[beefmagic]

Before I get flamed for starting another 66SL thread, I've done a ton of searches (shocks, turner forums) but haven't found this info yet. I'm fairly familiar with how the fork works but haven't been able to find much information on lighter folks running the 06 66SL.

What is the minimum PSI required in the positive air chambers? Can you have 0 PSI in there and not have any air or oil leaking problems?

I also read a thread where someone said that you CAN run 0psi in the positive and pump up the PAR higher to get a plusher ride. However, I wasn't sure if the poster was confusing the 06 and the 07 66SL which I understand has differently behaving internals. Just need a confirmation on this before I try it and blow up my fork.

By the way, I'm about 145-148lbs. suited up and currently running the fork at 150mm.

 

[be350ka]

I have heard the same thing, but I dont know for sure. Ask Rene, MK_, TNC since they all have some extensive time on this fork. It may be beneficial to call Mike or Guidean (sp) at Marz.

 

[TNC]

Dang Beef, from your avitar, I didn't realize that you were a lightweight...LOL!...but let's stay away from comparing our avitars to our real personna...mine included.

I know of no reason in the design of the fork that requires a minimum psi in the (+) chamber. I take some of that experience from the Doppio carts in my coil/hybrid Z150SL forks where I don't run more than 2 psi in the (+) chamber. I do notice that if there's no pressure in the (-) chamber, there is almost always some noticeable and annoying top out...and more initial seal stiction. I believe the owner's manual shows (not warns) a minimum of 30 psi, but I think most people are running around 20 psi when using both chambers. I wouldn't be afraid to use any low pressure that works

Yeah Beef, on that PAR I could swear I saw SSINGA's comments on an '06 66 where he is running a relatively high PAR, but it doesn't work for me. I run 0 PAR to get full travel. The explanation of PAR in the '06 manual certainly sounds like it affects only the last part of the travel for bottomout, but there is a cryptic use of the word "compression" which is usually associated with actual damping and not a spring medium. However, being as you're a light rider, I'll be surprised you'll need PAR for bottomout or PAR if it actually increases the compression damping.

 

[beefmagic]

Thanks for the replies guys. TNC, yeah my avitar is a bit misleading. It wasn't intentional, I just really like that pic of snowflake, the albino gorilla!

The owner's manual also says to just set it for sag. I couldn't find any real numbers for min or max psi. I think I saw SSinga posting that he put 20psi in the PAR. That would be overkill for me. I haven't had too much time messing with the pressures yet, and correct me if I'm wrong, but it seems that PAR adds a bit of compression as well. I know the manual says that it only affects the last part of travel, but I think that I've read other posts where people have said that it affects other aspects of the travel.

What I'm trying to do is make a really soft positive air spring where I could get lots of sag and then up the PAR a little or a couple of clicks of compression to tune the progression to my liking.

 

[TNC]

I really think the PAR on the '06 does little except for the very end of travel and seems to act more like the bottomout chamber on an SPV shock...or boost valve. On the '07 it's quite apparently a different animal and does affect mid-stroke performance.

I don't know...at your weight I cannot imagine that you'll need much compression input, but hey...the nice thing is it's an air fork and you can putz with everything on it and waste nothing but time if it doesn't suit you. That's the beauty of both models of the 66SL. I'm reallly pleased with how my '06 model doesn't dive excessively while remaining plush in the middle. My '04 Z150SLs didn't perform the best in this area.

 

[Bikezilla]

I really think the PAR on the '06 does little except for the very end of travel and seems to act more like the bottomout chamber on an SPV shock...or boost valve. ..

FWIW some folks have found the PAR can have other affects as well:

It is like spring preload, DHX BO and BV all rolled together. 0psi PAR and the fork is divey mush. 10psi PAR and it rides a little higher, is still supple, but dives a bit. 20psi PAR and it rides like a nice trail fork with decent sag and more bottoming protection, but still goes deep into travel on g-outs, but getting that last inch of travel is tough. 30psi PAR and the fork sags very little and the ride is a bit harsher, but bottoming is very well controlled. I did repeated test drops yesterday (to flat, duh) and without changing any other setting on the fork other than PAR, I got a pretty good feel for what it does.

I always wondered why no shock company really puts all the tuning effects in their manual. The designers/engineers gotta know what the bits do... why not just say so?

 

[TNC]

Zilla, on the '06 you find the PAR to have what influence other than end of travel bottomout control? This is getting confusing...LOL!

 

[Bikezilla]

I haven't had the opportunity to test Tscheezy's observations I quoted above. I believe he is saying it can help control dive.
Seems easy enough to try.

