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Hey all,

Thought about posting a new thread but this place seems like the more appropriate place for my questions.
I have a Manitou J-unit 24 fork that's gonna be used on a 24" DJ type bike, so smooth trails and decent sized doubles, and possibly some street is the name of the game. The rider is rather light at about 55kgs.

The plan is to grab the tuning kit from ol' mate Dougal.
A quick squish indicates that the current tune (youth apparently?) will be a bit shithouse for fast, smooth and lipped jump lines.

Yes I have a copy of the tuning guide, and will start with the jump tune

What is the goal with damping curves for jump bikes? lots of support from the platform? any other considerations apart from 'hard as ****'?
Is the 120 psi pressure limit a 'hard' limit on the J-unit?
Any oil recommendations?

First time shim fiddler but I'm decent with mechanical stuff, graphs are my bread and butter and I like them.

Cheers.
 
Tuning a new to me older Machete 120mm 29+ Boost fork that I've reduced to 100mm and upgraded to ABS+.
The aim is a better fork for full suspension single speed XC/marathon type riding than the Reba boost that was on it.
The Reba is lighter and 30mm less A-C.

I'm looking for a reasonable platform when locked out, supple up top but able to handle any surprises on the course or mistakes made in the latter stages of a 6hr.

Started with the stock trail stack (11x.5, 19x.2*2, 17.5x.2) as the stock XC stack had far too much platform and not enough velocity dependency (if I'm understanding that correctly?) for normal training.
The stock trail stack hasn't got enough platform.
Next test will be with 11x.5, 19x.2*3, 17.5x.2 to give some more platform and HSC.
At least that's the idea. Reality may be different.
I'm using a ShockWiz to help tune.
 
Hey all,

Thought about posting a new thread but this place seems like the more appropriate place for my questions.
I have a Manitou J-unit 24 fork that's gonna be used on a 24" DJ type bike, so smooth trails and decent sized doubles, and possibly some street is the name of the game. The rider is rather light at about 55kgs.

The plan is to grab the tuning kit from ol' mate Dougal.
A quick squish indicates that the current tune (youth apparently?) will be a bit shithouse for fast, smooth and lipped jump lines.

Yes I have a copy of the tuning guide, and will start with the jump tune

What is the goal with damping curves for jump bikes? lots of support from the platform? any other considerations apart from 'hard as ****'?
Is the 120 psi pressure limit a 'hard' limit on the J-unit?
Any oil recommendations?

First time shim fiddler but I'm decent with mechanical stuff, graphs are my bread and butter and I like them.

Cheers.
Jump stack is incredibly stiff. I wouldn't put one under a 55kg rider unless they were mad-core.
I've been riding a bit of ABS+ lately and found two 17.5x0.1mm shims (no platform shims) were working well for choppy grade 5-6 trail. Anything more kicked too much. You can go much firmer on smoother trails with single big impacts.

The Youth Tune is:
8x17.5x0.15(2), 8x91x0.15,8x11x0.5mm.
I don't have a dyno for that tune. But I think it's a very good starting point for a jumping kid.
 
Next test will be with 11x.5, 19x.2*3, 17.5x.2 to give some more platform and HSC.
At least that's the idea. Reality may be different.
Right amount of platform, too much HSC. Felt very similar to the Reba.
Next is swapping a 19x.2 with a 19x.15 to soften the HSC and a thinner speed shim to bring a little of the platform I'll lose back.
In theory...
 
Oops. The rebound pop-off washer looked like a wave washer. Quite bent. That'll invalidate the previous tests...
Luckily I just got a tuning kit from Dougal.
11x.5, 19*.2*2, 17.5x.1 seemed quite nice. Won't get to test it properly before the race tomorrow night though :(
 
Marvel 100mm fork on a Kona Unit SS.
90kg rider, riding everywhere.

It'll be used for playing in the hills, XC racing, back country epics.

As it's a single speed, I'll be using the locked out platform most of the time and the stock XC stack is a little too rock solid.
Maybe a platform breakaway around 400Nm instead of the stock 500?
Tried with one 19x0.2 removed, but not enough platform.
Replace one of the 19x0.2's with a 19x0.15?
You can also place one or more 12mm shims under the stack. These shims don't have to flex, but just reduce the 0.6mm preload that is normally placed on the XC stack.
If you use a shim of about 17mm diameter it will also add to the overal speed sensitivity, which might be a good thing, or a bad one if you prefer a digressive (blowoff) feel.
80kg rider now :)
The ABS+ damper has been transplanted from the Marvel to the Machete and from the Kona Unit to the Giant Anthem - still single speed.
It looks like I've ended up with 19x.2, 19x.15, 17x.15 which is giving a good platform and support at the speeds I ride/race at.
Played with 80psi and a RockShox token (machined down to press-fit in the topcap) and liked the progressiveness, but never got past 90% travel.
Back to 85psi and no token.
I'm finding myself adjusting the LSC often enough that a Milo might be the ticket.
 
if you can't find a milo i think i have one in my bin. just saw you're in NZ, but the offer is still there
Got one in my bin too :)
Managing to get 8 clicks of the shifter from locked out to just over 1/4 of a turn more open.
I'll see this afternoon if the steps are suitable for racing.
 
