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I am trying to find this bolt size to use  with a 4 lug to wide 5 adapter

M14x35mm fine /counter sunk / allen wrench drive

That combination provides me with a flat surface on my  adapters that allows me to run drumskins or Fuchs on my car. Currently I have studs and nuts that protrude beyond the surface.

Stan, helpful as always, found me a source for the combination adapters and bolts in Italy.

I contacted them to confirm bolt size. Instead of saying yes or no as to whether they were providing the bolts I needed in the kit, pretty simple to measure the bolt, they sent me four pictures to translate on my own.

Could somebody with more knowledge than me (that means a lot of you) tell me if, based on these photos, theses are the right bolts? Clearly they are countersink, allen drive, but I need to know if they are the right size.

Thanks,bolt size 2bolt size 3bolt size 4bolt sizebot size 4





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As a reference, this is what I am trying to get to. I imagine I could go to a 40mm length as I don't think the length of the bolt interferes with the brake. I mmay also be able to get the bolts from England and not mess with buying the whole kit, as I have the adapters already.

In the example below, the guy could only find M14 / coarse bolts so he had everything machined to fit. 425863


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Last edited by Panhandle Bob

OK, Lessee.  It took me a while to figure out what measurement basis he was using (English or metric) and then do some calcs:

12mm = .472"

14mm = .551"

So, from the photos, and I'm reading the bottom scale of the caliper which I'm assuming is in centimeters, from the "zero", not the end of the sliding rail - top photo to bottom:

Top Photo, head flare depth:  .8cm = 8mm = .315"  (about 5/16" )  Don't know the angle.

2'nd Photo: thread length:  2.6cm = 26mm = 1.02" 

A 4-bolt hub, VW wheel bolt has .75" or about 20mm of thread for the steel wheel thickness but it's a hex head on top of the flare cone - Slight apples and oranges, there so I went with the threaded shaft length measurement for both. 

3'rd photo, head flare diameter:  2.7cm = 27mm = 1.06"

4'th photo "Image not found"

5'th photo, thread diameter =  1.4cm = 14mm = .551"  

It looks like a 1.5 pitch thread, the same as a VW - that is not a "fine" thread.  I just measured a VW wheel bolt and it's a 1.5 pitch, and my VW wheel bolts are 14mm (.551").


I would buy 'em from the UK or Italian places.  I just did a quick look on my usual three sites (McMaster, Fastenal and Tri-State) and came up with Bupka in that size/shape/pitch.  I remember looking for bolts similar to those in the US a while back and gave up, taking a different route (but my spacers are 1-1/4" thick, giving me those options). 

12.9 bolts for that application is fine.  Get the 25mm length, if you can, but as you say, there's nothing back there to interfere with them if they're a tad longer (and you can always shorten them with a cut-off wheel).

BTW, the overall bolt length (above) is 2.6cm (bolt) + .8cm (flare) = 3.4cm = 34mm so maybe they're specifying a 35mm bolt overall length given the thickness of their adapter metal.  Be careful on that.

So, my advice to get it right the first time, is to take an existing wheel bolt that you're replacing to a mechanic or a machine shop and ask them what it is for size, pitch and length and order that.


Last edited by Gordon Nichols

If it makes you feel any better, I ended up grinding off much of the hex cap from all of my wheel bolts to then be flush with the surface of the adapter ring.  That left about 3/16" of the original hex cap - just enough to get on it with a socket to tighten them up to 80 ft. lbs...   For attaching the Fuchs rims I went with studs through the adapters - Wasn't about to go through all that nonsense, again.......

Sometimes "Hokiness" is required to make things work.

The English at that place: not so good. I corresponded for about a month on an A-arm suspension, just trying to get a wheel travel spec. I finally gave up.

I think that adapter and those bolts are going to work. My concern with ordering the bolts from the UK is that the adapter ring will likely not have the proper angle chamfer, since metric chamfers are also different than SAE. Getting your adapters remachined will likely cost more than the whole Italian set-up.

