[mullen119]

Thats funny I just read that pdf a couple of minutes ago. I like the sound of the linear stack. The whole reason this fork was bought was to play with the shim stacks. Time to order a bunch of shims.

There are a couple of links to shims in this thread but I have not seen a 17.5mm OD x .02mm for sale anywhere. Do you have to get these from Manitou?

As said by newfangled, Just use a 17mm shim. I would also buy them from the link he posted because the MXtech website keeps getting hacked for some reason. Post your results one you find a stack you like:thumbsup:

 

[PMK]

They don't offer shims in a thickness of .02mm.
You should be looking for .2mm.

FWIW,
.1mm is approx .004 inch.
.2mm is approx .008 inch

.02mm is approx .0008 inch

 

[mullen119]

They don't offer shims in a thickness of .02mm.
You should be looking for .2mm.

FWIW,
.1mm is approx .004 inch.
.2mm is approx .008 inch

.02mm is approx .0008 inch

Thats what I meant to type. Im sure he figured it out when looking them up.

 

[newfangled]

I'd also thought about going to a motorcross shop, but decided online was easier. Anyone know if moto shops would be likely to have the right shims in stock?

 

[mullen119]

I'd also thought about going to a motorcross shop, but decided online was easier. Anyone know if moto shops would be likely to have the right shims in stock?

I would be surprised if they did. Most shops dont tune suspension in house.

 

[J. Random Psycho]

Some facts about Minute MRD, Absolute+, Mars Air

MRD Absolute+ shims have not been covered in this thread so far.

My Minute MRD, 100 mm travel, 20 mm thru-axle, came with the following shims, starting from shaft:

narrow clamp shim, 9 x 0.2(*) mm x (1)
wide clamp shim, 11 x 0.1 mm x (1)
blow-off shim, 14 x 0.15 mm x (4)
preload reducer shim, 9 x 0.1 mm x (3)

Which is a strange stack: a lot of equal height blof-off shims, reinforced by a wide clamp shim, and preload reduced by as much as 0.3 mm. The fork was impractical to ride with needle fully closed, too much platform and spiking. Running the needle in semi-open positions was a compromise between plushness and bob/dive.

I have installed a 0.2 mm M6 precision washer (technically it's not a dedicated damper shim) to use as the speed shim and only left 1 blow-off washer (now preload reduced by 0.2 mm) and the narrow clamp washer. I hope that this setup resembles tune EK-012611-02 from the Manitou document, which only mentions non-MRD dampers.

I am yet to test this setup in real use -- waiting for the current cold spell to end.

_____________________
(*) This number is taken from memory.

PS
I'm overhauling the fork completely anyway, and have changed the stock coil spring (color code red, which is medium I guess) for spring code 83-3172, which was sold to me as firm, although it has no color markings. It feels firmer by hand indeed. It's also 3.7 mm wire thickness and 87 mm long, as opposed to 3.4 mm and 77 mm respectively on stock spring.

I had to shorten the rubber top out bumper (the one on spring rod) by 10 mm to accomodate the longer spring.

Also, it's a known fact that there is no spring grease/semi-bath oil separating seal in Mars Air forks. Which results in oil penetrating coil spring chamber in use, where it attempts to dissolve the grease (even if you only leave enough grease to cover stahcnion wall from inside -- they put a huge amount of grease in during assembly) and gets thickened in the process. This thickened snot-like mixture has trouble reaching the upper bushing.

What I have done is cut a 4/2 mm heat shrink tube into several 1 cm pieces, piloted them on the spring wire, distributed them around and shrunk them until they are unable to move. I used no grease at all, relying instead on the tube and quality motor oil to protect the stanchion wall.

 

[mullen119]

MRD Absolute+ shims have not been covered in this thread so far.

My Minute MRD, 100 mm travel, 20 mm thru-axle, came with the following shims, starting from shaft:

narrow clamp shim, 9 x 0.2(*) mm x (1)
wide clamp shim, 11 x 0.1 mm x (1)
blow-off shim, 14 x 0.15 mm x (4)
preload reducer shim, 9 x 0.1 mm x (3)

Which is a strange stack: a lot of equal height blof-off shims, reinforced by a wide clamp shim, and preload reduced by as much as 0.3 mm. The fork was impractical to ride with needle fully closed, too much platform and spiking. Running the needle in semi-open positions was a compromise between plushness and bob/dive.

I have installed a 0.2 mm M6 precision washer (technically it's not a dedicated damper shim) to use as the speed shim and only left 1 blow-off washer (now preload reduced by 0.2 mm) and the narrow clamp washer. I hope that this setup resembles tune EK-012611-02 from the Manitou document, which only mentions non-MRD dampers.

I am yet to test this setup in real use -- waiting for the current cold spell to end.

