5x114 to 5x100

[Mt.HOODrat]

hey guys, just an idea i had the other day.

i am currently a second year machine tool technology student at a great machining program. my metallurgy instructor is an old hotrodder and owned his own machine shop for 30 years. in their day it was common practice to redrill bolt patterns for expensive custom wheels for when guys did ford 9'' rearend swaps.

he overheard me talking about how i have 5x100 and wish i could run the sti bbs 5x114. he tells me to get a set and redrill the holes to 5x114. by simply drilling the new bolt hole pattern in the voids between the existing holes. i thought maybe strength was an issue, but a well versed metallurgist ensured me it was not an issue, as many aftermarket aluminium wheels come as universal with eight existing lug holes. this would be cool, cuz then you'd have universal sti BBS's!! 5x100 and 5x114 would be awesome.

he also mentioned a method called "egging" where in differences as small as 7mm radially (about .275''), you can just re drill the existing holes in a smaller bolt circle pattern. not sure how it would look. dont think i would care much. get them re pow coated and you wont notice as much. this sounds like the easier option, but how would that affect the lug nut seat? who knows. i need to have one of these wheels in front of me.

i need some one to post close up pics of the bolt circle pattern on the outside of the wheel and the inside of the wheel contact surface of the bolt hole pattern. so i can plan for tooling, such as the shape of the lug nut seat. i want to try this on a bridgeport knee mill with a digi D.R.O. any input? i could buy a rashed 05 sti wheel for 100 bucks to try it out and see if it fits.

[Mt.HOODrat]

c'mon guys i need some pics and input!! id be willing to do this for people in the nw are provided ive worked it out THOROUGHLY. i think it would be a cool mod, rock bbs's without swapping to sti hubs and shit. wouldnt take me long to do 4. just the painstaking dialing in of dead center of the bolt circle pattern with a dial indicator.

[Mt.HOODrat]

really no one? do i really have to go to nasioc for this? is there really no one interested in this enough to even post a comment?!?

[PhyrraM]

I guess most of us realize that there are plenty of wheels out there without having to go to 5x114.5.

[Florin1]

Hey man. Good luck on your adventure Let me know what you come up with. I dont think you can re drill your stock hubs. I've already tried. See my thread on nasioc. http://forums.nasioc.com/forums/showthr ... ?t=2110667

Also, i have a rashed 05 sti wheel if you wanna buy it. What i ended up doing was buying 5x100 to 5x114.3 spacers, which were a little too wide (popped my wheels out a little too much, looked stupid). So i ended up buying r180 hubs for the rear.

[Mt.HOODrat]

I guess most of us realize that there are plenty of wheels out there without having to go to 5x114.5.

really innovative thinking there....lol
i think it would be awesome to have a set of universal 5x100 5x114 sti bbs.
that would appeal to wrx guys as well. i try to think of services i can offer with my new skills, because im an enthusiast and a machinist trying to make a lil side money. there are tons of used sti bbs sets in the northwest, so i saw a small possibility im now exploring.
i guess i like to put my hands on things and create, to show my buddies and say "yeah, i built that shit"

and i dont mean to re drill the hub. the wheel itself. and would in fact be interested in your rashed wheel, if its reasonable price. pm me i want to get this going, epecially now since there is an obvious lack of interest.

[asotwavb]

If you've got the knowledge, tools, and ambition, why not? Seems like a plausible idea. I know a guy up at my apartment with a set of these wheels. I would be more than happy to get my digital camera and tripod out and snap some close ups. Might not be for a week or so.

-William

[Mt.HOODrat]

would be helpful, post some when you can, it'll probably be before i am able to obtain one.

but yeah, Florin, i dont care if its rashed, just cant be bent. i was going to say id come get it, but im right on the southern border of washington. bout 4 hours away i think. maybe ship it to me? if you can, snap close up pictures of the lug circle pattern on the outside of the wheel and the inside contact surface. id appreciate it a ton, this might be do-able.

[Florin1]

Pm'd you before i read your last post. Lol. The one i offered is indeed bent. I actually have 2 sets of 05 sti wheels. (dont ask) .I actually have 2 bent ones, both still held air in the tires, and 2 or 3 rashed ones, and the rest in very good condition. I'll get you some pix soon. I can actually get cell pix asap, but dont know how clear they need to be. Also, do you want me to put a tape measure in front of it? I'll pm u my number and just shoot me a text, and i can send pix straight to your phone.

