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Discussion in 'Dakar champion (950/990)' started by Pitster, Aug 17, 2016.
As in a 230 "branded" spring?
I dont remember the spring markings but by 230 I mean the shorter option of 2004 Adv, which I recall to be the 230mm rear travel. 255mm is stock SE stroke, to which full lenght (391mm if I recall right) the smaller "shim" limits the travel.
In real life the stroke is actually longer than stock SE, since it bottoms deeper.
Stock SE fork springs are 5,9 rate and work very well in the adventures...
The 2004 950 Adventure has a total shock length of 379mm (392mm for the taller S), and is listed as having 230mm of travel for standard and 265mm for the S. Springs are 140-255 and 140-265 respectively. The SE spring is listed as 140-215. My current spring is 150-255.
I don't actually know what the "-255" component of the spring number means.
So your suggestion is to go with the 140-255 spring from the 2004 standard 950? I certainly don't have a problem with my rear being too soft, it always seems to deal with whatever I throw at/on it, so it will probably be OK with the slightly lighter spring. I suppose I could also have a spacer fabricated to give me exactly 250mm rather than 255mm, matching the SE front leg travel. Assume this would mean more preload on the spring though.
Reaching the edges of my knowledge by now...
That's good to know! The cartridges arrived today so I'll get the springs ordered once I know what I need for the rear.
The two numbers on the springs are rate and free length (free as in uncompressed) so a 140/265 has a 140 rate and is 265mm long. Don’t confuse spring length with travel / stroke...
So I wonder whether I can keep the same spring in that case...? The 2004 950 has the same free length as mine, and @skuikka suggests that one will work without the internal spacer (though the fact the S runs a longer spring might suggest otherwise).
Hold on - let’s back up for a moment. What have you got and what are you trying to achieve. I’m unclear
Haha, now you're asking for trouble.
Got a standard 990 ADV 2008, and have just got a set of SE front cartridges which I'll install with SE springs to get a 250mm front-end.
Then, I want to mod the shock to match. As I understand it, I'll need the thinner spacer (or a custom one to achieve the exact extended length I want) and then an appropriate spring.
At the moment I'm trying to figure out which spring (if any) is going to work.
It seems like I might need a custom spacer and a custom spring, or I'll need to settle on a 245mm rather than 250mm rear end from a 2005-6 "S" or a 2011 R.
Ok - your standard height Adv shock (it doesn’t matter for now if it’s a 210mm, 230mm travel, etc) uses a 225mm length spring with the internal shim that happens to be the thickest one; about 28mm thick (to limit stroke - travel). Your shock also uses an external 25mm thigh spacer (black alloy) on top of your 225 length spring to achieve the preload KTM wanted and still allow for additional preload with the adjuster.
The 245mm travel bikes used this 225mm spring with that external 25mm spacer and an internal shim that is thinner than the thick one you have (I believe it may have been the 10mm thickness...) of this is what you want to achieve then reuse everything you have but replace the internal shim
If you want 255/265mm of rear travel, you use the thinnest internal shim mentioned in this thread and you use either the 255mm length spring or the 265mm length spring. Both should be available and I believe the 255 is only available in the 140 rate whereas the 265 can be found in 130/140/150 rates. Doing this with the 255mm length spring will give you zero preload with the adjuster fully out and using the 265mm spring length will net almost 9mm of preload with the adjuster all the way out.
Be cognizant of the rubber bump stops on your shock - they did vary from year to year and model to model but are all within 5mm of each other in terms of their height.
Does this help?
That helps a lot! Thanks Alon.
With respect to preload, do you recommend going one way or ther other (i.e. 0 vs. 9mm with adjuster wound all the way out)?
I think that’s something you need to decide. I generally prefer as little preload as possible but in the case of my own bike, I run the 265mm spring with that 9mm preload and I’m very happy with the results. The 265 length is also more common and easier to find.
Besides great info in this thread. What are "we" trying to do?
I also found a 6,4 spring, measured. Too hard for me.
I am running with 5.0 which is almost soft: probably the 5.9 works perfect.
about the spring of the shock: has anyone tried anything softer? I run (without luggage) with an 86 and find it much better than the 140 which bounces a lot.
( with this soft spring I made 1mm bypass hole in the piston because the rebound was too slow also with the rebound completely open )
Tourist, not race.
I believe it began as a “use an Adv shock in an SE” but has morphed slightly.
On my SE, I’ve swapped fork springs from the stock 5,9 to 5,6 (WP Ktm 950sm fork springs) and I’m using an Adv shock which I ran a 130/265 on and swapped out for a 140/265. I’m 102kg and 6’3” - never carry a passenger but ride regularly with some luggage. My SE is 183kg dry and I’ve now installed one of those rear left side plastic tanks for an upcoming big trip. Surely I’ll be cranking up the rear preload once fuel and luggage are added.
By comparison I’m 72Kg on a ~200Kg dry bike with generally a fair bit of luggage and fuel. Not overloaded, but trips are usually multi-day and remote. Pillion-free zone.
I’m leaning towards the 140-265 spring as I think I’ll benefit from that extra bit of preload on mine considering there’s not an easy 150-255 option.
did you also changed the valvling?
I wanted ultra plush and yes, did some shim stack swapping. I don’t bottom out, I’ve got loads of front end feel and traction but I also don’t do MX style jumps on my bike.
i'd love to hear a bit more in depth about the shim stack swapping.