[Cave Dweller]

Hi guys,

I just converted my boxxer team to a wc with a new leg, air pitson and top cap. Followed the service instructions and everything went together fine.

Went out riding today and the fork feels great, better then the coil, but my fork won't use the last inch and a bit of travel, ie im getting about 6.5 inchs. I droped the air pressure right down to 100psi and it goes a little further into the travel (goes to about 7 inchs) but it was still not bottoming out, even off drops and jumps, and i am 95kg.

Is this normal?? It must have something to do with the air spring as the less presure the more travel it uses. Anyone help me out.

Thanks

 

[caputo1989]

Tune down the preoad

 

[bjanga]

Air springs get super progressive as they compress, yes?

 

[Cave Dweller]

Tune down the preoad

How would i do that, its an air spring, no preload.

Air springs get super progressive as they compress, yes?

Thats what i thought, but it just seems odd, almost like the negative air spring chamber is reaching a vacum and not allowing it to go further.

 

[Eurotrash]

I have seen with my own eyes 4 2006 boxxer WCs with the bottom of the motion control side stanction torn right off at circlip. I called the local distributor and they gave me the standard response, impossible, rider error blabla.
Called TF in the uk, he's seen one as well. He recons could be caused by air side over extending, thus making the MC side top out on the motion control cirlip and it ending up tearing the bottom of the stanction off.
If it is really caused by over exteding (no guarantee it is) it may be fixed by simply running the MC side top cap a tad lower than the air side.
just a quick warning, maybe it's just a bad batch, maybe not.
Cheers

 

[zmtber]

my wc is like that as well can't and most likley will never bottom the thing out o well its a good and bad thing, i say get use to it

 

[DoubleDown]

1: Make sure you don't have a ton of oil on top of the piston on the air side. This changes the size of the positive air chamber making it ramp up quicker. Should be 2-5 cc's.

2: Make sure there is only 10-20 cc's of oil in the lowers on the air side. Again, too much oil causes the fork to ramp up quicker resulting in less travel.

 

[dropmachine]

also make sure you don't have air trapped where its not supposed to be, like outside the cart.

 

[Cave Dweller]

1: Make sure you don't have a ton of oil on top of the piston on the air side. This changes the size of the positive air chamber making it ramp up quicker. Should be 2-5 cc's.

2: Make sure there is only 10-20 cc's of oil in the lowers on the air side. Again, too much oil causes the fork to ramp up quicker resulting in less travel.

1. I put 3mls of 15wt oil in the spring side for air piston lubrication.

2. I put 15mls of oil in the spring side for lubrication of the leg

Thats what i mean, i follwed the rebuild instructions but something doesn't appear right, unless its normal?

also make sure you don't have air trapped where its not supposed to be, like outside the cart.

I was thinking that, but wanted to check to see if its normal before pulling the fork apart. I don't see why though, everything was brand new.

I did put a dab of grease on the air piston shaft though, i wonder if its maybe allowing air to pass? Sounds like im going to have to pull it apart to see whats going on.


So, do people actually manage to bottom their boxxers, or has zmtber and myself have an issue?

 

[dhkid]

here's an idea, let out all the air in the air spring, fully compres the fork and open the bottom nut, let the air thats in the lowers out, so that when its fully extended there will be a vacumm in the lowers, then again you could end up with negative travel. maybe experiment how much air you want in the lowers.

 

[skyst3alth]

1. I put 3mls of 15wt oil in the spring side for air piston lubrication.

2. I put 15mls of oil in the spring side for lubrication of the leg

Thats what i mean, i follwed the rebuild instructions but something doesn't appear right, unless its normal?



I was thinking that, but wanted to check to see if its normal before pulling the fork apart. I don't see why though, everything was brand new.

I did put a dab of grease on the air piston shaft though, i wonder if its maybe allowing air to pass? Sounds like im going to have to pull it apart to see whats going on.


So, do people actually manage to bottom their boxxers, or has zmtber and myself have an issue?

I'm 185lbs, run 125psi, 5 clicks in on high speed and 3-4 on low speed and bottom on a frequent enough basis...something's up.

 

[Cave Dweller]

I'm 185lbs, run 125psi, 5 clicks in on high speed and 3-4 on low speed and bottom on a frequent enough basis...something's up.

215lbs, was running 160psi, 3 clicks LSC and 6 clicks HSC. Your air pressure is 20 psi less the RS recommendation, like mine, something is up with the fork i suspect.

I will pull it apart when i get a chance and will post back the results once i figure out whats going on

 

[DHS]

the recommendation is off for everyone. thats normal.

 

[Cave Dweller]

I have a question.

In the SRAM rebuild manual is says

"36. Insert the spring (left) and damping (right) upper tube assemblies into the lower legs. Ensure the dust seal lip does not fold under and is seated correctly around upper tube (figs 36a/36b).

