6 "lug" conversion, yee haw!

tim_81coupe · Post by **tim_81coupe** » Wed Jun 07, 2006 7:56 pm

OK guys I'm starting this thread as my first step towards fitting new Hilux steelies to my MY wagon. I am going to be changing my stud pattern from the unique 4X140 to the common 6X140 (or 6X139.7 if you want to be smart).

My intended goal with this project is to fit a brand spanking new set of steel 16" wheels to my wagon, and fit some nice rubber too. The wagon will also be undergoing various suspension modifications at the same time, starting with a 4" lift kit and random L series parts. The major concern I have with the stud pattern change is regarding the safety of it. Realistically there's enough information out there for me to go and spend some time with a drill and get a result, but I want this done right.

I have always kept an eye on people who've done this swap. As far as I can tell it originated in the US of A, and the USMB is full of people who've done it. The reason I am posting this here though is because I want people to honestly tell me if something is going to be dodgy or not. Plus I trust you lot :P.

My plan is to start the same as everyone else: whack out two opposing studs. From there I'm going to mark the centres of the new holes using a wheel, and double checking these points mathematically (easy because I have CAD). Next I'm going to have these holes drilled in an engineering shop, and the material behind faced exactly parallel to the front. I don't want the new studs to sit one iota out of line.
From there I'll have the old holes welded up, and it's here that things get tricky. Because the hub is a cast item, simply welding it will cause stress fractures within the material. I beleive the standard process to stop this is to heat up the hub, can anyone verify this?
Final step will obviously be to fit the new studs and then the wheels. I'm thinking 225/75R16 BFG Muddies, although I'm not entirely sure.

There will be a fair bit of guard trimming and structural reinforcement to go with all of this too.

The two main pieces of reference I've been looking over in regards to this are:

SubaruBrat.com's Guide
and
Phizinza's Guide

Both of these guides are along similar lines, and both bring a smile to my face when I see the end results. However both send a chill up my spine, and it's this I want to avoid when doing my hubs.

Thoughts?

PeeJay · Post by **PeeJay** » Wed Jun 07, 2006 8:04 pm

Is there any structual reason why the extra holes need welding up? Since you are going from 4 to 6 studs I would have thought the wheel itself with the 2 extra anchor points would be more than enough bracing to make up for 2 small holes. I would have thought welding would weaken the whole hub which the wheel would not be able to compensate for.

tim_81coupe · Post by **tim_81coupe** » Wed Jun 07, 2006 8:09 pm

It's not so much a structural issue as it is a balance issue. I don't like the idea of having a hub thats not radially symmetric.

BaronVonChickenPants · Post by **BaronVonChickenPants** » Wed Jun 07, 2006 8:23 pm

I have emailed Scott at subarubrat.com about this, he said with the ER27, 30-odd inch tyres and some serious abuse he hasn't noticed any cracking or deterioration of the hubs....BUT Wild horse and me were discussing this method and he approached an engineer about it, the engineer said he would not recommend it because you have to drill through and grind off 2 of the 4 reinforcement sections on the rear of the wheel face, you'll know what I mean as soon as you look at it.

I know this doesn't help as I've given you 1 for and 1 against but at least you're a little more informed now.

Jordan.

waggaclint · Post by **waggaclint** » Wed Jun 07, 2006 8:24 pm

it all looks pretty straight forward it should be safer really with two extra studs

smoov · Post by **smoov** » Wed Jun 07, 2006 8:39 pm

call me crazy, but i'd be happier to modify the wheels rather than the hubs.

or get 15" 4x140 wheels...but that defies cost efficiency that is mostly the primary reason we love the subaru...

is there any chance of getting remanufactured hubs?

MUDRAT · Post by **MUDRAT** » Wed Jun 07, 2006 9:40 pm

Hmmmm . . . this is interesting.

On one hand, the manner in which you plan to do this is probably the best way to go about it. I'm pretty sure you could normalise the hub after welding it, the same with the brake drums, but I'm not sure how much this will cost. I think you're sure on the right track.

On the other hand, modifying the wheels would probably prove cheaper (if you could find a shop to do it) and in the end may be stronger - the trick is finding the shop to do it.

