I have no problem with modifying a shock if its better. I just don't want to take the entire bike apart to do it. I guess I need to read up more on rear shock choices.

[InvisiBill]

I don't know enough about the 250 to say what the proper spring rates are (I'm only going by RaceTech's calculator), but find out what spring rate you need for your weight before throwing random parts at. Everything will work much better if the spring rates are matched to the weight they're supporting.

The EX500 springs are nothing special. The fork springs at .585kg/mm are good for a ~110lb rider according to RT. For 190lb, they suggest .70kg/mm (about 20% stiffer than the EX500 springs). The rear spring on the 500 is only 300lb/in, compared to the 440lb/in on the PreGen shock (different years might be different, but the one I got on eBay was definitely stiffer than my 500 spring). The NewGen's spring is 520lb/in, which is good for about 220lb on that bike (PreGen rear isn't listed on RT's calc and I don't know how different they are). For 190lb on a NewGen, they recommend a 490lb/in spring (about halfway between the PreGen and NewGen rates). If you want to use the EX500 shock, I would suggest swapping your stock spring onto it first. You can put generic aftermarket springs on it, but you might have to do a bit of work to get the larger spring to sit nicely on the shock and there could be dogbone-spacing issues (though I think the PreGen setup gives more room). In my eyes, the only benefit of the 500 shock is the preload adjuster.

The emulators serve a different purpose from the springs. The springs allow the suspension to bounce (hopefully matching the supported weight well), and the other fork internals control that movement. In the stock damper rod setup, you have holes of a certain size and oil of a certain weight. Those two combine to provide a certain damping rate. For a certain size bump, that damping rate will be ideal. For smaller bumps, it will flow too much oil and the suspension will feel soft. For bigger bumps, it won't be enough and it will feel hard. The emulators add some extra parts that allow for better handling of the damping. Instead of one sweet spot and everything else being (different levels of) wrong, the emulator's spring can be used to set a curve for how damping is handled. This allows it to handle a range of damping better, instead of just a single point. You can always add them later if you want to improve things even more.

As for comfort vs. performance, a spring that's way too soft for your weight will actually result in a rough ride. If the spring is too weak, the suspension will flail around. Putting stiffer springs on results in the suspension moving in a more controlled way, so the result is actually a smoother ride. Obviously this isn't referring to slight tweaks up and down around the proper rate, but once you get too far on the soft side, it actually will get rough.

[jgcable]

What do you think would be the better option for the rear? I have already settled on getting the sonic springs .80 weight based on the calculator and my weight.
I have narrowed my choices to a 2008 new gen 250r rear shock or a ZX600C rear shock from 1994. I am thinking the ZX600C shock is better because its air/oil and very beefy but I also have to consider its a 20 year old shock and the new gen shock is only 6 years old. I would change the oil in the ZX600C shock of course but I don't know if its better to put an old shock in or a new one. I don't race. I just want the bike to have less sag and feel less spongy in the rear. I weigh 190 and it probably sags 2 inches just by me sitting on it. Also.. it feels spongy in the rear.

[InvisiBill]

I'm no expert on the 250, but you may want to consider going down to a .75 or .70. RT's calcs are bike-specific (they actually have different calculations for PreGen and NewGen even). I've heard before that our bikes' front ends are more "standard" or "sport touring" than a true sport bike, affecting the spring rates needed. I've seen it suggested to go down one step lower than what RT recommends even. Again, you're free to do whatever you want, but I think you might be overestimating a bit (I'll gladly defer to anyone who knows better though). Even the .75 is over 70% stiffer than the stock springs, so it'll be a huge improvement even if it ends up being a hair under the 100% ideal rate.


How much detail do you know about the ZX600C's suspension?

Originally Posted by InvisiBill

http://www.nestreetriders.com/forum/...hock-Swap-Myth

This is coming from someone who has had shocks from two different bikes installed, so don't think I'm trying to say that you should never try a shock from another bike on yours. However, keep in mind that there are a lot of details involved in the operation of a suspension system. Just randomly picking a shock off another bike is likely to give you bad results, even if the shock works great in its original bike. You need to take into account the spring rate, stroke length, and the valving (and how they work with the hard parts on the bike), on top of just whether or not it has more adjustment features.

The NewGen shock will basically be a respring and give you preload adjustment. I wouldn't expect huge differences in the shock's actual performance simply because they're both basic, budget bikes (which are pretty similar on top of that). I don't know exactly what rate you want in the rear, but based on the NewGen's calc, the 520# spring on its shock might be a bit much. If you can find one cheap enough, give it a shot. Another cheapish option is swapping an aftermarket spring of the proper rate onto an EX500 shock (drop-in replacement with preload adjustment and easy disassembly, though the bigger spring might need a bit of extra space), which would allow you more choices to pick the spring rate you want vs. trying to find a stock shock/spring that happens to match what you want.

For whatever it's worth, I personally have a NewGen shock on my 500 because the spring rate is correct for my weight, and I assume the shock is fairly similar to the stocker. I'm treating it as just a budget way of getting a respring to match my weight. I recently snagged a used Penske for a good price and now I'm just waiting for my new spring (basically the same rate as the NewGen's, it came with one close to the PreGen's) to get here.

