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View Full Version : True FULL suspension travel Mod


zzmods
03-12-2005, 02:33 PM
Ok well I wasn't sure if I should post this here or in the mods section, but since this mod is only for the MT I decided to put it here. First of all, something similar to this has been mentioned before but the methods posted at the time where just ideas and nobody has posted any results from performing this mod. The mod included drilling holes in the pcb cover to allow the suspension rods to travel farther to give you an added 1/16" travel. Well this does not work because the pcb cover does not limit these rods travel. The rods themselves do.
If you look carefully at the rods the springs are mounted on, you will find a flare about 1/2" down from the top. This flare prevents the rods from traveling freely through the hole (labeled "B" on the pic below). The bottom section of this rod (labeled "A" on pic below) still sticks out about 1/8" when the front wheels are presses down and suspension fully compressed. Some people have clipped this off to give some added clearance and if you have done this, you cannot perform my suspension mod for obvious reasons. Also, if you have cut any part of your pcb cover out in the area circled in the second pic you cannot perform my mod. The pcb cover must be in stock condition.

OK, lets run through a true FULL travel mod.
http://tinyrc.com/forums/images/zzmods-mtmod2.jpg http://tinyrc.com/forums/images/zzmods-mtmod.jpg

Tools Needed
-----------------
3/32" drill bit
#1 phillips screwdriver


1) First remove your trucks body cover.

2) Remove the two screws holding down the pcb cover and remove the cover (set somewhere safe).

3) flip you truck upside down and remove the two screws located at the front of the chassis (set somewhere safe).

4) Pull the chassis open just enough so you can slide the suspension rod out of the hole labeled "B" in the pic (recommended you do just one wheel at a time).

5) Remove the spring and set it aside for the moment, now using the drill bit, bore the hole out enough to slide drill bit through freely. Blow loose shavings out.

6) Now take the spring and give it a little stretch and place it back on the rod. Pull chassis open enough to slide thr rod back in the bored hole and squeeze the chassis back shut.

7) Now test the suspension to make sure it travels FREELY. In point "A" in the pic, the suspension rod should be flush at the bottom if done properly.

8) Repeat steps 4-7 on the other front wheel.

9) If both front tires now travel to their fullest potential, replace the two screws in the bottom of the chassis. Place pcb cover back on and replace their screws.

10) now test you suspension again. The suspension rods should travel all the way until they hit the pcb cover. This still allows point "A" in the pic to travel until flush when fully depressed. If the pcb cover was not in place, fully depressing the wheels fully may make them pop out of place so it is good that the pcb cover stops them where it does.

11) If all is good, replace your body and enjoy an extra 1/8" of suspension travel!

zzmods
03-12-2005, 02:35 PM
the other pic :)
these are not my pics as I do not have a digi cam. Just used them to illustrate. :)

ZipZapin
03-12-2005, 07:04 PM
Your first picture does not work for me. Nice write up.

Racer9
03-27-2005, 05:28 PM
I did this today mostly because my dang steering is sucky. I think this mod greatly improved it because now it doesn't hang up as easy on bumps and stuff. It would work better if we had slightly softer springs. More easily compressed so you can actually use all the travel.

Good job!

zzmods
07-30-2005, 08:05 AM
I was cleaning out my hard drive today and found a couple images that were supposed to be posted here. Seems I was in a hurry. The pics got a bit fuzzy when i resized them, but I had to do it. The original image size was HUGE!!! :eek: Anyway...It can be difficult to see the bottom of the suspension rods in these 2 pics but you can still see the difference in the spring compression, space between body and tires, and the angle of the white dog bones in the front wheels. Full compression of the suspension takes VERY little resistance. You want the rods to travel as freely and smooth as possible.

Okay the pics...

zzmods
07-30-2005, 08:20 AM
...and suspension compressed.:eek:

frizzen
07-30-2005, 01:24 PM
Oh yeah, I did this mod months ago and ment to post that you CAN do it even if your PCB cover has been drilled or taken off completely! I drilled mine to get even more travel after I'd done the mod, it won't come out unless you're putting WAY too much stress on it anyway.

