maxx 2.5 - 3.3 compatibility question - RC-Monster Forums

schofield · 11:05 AM

i am trying to put 3.3 shafts on 2.5 arms and knuckles. am i kidding my self?
3 points of conflict i have found.

1. the shaft slightly rubs the shock mounts on the arms.
2. i had to use washers to make up the width difference between the 3.3 ball connecters and the 2.5 wheel shafts.
3. slight rubbing on the upper 2.5 arm from the 3.3 shaft.

all can be remedied with a little dremmeling. but im not sure i will be able to get the nuts on the back side of the shock mounting screw. i could i guess run the screw the other way and use the nut to hold the shock on.

motors will probably 700ho's or 775 dewalt motors, probably not brushless as i would need a new raido. and i would like to run A123's but again no budget so she will probable be a roller for quite a while.

or should i just use my 2.5 shafts till i can afford 3.3 knuckles / arms/ wheel shafts / connecting rods, (could be years)

any ideas, i have no budget just what i have on hand, some budget but not till next month. (i get a rc allowance from my wife)

schofield · 05.19.2009, 01:23 PM

anyone still run 2.5 maxx's?

lincpimp · 05.19.2009, 02:15 PM

You will have to clearance the upper arms if you plan to run the 3.3 sliders. The new uppers that traxxas sell have the clearance cuts on them already, but easy to do with a dremel or bench grinder. I have always used the 3.3 knuckles so I am not sure how well the 2.5 knuckles will work. Looks like you have modded the 2.5 axles to fit so I guess that will be ok. I never use nuts on the shock screws, so that would be why I have never had clearance problems. Traxxas does not use nuts when they assemble the shocks to the arms either...

2.5 shafts suck, the 3.3 sliders are a much better item, especially if you plan to run high torque motors like the 700s you mention.

schofield · 05.19.2009, 02:19 PM

the nuts on the shock screws was recommended by misbehaving for the rpm arms.

schofield · 05.19.2009, 02:21 PM

thank you, i will mod my way through it. lol

lincpimp · 05.19.2009, 02:22 PM

Quote:

Originally Posted by schofield

thank you, i will mod my way through it. lol

Let us know how the mods work out for you. Seems like getting the 2.5 axle on the 3.3 u joint was the most though intensive part, everything else should be pretty simple to do.

schofield · 05.19.2009, 02:30 PM

thank you. this is my first real modded vehicle, i have made bumpers and body post before, but not like this. i just got done trying to installing new style steel idler gears in the old e-maxx tranny and found the width problem that occurs. so now i have a locked tranny, no more problem, and i don't have to worry about a shifting servo location.

i know this is all small stuff for your guys. but if i had the tools and materials i would build a proper rc-monster.

Overdriven · 05.20.2009, 02:50 PM

I know what it's like to on an allowance too. I've personally clearanced RPM arms for the driveshafts with a sanding drum on a dremel before with no issues. Rpm makes a set with the required dimple, but I had to clearance mine further for the extra high ride height I was running. I'd run it with the 2.5 knuckles and axle shafts, go for a motor first before new knuckles. The only thing I'm worried about is how much material was removed from the axleshafts to fit the 3.3 shafts. But I'd only be worried when they break. Good work, lack of $ is the best inspiration IMO.

schofield · 05.20.2009, 02:58 PM

Quote:

Originally Posted by Overdriven

I know what it's like to on an allowance too. I've personally clearanced RPM arms for the driveshafts with a sanding drum on a dremel before with no issues. Rpm makes a set with the required dimple, but I had to clearance mine further for the extra high ride height I was running. I'd run it with the 2.5 knuckles and axle shafts, go for a motor first before new knuckles. The only thing I'm worried about is how much material was removed from the axleshafts to fit the 3.3 shafts. But I'd only be worried when they break. Good work, lack of $ is the best inspiration IMO.

i haven't removed any material yet and the only place they hit is the top arm and its just a nick, and just a wee little where the shock mounts to the lower arm.
i could probably rub enough material off with my finger

also is it ok to shim here (yellow circle) with washers , will it off balance the shaft?. even on both sides

Overdriven · 05.20.2009, 08:33 PM

I think you'd notice tires being out of balance before you notice the shaft. I've done that before on a center shaft which spins faster and never noticed anything out of the ordinary.

For the a-arms, at ride height it may only barely hit, but at full droop (wheels off ground) you may need more clearance. I had to widen the stock dimple quite a bit (only slightly deeper) on mine because I was riding really high

rawfuls · 05.20.2009, 09:22 PM

Hmm, I am running 3.3 sliders on my 2.5 maxx arms, they're pretty good right now *knock on wood*......

Then again, I need the oversized bearings to completely run everything (I can run em with the outer bearing, but the toe in and out constantly changes without the inner bearing.

They're great, nothing is binding (I hope), and it runs pretty well... *knock on wood once again*

EDIT1:

By the way, I bought new turnbuckles and knuckles, as they were needed.

schofield · 05.21.2009, 08:44 AM

Quote:

Originally Posted by Overdriven

I think you'd notice tires being out of balance before you notice the shaft. I've done that before on a center shaft which spins faster and never noticed anything out of the ordinary.

For the a-arms, at ride height it may only barely hit, but at full droop (wheels off ground) you may need more clearance. I had to widen the stock dimple quite a bit (only slightly deeper) on mine because I was riding really high

i have tested the ride high by bolting on a shock and seeing, and it looks pretty good.

schofield · 05.21.2009, 08:45 AM

Quote:

Originally Posted by rawfuls

By the way, I bought new turnbuckles and knuckles, as they were needed.

i dont need any of those because im using all other parts are 2.5 just the sliders and ball joints are 3.3

rawfuls · 05.21.2009, 10:13 AM

Ah, I left the shaft alone, as I hate messing with the UJoints, mainly because they're a pain in the butt if you don't have that screwdrive with the little hole cut out, which makes it so much easier to work with.

I just need my inner bearing, and I'm good to go, oh, and a new diff.

schofield · 05.21.2009, 11:13 AM

Quote:

Originally Posted by rawfuls

Ah, I left the shaft alone, as I hate messing with the UJoints, mainly because they're a pain in the butt if you don't have that screwdrive with the little hole cut out, which makes it so much easier to work with.

I just need my inner bearing, and I'm good to go, oh, and a new diff.

3.3 ujoints are different then 2.5 no tool required