SPRING SIDE (LEFT): Slide the spring assembly/upper tube completely into the left lower leg until the spring shaft stops and rests in the lower leg shaft bore hole. Look through the bolt hole in the bottom of the lower leg to make sure the shaft is aligned and seated in the center of the bolt hole."

The bit in red, does this mean i am supposed to push the leg right down until it bottoms out? I just put the leg in far enough so i could get the bolt into the shaft, like what the bit in blue says. If i was supposed to bottom it out i think i have found my issue..........

 

[RaID]

I have a question.

In the SRAM rebuild manual is says

"36. Insert the spring (left) and damping (right) upper tube assemblies into the lower legs. Ensure the dust seal lip does not fold under and is seated correctly around upper tube (figs 36a/36b).

SPRING SIDE (LEFT): Slide the spring assembly/upper tube completely into the left lower leg until the spring shaft stops and rests in the lower leg shaft bore hole. Look through the bolt hole in the bottom of the lower leg to make sure the shaft is aligned and seated in the center of the bolt hole."

The bit in red, does this mean i am supposed to push the leg right down until it bottoms out? I just put the leg in far enough so i could get the bolt into the shaft, like what the bit in blue says. If i was supposed to bottom it out i think i have found my issue..........

i read that as the leg right down until it bottoms

 

[Shepherdwong]

I don't think it means you push it until it bottoms. Just to contrast it to the damper leg which you push half in and inject the 15 wt. in.
:hot:

 

[CBJ]

I'm 185lbs, run 125psi, 5 clicks in on high speed and 3-4 on low speed and bottom on a frequent enough basis...something's up.

155lbs and I run 110psi and same comp settings. Super plush and great buttom out protection but I still get full travel.

 

[J5ive]

I also get full travel. I just rebuilt the air unit after I had a fair bit of oil running past the dust whiper. All the rings looked in fair shape and no other issues seemed apparrent, I replaced the lot- all rings and seal- and its perfect again now. Sounds to me like the air isn't sorting its self out between the + and - like it should. I'd try again and check all the o rings. Lube em up. Mine definatly bottoms out. Not harsh, but I chew the travel at times, but thats me probably trying to get a decent amount of sag in the 'car park' on a cold fork.

 

[julian_dh]

it pretty funny though cause every world cup ive tried has felt like garbage compared to the spring team. but i think alot of people dont rebuild that fork as much as they should.

 

[skyst3alth]

it pretty funny though cause every world cup ive tried has felt like garbage compared to the spring team. but i think alot of people dont rebuild that fork as much as they should.

I just rebuilt mine after neglecting it for a bit (not on purpose), feels amazing now, like night and day.

 

[Cave Dweller]

I turned it upside down last night, tapped out both footnut bolts and pushed down the lowers about 1/2 way then re-did the bolts.

Doing the "push down in the carpark test" i am getting more travel, i don't think i will have much trouble bottoming it now I will find out this weekend if it worked or not.

I didn't have time to measure my exposed stachion but it seemed like it had alot of negative travel, i could pull it out 1/2 to 3/4 of an inch when i held the tire with my foot and pulled up, i suspect this is the 2 rubber stops compressing.

Need to fiddle with it tonight to make sure it is not going to rip out the rebound shaft from the MCU side, i am fairly sure the air has more negative travel then the spring.

And for the record, the air felt better then the coil, i guess you just need to keep on top of maintaining it.

 

[peachy]

wow so i guess it's normal that i'm running 105psi on a 120lbs rider. the chart is off.

why is it that for the first inch (or less) the WC isn't as plush as the Marz 888? isn't there a grease that will remove that initial stiction?

 

[skyst3alth]

wow so i guess it's normal that i'm running 105psi on a 120lbs rider. the chart is off.

why is it that for the first inch (or less) the WC isn't as plush as the Marz 888? isn't there a grease that will remove that initial stiction?

Yeah regrease the seals, it'll feel better.

 

[peachy]

when i changed the oil (lowers only) i just used some of that Torco RFF 20wt to lube the seals... are u using using something else like red rum or something?

btw, so after 2 months i changed the lubrication oil (lowers)... should i change the dampening also? does it get dirty?

 

[banchee man]

if you are experiencing stiction than use some slick honey that stuf has always worked for me

 

[davep]

when i changed the oil (lowers only) i just used some of that Torco RFF 20wt to lube the seals... are u using using something else like red rum or something?

btw, so after 2 months i changed the lubrication oil (lowers)... should i change the dampening also? does it get dirty?

Read your manual.. the oil seal and dust wipers need to be greased with a thin grease, every time you change the bushing oil! Try slick honey.

BTW what you did, only changed the lube for the bushings (about 25% of a rebuild) Inside both stantions you have many moving parts that are sealed either to air (spring side) or oil (MC side). In total there are like a half dozen o-rings and shaft seals that all cause stiction and ALL need to be cleaned and greased on a regular basis. You cannot expect a significant reduction in friction if you only service 1/4 of the causes of said friction.