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CSR Fork springs from .48NM to .52NM

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The stage is set going from .48nm to .52NM                       215 to 225lb rider weight range

I left off with the .48's at   105 mm oil height,  2.5 preload turn and  21/14 rb

 

I also took the time to see how ktm sets the preload, with zero preload turn, they seem to target 4mm, that happens to be what racetech also recommends, the 2015 base setting is supposed to be set at 2 turn in preload, which adds an additional 2 mm , so that's actually 6mm preload at that setting. This assumes the springs are all the same length, and ive only dealt with the oem springs and the CSR springs, and they are right there on target with each other length wise.  Which is good, cause ive bought eibach aftermarket springs years back and one spring can be a 1/2 inch longer than the other, just poor quality control, and then can you really trust the spring rate if they cant get the length right.

 

so where to set the .52's?

I decided to go with 116mm oil height

left compression at 21  but tighten rebound to 11 out ( this because the last time I jumped 2 spring sizes it needed about 4 clicks of additional rebound damping)

and went back to the standard 2 turn in on preload for intial testing.

I think that's reasonable settings to get started.

 

Edited by Spud786

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On ‎7‎/‎5‎/‎2017 at 9:55 PM, Spud786 said:

 

 

so where to set the .52's?

I decided to go with 116mm oil height

left compression at 21  but tighten rebound to 11 out ( this because the last time I jumped 2 spring sizes it needed about 4 clicks of additional rebound damping)

and went back to the standard 2 turn in on preload for intial testing.

I think that's reasonable settings to get started.

 

Before riding, I pounced on the bike a few times and I felt the front might be a little stiff, so I dropped 3 clicks on compression(24out), and one click out on rebound (12out).

I went on a 120 mile break in ride, initial feel felt fine, and didn't adjust any settings the whole ride with the exception of one click quicker rebound late in the ride for a test ,which promptly got put right back where it was. So the rebound I seemed to have gotten spot on, not to quick , not to slow, the bike flys straight and controlled in the air, and corners stable. why did I change the rebound, is because I wanted to see what effect it had on a rock section.

This ride covers a wide range of terrain from soft forrest ground, to loose rolling cantaloupe rocks, 70 mph single track, to light track jumping, and rough potholed) backroads.

Surprisingly , this .52 change didn't cause an imbalance with the rear shock.

Was this change night and day ?  no it wasn't   , the performance is actually comparable to the .48's in several areas. Keeping in mind the .48's were running higher compression, higher preload and higher oil height. All that was reduced on the .52s  , basically exchanging hydraulics for spring action, and thats really the way it played out.

One area looking for improvement was larger jump landings where I could never get the .48 totally compliant, there seems to be an improvement with the .52's , and I have a tweaked left wrist from hard landings on the .48's, and it didn't get aggravated with the .52's with the lower oil height and compression. So I'm going to rate a 10% improvement there.

Half way through the ride , I felt there was  improvement in many places, and only a couple of places I feel the .48's where better, so that will need to be tested further, mainly I had a little (eye flutter) on my 70 mph single track sectiion with the .52's, but its fine on other areas,  also have some 1.5ft deep square edge whoops and the .52s felt better there.

so basically many areas the ,52 seemed to work better, and a couple areas I give the nod to my .48 as better, If not suspension ,but the attitude of the bike through the obstacle, thus far anyway.

One Of the things I mentioned previously, is the hydraulic settings that I had on the ,48's, gave up some feel on lose soft ball to cantaloupe size rocks.  I gained a touch of feel back with the,52's with lighter Hydraulics, but not much, almost a wash.

 

But intial testing , both setups are in the same ball park, with the exception of bigger jump landings, go to the .52's  . But next round I'll be reducing a click or two compression, and this could have an affect on those larger jump landings on the .52's.   So testing has more to come.

 

 

 

 

Edited by Spud786

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 Could you please give us a film clip of a 70 mph singletrack section, this is something I must see ...

 Around here are single track section is 32 inches wide and second or third gear 

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32 minutes ago, E-TECH said:

 Could you please give us a film clip of a 70 mph singletrack section, this is something I must see ...

 Around here are single track section is 32 inches wide and second or third gear 

This is probably more to your thought on slow single track,  but I have areas that are 12 inch wide track , that I run at 70 mph. What else would you like to call it , Im not too picky.