225/75/16 are big tires.

bluesteel · Post by **bluesteel** » Wed Jun 07, 2006 11:16 pm

i have done the 6 stud hub drilling (hand drill through a spare wheel and go for it) this is not the best way to do it and it needed to tack weld the back of some of the studs to make sure they stay there

ive put the monsterwagon through some decent abuse.. even some decent highway speeds.

i dont have any cracking yet and nothing feels off balance (even with muddies on 8O )

i havent put many k's on them yet tho, probvably never will

so far i feel pretty safe with them, more worried about something ive overlooked and not tightened properly

if you do it, definately go a proper drill press or get a pro to do it. the perfect size drill and a nice vertical press will make the job so much easier and better

- oh and its running 30x9.5x15 muds

bluesteel · Post by **bluesteel** » Wed Jun 07, 2006 11:26 pm

Phizinza just did a nice write up of how to do it this

http://webmaster.beverleypaine.com/6stu ... rsion.html

gives you a good visual if your contemplating it

steptoe · Post by **steptoe** » Wed Jun 07, 2006 11:48 pm

Bluesteel has covered concerns I meant to raise with you last Saturday. When reading of these six stud conversions I was not sure if those guys were just off roading (and wouldn't notice minor vibrations) or if this backyard engineering would show up imbalances at highway speeds. Looking inside a rear drum , you sort of imagine six holes and what they have to sit in...thinks bodgy...

tim_81coupe · Post by **tim_81coupe** » Wed Jun 07, 2006 11:55 pm

bluesteel wrote:Phizinza just did a nice write up of how to do it this

http://webmaster.beverleypaine.com/6stu ... rsion.html

gives you a good visual if your contemplating it

I did quote Phizinza's page in my initial post.

Yes Baron and Jono, I have seen the inside of the rear drum and I've just realised my mistake in my first post..... vehicle will be running rear discs.

There will be considerable horsepower on one end and considerable load on the other, I'm getting worried just thinking about it. One more mistake I've made too, the tyre size I'm looking at is 235/70R16. That's just under 30".

seagull · Post by **seagull** » Thu Jun 08, 2006 12:46 am

welding will make the metal very hard to drill

what gear box are you running ,mmm may be you have this on you listing I have a look .

BlackMale · Post by **BlackMale** » Thu Jun 08, 2006 10:33 am

Tim I fear that you will kill us all

mattims · Post by **mattims** » Thu Jun 08, 2006 3:34 pm

try and keep to the topic jaffa.. im pretty sure we all know tims going to kill us all. Its just not really related to to the wheels..

just jokes tim.

chriSTIan · Post by **chriSTIan** » Thu Jun 08, 2006 10:08 pm

Tim
You can always get the weld x rayed ,that way you'll know for sure if its all ok in there.

stinky · Post by **stinky** » Fri Jun 09, 2006 8:21 am

I'm probably going to attack it from the other angle and drill the rims. I'm just not 100% what offset etc I should be asking for @ the wreckers.

I've heard Nissan Navarra offset bandied around, but also Toyota.

MUDRAT · Post by **MUDRAT** » Fri Jun 09, 2006 9:02 am

The Navara 16s would be pretty close I'd think, as with the skinny wheels that 90-series Prado came out with.

Why 16s by the way? Choice of small chunky tires is better with 15s.

stinky · Post by **stinky** » Fri Jun 09, 2006 1:45 pm

no ... I want 15s! where did you get 16 from? Ideally I'll just get a set of 15" steelies ( like the sunnies ) of the correct offset and drill them out. I don't mind how far they stick out I'll just do some ghetto guards.

mattims · Post by **mattims** » Fri Jun 09, 2006 1:49 pm

the correct offset has more benefits than just stopping the wheel sticking out past the guard. If the offset is incorrect you will get alot more feedback through the steering wheel and any wheel vibrations will be amplified. Also you will find that it tends to wear out the steering components quicker with the incorrect offset. And it does quite badly affect how the car responds when you hit a bump or pothole.

but thats just my experience, if its an offroad car then its probably not that much of a concern (i run desert rats with the wrong offset on my offroader and there fine for that, i just wouldnt want them on a daily driver)

vidler · Post by **vidler** » Fri Jun 09, 2006 7:32 pm

ive recently been experimenting with welding hardened material, remember that cv i sheared at romeo road ages ago??? well ive welded that back together, but im yet to test it in my car so im not sure if it will hold up.

You would need to preheat to around 250 deg and keep it hot while welding, then slow cool it by burying it in sand or wrapping tightly with a hessian bag etc. as for cracking etc, i can do a dye penetrant test, its just a simple way of looking fro cracks on the surface, involves 2 spray cans...

and the other thing you have to worry about if welding up the holes is applying uneven stress on the hub, which could warp it slightly. in my point of view, its more effort than its worth