[al399]

Hello, fellow Desert_Sleders...
I have a question regarding sag adjustment related with the Desert Sled manual. What I knew was that sag adjustment had to do with the weight of rider plus luggage or passenger. Meaning that you adjust the sag of the bike accordingly and always in relation with the weight you carry. While I was reading the manual I noticed that there is SAG adjustment for road use and sag adjustment for off road use.
At the 1000kms service I plan to set the front and rear suspension rebound and compression closer to the off road use because I want the bike to ride bumps holes etc softer.
What should I do with the sag adjustment? I knew that with the rider on the bike on the pegs the rear spring should be 30%=about 50-60mm less than when with the rear fully extended...
Shall I make a different kind of adjustment of sag if I opt to soften the compression and the rebound front and rear?

 

[Max Kool]

(warning, by all means, I'm no expert. The below works for me though. I'm an average guy, weighing an average 190lbs all dressed up)

I think I know what you're trying to achieve. The suspension of the Desert Sled can be harsh on small, sharp bumps. We've all tried to make it better. What I found what works, what doesn't on the Sled.

- The suspension gets better after 2-3000 miles
- Try to get the front at 25% rider sag, most likely by adding some preload.
- Try to get the rear at around 30% rider sag, but make sure there is still static sag! Too much preload and the extension of the rear suspension after a bump will upset stability (yep, causing the bars to slap). Just make sure when you're standing next to the bike you can still pull the tail up a few mm's. If it's already fully extended on the spring only, you've gone too far.
( I would like to try a linear spring one day, I'm not really fond of the sudden transfer from the softer ratio to the stiffer one. Feels a bit like bottoming out.)
- If after setting the front and rear sag as suggested above the bike starts steering lazy, consider tuning the geometry by sliding the forks up in the triple trees a few mm's (I did that and made a noticeable difference)
- The forks are highly adjustable in compression and rebound, and react very well to tuning adjustments except for high-speed compression. They remain harsh in short sharp bumps. Don't overly soften the front damping, this may lead to wallowing in corners. I actually have the front compression at 6 clicks out instead of 8, rebound set to stock.
- Rear rebound is interesting. There's a lot of adjustment in the first half turn, but I haven't noticed much difference after 3/4 turn and more.
- Tire pressure!! Don't over inflate your tires. These tires are also found on bikes like the BMW R1200GS, CRF1000 Africa Twin and KTM 1290, bikes that are easily 50-75kg heavier than the DS, especially with all the farkles and luggage. They are pretty stiff and don't need much pressure on our bikes imho. Riding solo Ducati suggests 32/32 (front/rear). I would even go lower. I've been riding them solo at 30 front and rear and love it. If I go over 34 psi the ride becomes notably harsher. If you ride with luggage or a duo you need to air up of course. Find your sweet spot.
- If you really want to go all-out, consider converting your wheels to tubeless. Less unsprung mass, and it feels like the carcass of the tire is more pliable. The ride just feels smoother tubeless at the same tire pressures. As if the pressure was 2-3psi lower. Not for the faint of heart though.

And at some point, it is what it is. The wheels from the DS are heavy, and it seems to have too much high-speed compression. Certainly something you learn to live with. This bike is a hoot!

 

[al399]

At 710kms the suspension already starts to break in and feel softer than in the beginning. Thanks a lot Max.

 

[danketchpel]

Max,

I'd agree with you on the tires, I believe they are part of the problem given their rather flat profile. They don't absorb bumps very well at all and I've found the same approaching 33-34 psi will make things harsh.

I also think the rear spring progression rate is not very good. There's a very soft section (you see the lower coils very close together) then the straight rate. I've found you use up 70-80% of the initial rate in just rider sag and then you get this quick transition to the firmer straight rate, it's wrong. If you look at Ohlins springs they have a different spring wind that's more progressive and I believe a different spring would help matters. I also suspect the front springs are not progressive but straight rate and that's not helpful either as I've found when you back off preload to get decent initial small bump absorption they will bottom fairly easily on larger bumps. More progressive wound springs in the front would also help

I also agree the high speed compression rate is too stiff, or doesn't blow off easy enough and the rear rebound is strange, all of the adjustment is pretty much between 3/4 to 1/4 open, the rest is useless. I have adjusted it so it won't pogo but it still floats just a bit at higher speed and if you go tighter it just packs up, odd.

I think what you found about going tubeless is a great next step and after that narrower/taller profile tires would help even more, possibly tires with a more pliable carcass. I wish I had a light weight set of wheels I could just toss on to see how it affects things but that's a dream.

Dunno, I'm still working to find a really good solution and I'm not there yet. It's better, but not what it could be for sure.

 

[al399]

@ the 1000kms service we tried a couple things to make the bike ride road bumps at higher speeds ~65-70 mph in a less harsh way. They told me that mostly the rear but also the front springs seem too soft and they sag. They added a bit of preload. It made the bike keep better touch and contact on the bumps but the harshness did not go away.
What puzzles me in the bikes manual is 1) the fact that preload should change from tarmac to off road. I knew preload adjustment had to do with riders weight which remains the same be it on road or off road. and 2) on the road the riders guide suggest 7mm preload for the front springs and 14mm for the rear. I thought that both front and rear springs should have the same preload so the bike is straight.
In the coming week I will go for extensive sag measurements and play a bit with the rest of the settings. rebound and damping in front and rebound on the rear. I think my next upgrade on the bike will be ohlins shock and rear spring and ohlins springs for the front.

 

[beetleything]

This is interesting and educational -

 

[al399]

Someone posted it in another forum in a relative topic...I started...