If I could otherwise continue with my thread please.

 

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This time of year is the harshest on suspension, ground has no moisture and hard as a rock. Which is probably ideal conditions.

Okay, it is confirmed a definite improvement on larger jump landings with the .52, I actually dropped 3 clicks on compression and thought it was the plushest at full bottom. However don't really like that compression setting in other areas. I may actually be able to drop oil height more.

So On the 3 clicks further out, (27 out),  I could feel the head attitude of the bike drop , not sure I liked it, suspension felt more rigid. So I tried 1/2 higher preload(that was bad, so tried 1/2 turn less preload and rode that for a while, till decided to go back to original preload setting.

Pretty much went back to the original setting of yesterday.

so I may scale back oil height to 120mm, but don't feel like tearing the forks apart at this time.

 

But right now, I think trail wise the .48's are better , bottoming plush wise the .52's, with the settings that Ive used.

 

I don't even want to think about the rear right now, but I'm running 152 psi nitro, so alittle stiffer than standard shock with the 8.0 spring

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Update , two more rides , and pretty much have stuck to original settings as mentioned previously with the .52's, after trying a few different ones.

Definitely going to try a drop in oil height, to somewhere around 120 or 125mm, presently at 116mm.

 

So far Im not really pleased over all, with the 52's (no magic), they have their instances where I like them, but not overall. We'll see if a different oil height platform changes things up.

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Ive revised oil height from 116mm  , and dropped it 9mm , to 125mm . Figured might as well go for the gusto, and move oil height back up as needed.

It softened the fork a lot,  and I pumped back up the compression 3 clicks.  

 

so coming from 116mm oil height /  23c/11rb  / 2 turn Prld     to::    125mm oil height /  20c/ 11 rb   /  2 turn prld   for beginning new test.

 

Not sure how it will play out bottoming wise, but we'll see.

 

On a side note, Im beginning to see some streaky wetness on my non brake side fork  seal, the  brake side is dry and replaced at 300 hours, but this other seal has near 600 hours, so I'll be back inside of that fork within the next week.

 

 

 

 

Edited by Spud786

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Have you done anything yet to the rear spring rate and/or C/R valve settings, or only the front?  When I read through some of the changes, it seemed you were making changes that softened the front, maybe due to imbalance with the rear?

I'm reading all this with interest.  In the process of respringing my 17 FE501 (I'm 245 lbs dressed out, so was killing the stock springs).  I went up 3 spring rates front and rear.  I was surprised to find on the new bike the fork oil gap at 130mm vs a spec of 110mm +10/-20.  I'm using an initial setting of 105mm (center of spec) as I ride a lot of whoops and had serious bottoming out.  Changing to TuBliss as well as new tires (Michelin StarCross 5 Intermediates) due to sandy loam/whoops, hoping for some better traction than the POS Continental TKC80's that came on the bike.

Made similar changes back when I had my 05 KTM 450EXC.  Suspension is definitely the most important improvement I have ever made to a bike.

Keep up the posts.

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1 hour ago, markbfe501 said:

 

This is on my 2015 500 open chambers and 50mm rear shock, I was already up two sizes front and rear over stock, the front is now 4 sizes up, which I'm now testing. Ive not seen an obvious handling imbalance at all with the rear at this time. That doesn't mean I wont change the rear later, Im just focusing on the front.

A handling imbalance I describe as a squatting rear when cornering or flying. The only other difference Ive done to the rear is a higher nitro charge 152psi, not that I recommend it, but it definitely stiffened the shock, and I had to adjust settings as a result. The original charge was an assumed 142 or 145 psi, I later tried 149 psi, didn't notice any difference, at 152 psi definitely noticed , again not recommending just stating what Ive done thus far. 

I was high enough on oil height with .48 springs, that I felt I could do better with larger springs and less oil, which is still a work in progress.

Original set up on the ,52 springs , has showed some promise.  Whether I can truly achieve an overall better set up than my .48's is what Im working on. But no I definitely do not want a stiffer rear right now.

 

Just alittle info for you, with stock .44' frk springs I ran 23 rebound, .48's I ran 15 out on rebound ,  .52's are requiring 11 to 12 out on rebound.   The 2015 valving has a pretty good spread to cover these necessary adjustments, luckily.