[Mt.HOODrat]

rashed is fine, it just cant be bent, it wouldnt sit 100% flush on the table, therefor couldnt assume the turret head is dead parallel to the bolt holes.

and yeah if you could just take pics of the hole circle pattern on the outside and the inside that would be cool. dont need to be crystal clear, i just want to see the surfaces i will be drilling, like what the lug nut seats look like, and what the inside contact surface of the wheel looks like as well. i pm'd you my number, text me some pics if you could.

[PhyrraM]

really innovative thinking there....lol

Nope. You asked why no response. I gave one possible reason.

[Mt.HOODrat]

ok.... thanks for your input....

[Apex3]

I guess most of us realize that there are plenty of wheels out there without having to go to 5x114.5.

really innovative thinking there....lol
i think it would be awesome to have a set of universal 5x100 5x114 sti bbs.
that would appeal to wrx guys as well. i try to think of services i can offer with my new skills, because im an enthusiast and a machinist trying to make a lil side money. there are tons of used sti bbs sets in the northwest, so i saw a small possibility im now exploring.
i guess i like to put my hands on things and create, to show my buddies and say "yeah, i built that shit"

and i dont mean to re drill the hub. the wheel itself. and would in fact be interested in your rashed wheel, if its reasonable price. pm me i want to get this going, epecially now since there is an obvious lack of interest.

A lot of people aren't interested because it's sketchy. VW guys do it all the time, but the wheels are designed to be drilled a certain way, by redrilling you're taking out rigidity from the wheel, especially if you don't fill the old holes in, which is what is normally done when wheels are redrilled.

As for STi wheels, I don't see it being worth it if you're planning to sell, they aren't going to be worth more for the aforementioned reason, most of the time people redrill because the wheels either don't come in the bolt pattern they need or they already have them and want to put them on their car.

[Mt.HOODrat]

it's actually not sketchy at all if you put a drawing of the wheel into a solid works program to stress test it I think you'd find that extra holes do not take much structural integrity away from the wheel . It's sketchy if you do not understand what you're doing. if you have a general understanding of how aluminum reacts to stress, not at all . I guarantee a stock steely is nowhere near as rigid as a bbs even with the extra holes. 3k lbs distributed between 4 wheels, 750 per wheel.150 lbs per lug. I'm sure there are much greater forces applied when actually driving, and I'm sure that this a very crude calculation, but my point is that I really don't think strength is an issue. my metallurgist instructor who worked as such for alcoa aluminum for 25 years agrees.

I never intended to sell the wheels I just wanted to sell the service of machining the wheels . if it worked out . just been throwing around ideas quite a bit could actually use some side paper. I know the idea isn't completely practical, but if people gave up everytime there were already parts available or something sounded sketchy, tuning and
hot rodding wouldnt be much fun.
thanks for the input guys I'm trying to scrounge up money to purchase a single wheel from florin , so I can do some actual stress testing once I actually drill the holes. I plan to find out how much tensile force it takes to pull a wheel stud and nut through hole, and how much torsional force it takes to force a stud to displace the material between the bolt holes. I will bet the wheel studs will shear before the wheel fractures but we will see. If these tests are reassuring then I will purchase a full set to redrill.

[Apex3]

It's more about fracture from hitting potholes/curbs, not so much actual driving. A stock steelie isn't as strong, but it's aslso not gonna break if you hit something.

And yea selling the service you probably could make some money.

[Florin1]

So I take it you got the pix then?

[Legacy777]

He is right....a lot of aftermarket wheels have two sets of bolt holes....including mine.

http://main.experiencetherave.com/subar ... P_6601.JPG
http://main.experiencetherave.com/subar ... P_6603.JPG

I just like this pic
http://main.experiencetherave.com/subar ... P_6630.JPG

[Apex3]

He is right....a lot of aftermarket wheels have two sets of bolt holes....including mine.

http://main.experiencetherave.com/subar ... P_6601.JPG
http://main.experiencetherave.com/subar ... P_6603.JPG

I just like this pic
http://main.experiencetherave.com/subar ... P_6630.JPG

I am aware, but those are designed to have two sets of holes, these are not.

[Legacy777]

I am aware, but those are designed to have two sets of holes, these are not.