_____________________
(*) This number is taken from memory.

PS
I'm overhauling the fork completely anyway, and have changed the stock coil spring (color code red, which is medium I guess) for spring code 83-3172, which was sold to me as firm, although it has no color markings. It feels firmer by hand indeed. It's also 3.7 mm wire thickness and 87 mm long, as opposed to 3.4 mm and 77 mm respectively on stock spring.

I had to shorten the rubber top out bumper (the one on spring rod) by 10 mm to accomodate the longer spring.

Also, it's a known fact that there is no spring grease/semi-bath oil separating seal in Mars Air forks. Which results in oil penetrating coil spring chamber in use, where it attempts to dissolve the grease (even if you only leave enough grease to cover stahcnion wall from inside -- they put a huge amount of grease in during assembly) and gets thickened in the process. This thickened snot-like mixture has trouble reaching the upper bushing.

What I have done is cut a 4/2 mm heat shrink tube into several 1 cm pieces, piloted them on the spring wire, distributed them around and shrunk them until they are unable to move. I used no grease at all, relying instead on the tube and quality motor oil to protect the stanchion wall.

Instead of using the washer, You should get the results you are looking for by removing one(or maybe even two) of the blow off shims. It would allow the stack to blow off easier while still using damper shims. You can also add the shims you remove to top of the stack to give less platform, but keep a little more HSC overall

Let us know how it rides when you get a chance:thumbsup:

 

[J. Random Psycho]

Instead of using the washer, You should get the results you are looking for by removing one(or maybe even two) of the blow off shims. It would allow the stack to blow off easier while still using damper shims.

I'm going to order some real shims, of course )
But will try my luck with the improvised shim washer for now. I googled up, and they seem to be made of spring steel and with good tolerances. The one I used is 12 mm OD which covers MRD piston ports but clears the raised edge, just like how a speed shim is supposed to fit.

You can also add the shims you remove to top of the stack to give less platform, but keep a little more HSC overall

Would this be a form of 2-stage shimmed damping that was mentioned in this thread?

Let us know how it rides when you get a chance:thumbsup:

Will do!

 

[mullen119]

Would this be a form of 2-stage shimmed damping that was mentioned in this thread?

Yep. It would allow the stack to open partially on smaller hits to feel less spikey, but keep a good amount of damping on big hits.

 

[J. Random Psycho]

Well, here's how that 0.2 mm "speed shim" and 0.15 mm blow-off shim combination feels in room test with needle fully closed: no perceivable blow-off force on low-speed movement, and a suddenly appearing spike feel when I try to compress the fork faster.

Feels like 0.2 mm is way too thick of a speed shim for MRD. At least the improvised type. Since any blow-off force seems to be absent, I'm not even going to try this stack on a real ride.


Next stack to try, starting from shaft:

narrow clamp washer (it's 0.25 mm, I've just measured it)
wide clamp washer
2 x 0.15 mm blow-off shims
1 x 0.1 mm preload reducer
2x 0.1 mm "speed shims", hopefully for 4 times less stiffness than 1 x 0.2 mm (not gonna give up on that idea right away..)


PS
Results are weird. I expected the blow-off force to be about half of what there initially was with 4 blowoff shims and 0.3 mm total preload reduction (which was way too much). But there is still no detectable blow-off force. And the higher speed spike remains, it just requires me to push the fork faster to trigger it, than it was with 0.2 mm "speed shim".


Anyway.. next stack, starting from shaft:

narrow clamp washer
wide clamp washer
3 x 0.15 mm blow-off shims
2 x 0.1 mm preload reducer
1 x 0.1 mm "speed shim".


PPS
I'm using a very light oil, Stendec Crystal Fork Fluid 2.5W (stock oil that I dumped was definitely heavier). This must be why very low speed compression with needle closed feels like there's an orifice still open. Oil must be having very little trouble flexing whatever "speed shims" that I tried, and (what is mysterious) up to 3 x 0.15 mm blow-off shims, preload reduced by 0.3 mm.


PPPS
I went back to (almost) the first stack I was going to try, but with wide clamp washer added:

narrow clamp washer
wide clamp washer
1 x 0.15 mm blow-off shim
1 x 0.2 mm "speed shim",

and this time changed the oil to a 1:1 mix of Stendec 5W and 10W. Weeeeeeell... it feels better now (with needle sitll fully closed). Much more explainable. What was preceived as absence of blow-off and a sudden spike, is now a platform-like feeling that with reasonable force opens to what feels like heavily damped travel (real riding will tell whether it's too heavy or not).

I guess that the light oil was (in small quantities) bypassing the (defective?) check valve on the front side of piston. It would have had little effect when riding, but on manual room test even the small blow-off force kicking in at higher speeds was perceived as a spike (which it wasn't, it would open if I pressed harder, but in comparison to very low speed free travel it felt like hitting a wall). It's as if the needle was not fully closed, but instead 1-2 clicks from closed.