 

Edited by Spud786

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Thanks.  Can't wait to get mine back together to start dialing it in.  Sandy whoops up in Michigan earlier this month were miserable with the stock springs (I lived in the bottom half of travel), given my weight and the stock tires.  Will be back up there again in early August, and expect to feel an entirely different bike.

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On ‎7‎/‎18‎/‎2017 at 7:12 PM, Spud786 said:

Ive revised oil height from 116mm  , and dropped it 9mm , to 125mm . Figured might as well go for the gusto, and move oil height back up as needed.

It softened the fork a lot,  and I pumped back up the compression 3 clicks.  

 

so coming from 116mm oil height /  23c/11rb  / 2 turn Prld     to::    125mm oil height /  20c/ 11 rb   /  2 turn prld   for beginning new test.

 

Not sure how it will play out bottoming wise, but we'll see.

Okay so 125mm oil height definitely changed things up. Noted: I increased compression to compensate for lower oil height, mentioned above. I did not make any suspension changes on this ride.

Looking back , The previous 2 areas that I liked on the .52's with 116mm oil height ,was the bottoming cush on larger jumps, and big Hard  2 ft  square edge whoops, where the front can fall into, those were the best things, everywhere else I didn't really care for so much , plus the last half of the ride I'd always begin to feel the stiffness in the suspension, which became annoying. Silty hard pack was not as precise (feel wise or traction wise) nor other areas, like softball to cantaloupe size rocks.  There is a borderline where you absorb the rock or Push the rock, ofcourse pushing the rock is not ideal.    125mm I also regained better absorption with (solid) jagged rock creek bottoms.

Anyway, at 125mm oil I gave back the two areas I like most ,mentioned above, but regained, all the areas I didnt like. I regained more feel on rocks and slicker conditions, and didn't have the stiffer suspension feel late in the ride. 

Keep in mind Im comparing all this to my .48nm set up , which was pretty good, Im not seeing a huge gain for dual sport or trail bike use. Yeah focusing on Motocross the 52's give more Big hit dimension, with various set ups(like my original).

So my thoughts at this time, for someone with .48's, the move to ,52's , may not be exceptionally fruitful.

If you had no springs and debating between .48's and 52's , imo , its a toss up.

 

I will continue testing, but those are my thoughts thus far, I am debating adding 2 or 3mm oil height back into the fork, or I could try another click or two compression. Im probably more happy at 125mm than 116mm , even though I gave up those two areas that I like most about the 52's.

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Today I decided to go 2 compression clicks in, from 20c/rb   to  18/ 11rb   125mm oil  , noticed right way the front was taller , felt fine over straight line rough.

It felt alittle stiff cornering , and not settling well espeically on silt covered hard pack , and lacked feel. However I regained the larger jump and square edge Whoop Cushiness.

Anyway rode that for a good 70 miles to thoroughly test all conditions, before changing back, and finishing the other half of the ride.

 

Im thinking to raise oil height back  up 4mm  to 121mm and see how that does.  also Late ride, stiff suspension wearing didn't happen, so thats good.

 

Obviously the original 116 oil height is definitely a no go, cause I always developed late ride suspension stiff annoyance, so maybe I can go back to an in between setting with 121mm and regain the larger jump cush, without pumping up the compression, and killing the corner suppleness.

 

 

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I mentioned earlier in the thread, that my non brake side fork seal was developing weepage. I took care of it during the week, I lost about 1mm oil height or 1cc of oil, so not a serious leak over 400 or 500 miles, but needed dealing with while I was in there, Changing back from 125 mm oil to 120mm oil height.

I hadn't changed my fork oil since January, it was actually clear till I poured out deeper, then it started greying up slightly. So time for an oil flush anyway, and the .52's should have completed shedding any breakin debri.

 

I tested 2 different settings on the 120mm oil height (Honda ss7 is my standard oil),  20c/11rb   and  22c/12 rb  and there is considerable differences between the two settings .  I started out weak and tired today, which has a significant effect on testing, verses being at full strength and pumped.

However during the ride, the additude of the bike was keeping me pumped up, and not displeasing.  More than likely Im in the range of the optium setting for the .52's, I'll reviste these settings tomorrow.

 

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Okay, so I have some usable settings for the next 6 months, and may revise occasionally over time.  215-225lbs ,  stock tank

Was the move to .52nm worth the time and money over .48nm  , Much different valving settings for sure.

