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Bagstr

Suspension Tuning - Actually - KTM 450 XCW

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The Day in Anza Borrego South ( Carrizo Wash South Dec. 18 )  turned out to be a productive day setting up the bike's suspension. I had it pretty close to good, but I learned some good limits and how to get the best feel for my needs. George at Suspension 101 in Alpine got me set up with the correct springs back when I first got the bike. Since then he has done good work servicing the units and giving advice. The clickers were always straight forward and I have been comfortable with that for awhile.

The Turning Feel has been the Holy Grail.  Again, I have had it close but being unschooled with the finer elements I knew there was more to being the best it could be. Jimmy Lewis always says these KTMs are tunable, well then let's tune the thing.  George advised me to get the Rider Sag to 112mm for my PDS '16, so that is where I have been. The manual gives a range of 105-115mm.  Turns out That is a really big change in feel on the bike. I will give my feeling about the forks later. KTM gives no hint of what's going on there. With George's springs for my weight and the clickers, the bike tracks well and controlled in a straight line.

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I used the South Carrizo Road as the Test Facility as it has a nice mix of tight sandy turns and open DG type uneven straights.  About 3 miles, I would guess one way. My technique was to systematically run up and back the same track with various settings and compare results. Run one @ 112 mm Rider Sag - Run two @ one full turn of the spring compression ring less R. Sag - Run Three @ one full turn more compression from the 112mm. After Santa visits, I will have one of those fancy sag measuring devices. At that time I will report back. To me the measurement is secondary to the actual feel when riding. The starting point of 112mm was pretty good in that I felt comfortable with the front end stability and could carve a controlled line. Still,,,  I was feeling a little push wide or inside dive in some conditions. It's just a feel thing, I really didn't know if it could be better.Run two the rear sag was one full turn softer.and I immediately felt a more lazy unresponsive turn character. Stable but slow. So back the other way for Run Three with one full turn more compression from the 112mm starting point. Now the character was hyper sharp and fast reaction. Maybe appropriate for a track, but not the Dual Sport riding I do. The feel was not comfortable enough for me, nervous. The shock adjustment ring has 12 lobes for a complete turn. easy to figure 1/2 and quarter turns. The forth Run, I backed the compression off to 6 lobes or one half turn more compression from the starting 112mm. Each of these adjustments resulted in noticeable change in the feel. run four produced an improved result from my starting point. Confident, responsive turning action with a stable feel. Emotionally, I felt the confidence build as I got closer to the mark. 

Someone must be able to explain the physics of what sag adjustments are doing to alter the bike, but that someone is not me. Riding along I was trying hard to come up with a visualization to explain how the changes affect the tracking; Sharp knife / Dull knife; narrow water ski / wide water ski. Would think the angle of the fork changes a touch. This morning I think it could simply be the balance between more or less pressure on the front tire. There certainly is a gyroscopic energy going on when the bike and rider is in motion. The Carve of the turning line can a wide push or a grabby dive to the inside. A nice cut through a turn without that inside "grabbyness" is a powerful tool.   In the end I felt that I had learned what character direction the Rider Sag changes were going to produce. That is a big learn for me! I will get the actual Rider Sag number later. As a side note:  The traction conditions where pretty ideal for this exercise, damp sand and Dry DG soils. I managed to find some muddy conditions, but stayed mostly away from that. My next Learn will be what direction to go when the sand drys out and gets deep again. At least I know more about the dynamics.

After I felt the rear was as good as it could be, I turned my attention to the forks. They are marked with two rings at the top. I have run both, lately running two rings out with the 112mm rear setting. I ran the test route with both and had the best result with two rings out of the top. One ring was heading back into the lazy zone.

All this testing took me over three hours and 28 miles on the test road.  Something I could never have done with a group of riders. Once I was content with the settings, I took 50 minutes to run up Arroyo Seco del Diablo and across the Tapiado Cut-across trail to the Tapiado overlook and back.  Dynamics were great! 

  Bagstr

               Whale Peak near Arroyo Tapiado

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Nice that u can feel changes that small, i normally cant and just throw my suspension at george and say fix it. He says did u mess with clickers, my answer is always nope i dont like it. Then we get it just right after he magically reads my brain waves. But having said that 2017 300xc tried at 105mm sag with linkage on hard single track was good went to 112 hated life back other way to 102mm and im a happy camper

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Great job Bagstr:good:

I plead with some to play with the sag and clickers. Want to learn fast just go wholesale and close a clicker just to see what it does and then you can put it right back. Just write down the clickers before you start so you can return them.

