DEX210: Alternatives for Low Roll Center/LRC

[micholix]

Originally Posted by Origineelreclamebord

I wouldn't fully agree on that one - Durango seems slow at times releasing improved parts or updates.

Also, take in consideration that a design can't be best in all conditions on all tracks. I can imagine the HRC works well on high traction tracks like Blue Groove conditions or dry UK Astroturf. However, Dutch and Belgian tracks have way less bite than that and are quite bumpy. Combine that with my decision to drive the DEX210 in mid-motor in all conditions and LRC modifications start to make sense. Since the trend is that tracks are getting smoother and grippier it's not at all unlikely the DEX210 didn't see many miles on low-bite, bumpy tracks - even more so as their team drivers usually drive on high profile events with well prepared tracks.

An example where mods already worked is the amount of rear droop: It's quite limited out of the box (the shock can give much more droop than the chassis allows). After the mod it is not limited by the chassis anymore, but by the shock. It added about 6-8mm of droop I think. It helped a lot, but it's still very snappy on-power like Johny5 mentioned.

So to make it driveable I removed a lot of steering, so at least it then lacks grip on the front and rear. It's a blast drifting through every corner to get around, but it's not the way to go I know I can soften the rear end some more, but it won't be enough. The LRC will (hopefully) give the rear traction the car needs so I can (finally) make the front end more agressive.

Hello Origineelreclamebord,

I would like to drive my Dex210 allso with MM on all tracks here in austria, and we have same conditions on our tracks, like they are bumpy and sometimes with realy less bite.
I've just bougth my dex210 and i'm interested to this rear droop mod, you told.
May you can tell me, how this mod works, or give me a link?
I'm new to 2WD, so it would be very helpful for me.


Thanks in advance

[Origineelreclamebord]

This is the mod:




It is pretty simple. First, you remove the droop screw (or one that doesn't stick out below) - this should already give you a few millimeters of droop. You may notice then the suspension arm is still touching the chassis plate, and if you unscrew the shock from the suspension arm you should see the eye of the shock extends further down than the mounting points on the suspension arm - so you can gain some more droop.

You can do this by getting out a Dremel and shave off material from the piece of the chassis plate which normally stops the droop screw. Alternatively, you can remove the lug alltogether: If you choose for a Low Roll Center Modification too you have to remove it anyway.

[dex210Nick]

be careful with that much droop. one of my cvd's would bind at full droop when I first built the car. It was enough of a bind that it messed up the outdrive on that side of the car.

[Origineelreclamebord]

Thanks for mentioning it, I forgot an important detail! I use long ball diff outdrives - the standard outdrives are too short even without added droop (the driveshafts nearly fell out). The Gear diff outdrives are also longer than the standard ball diff outdrives, so both of these will work with the mod

[micholix]

Thanks for the quick replay and your help!
Also for the warnind, with the outdrives...

Thanks again?

[Jonny5]

In addition, or as an alternative to removing the droop screw, I countersunk the hole in the arm using a drill bit and some finesse. Same result as you have shown, and you still have the droop screw should the need arise.

[Origineelreclamebord]

Nice one Jonny5

By the way, I was just wondering: Does someone have an LRC conversion to confirm it's the hinging point that's 2mm lower? (And not the actual roll center that results from ALL the geometry).

[Origineelreclamebord]

I've been looking at the LRC some more, and ordered an RF Hanger (LRC) from RDRP...

It turns out the thing has exactly the same geometry as the 0 degree anti-squat one from the DEX210 kit! So the LRC kit from RDRP only makes a difference when you run anti-squat.

So for anyone looking to try a low roll center: Buy a 1.5 deg or 3 deg RR hanger seperately - you don't need the RF or 0 degree RR hanger.

I've been looking into why they didn't lower the RF block. It turns out the suspension arm would rub (quite seriously) on the chassis plate. Then the question remains if it may be preferable for the car's handling if the RF hanger is lowered any further - I'll be looking into that next.

EDIT: I have been looking into this: It turns out a TRF201 has a 3mm lower roll center at the RR hanger (both cars adjust the roll center at the RF hanger). That's quite a difference. I can't measure other modern 2WDs at the moment, but I think most cars won't be around the 210's roll center, but around the one of the 201.

EDIT 2:

I've put the roll center in a CAD model. Thanks to Jimmy's nice X6/B4 comparison pictures in one of his reviews, it's easy to compare the differences:



The DEX210 inner hinge pins and ball studs are about 3-4mm higher than the B4's. The X6's story is more complicated: On clay I recall the ground clearance should be the same as the way the B4 is pictured, so that'd put the hinge pins at a similar height (but further apart) and the gearbox higher up.