[jgcable]

Originally Posted by InvisiBill

I'm no expert on the 250, but you may want to consider going down to a .75 or .70. RT's calcs are bike-specific (they actually have different calculations for PreGen and NewGen even). I've heard before that our bikes' front ends are more "standard" or "sport touring" than a true sport bike, affecting the spring rates needed. I've seen it suggested to go down one step lower than what RT recommends even. Again, you're free to do whatever you want, but I think you might be overestimating a bit (I'll gladly defer to anyone who knows better though). Even the .75 is over 70% stiffer than the stock springs, so it'll be a huge improvement even if it ends up being a hair under the 100% ideal rate.


How much detail do you know about the ZX600C's suspension?



The NewGen shock will basically be a respring and give you preload adjustment. I wouldn't expect huge differences in the shock's actual performance simply because they're both basic, budget bikes (which are pretty similar on top of that). I don't know exactly what rate you want in the rear, but based on the NewGen's calc, the 520# spring on its shock might be a bit much. If you can find one cheap enough, give it a shot. Another cheapish option is swapping an aftermarket spring of the proper rate onto an EX500 shock (drop-in replacement with preload adjustment and easy disassembly, though the bigger spring might need a bit of extra space), which would allow you more choices to pick the spring rate you want vs. trying to find a stock shock/spring that happens to match what you want.

For whatever it's worth, I personally have a NewGen shock on my 500 because the spring rate is correct for my weight, and I assume the shock is fairly similar to the stocker. I'm treating it as just a budget way of getting a respring to match my weight. I recently snagged a used Penske for a good price and now I'm just waiting for my new spring (basically the same rate as the NewGen's, it came with one close to the PreGen's) to get here.

I don't know anything about the ZX600C shock other than what I read here. I do know that Air/Oil is the preferred shock for most applications. The ZX600C looks to me to be a direct bolt in (with the possible exception of having to add a slightly larger lower bolt). I have no problem buying one and replacing the oil in it. I am just wondering if its worth the extra effort when I can just buy a New Gen shock and drop it right in. I am not racing. I am just road riding.

[jgcable]

Just a quick question... a Ninja 300 shock is a direct drop in for my 2003 correct?
They seem to be a lot less expensive (and obviously much newer) than the New Gen 250r shock that I am finding on Ebay.

[Qomomoko]

Originally Posted by jgcable

Just a quick question... a Ninja 300 shock is a direct drop in for my 2003 correct?
They seem to be a lot less expensive (and obviously much newer) than the New Gen 250r shock that I am finding on Ebay.

not test done yet but I have read multiple times that yes, a ninja 300 is a direct swap into the pre gen b/c the ninja 300 shock is the same as the new gen rear shock but with some internals changed making it a little stiffer.

what is the spring rate of a ninja 300 you ask? I dont know either but trying to find and hope its .7kg/mm and no more than .8 kg/mm

editing for misinformation

the following I have now read on this forum for the REAR shock
: pregen 440 lbs/in = 7.8 kg/ mm ............
:newgen 520 lbs/in = 9.2 kg/mm............. ok up to a 220 lbs person

if you weight 190 lbs then it is recommended 8.75 kg / mm or 490 lbs/ in

not sure what k for the REAR shock for 160 lbs person or 175 lb person on a ninja 250..

I was confusing K's for rear shock and front suspension and still much to learn...

[Ghostt]

I have a pre-gen, so I personally cut, and set sag on a pair of EX500 fork springs to a new rate of .85g, I also did the ZX600C rear shock, just needed to buy a longer bolt for the bottom mount. I also run 15wt. synthetic fork / shock oil.

I like the set up, as I weigh 220 lbs with gear on. I particularly like the adjustability of the rear shock now, just adjust the air pressure, and your set.

[Qomomoko]

Originally Posted by Qomomoko

not test done yet but I have read multiple times that yes, a ninja 300 is a direct swap into the pre gen b/c the ninja 300 shock is the same as the new gen rear shock but with some internals changed making it a little stiffer.

what is the spring rate of a ninja 300 you ask? I dont know either but trying to find and hope its .7kg/mm and no more than .8 kg/mm

editing for misinformation

the following I have now read on this forum for the REAR shock
: pregen 440 lbs/in = 7.8 kg/ mm ............
:newgen 520 lbs/in = 9.2 kg/mm............. ok up to a 220 lbs person

if you weight 190 lbs then it is recommended 8.75 kg / mm or 490 lbs/ in

not sure what k for the REAR shock for 160 lbs person or 175 lb person on a ninja 250..

I was confusing K's for rear shock and front suspension and still much to learn...

so much to learn and unconfuse my self with

[Ghostt]

Originally Posted by Qomomoko

so much to learn and unconfuse my self with

No worries, it's an ongoing process, that never ends for EVERYONE.

[Singh2jz]

My .02:

Front: sonic springs w/ 15w oil. I think you already chose this option?

Rear: Gixxer shock. You might have to mod it to fight, but idk for sure. If you want something thats plug and play, then go for a 300 shock.