I agree, but if someone has the ability and skills I'm sure they can model/review those wheels and determine whether from an engineering point of view if they are ok to drill additional holes.

[Apex3]

I am aware, but those are designed to have two sets of holes, these are not.

I agree, but if someone has the ability and skills I'm sure they can model/review those wheels and determine whether from an engineering point of view if they are ok to drill additional holes.

Agreed, but a second year machining student does not have that ability.

I dunno, do it, I'm sure it'll be fine if you don't plan on hitting any curbs, but I wouldn't personally, at least without filling in the old holes.

[Legacy777]

Agreed, but a second year machining student does not have that ability.

I dunno, do it, I'm sure it'll be fine if you don't plan on hitting any curbs, but I wouldn't personally, at least without filling in the old holes.

Agreed

[93forestpearl]

Filling in the old holes on the STi BBS would be a bad idea unless you plan on getting the wheels heat treated, which would be quite expensive. Welding on an aluminum alloy anneals the material and you lose a lot of its strength. Even powder coating wheels at too high of a temperature can cause problems.



As far as modeling the stress on the wheel itself and more notably the hub face of the wheel, there are MANY other factors other than static weight of the car to account for. Cornering introduces massive bending moments into the equation. This assumes a perfectly smooth road. Add in some bumps during cornering and the forces multiply, possibly by an exponential amount. Throw in some weight transfer and these kinds of things get interesting real quick, and guessing at these numbers is extremely difficult, if not impossible unless you have intimate experience with this.


As far as redrilling brake rotors goes, it is much easier and safer. The forces are only tangential to the edge of the rotor so there are no bending moments. A friend of mine have been running some on his STi swapped GC Impreza for many years without issue. (full STi drivetrain with SVX backing plates and redrilled SVX rotors for small brakes)



I hope this helps.

[skid542]

MtHoodRat - I'm not going to tell you which way you should go as there is plenty of evidence to say that this could work but there are also a lot of factors that need to be considered when making this type of change.

However, since you're new to the BBS I figured it might be worth noting that several of the people providing input on this subject are not only degreed engineers, but intelligent and good engineers - Josh, Dan, myself and likely others (sorry guys, Josh and Dan were the only ones to come to mind but I know we have a lot more geeks on the BBS).

Personally I have spent two years doing stress analysis on primary (think main spars) and secondary aluminum aircraft structure (I own an AOE degree). All under FAA oversight and authoritity - so I know a couple things about aluminum...

From that I would issue two very distinct words of caution.

First - don't trust FEA analysis blindly. There is a very good reason the FAA and several governing bodies does not trust FEA except under very prescribed conditions. FEA is an extremely powerful tool but it requires the operator to design the model correctly. This is only truly accomplished if the engineer fully understands the stresses going into the model and how they interact. Without a full understanding of stress analysis you will not be able to accurately read the results or even have an accurate model.

Second - Fatigue, fatigue, fatigue, fatigue!! Nobody has directly mentioned this yet. Static strength is rarely the cause of failure in structural systems. It's fatigue. When it comes to alum. that's not only fatigue due to stress cycling but also corrosion. A wheel gets stress cycled alot. If you look at your SN curves it's not difficult to imagine a rim getting cycled enough to really place it out there in terms of acceptable stress. This is very true when you make any comparisons to a steel rim. A steel rim is not as stiff, but it doesn't have to be as stiff to keep local stress levels down due to fatigue concerns. There is a large difference in fatigue life of brittle materials vs. ductile materials.


I don't want to be a nesayer or tell you not to pursue this or even say it won't work. Don't get me wrong, the BBS is built off innovation and doing things outside the box. I'm just saying you should be very aware of what you are doing. Rims have changed a lot over the years in an effort to make them lighter, and more importantly cheaper. This is done by minimizing material usage and consequently there may not be as much beef as there used to be on old wheels or wheels explicitly designed for multiple lug patterns.

You probably know these things and have heard them before, but I'm saying them again because you don't want a wheel to fall off unexpected driving down the road .



Hopefully this helps a little too.

[Florin1]

And this is what happens when an aluminum wheel fails at high speed.
http://www.streetfire.net/video/officia ... 228593.htm

Although i don't think we need to worry about a subaru going this fast. (Crash happens in the second half of the video)

[xise]

old thread I know...just wondering why no one mentioned that 04 STi BBSs are 5x100 and would bolt right up