But if you stable at 30 degrees on the dwII deck it’s worth a try I think. Maybe start with reduction in the back and see if it helps.
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100kg equipped 
doesn’t feel so dangerous 
I don’t think you go faster than 12mph in that whole video. not sure what it’s supposed to prove but it sure as shit don’t show that your board is set up to be stable at 60km/h.
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Never claimed such a thing for that video and I don’t have to prove anything.
Try dewedging the rear to about 25°. I’m running a Comp 95 with yellows loose af up front, and oranges loose to medium tight on the rear dewedged -5°, so 30/25 split. That little change in the rear was huge. Feels way more stable up to 30mph+ (50kph), with no wobbles at all. Still feels quite maneuverable with loose trucks in the front, so with your 35° noise, you should still have good steering even with stiffer blocks. That’s assuming, of course, that your wheels & tires are balanced well. I originally got wobbles on the bench before balancing my wheels, and I’m sure that contributed to wobbles on the street. After balancing and dewedging, smooth and stable af, even that time I ran fully loose yellows in the rear and NO blocks up front 
, you know, for science. Also, I’m around 80-90kg depending on whether I’m riding butt ass nekkid, or fully geared up, so I’m no lightweight. 
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The Matrix II king pin is an 8mm x 80mm shoulder bolt. Note: Those are the dims of the shaft (not including the threads) - refer pic. The king pin thread spec (and associated nut spec) is M6.
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Yeah, I can back this up. Decreasing back angle makes a huge difference. You can increase front angle to compensate. Wobbles primarily originate from back truck. You can get an equal turning radius with much less wobble but it does change the feel of the carve. Stiffer blocks in back is good too for the same reason (as others have said).
As for @rich’s wobble specifically, I’m perplexed. The Matrix IIs really are good in that department so I’m thinking it could be power related but that could just be old fashioned blame shifting. I’m interested to hear the results of the unpowered downhill speed test.
The askew mount too is weird too. Is it the same on both sides of the truck? Is the other truck the same (if that’s easy to test)?
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I can try to decrease to 30° or even 25° and see if the speed wobbles still occur but first I’ll try a few other things. First I want to compress the red shock blocks further for science. Also riding downhill without power is interesting. I just hope the brakes are strong enough to stop the possible wobble 
. Or if there is no wobble it could start during braking 
. Need to work on the weekend but gonna test it next week and report back.
Maybe I’ll try to film the speed wobble as well, wanna see how it looks.
Yeah it’s really strange especially because I don’t get speed wobbles on the DWII board with orange shock blocks. Also after further searching in the forum I found more post about people riding Matrixx II trucks with orange (or even yellow) shock blocks above 30mph.
The same but different askew. I can’t try it on the other truck now but I would guess it’s the same. I don’t know if it’s the batch or the oil-slick only but the shape is a tiny bit different to the black Matrix II trucks I have. That means when I push the motor mount against the hanger (without bolts) it wiggles on the oil-slick and stays put on the black hanger. For normal MTB it makes zero difference so there is nothing to blame but in combination with the motormount (or at least the one I use) it does.
I counter-balanced all wheels before filling in some green slime (it’s not possible afterwards), now they a bit out of balance but not dramatic. I can lift the rear and go full throttle without problems.
sounds like a good training for balance!
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Just out of curiosity, does this happen the moment you reach top speed when accelerating ?
I recently noticed some weird behaviour on my MTB where it feels that the motors do not top out at the same time.
This leads to a wobble exactly as it tops out. It is recoverable but not very pleasant. After that the board is stable as a rock.
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Tack on question, are you running any traction control?
No traction control.
No it’s between 60-80% of top speed depending on the used shock blocks.
Damn hope you’ll find out what’s the problem
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Can you do a test run with it enabled to see if it cuts your second motor early or allows the second to catch up smoothly?
It sounds like you are getting pushed so that your weight is more on the rear of the board. Have you tried leaning hard into the acceleration? I’ve noticed weight distribution plays a huge roll in speed wobbles even if your board is setup properly. 70/30 on the front end
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I mean you are right, in offroad conditions I always put more weight on the rear because of much better control and traction.
If I would put more weight on the front I would fall all the time eg. on gravel or soft dirt. The same for tight curves. If I lean back a bit and am too fast the rear wheels start to slide. I just shift my weight more forward and can succeed the turn. But if I put more weight on the front then the front wheels slide and I fall without any chance to correct anything.
Or when riding at higher speed and the surfaces change from eg. concrete to loose dirt I put 80-100% weight on the rear because otherwise it can be very painful, guess why i know 
But I get your point and it makes sense when riding on concrete. I’ll try if different weight distribution makes a difference regarding wobble 
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@rich Seriously, before you get into too much other crazy stuff, tried dewedging the rear by 5 or 10 degrees and see if that doesn’t just fix the problem. I don’t recall ever having any speed wobbles on my Matrix 2 trucks, at least up to around 50kph (my personal speed limit), but at 30°in the rear, it did feel a bit twitchy at that speed if my blocks were too loose. Since -5 degrees was such an improvement in stability, I would guess +5 degrees in the other direction could introduce the wobbles you are dealing with.
And just this week I was blasting around a wide open dirt field that was so bumpy I had to wait my back leg as if I was plowing through powder on a snowboard, and it was completely stable with the front being nice and turny still.
And yes, riding with no blocks up front and loose yellows in the rear is great for balance training and testing your ankle strength. Side effects may include a wee bit of testicle retraction and anal puckering though. 
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The last days were beautiful and warm here but had to work. The next 2 days I have off but the forecast says it’s raining both days. If it stops I’m ready to get dirty 
Regarding tip angles I made some interesting measurements which I want to share. For comparison I measured the MBS DW II deck as well. Don’t take it 100% accurate but it gives you an idea.
I’m 74kg (163lbs) and the HolyPro deck has 16ply
unweighted:
Holypro [ 33°] | DW II [ 32°]
weighted:
Holypro [ 36,8°] | DW II [ 33,4°]
pushed down a bit (simulating normal offroad)
Holypro [ more than 40°] | DW II [ 35°]
pushed down more (simulating heavy offroad)
Holypro [ more than 45°] | DW II [ 37°- 38°]
So in reality the tip angles during riding are between 37° and more than 45° with the Trampa deck.
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Good thing I could test for 2 days Bad thing the issue is not solved yet.
I tried everything like to move most weight to the front or exactly in the middle. No difference at all. Very little or hard acceleration makes also no difference. Loose or hard cranked down red shock blocks marginal 1-2km/h difference. It’s always between 44-46km/h (27.3-28.6mph)
Then I mounted a -5° E-Toxx angled riser. I can feel the different angle when steering but the speed wobbles are the same. WTF!
Here the video evidence
The last hope is that it is FW related, I could try to downgrade from 4.0 to 3.62.
I’ve read that @DavidC had some wobble problems with FW4.1. Did the wobbles behave similar to the ones shown in the video?
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I had similar issue that was vesc tool. It was always at the same speed. I could audibly hear the motor switching i assume left to right… I changed over to ackmaniac firmware and the issue was completely gone.
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Jesus you are the second person now, I’ve never read something like this before or maybe I missed it. But many guys use new FW, that’s strange.
Definitely gonna downgrade FW and test it on weekend. I’m so curious, can’t wait!
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