Softer springs make this even better! Here's mine showing the kingpin travel

http://img.photobucket.com/albums/v413/frizzen/RC/Jeep_1.jpg

chilli_mp138
08-02-2005, 10:30 AM
frizzen, zzmods--

After taking apart the sixth ZZ MT in my garage, I began rummaging through my model railroad parts collection and pulled out a small bottle of Athearn motor brush springs. The springs are the same length and diameter, but much softer. They are Athearn part number 84014. Have either of you tried them?

BTW, this sixth MT was purchased used this past weekend. The steering does not return to center. It drives nicely that way. I doubt I'll repair it.

chilli

frizzen
08-03-2005, 06:24 PM
No I haven't tried model railroad springs, mine are from a plastic pullback dune buggy I got when I was in preschool (to give time scale I got my AAS degree about 2 years ago). My springs are longer, yet softer even with the preload to make them same length.

So how well does it do without the steering return?

chilli_mp138
08-06-2005, 08:46 PM
frizzen--

It drives about like most Hoosiers do on I-70 between your place and mine! It's still running stock motor and gears (all green) and handles very well. I have yet to try it running faster--there might be a big difference in steering.

On another MT subject: Have you ever run an MT on foam rubber tires? Back in the late 1960's, during the height of the slotcar craze, we built sponge rubber tires (then we'd soak them in oil of wintergreen--fantastic adhesion on the track). What's your estimation on such tires for MTs and their climbing/crawling abilities--less the wintergreen? I have in mind some detailed plans for building a pair, but wonder if it might not be worth it. E-mail me off-forum if you're interested in discussing this further.

chilli

frizzen
08-07-2005, 04:40 PM
It drives about like most Hoosiers do on I-70 between your place and mine!
Awww man, so it's too fast and all over the road? :eek:

I have NOT tried running on foamies, yet. Though now that you mention it the 1/32 scale foam slotcar tires might be about the right size! (gotta find some to compare) They'd be absolutely ideal for indoor on like low pile carpet or clean smooth surfaces. I'd think if you were doing straight rock crawling, those should be pretty good; though would probably "chunk" if the rocks are very sharp. If you're driving in dirt or mudding, expect worse grip than the chevrons.

I'm definately interested in this idea. You'll have mail...

Michael.mt2k
12-18-2005, 01:39 PM
Originally posted by frizzen
Oh yeah, I did this mod months ago and ment to post that you CAN do it even if your PCB cover has been drilled or taken off completely! I drilled mine to get even more travel after I'd done the mod, it won't come out unless you're putting WAY too much stress on it anyway.

Softer springs make this even better! Here's mine showing the kingpin travel

http://img.photobucket.com/albums/v413/frizzen/RC/Jeep_1.jpg

Really nice work! (and a beautiful photo!)

I myself just finished doing this mod on a MT chassis from the parts box and it's impressive how drilling out the chassis holes and PCB cover free up the suspension travel!

I've already found a supplier of the Athearn 84014 springs kit and I'll be ordering them tonight.

You better believe that this will now be a standard "must do" mod for all my MTs as soon as my springs arrive.

These are the kinds of mods I remember from a couple/few years ago.

Great stuff!

Michael.mt2k
12-21-2005, 10:07 PM
I've ordered my Athearn springs, although they won't be here until after Christmas.
http://discounttrainsonline.com/Athearn-Springs-36-Pieces-Motor-Brush-Springs/item140-84014.html

I've drilled out my PCB covers and the chassis holes.

I'm looking forward to seeing how they do!

Michael.mt2k
12-30-2005, 11:49 AM
Those springs are great!

I don't know why they don't come like that already!

The only MT I would leave the stock springs on is maybe a hyper-speed modded one, but I'm setting up all mine with em for now!

EDIT

It's very cool to see my yellow motor/greared MT rear up in front when it takes off.