Aluminum Bulkheads

Welcome to RCTalk

Come join other RC enthusiasts! You'll be able to discuss, share and private message with other members of our community.

kswiencki

RCNT Talkaholic
Messages
253
Reaction score
0
Location
Northern RI
RC Driving Style
  1. Bashing
So surfing around... lookin at t-maxx parts... found "hybrid" aluminum bulkheads from fastlanemachining. it says to used 1/8 gears?!?!?!?!? how would that be a performance gain? isn't their only so many 1/8 scale cars/trucks? what about 4WD?
 

Rolex

Hoof Hearted
In Memoriam
Supporter
Military Veteran
Build Thread Contributor
Messages
35,148
Reaction score
1,676
Location
In my recliner
RC Driving Style
  1. Bashing
  2. Flying
I have the 'Hybrids' on my Savage from FLM. I highly recommend ANYTHING they produce. Just make absolutely SURE that you don't buy their parts from Addicted2RC.

AllAlloy.jpg
 

Lessen

Super Awesome!
Supporter
Messages
13,855
Reaction score
4
Location
Aurora, Ohio (Cleveland)
RC Driving Style
  1. Racing
I also have FLM hybrid bulks, but mine are for the TMaxx. Get 'em from www.rc-monster.com . they have the diffs as well. Dont' forget about the outdrives, they don't come with the diff set.
 

Rolex

Hoof Hearted
In Memoriam
Supporter
Military Veteran
Build Thread Contributor
Messages
35,148
Reaction score
1,676
Location
In my recliner
RC Driving Style
  1. Bashing
  2. Flying
Lessen, can you shed any light on his 1/8 question? I don't even remember if I had to swap gear sets or if they came with it.
 

Lessen

Super Awesome!
Supporter
Messages
13,855
Reaction score
4
Location
Aurora, Ohio (Cleveland)
RC Driving Style
  1. Racing
Oh... as far as performance gain?

1/8 diffs are faaar superior to stock TMaxx diffs. The ring and pinions are stronger (the set that you can pick up at rc-monster is made of hardened steel, not just regular steel) I know those diffs look expensive and if you look around you might be able to pick them up cheaper but you have to realize that Hot Bodies (the actual MFR) makes both a standard set and a set that has been hardened. The extra cost comes in the process obviously. Anyways.... The gear ratio is also different than TMaxx diffs. The gear ratio is such that the same speed at the tranny translates to less speed at the wheels with 1/8 diffs as opposed to TMaxx diffs. I dont' know that there is a performance advantage here but it does mean that the tranny has to turn faster to reach the same wheel rpm's that the stock TMaxx diffs would create. This will alter the timing of your 2nd gear shift point. you don't necessarily NEED to gear your truck up (with a spur or clutch bell change) but if you don't you will lose top speed if you go to 1/8 diffs. If you don't care about top speed then it's no big deal. That plus side is that you're going to gain BIG TORQUE at the wheels with this change. Also, you add the ability to tune your diffs because 1/8 scale diffs are oil filled so varying diff characteristics can be achieved with different viscosity oils.

as far as coming with the diff sets.. no. Those are available seperately. This is a bigtime upgrade and thus is big time $$$. All in all it's gonna run your around $300 or so from what I remember. I actually sold a car to fund it.

How's that Rolex?
 

Rolex

Hoof Hearted
In Memoriam
Supporter
Military Veteran
Build Thread Contributor
Messages
35,148
Reaction score
1,676
Location
In my recliner
RC Driving Style
  1. Bashing
  2. Flying
Excellent, Lessen. I think that would even impress Ed Asner. (You need to be a Letterman fan to understand that)
Anyway, kswiencki, there's the exact info you need. That's what we do best here.
Thanks, Josh. :)
 

cobra198

RCNT Champion
Messages
178
Reaction score
0
RC Driving Style
  1. Bashing
I just got the FLM hybrid bulks with new diffs for my tmaxx. So far they are great, I would highly recommend.

Just curious why you say not to get them from Addicted2rc (thats where I got mine). I was looking to only upgrade the front at the time (cause the front was the only thing broken) and it looked like Rc-monster only sold both front and back at the same time. Anyhoo, was just curious about that.
 