Last edited by Stan Galat

I have a tap and die set that has 12mm x 1.5mm and 1.75mm, so hence the fine and coarse thread definitions. I prefer to just write the actual size to totally eliminate any confusion. VW/Porsche indeed use both 12mm and 14mm, both in 1.5mm pitch.

I'd buy the bolts only and have a local machine shop chamfer your adapters.

A complete new front wide five disc brake kit is only $380 (-- to $500 for others)  (and that doesn't appear to be Empi product).  It would be a sure fix and 2 hour job.  You could sell the old 4 lug front disc parts for $100 on CL to offset some of cost. You'd have new calipers, rotors, bearing and hose then.


Image result for vw wide five front disc brakes


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  • blobid0

X2 for the AC disk brake kit.   And pads are 1990s VW rabbit, so easy future maintenance.  Call SoCal auto parts... they know our cars, work w/ all builders, can tell you what you need.

a few more $$$, but not much more than the bolts you found.

i debated the 4 to 5 stuff conversion for a while... grad I did!  Lots posted on “how to” and “lessons learned”.  I can look for my old cheat sheets/ what I posted if you are interested.


Last edited by Lfepardo

The 1 criticism about the AC Industries wide 5 kit- the rotor/hub assembly is really (I mean really!) heavy (the thing is 1 big hunk of cast iron), and if you're concerned at all about how your car performs you want to be using lighter suspension/brake components, not heavier. l don't know anything about their fit and finish, but CB Performance makes 2 ball joint, wide 5 disc brake kits (standard height, lowered) with aluminum hubs-

@Lfepardo- what else did you find in your research?

Last edited by ALB

$1200? Double that cash and you're near to my setup. They aren't the absolute lightest, CB and CSP take that prize. But I submit my Airkewld setup will out-brake anyone else. On the road or even on the track, with no fade, ever.

I can't even process how much unsprung weight you carry with those big cast iron AC Industries hub/rotors. Isn't the whole point of our cars performance and light weight combined?

Best investments so far on my car: Airkewld brakes, Vintage 190 wheels, and homemade front anti-sway bar. You see how they all have to do with braking and handling and lighter weight?

Don't know if this has been addressed, but if you do swap the front brakes, you usually have to swap spindles. The 4 lug discs use Karmann Ghia disc spindles, and you'll need ball-joint drum spindles for almost every wide5 disc conversion.

@DannyP's right- weight is so important if you're looking to get the most out of your car!

"I can't even process how much unsprung weight you carry with those big cast iron AC Industries hub/rotors. Isn't the whole point of our cars performance and light weight combined?"

I got a close look at an ACI hub/rotor over at a friend's place and couldn't believe how heavy they were. Remember, any added weight to the car not only affects braking/handling, it affects acceleration as well. 

"Best investments so far on my car: Airkewld brakes, Vintage 190 wheels, and homemade front anti-sway bar. You see how they all have to do with braking and handling and lighter weight?"

Hey, you're building the car to be fun, right? A few prudent choices just make it that much more fun.

Danny- on the front did you go with the 2 piston cast, 2 piston Wilwood or 4 piston Wilwood calipers? Did you look at the Coolstop Brakes at all? 

Do you know what the Airkewld brakes weigh? Kevin Zagar told me his front brakes weigh 47 vs 53 lbs (iIrc) for Karmann Ghia disc assemblies. Al (and sorry Bob for the thread drift...)

I've got 4 piston Wilwood calipers in the front. The calipers are aluminum and very light.

The rear uses the same Varga caliper with ebrake as everyone else. In my opinion the rears are way too heavy, and I'd like to find a lighter caliper solution.

I changed the front pads to a Wilwood compound that works for street and track, with a wider heat range. Pretty sure it's Polymatrix Q which has has some ceramic in it.

I don't know the weight of each corner. The spindles are the same and the caliper brackets should be very close in weight. I know the CSP have very light hubs, and next lightest would be CB, then Airkewld. The SoCal ones have to be 10 pounds more each at least. I would assume the rotors are all around the same weight, it's the calipers and hubs that can pay dividends in weight-saving.


for my driving style- cruising ( not spirited or track)- my criteria was narrowed to:

- using the Vintage 190 wheels ( lighter that Cip1 steel wheels)

- improved braking.