 

[badburn666]

Marzocchi 55r 08'

Hi guys,

Im all the way from the Philippines and I read one of you forum posts. I own a Marzocchi 55r 08 model. It seems to lock out and I only get 2-3 inch travel and even less sometimes. This form is supposed to be 160mm travel.

I read that you can drill into it and make it work again.

Im am not really sure how to do it so I am researching for more info and photos as well.

It'll be a great deal of help if you can send me more specific details.

Thanks much!:thumbsup:

regards,

Nicolas

 

[J. Random Psycho]

badburn666,
you may want to look here, for instance.

 

[badburn666]

55r

yup, read that already. thanks though.

Still need more instructions and illustrations for it.

 

[MPH_66]

Also, it's a known fact that there is no spring grease/semi-bath oil separating seal in Mars Air forks. Which results in oil penetrating coil spring chamber in use, where it attempts to dissolve the grease (even if you only leave enough grease to cover stahcnion wall from inside -- they put a huge amount of grease in during assembly) and gets thickened in the process. This thickened snot-like mixture has trouble reaching the upper bushing.

What I have done is cut a 4/2 mm heat shrink tube into several 1 cm pieces, piloted them on the spring wire, distributed them around and shrunk them until they are unable to move. I used no grease at all, relying instead on the tube and quality motor oil to protect the stanchion wall.

I recently changed the ride kit on my Minute Pro (also has the Mars Air) and can confirm that your grease experience was not an anomoly. The stock spring was covered in huge globs of grease. Manitou's excessive use of grease for the spring seems somewhat strange given that the service manual says you're supposed to "lightly" grease it.

I followed the manual's instructions and lightly greased the new firmer spring. I'll see what the grease does to the semi-bath oil next time I service it. If it looks like it's making a thick soup, I'll give your heat shrink tubing idea a shot.

Do you think it makes any difference in the type of grease used? Manitou used copious amounts of a red grease that seems thinner than the standard white teflon grease I usually use. It seems like using thicker and less grease would reduce the sem-bath/grease soup risk.

 

[J. Random Psycho]

Do you think it makes any difference in the type of grease used? Manitou used copious amounts of a red grease that seems thinner than the standard white teflon grease I usually use. It seems like using thicker and less grease would reduce the sem-bath/grease soup risk.

Well, when I first overhauled my Mars Air sprung Minute (did it out of the box, before first time installation) I used a little Rock'n'Roll Super Coat on the spring. I also removed most of the red grease, only left a thin layer on stanchion wall. The results were less snotty than with my previous Mars Air and TS Air experiences with other forks, -- a considerable amount of oil actually leaked out of spring side lowers when I started overhauling it the second time (that's when I wrote that post).

Before that, when I used to leave some red grease on the spring itself (still removed most of it before 1st install), I only got several drops of oil from (spring side) lowers on next overhaul -- and the lower leg was invariably filled with goo.

On our more local forum I once suggested devising a seal in the plastic stanchion lower end nut around the compression rod. Some guys have given it a try. A recent successful attempt was to cut a groove in plastic, put a petrol-resistant o-ring in there and polish the rod (as I suggested). I don't yet know how he cut the groove (but see below), but he says that the result is very promising so far -- no oil penetration and negligible stiction.

Edit: he used a dremel.

 

[newfangled]

This isn't about reshimming, but I'm hoping some of the manitou experts might be able to help out.

I just serviced my 2011 r7 for the first time, and when I was putting it back together it seems like the threads at the bottom of the leftleg/compressionrod are stripped. The manual says to tighten to 45-55 in-lbs, but I can only get it a little more than fingertight and then it spins and spins. I don't think I stripped it, but the threads are just plastic so it seems like it would be an easy thing to do?

Anyway, I'm assuming that running it like this would be a bad thing and that I should try to track down a replacement compressionrod assembly? Or did I miss something during reassembly that's preventing me from tightening it up? Any advice from the experts?

 

[J. Random Psycho]

newfangled,
yes, the plastic nut threads can be stripped. Examine them closely.

Also examine threads in the stanchion, just in case -- maybe there's something that fscked up the plastic thread.

 

[mullen119]

The piston may be spinning in the stanchion. Take the lowers back off and put the bolt back in and tighten it. If the compression rod is spinning with the bolt then the piston is spinning in the stanchion. To fix this, hold the compression rod to stop it from spinning while tightening the bolt. This should clean out the threads and allow you to tighten it when the lowers are attached.

 

[newfangled]

Thanks mullen, I'd considered taking it apart again and threading it in without the lowers, but I was feeling too lazy. I'll give that a shot, though.

 

[J. Random Psycho]

Ah, that bolt. I thought it's about the plastic nut that you turn with 22 mm wrench. One came from factory with stripped threads recently.