 

as mentioned yesterday I was tired, but when Im tired and not disliking the suspension, that's really a good sign. Today proved to be the case with some rest. Those settings were good enough to pursue.

Example , one area of clear improvement

I have a down hill ravine with successive 1 to 1.5 ft cross ruts (black dirt) and then, through softball cantelope boulders at the bottom, pace around 50 mph, before hitting a vertical uphill and catching alittle air at the top, the .52's take that in stride and more controlled.  The .48s sometimes was like riding a jack hammer through that section, especially if you touched the front brake at all, not always but the .48's seemed inconsistent though that area, which makes you question confidence, how they are going to react that particular time, sometimes they felt good and others, smacking your Jaws like a jack hammer.

Another area where I had the ,48's dialed was dropping in and out of a creek bed on a pace, IMO the ,48's and the 52's while close , I give the edge to the .52's, just cause Ive pushed the pace over the .48's.

So That's a clear difference, but overall well set up .48's are right there or better in other areas IMO.

 

So did I gain in some areas , and a wash in others, yeah that's kinda of the way it looks, we'll see how .52's feel with the rains come, with traction levels. But I have pretty much achieved the same zone that I had the .48's in, with some mild pro's and cons between the setups.

 

 

 

 

 

 

 

 

 

 

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This past weekend I made no changes at all, and with 10 to 15 hours on the .52 springs, everything has seated  2015 OChamber , stock tank

running 120/121mm oil height (ss7)  , 2 turn in preload (6mm total preload) , 20/21 comp with 12 rebound

 

I came from .48nm , 105/110mm oil height (ss7), 2.5 preload(6.5mmtotal preload) 21c/14/rb

 

Not a Huge performance change, alittle better feel in higher speed big hit performance with the .52's, which the .52's are more predictable(they work pretty good).

 

some mentioned what about the rear compatibility?  right now, I don't seem to have enough issue with the rear to venture out with anything different(with clarity of what to change) if I so desired. I mentioned the 152 psi, stiffened the shock a lot. Which actually caused me to quicken the rebound (several clicks), which is odd. Been running this rear since January, tested all preload ,comp and rebound settings(in the early beginning, after initial move to 152 psi.  Id say if I stepped back down the nitro, I might notice an issue, with imbalance.

anyway, just an update for entertainment purposes

 

 

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A few months later and 40 plus hours, the .52 fork springs, the biggest benefit has been large square edge  whoops , they really stand out there as better cush.   Verses higher oil height and lighter springs, the .52 are 4 sizes larger than oem and I came from 2 sizes over .48nms.    Small logs are cushier too.

I just spent some coin on new front rotor and new pads, but looking to make a rear spring change, and probably a progressive (already a size and 1/2 stiffer than oem). They arent cheap so Im debating, and definitely not sure.  But it seems difficult, to get the shock set for normal cush and then be able to slam a jump face, with the rear shock bottoming solidly. You set damping for the jumps and then it sucks everywhere else and vice versa.

 

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So I spent the last couple months, with these settings on the .52nms, 120/121mm oil (Honda ss7) , 20c/12rb , 2 turn preload . Very stout and usable.

When the fall came and leaves started falling, hidden small rolling broken branches under the leaves and soft soil ,  When cornering, the level of traction feel was not ideal , especially hitting one of those hidden rolling branches, The PROPER FEEL was just not there, like too stiff. 

So I was out on one of my small grass tracks with very slick powdery dry soil, and thought Id drop compression 2 clicks.

I started hitting corners having just come from 20 compression, and the feeling at 22 clicks out, was that I was getting a low tire, that feeling though, was the  traction FEEL level, jumped up considerably. I took the same set up to my leafy , hidden rolling branch forrest area , and worked better there two, as I had much more cornering feel , and responsiveness.  Jumps and big hits still fine also.

 and pretty much locking the front down there,(((( .52nm Honda ss7 at 120/121mm , 22c/12rb  2 turn preload  )))))

 

 

Now I want to go after the 8.0 kg rear, cause I cant make it be superbly compliant on steep jump faces, and normal stuff at the same time , I just think there is some room for improvement.  The choices I'm looking at are an 8.4 kg straight rate  or an 8.1 -9.9kg progressive.

 

And I really don't know which way to go, there's so much back and forth on straight rate verses progressive.

 

 

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