63 degrees of wheel rotation with this mod! This is the ultimate in turning ability and durability for the MGT. Read on........................

UPDATE; May/06, having troubles with EB4 S3 knuckle breakage in rear! This is still a fabulous mod if you want to get tons of steering in the front, but you may wish to leave the rear MGT knuckles alone, maybe just upgrade to aluminum knuckles, or RPM knuckles.
Follow-up; July/06 - I boiled the rear knuckles for about 15 minutes, then let them cool slowly and re-installed. Have used them for four race days and no problems........
Final Take on Rear Knuckles; Sept/06 - The TTR knuckles just don't have the strength to use in the rear. Too bad, as they fit well, but the brittle plastic just won't take a tumble in a 11-pound MT. Great mod for front knuckles though.
Still another update; March/07 - STOP! Don't do the TTR mod. We are modding RPM knuckles instead! Click here for info!

Well, I got sick of breaking knuckles, axles, and wearing out the puny bearings. so I mounted up Thunder Tiger (TTR) EB4 S3 knuckles, which are VERY beefy knuckles. They use 10x19x5 inner bearings (bought a pack of 10 for $10) and standard buggy-size 8x16x5 outer bearings. You need to use stub axles from FRONT axle assemblies of the EB4 S3. The MGT long axles and CV pins (AE or TTR) fit right into the Thunder Tiger stubs. 17mm TTR hexes (or 23mm KMW hexes) fit right on, and the whole setup is super solid, with minimal (really none) wheel slop. I can easily switch between 17mm or 23mm wheels now.

I used RPM a-arms and had to shorten them all by about 1/4", in order to get axles deep enough into drive cup, plus I had to ream out the a-arm holes with a 13/64 drill, to get the larger pillow ball shafts in. I had to shorten the arms because the pillow ball shafts extend further towards the chassis, because of the larger knuckles and bigger pillow balls. I used RPM arms because there was extra material around the pillow shaft area which would accommodate a deeper pillow shaft hole.

Also, I used spacers (about .1") under the ball-ends when mounting turnbuckles to knuckles. The spacers were necessary to eliminate bumpsteer. I can detect virtually no bumpsteer now when moving a-arms up and down. You may (or may not) need spacers. Just check for bumpsteer when you're done by moving a-arms up and down. You should detect no left/right movement in the wheels as arms go up/down. Add/remove spacers as necessary to eliminate bumpsteer.







 

I used the stock MGT long axles (and pins) and just connected them to the new 8mm TTR stub axles, with a dust cover over the CV joint. I had to buy a whole set of EB4 S3 front axle assemblies just to get the correct stub axles, as the stubs were not available separately, or at least, I couldn't find them separately. So, you need to buy the complete front axle assemblies for the EB4 S3, in order to get the proper stub axles. You will be utilizing the stock MGT long axle shaft and mating that to your new TTR stub axle.

Complete parts list for this mod:

1) RPM a-arms - $40 for 4 sets (Tower) part #LXGWR5

2) Knuckles - $20 for 2 packages (A-Main) [part #TTRPD1915]

3) FRONT axle assemblies - $40 for 2 packages (A-Main) [part #TTRPD1874]

4) Bearings - 10x19x5 - $10 for 10 (A-Main) [part #AMN6800-2RS]

5) Bearings - 8x16x5 - about $10 (anywhere)

6) Thunder Tiger lightened Pillow balls - $26 for 2 sets (A-Main) [part #TTRPD1863]

7) Pillow ball retainers - $10.50 for 2 sets (A-Main) [part #TTRPD1917]

8) 17mm hexes - $6.50 for complete set (A-Main) [part #TTRPD1924] (see note below for 23mm hubs)

Total cost, about $160

NOTE: you only need 4 of each bearing, but it's always good to have extras...........

NOTE #2: use front axles from the EB4 S3. You gotta remove the TTR long axles, you are gonna end up using just the TTR stub axles, in conjunction with the stock MGT long axles and MGT (or TTR) CV pin.

NOTE #3: Here's some beautiful 23mm hubs from KMW that fit perfectly: 23mm KMW Hubs
 

TURNING RADIUS

I checked turning ability on the setup board. With the initial install, I found that the TTR knuckles were not allowing as much turning as I had before, with the modded MGT knuckles. With the TTR knuckles I was getting 27 degrees for inside turn and 17 degrees for outside turn (27/17). With the modded MGT knuckles, I was getting about 32/18. The new knuckles are slotted to allow a lot of extra turning, so it's just a matter of taking advantage of that design.

Here's a pic of my setup for measuring:


So I look at assorted options and eventually discovered that the longer arm of the TTR knuckle meant less travel was actually getting to the knuckle. The ball-end was mounted further away from the knuckle, so all I did was to drill a new hole to mount the ball-end closer to the knuckle itself, as in this pic below. After I drilled the new hole, I checked turning again and I was back at my original MGT rotation, with maybe a little extra, at 33/20, for a total of 53 degrees.




By virtue of their design, the TTR knuckles will actually allow much more travel still. The problem is getting the servos to create all the movement necessary. But the TTR knuckles will actually allow turning of 38/28, with no turnbuckle attached, so there is still more turning available!!! Of course, you rarely need this type of turning, but if you're on a tight track, with real sharp corners, then why not have it available? You can always use dual-rate to dial out steering if you don't need it.

Check out the knuckles comparison:



But wait, there's MUCH MORE TURNING to be had, LOL!!!   see below

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Ultimate success at last. 63 degrees of total wheel rotation!

I am getting 38 degrees on inside turn and 25 degrees on outside turn, for a total of 63 degrees. This is unreal, as the best I was getting with stock MGT (modded) parts was maybe 53 degrees.

I got the big boost in turning by moving the mount hole on the two steering bell cranks (see pic). This was easy to do on the stock plastic bellcranks, but wouldn't work with aluminum FT steering kit. Plus, this puts extra strain on the steering servo, but I got that taken care of with two Airtronics 94358's in there. You could easily install two cheaper servos for this mod, and still have kick-ass steering.

There is no two-wheel steering MGT on the planet that will crank the wheels harder than this, heheh. As a matter of fact, this truck may crank the wheels harder than any MT out there!

If you do this mod and want to get the full 63 degrees, you'll definitely need to make a custom steering rack, to move the turnbuckle mounts further away from the diff case, otherwise the inner ball-ends will hit the diff case and limit you to about 52 degrees with the stock steering rack, even if you did all the other mods.

My steering snaps back and forth like you wouldn't believe. I have my dual-rate backed off to 74%, so I have tons more steering in reserve (adjustable while racing) with a few clicks on the DR button. Also have my expo backed way off to compensate for the quick steering.



63 degrees, that's gotta be a record for a MGT (or ANY truck!)................. woohoo!