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Differential and Hub stubs - Group Buy, anyone?

8K views 38 replies 16 participants last post by  revvhappy 
#1 · (Edited)
Arnout on Supraforums has made a set of diff AND hub stub shafts out of high grade tool steel. I messaged him, and he said he would be interested in doing them for us.

He said a minimum of 10 would needed to be made.

I don't know how many people are interested in these, and they will be comparable in cost to OEM MKIV six speed stub shafts. Around $225 per piece. He'll also need a spare set, if anybody is willing to put some up for R&D.

http://www.suprastore.com/subitost226s.html


(MKIV shown)

It would be more expensive for me to just have a set made, but it also doesn't help anybody else...
 
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#2 ·
Is there a plan to get new stubs made for the control arms? They are just as weak...
 
#3 ·
Hub stubs and diff stubs, both. I am not sure if you meant for the hub or not.

The material is stronger than MKIV OEM grade (These parts are discontinued from Toyota, whereas these parts are made entirely out of billet tool steel (34CrNiMo6 for the side shafts, 42CrMo4 for the bearing carrier)), which I'm sure, is already stronger than the 1980's grade that came with our cars.

Edited original post.
 
#5 ·
He can make any ends you want. I'm sure there can be a one off made in the batch. He is already discussing using the Porsche 930cv ends for the MKIV, and it wouldn't be tough for him to use the information he already has to cut them. Literally no problem.

This is the first time anybody has said yes to this, and it's someone the community can trust.

If there is enough interest, this can happen. I'm not in a rush, either. I'm still figuring out how I can break the TrueTrac with torque. Haven't gotten to that point yet.
 
#6 ·
Reason for the 930cvs is it makes for very easy axle upgrades. Whoever designed the mk2 axle pattern had to purposefully make it hard to make an adapter.
 
#7 · (Edited)
I had to look far and wide to get some made. They are very good, and I still have the contact. George @ Raptor Racing can get these axles.



Fit is excellent. Strong dollar at the moment doesn't hurt, either.
 
#9 ·
Any more interest in these?

So far other than myself, one set with the porsche 930 joints seems interested.
 
#10 ·
Hmm not sure if I'll need a set really soon.. haha I was guessing the half shafts- true trac would be the weak point.. and If the half shafts break but I buy beefier ones and then the diff instantly becomes the weak point. I would probably rather swap a 9" rear, or not gamble true tracs. I have little knowledge or experience in true tracs, but recall that 600 thereabout being a kill number for any spirited driving. Not sure I plan on driving the car super hard once i'm there.
 
#11 ·
Spirited driving on any kind of HP will generate more heat than the diff can dissipate. I'm curious to know if anybody has broken a truetrac with HP alone. So far, I haven't found that number. ;)
 
#12 ·
Torque? lol I know some people who do know... and there is a number, I saw Jacks transmissions I believe add a cooler to R154's being used in high hp applications... I believe the same thing could be added to a differential I guess? not sure it would help diffs since snappy torque is generally the killer not hard running.
 
#13 ·
Spill the beans, what's the magic torque number?

My 1J should make a hair over 276hp. ;)

I've heard a dog box is rough on diffs, anyway.
 
#14 ·
Hmm, well I'd have to ask for a specific number, Think everything up to 550whp is pretty solid.. anything pushing those limits starts to gamble.. anything past 600 I hear they aren't reliable, but I don't have solid proof yet besides a decent source. Doesn't mean one can be run at 1000whp. just depends how you use it.
 
#15 ·
No one has killed a true trac yet. Axles, axle stubs, wheel hubs, ring and pinion gears, but not the true trac itself yet. One guy was launching on slicks with 700rwhp, didnt break the truck track, was snapping wheel hubs and axle stubs as he had already upgraded the axles.

So is he going to make the axle stubs and the wheel hubs? If he makes wheel hubs, I might be interested in a set in 5 lug. That would let me run the 8.8 diff with the stock control arms and "hopefully" hold up. At $225 each, i think I can swing that.
 
#17 ·
Very interesting. Can you just have these drilled for 2 or 3 different bolt patterns for other common swap out upgrades at the same time?
Saves on set-up makes a more universal part for potential half shaft conversions down the road.
I would like these, but know I'd have to upgrade at one point to something beefier.
Perhaps, make a version that will fit a flange 1310 cardan joint... lowered cars might be able to get away from the CV joints with a lesser angle. Just talking out loud...
 