Lessen

Super Awesome!
Supporter
Messages
13,855
Reaction score
4
Location
Aurora, Ohio (Cleveland)
RC Driving Style
  1. Racing
He had a bad experience with Addicted2RC.

This isn't an upgrade that should be done "one at a time". Because it changes the gear ratio at the ends of the truck doing one end only will put extra stress on the drivetrain. Basically, in your case, the front wheels would be turning slower that the rear.. so the truck would essentially always be braking in the front end because the tires are trying to turn slower that the vehicle is going. Or on the other end of the scope the rear tires would be trying to turn faster than the truck is going. This is an issue because monster trucks do not have center differentials. If they did, it wouldn't be a problem.
 

olds97_lss

RCNT VIP
Supporter
Build Thread Contributor
Messages
19,985
Reaction score
1,646
Location
Dekalb, IL
RC Driving Style
  1. Bashing
Is there any info on the step up you would need to do in spur/cb to compensate for the diff ratio change?

Also, what diff cups do you use? What do you use for axles to the wheels? What do you use for center axles and trans cups? I don't see anything at monster or fastlane machine other than the diffs themselves and diff cases.

Just curious. When I looked into this many years ago, the only ones around where UE for around $400 for the whole shebang and they sold different trans internal gears to compensate for the ratio change and included the axles/cups that you could use.

Just as general info, running 1/8 scale diffs allows you to run a BB conversion in a maxx without worrying about the weak 1/10 diffs shelling out on you every weekend. Believe me... they do and it stinks. That's the "performance" gain, but really isn't a performance gain, rather a vast durability gain.

Also, if you don't want to dig that deep into your pockets, and you don't intend on running a BB engine (sticking with a 3.3 or 2.5 or 18), then I'd just suggest getting better bulkheads to avoid lengthy repair sessions when you smack into stuff. And maybe alloy diff housings to extend the life of the stock diffs. GA used to make some of the best bulkhead kits available, out of 7075 alloy for $140 for a kit for front/rear including braces... but it appears their site is no longer available. With that in mind, FLM does make just normal bulks, which would be a good investment if you don't feel like spending so much, or even the standard "bulkless" for stock diffs. Then you get alloy diff cases to help prolong the life of your stock diffs (proper shimming, zero flex throwing off mesh) and the toughness of alloy bulks.
 
Last edited:

Lessen

Super Awesome!
Supporter
Messages
13,855
Reaction score
4
Location
Aurora, Ohio (Cleveland)
RC Driving Style
  1. Racing
Lemme see what I can dig up.

well, first off it depends on which tranny is being used. I have the old school 2.5 tranny and with the 1/8 diffs my gear ratios are..

1st gear: 7.772
2nd gear: 5.307

however, these ratios do not include the spur/CB ratio. I have an 18T CB and I'm working on having custom spurs made which will be 54, 56, 57,58 and 60 tooth.

A standard box stock 2.5 TMaxx has a 2nd gear ratio of 16.1:1
I will be at 16.511 with an 18T C/B and 56T Spur.. now mind you these are 1.0 module cut clutch bell and spur, not 32 pitch or whatever Traxxas uses in the TMaxx.

Basically, I'm building my truck to be a torque monster :D

A Box stock TMaxx 2.5 1st gear is 24.1 : 1
Mine with RB ST28 & 60T c/b will be 25.91 : 1 AND that's with a .28 engine, not a .20

I should be able to pull teeth with it :)

if someone can dig up the stock diff ratio (or even just the number of teeth on the ring and pinion) we can figure out what change would need to be made with Traxxas parts to compensate.
 
Last edited:

cobra198

RCNT Champion
Messages
178
Reaction score
0
RC Driving Style
  1. Bashing
He had a bad experience with Addicted2RC.

This isn't an upgrade that should be done "one at a time". Because it changes the gear ratio at the ends of the truck doing one end only will put extra stress on the drivetrain. Basically, in your case, the front wheels would be turning slower that the rear.. so the truck would essentially always be braking in the front end because the tires are trying to turn slower that the vehicle is going. Or on the other end of the scope the rear tires would be trying to turn faster than the truck is going. This is an issue because monster trucks do not have center differentials. If they did, it wouldn't be a problem.