Keep in mind Bagstr needs a certain amount of sag for his weight and where he rides the bike for optimum performance. BP619 is tall so when he is riding he automatically rides further to the back of the bike. Add to that some girth, all muscle of course, to the equation and he will have a lot more weight rearward. So to steer he may need a bit less sag to keep the bike steering when he is crushing the rear end.

Then consider where the forks are in the triples. Adjusting those is nearly identical to sag changes. Get a sag base line before you go. If you are serious I suggest standing on the pegs, balls of your feet, hands at your side, balanced. When sitting just an inch forward or back and it will change your sag considerably but standing you get the same same each time. The sag will not be the same as sitting but that does not matter as long as you have the baseline and then test. It could show 107mm and for you standing it may be optimum and steering well it is correct for you. Sag numbers are suggestions so when you see or hear a sag number remember it is a ball park always, until you test for yourself. A large rider sits further back what happens to sag then? A 200lb midget would if setting sag sitting may have a lower sag number than a tall 160lb rider.

We should do a clinic at McCains or Ocotillo?  I would do it free just kick me some gas money, but I would want to get Noah on board to help out. He is a master at dial in. We have learned much together. Would have to compensate Noah though as he is doing some training and teaching these days. Business is business.

We did a dial in day a few years back and I was overwhelmed and was unable to give individualized attention desired, so the numbers would have to add up if anyone at all is interested.

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Yup woth the digital sag scale its amazing atleast for a guy my size and "girth" how me being in full attack position which is hard on my back to maintain vs my normal trail riding position which to 5'8" guys always comment im standing wrong will change sag by almost 10mm. 

George ill text u about a clinic i know me and blake will be in, as we have been bugging you for one at mccain for years 

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Great write-up Bags. Nice to see that you are open to experiment with the handling of your machine and making it your own. Suspension tuning is not magic, as you have found out on your test-day. Good job! 

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George, Thanks for chiming in on the conversation. I will be up for a Tuning Day ( and bring cash ) to get intel on how to use the clickers without mashing everything up. 

As you know conditions of the soil you are riding on complicates the issue. When we go from damp hardish sand to 4-6 inches of sand, should we be adding or subtracting Rider Sag?  Would a rider be adding more or less Trail?

 George, You are a tremendous asset to SDAR!  

  Dave

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I think sag is pretty much set unless you are changing the type of riding. Single track less sag for tighter steering or desert racing more sag for stability. Soil changes not so much. Desert being sand more sag does allow the front wheel to float a bit easier.

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Will talk to Kepple and see what dates will work.

Noah and I are under the gun to set up a new set of bikes for the Worcs series this season, so things may be a bit tight for a little bit.

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6 minutes ago, Suspenders said:

Will talk to Kepple and see what dates will work.

Noah and I are under the gun to set up a new set of bikes for the Worcs series this season, so things may be a bit tight for a little bit.

I’m patient. 

 

But no stickers on the truck. 😉

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Looking at the Worcs schedule it looks like  after the Devore race Feb 1st we have 30 days till Havasu race. That might be good.

We will nail a date down soon.

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My 18 500 EXC  has been sprung and totally reworked by George. I mostly ride desert. I don’t mess with sag. I’ve played with clickers a lot.   

My biggest gains lately have been playing with high speed compression on the rear shock to stay on top of the whoops. I’m 11/4 turns tighter than base line. 

If im riding all sand -Glamis I’ll tighten compression clickers front and rear. 

Front wheel was beating me up. Way to busy on small washboard chop in washes. 2 minute phone call to George he had me add 4 clicks of rebound and it solved that. 

Body position has a huge effect on cornering for me. Nuts up into the tank my bike carves amazing. 

Stand up and lean back for whoops. 

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Bump

Getting ready to do a run in the Sand;  After review, my memory is refreshed.  Fresh intel from my Dez Contact tells me the sand has dried. 😎

Thinking to run the forks "down" to one ring for the softness of being. My first Repor was in idea conditions, now, no so much.  George, word is you are busy with the scofflaws that have been riding through the Virus Pandemic.  As you have time, It seems time to have a Suspension Day would benefit understanding.  With serious 10ft physical distancing.

Looking for absolution, Bagstr

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On 12/12/2018 at 10:00 PM, Bp619 said:

Nice that u can feel changes that small, i normally cant and just throw my suspension at george and say fix it. He says did u mess with clickers, my answer is always nope i dont like it. Then we get it just right after he magically reads my brain waves. But having said that 2017 300xc tried at 105mm sag with linkage on hard single track was good went to 112 hated life back other way to 102mm and im a happy camper

PDS and linkage are way different for sag settings.  but that is as far as I will comment , but really knowing the systems. Meanwhile listen to George he will get you dialed in. also terminology Spring preload is sag, comp is adjuster, reb is adjuster.

 

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