- simplest modification possible... no adjustments to beam or rear swing axle set ups.  Keep wheel spacing unchanged in car.

- wife imposed budget of 1000$.

So after getting the back spacing/ weight specks/pricing for the Vintage wheels I collected the same information /offset impact of CSP, Airkwell, CB, AC disk kits... and did the math.

- AC kit was heaviest, with true 0 offset impact to existing wheel position in car, and when combined with Vintage wheels had a small weight net-net improvement.. of -2lbs as compared to the original combined system ( wheels, brakes).  And taking advantage of sales over 3 months total set up was $1100 (2015$-2016$ base year dollars) including SS lines, CB aluminum brake covers, baby moons, wheel studs,  etc...

- all other disk kits  had an offset impact of 1/2”-7/8” ( moving wheels out).  They all had a great net- net weight improvement of +4lbs or better, but pricing was 50%-100% higher.

Final result- great braking  improvement, no net net weight gain, easy simple install, and cheaper than the alternatives.  I also siped the tires, which further improved braking distance and tire wear.

... the airkwell and CSP kits are awesome, if performance is key!

This truly is a madess.

Last edited by Lfepardo
Lfepardo posted:


....i debated the 4 to 5 stuff conversion for a while... grad I did!  Lots posted on “how to” and “lessons learned”.  I can look for my old cheat sheets/ what I posted if you are interested.

Any info on the pros and cons of each kit will be useful to someone. Please post all the info you have (if you can find it). Al

@Stan Galat and @DannyP- you guys are right, of course; what's right for 1 isn't for another.

@Panhandle Bob- And we were having so much fun spending your money!

Enjoy the rest of the day every one! Al

Pretty much any Wide5 front kit uses ball joint drum spindles. It's going to be a bare minimum of 1/4" to 3/8" wider PER SIDE as the caliper bracket mounts to the face of the spindle, where the drum brake backing plate was. Then you have the complication of the big, wide wheel mounting area on the hub which happens to be where the caliper goes. 

I ended up at at least 3/8" per side, but more like 3/4". The 2" narrowed beam in my car really pays off here as the wheels are where they should be with respect to the fenders.

Louis(LFepardo), is that your first name? It's Airkewld not airkwell

Best of luck to you Bob in your quest.

Yes... sorry for all the typos... been typing from my cell... fat fingers!,, , killing time while daughter auditions for the Nutcracker. ( she is into ballet, and at 11 this would be her 3rd yr in the Pacific NorthWest Ballet production.  Unfortunately/fortunately she is over 5ft tall, so her roles as a minor and non-professional dancer are limited.   This may be the year she learns the lesson on getting cut from a team. ;-(

will dig up the info per ALs request.



Last edited by Lfepardo

I hate to dig up the deep dark past but does anyone have a supplier for the m14 by 1.5 countersunk bolts. Part number really anything. 

I am running adapters in the front on my 550 spyder so I can use a 4 lug set of widened wheels with slicks for the track and the 5 lug wheels on the street. I am pretty much stuck right now short of machining a new adapter with more common threading or grinding down a set of lug nuts which would be unsafe. 


not sure of all the specifics you are looking for, and the length.  Vintage Motorcars would be a good resource- always best to give them a call. They are very helpful.

here are some links... with multiple lengths from 40mm to 100mm... in shiny or black colors.

M14- 1.5, multiple lengths:

M14 to fit in a 1.5:

M14-1.5, 45mm long:

vintage motorcars web: https://www.vintagemotorcarsin...product/wheel-studs/


Put studs on the 4 lugs and got the shortest grade 10.9 bolts I could. Cut the excess off above the head. Sticks out about 15mm. Since the covers are aluminum I just stretched them out. There is a small dent on the cover now but honestly even I have a hard time seeing it from more then 5 feet back.


So now I am back in wiring hell. Tried to use the supplied harness which is a universal and there are way to many circuits and wires in the harness. Going to pull it all out and make my own with the bare minimum of wires. Will make it easier to diagnosis at the track and find issues

Last edited by wearymicrobe

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