#20 ·
That also means new wheels and new brakes for the other folks. I'm sure either way will add up costs for the other half.
 
#21 · (Edited)
Not even considering the added strength of the parts being proposed, there has to at least be some additional interest in the stub axles if they can be made at a reasonable price. By far the most expensive and frustrating part of the 5 lug conversion is sourcing the rare 5 lug stub axles from Australia or Japan. They've generally always been in the $500 +/- a pair range shipped to the US and have always been a royal PITA to obtain. They're pretty much unobtanium these days. However, with those, the rear rotors only need 4 new stud holes drilled and the center hole opened up from 60.1mm to 67.1mm, which doesn't cost much. Nothing else needs changing on the rear. The fronts can be done a few different ways and none are that costly. However, we all know that it's still not an easy process by any means. And that in itself discourages some who would otherwise choose this route.
I chose to go this route a few years ago as there was no longer any decent tires for the OEM wheels. And at the time, the selection of larger diameter 4 lug wheels in appropriate offsets was small and all were quite expensive, even used! The selection of cheap 5 lug wheels was and still is incredible.
If stronger stub axles can be made at a reasonable cost, they surely could be made with a round flange and accommodate any and / or multiple lug patterns. Besides our 4 x 114.3 pattern, 5 x 114.3 (4.5") is not only common to many Toyota's. It's also common on many Ford's, Mopar's and many other vehicles. 5 x 4.75 is used on many GM vehicles. Any other desired pattern could easily be accommodated as well allowing a nearly infinite wheel choice.
I don't know what others would consider a reasonable cost for 5 lug stub axles though. And whether or not there really is much demand for these just to make 5 lug conversions easier could definitely come down to cost. However, my personal opinion is that the extreme rarity and subsequent difficulty sourcing the OEM pieces has always been the biggest deterrent to anyone considering this. It really doesn't matter how many options are available to convert the fronts or how cheaply it can be done if the only real option is adapters on the rear. Very few people consider them to be safe and reliable and for good reason.
I also agree that our diffs could use a cooler as it holds so little fluid and runs so hot. However, my personal preference would be a custom higher capacity cover with more heat sinking capacity vs an external cooler due to the potential for the cooler and / or lines to be damaged from road debris. Unless the diff fluid level and temp were monitored with low level and overtemp warnings, any damage to any external parts would very soon lead to at a minimum serious damage and potentially catastrophic failure. Sure, there's ways to pretty much prevent this. But they all add cost and complexity and sometimes just aren't feasible on otherwise relatively stock vehicles.
Just my 2 Canadian pesos worth concerning the feasibility of having stronger stub axles made and their potential value to the community. While a 5 lug conversion isn't cheap no matter how it's done, I believe the main reason many that would otherwise consider it, decided against it is mostly the near impossibility of and extreme difficulty obtaining the rare rear stub axles and also their cost. However, I believe that the cost was much less of a deterrent than a nearly total lack of availability has always been. As such, cost may not be as big an issue as it has always appeared to be. I'm sure most folks that have ever been interested in a 5 lug conversion for whatever reason very likely gave up after some amount of time for lack of this one absolutely required part. Personally, I'm very glad I chose to go this route and was very lucky to score a set of rear stub axles at the time. It has made finding larger diameter wheels much easier and cheaper.
Potential availability of the other stronger parts for those that need them is great as well. Especially as they would allow using other much more easily available stronger parts in conjunction with them such as the 930 CV's. Anybody with any experience in these areas knows that it's a never ending quest to find the next weak link. This looks like a good way to fix this one area and be done with it to me.
 
#22 · (Edited)
I would be in for both the diff stubs and the axle stubs(in 5 lug variant if possible) I already messaged OP and I'm currently breaking axles on my x73. I have a jz putting down 430/411 as well as a KAAZ 2 way.
I know that there are axle solutions, but I believe the next weak point would be the stub axles (stub hubs, which ever they are called) I'm currently running a set of 5lug hubs that were made from 4lug hubs. I would much rather continue breaking axles than risk breaking my only pair of 5 lug hubs.
This would be the perfect solution I believe to the problem!
 
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