X0 9spd shifter and the Milo works fine, and I used it far too much, but it doesn't feel right to be using it on this single speed.
I'd love to remove the dropper and put my carbon post on too, but I'm even more useless in tech without it :)
 
Hi all, I read a good piece of this thread already and would like to ask some advice regarding the shim stack on my manitou markhor.
I'am 90kg with 1,94m of height and got the fork on a 2014 Kona Unit riding it with 100mm of travel. I rode the stock XC stack for a while which I found ok but a little harsh with too much break dive, once the platform was exceeded. So I tried the production trail stack with on speed shim and two platform shims, which was not enough platform for my liking. I like to hammer into the pedals from time to time especially on flats or flow trails and also like climbing quite much which is mostly done out of the saddle.
So I added one platform shim to the trail stack (19x0,2). The platform is quite nice now when closed (have to stand up and hammer it to get movement), but the fork still feels too harsh for my liking although velocity dependency went up and small bump compliance is a little bit better. The wide open position is ok on trail. I also noticed the fork uses just 70% of travel so that could also be increased a bit, it feels a little too progressive somehow. At the moment I run it at 110 psi to get around 20% sag and avoid top outs.

I thought I eventually replace one 0,2 platform shim with a 0,1 platform shim and try that out, but wanted to ask if anyone has some advice what I could try to reduce the harshness a bit further by keeping a good amount of platform (I know its not an easy undertaking since the harshness comes as a byproduct of the platform setup).

The trails I ride are mostly what would be XC in the modern terminology - steep uphills, moderate downhills with mostly flowy trails, roots in various sizes, occasional steep sections - the kind of stuff where you have to work quite good on a hardtail and have to choose your lines wisely.

Thanks in advance!
 
If I put my Marvel back on my Unit, I'd run the same stack I've got on the Anthem (both single speed, standing climbing).
19x.2, 19x.15, 17x.15
Locked out for smooth climbing and one click open for normal trails.
Fully open for rough descents.
Get to about 90% travel on a normal ride (inc small jumps) and only closer to 100% if I stuff up.
 
Thank you, Ill order a 17x.15 shim and try that out, seems like a sound stack. I suppose you lower the plattform a bit with the second plattform shim which is thinner and the thinner velocity shim lowers the velocity dependency and progression a bit. Will try it as soon as the shims arrive!
 
Ok, short feedback:
I installed the aforementioned shimstack and padeled a few times around the house, and it feels pretty amazing. Keep in mind I have to test it on trail but first impression: the fork is more sensitive, small bump compliance is way up and harshness completely gone. When closed the fork is pretty stable, seems at least as stable as with the 3x 19x.2 shims but without the harshness. It also it travels further into travel and brake dive feels more controlled. Very nice!
Thanks a lot!
 
Big rider at 6'2" 250lbs building up a 29x3" hardtail using a Mastodon PRO (I had it from my fat bike build, and have been riding rigid). I am riding rigid now, and really really like the qualities of rigid with regards to pedaling platform, no brake dive, and being able to stand out of the saddle climbing w/o riding super low in the travel (which usually happens because of my weight).

I would likely enjoy the XC tune, but having very limited time to tune I am wondering if there are any tips on what people might think would work for my weight. I am also looking to do the remote lockout as well.
 
Jump stack is incredibly stiff. I wouldn't put one under a 55kg rider unless they were mad-core.
I've been riding a bit of ABS+ lately and found two 17.5x0.1mm shims (no platform shims) were working well for choppy grade 5-6 trail. Anything more kicked too much. You can go much firmer on smoother trails with single big impacts.

The Youth Tune is:
8x17.5x0.15(2), 8x91x0.15,8x11x0.5mm.
I don't have a dyno for that tune. But I think it's a very good starting point for a jumping kid.
@Dougal am I right that you have been testing Abs plus tunes for the New mattoc comp?
Are there any significant differences to the old Abs plus pistons? Because the old tuning guides do suggest thicker shims and thus substantially more damping...
 
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