 

[TNC]

On the fork dive, are you having any such issues? I've been impressed with the lack of dive based on my prior experience with my Z150SL. Yeah, I agree...one can fiddle with the adjustments on this fork to try just about anything, and that is a nice feature.

 

[SSINGA]

Thanks for the replies guys. TNC, yeah my avitar is a bit misleading. It wasn't intentional, I just really like that pic of snowflake, the albino gorilla!

The owner's manual also says to just set it for sag. I couldn't find any real numbers for min or max psi. I think I saw SSinga posting that he put 20psi in the PAR. That would be overkill for me. I haven't had too much time messing with the pressures yet, and correct me if I'm wrong, but it seems that PAR adds a bit of compression as well. I know the manual says that it only affects the last part of travel, but I think that I've read other posts where people have said that it affects other aspects of the travel.

What I'm trying to do is make a really soft positive air spring where I could get lots of sag and then up the PAR a little or a couple of clicks of compression to tune the progression to my liking.

Here are my observations. Now remember I am much heavier than 150lbs!

Setup with low PAR PSI and higher positives I found the fork to be a little mushy and had a good bit of brake dive. When I added more compression damping to tune out the dive I found the fork to be a little too spikey for slow speed tech stuff, especially when climbing.

My preferred setup is low pos PSI (17-18 for me) and higher PAR pressures (20psi). This keeps the fork riding higher but it is still compliant in the bumps while dive is minimized.

Beef- try 5-10 psi in the positives and 10 in the PAR. No more than 4-5 clicks of compression damping.

I haven't opened my fork since it's return from Zocchi so I have no idea what my oil levels are right now

 

[Bikezilla]

SS Thanks big time for the addl info.
TNC yeah at one point my fork was pure love. But after the Oil change I had forgot what settings I was using and the brake dive has been horrific. I was going OTB, hard on every ride. Same thing happened when I used a too soft spring in a '03 Z1.

I turned up the compression and upped the main springs and as SS said the small bump compliance went out the window.

I'm going to up the PAR and back off the compression some. My wrist is still f'ed up from the endo-itis I had before.

 

[Renegade]

Well Beefmagic, you are certainly going to get a lot of different set-up opinions regarding your question! At my anorexic 185 pounds, I never put any PAR in for trail riding. I would only add par. 10 to 20 pounds, for resort dh riding, with full body armor and big heavy tires. At that setting, the PAR only affected the last 1.5 inches of travel.
The times I tried PAR pressures for trail riding, I found that it limited my travel, and made the fork somewhat harsh.
I don't understand Tscheezy's post at all, in regards to my experience with the fork, and he and I are the same weight [except mine's all mush] .
All I can recommend is: experiment! Try out different settings, you can't hurt the fork by doing so.

 

[beefmagic]

Thanks guys for all the good info and suggestions. SS, your recommendations are very close to what I'm running now. Very low positives around 5-10 psi, negative to get me at 150mm, and PAR at 0psi or just a few pumps. 2 clicks of compression from full open. The fork is pretty plush and just a little bit of dive, but I don't mind a bit of dive as long as the fork is plush.

I'm going to experiment with higher PAR pressures and very low positives to see if its just my imagination that the PAR is adding somewhat to compression. It's good to know I won't blow up the fork with very low Positive pressures!

This fork has been awesome so far. It makes 4fters feel like curbs. The only downside is that it's making me want to buy a Avy chubbie!

 

[TNC]

Hey Zilla...this may be totally from left field, but something in your last comment caught my attention. You said you got bad brake dive after the oil change. Remember my oddball system for attaining minimum oil level in the damper leg? During one of those tuning episodes I got to feel what it was like to have just a hair too little oil. The fork was so smooth, but man the brake dive felt like I had half the normal air pressure in the fork...but strangely the ride height and sag were good. Well, being the genius that I am, I quickly traced it down to the fact that the damper wasn't fully immersed in enough oil to function properly. I don't know how many of you have run one of these with low enough oil to see how it feels. I was surprised that the fork seemed to be working just fine...until you smacked something semi-decent. Yeah...it had OTB written all over it. There weren't weird air sucking noises or anything like that coming from the fork. You almost wouldn't have known anything was wrong in a "parking lot" test.

So...this may have absolutely nothing to do with your situation, but just for the heck of it, I thought I'd throw it out there.

 

[Bikezilla]

Tnx for the idea TNC... too little oil is def not my problem as I started with 210mm at the oil change. I think it was too little main spring psi. I was able to dial the dive out but SBC seemed to suffer, that was a quick-fix tweak though. Since then I carefully reset the pressures and took 20ml out, but I haven't had time to test it on the trail yet.

Beef... watch out about that Avy... I got one and now my 66 can't keep up!