Ah, I didnt realize that it changed the gearing. I thought "modified gear" just meant it was more beefy so I wouldnt sheer it off again. Thanks for the tip. Ill go order another now
 

Rolex

Hoof Hearted
In Memoriam
Supporter
Military Veteran
Build Thread Contributor
Messages
35,148
Reaction score
1,676
Location
In my recliner
RC Driving Style
  1. Bashing
  2. Flying
As far as Addicted2RC goes, his inventory of FLM parts are slightly cheaper than other dealers because he's only a short drive from the Fast Lane Machine shop. However, when he sends you the wrong part because he's badly hung over, you're screwed. He doesn't care about customer satisfaction, even when it's his error.
I had to go directly to FLM to get it taken care of.
Fast Lane Machine is GOLDEN! Addicted2RC is a jackass.
 
Last edited:

Lessen

Super Awesome!
Supporter
Messages
13,855
Reaction score
4
Location
Aurora, Ohio (Cleveland)
RC Driving Style
  1. Racing
Also, what diff cups do you use? What do you use for axles to the wheels? What do you use for center axles and trans cups? I don't see anything at monster or fastlane machine other than the diffs themselves and diff cases.

I purchased what are Hot Bodies Lightning Hardened Diffs through rc-monster. They are listed in a different section that the bulks. You also need to pick up the 1/8 scale outdrives that attach to the pinions outside of the diff case going to the tranny. The outdrives are also available from rc-monster although I do not have them. I didn't realize I needed them and went ahead and had a set custom made for me before I realized that rc-monster had them (listed in a different section). I contacted rc-monster about changing the bulkhead listing to state that outdrives would also need to be purchased so folks would know what all they needed. I believe the folks over at rc-monster did indeed take my suggestion and make the change. My FLM Ice chassis conversion came with an extended rear dogbone but I will be ordering a new dogbone from RC Alloys to match the front dogbone I already have. They are ultra beefy. As far as drive to wheels I have good 'ole MIP. FYI, in order to use MIP shafts you will need to build your 1/8 diffs with the optional outdrives that come with them(these outdrives ARE included with the diffs). The standard outdrives are not long enough and the MIP dogbones may pop out at the extremes of the suspension.

FLM Hybrid Bulks
Hardened 1/8 Diffs
1/8 Drive Cup (need 2)
Custom center drive shafts
 
Last edited:

Lessen

Super Awesome!
Supporter
Messages
13,855
Reaction score
4
Location
Aurora, Ohio (Cleveland)
RC Driving Style
  1. Racing
I remember finding those back when I had a maxx and was frequently blowing center axles. $40 for a set of axles though... how did your front one hold up so far? Any wear on the dogbone ears?

I'm glad you asked. I'm VERY impressed with the dogbones themselves. However, not so much with their outdrives. Not hard enough. Randy (Racer1966) made me a set of hardened outdrives for my TMaxx. I know, $40 is a lot for a couple driveshafts but it's just another drop in the bucket considering what I have in the truck.
 

kswiencki

RCNT Talkaholic
Messages
253
Reaction score
0
Location
Northern RI
RC Driving Style
  1. Bashing
so is it worth the initial cost? i don't want to be dumping money on parts that are going to be hassle than factory......
 

Lessen

Super Awesome!
Supporter
Messages
13,855
Reaction score
4
Location
Aurora, Ohio (Cleveland)
RC Driving Style
  1. Racing
I think it depends on your view of "worth". If you're talking strictly "worth" as in $$ value then no. You'd be better off just buying a 1/8 scale MT. If you already have a Tmaxx and you want to customize it for the sake of making it more personal, and you enjoying the build, and money is less of an issue then I say go for it.

Consider that this upgrade is going to cost you about half the cost of a brand new 1/8 scale MT such as the SavageXL or LST XXL. Unless you absolutely love the TMaxx like some of us Maxx enthusiasts then I would NOT do the upgrade.

Bottom line- If you fear that one day you'll regret sinking big money into it then don't do it. You'll be happier in the long run.
 

kswiencki

RCNT Talkaholic
Messages
253
Reaction score
0
Location
Northern RI
RC Driving Style
  1. Bashing
it was more along the lines of upgrade... is it worth the cash for this upgrade? yeah, they look cool, but i'm looking for more function than form.
 
Similar threads

Similar threads

Top