Front wheel stud weakness?

[Mighty Quinn]

So I’m switching my “forward dated” 69 coupe (from previous owner) back to an rsr clone because they had cut open fenders for flares which subsequently burned off in a fire.

So I bought 11x15 and 11x9 maxilites and rubber. New flares, yada yada yada.

I’m new to Porsche’s so I was unaware that the aluminum spacers on the rear had to come off. I panicked when the wheels stuck out a mile. Obviously the old turbo look car didn’t have turbo width wheels.

After fighting and swearing with 50 year old rear wheel spacers I moved onto the fronts for spacer removal. I quickly realized you don’t remove those spacers because of the smaller bolts holding it on.

Here comes my question

I understand the smaller bolts on the front are because there’s only rotational force, no torque loading like the rear (less stresses involved) but wouldn’t it be better to eliminate the spacer, run more wheel and tire and have the front wheels on full size studs, not big studs connected by smaller bolts.

Is my idea counter productive, and wasted in effort because there’s no need to strengthen that area. Maybe this isn’t a weak point that I’m staring at.

Can someone set me straight and can anyone tell me if mods like I suggest have taken place?

[Flojo]

Originally Posted by Mighty Quinn

.. I moved onto the fronts for spacer removal. I quickly realized you don’t remove those spacers because of the smaller bolts holding it on.

Better to show a picture of what you're talking about.

I couldn't really follow and believe you confound the hub to be a spacer which is not.

[Mighty Quinn]

Here are the rear spacers I removed to fit the 11” wheels. The fronts look the same but for the inner mounting bolts being smaller than the wheel studs.

I call them spacers and I realize that’s the wrong phrase but my manual doesn’t really specify what that part is called. It just shows an exploded view and names all other parts surrounding it. Need a better manual.

[911pcars]

To review:
- your ‘69 chassis had F/R turbo flares, but they were destroyed by fire.

- you want to replace with Turbo flares.
- the car has wide F/R wheel adapters to accept Turbo width wheels/tires
- you have sourced wide F/R 17” wheels/ tires.

If the new wheels were designed to fit the factory-stock hubs, then you must assume they were constructed with the correct wheel offset to fill “turbo flares”. Best to confirm. Of course, it’s also possible you ordered turbo wheels to fit a factory turbo body, in which case the wheel offsets will be different and won’t match a non-turbo ‘69 chassis w/o spacers.

Your question (I think) deals with the spacer/adapters. Typically, the factory lug studs must be long enough to accept a plain spacer + the wheel and still have enough length to ensure full thread contact with the lugnut. However, in order to space the wheels further out, a wider spacer must have separate mounting areas, one set of 14mm holes to attach the adapter onto the hub and a set of 14mm lug studs to mount the wheel onto the adapter.

Wide wheel aapters for both front and rear should have the same 14mm mounting holes/studs as shown in your rear adapters.

It goes without saying you should fit the flares to the body with the wheels/tires in place. That about it? Suggest perusing the archives to review other potential interference issues (oil line, body and fender, ride height, etc.).

Sherwood

[stownsen914]

I call those "adapters" not spacers. They have a place, but personally I would not prefer them, as all the forces from the suspension and the drivetrain are put through these adapters, instead of from the hubs directly to the wheels. That might be fine for a street car, but for track or any aggressive driving I wouldn't use them. (In fact, some clubs explicitly disallow this style of adapter.) Long studs and traditional wheel spacers have their own limitations, but within reason I'd prefer them. Or better yet, get wheels that have offset use standard length wheel studs.

[Mighty Quinn]

Pcars, here’s my flares after I reinstalled new ones. I actually didn’t fit the flares to the wheels, I fit the flares to the rear bumper. If you have a good quality bumper and it’s fitted right, the flares will have all sorts of landmarks from the bumper that indicate the right place for them to land. Ignore the ride height for now, this pic is just to show how my rsr turbo flares worked with removing the adapters and runnin* an 11 wheel

I’m guessing it was a turbo look car but they didn’t run 11” wheels with -27 offset. That would explain the factory adapters, or spacers, or whatever

It’s the adapter on the fronts that looks weaker than the rear because of those smaller mounting bolts. Not the big studs like on the rear.

I’m assuming because stownsen914 also doesn’t like the smaller studs on the front that I’m right as well in thinking that’s an area that could be engineered better.

[Trackrash]

Those spacers should be bolted to the original wheel studs which are 14mm in the front.

Show us a pic of what you have on the front of your car.

[Mighty Quinn]

Rather than pull my front wheel of for photos, I stole a pair of images that are exactly what I have on my front setup.

One picture is the hub, ready to slip over a spindle.
The other pic shows the adapter/spacer wit the small 1/4” bolt holes to mount to the actual hub.

This is what bothers me, my front wheels being held on by 1/4” bolts.

So as the previous gentlemen in this thread stated, some clubs forbid this part from being on race courses. Can anyone else lend in to what I’m curious about here and hat he’s saying?

I used to be a deep sea tuna fisherman so everything was engineered double to keep us safe way offshore. I’m just looking at this part and wondering how strong it really is.

Porsche was an engineer. I’m not so maybe I’m overthinking this.

[Trackrash]

The hubs you are showing have no spacers. The wheel studs are 14mm which is VERY robust for these cars. The smaller holes, which are 8mm, are to mount the brake disc.

[sandiego]

The 1/4” holes in top photo are used to mount the brake rotor to the hub not the spacer or wheel. The studs in this photo go out the other side and are used to mount a spacer or wheel.

[Mighty Quinn]

Guys guys guys, I’m not in dispute that there’s no spacers, just a front hub

What I’m arguing about is that the front hub with very robust 14mm studs is only hanging on by 8mm studs!

Isn’t that a weak point?

My misuse of the word spacer has led to confusion.

I just want to talk about those 8mm bolts for the from hubs.

Big studs being held on by an equal number of bolts but half their strength concerns me.

But like I said....I am not dr porsche

[911pcars]

If your front wheel adapters attach to those M8 rotor bolts, ditch them and source the correct style adapter. Plan on increased maintenance of the wheel bearings.

[Mighty Quinn]

Awesome answer pcars, just the direction I wanted to be steered in. Thanks

So I’m not just sourcing the right adapter but I’ll also be sourcing the right brake rotor too? Any leads on where to find the adapters new?

[stownsen914]

You may have realized by now that the hub isn’t hanging on the 8mm bolts. The rotors attach there. The hub mounts on the wheels bearings to the strut spindle, and the wheels attach to the hub with those 14mm studs as you’ve seen. No dependency on the 8mm bolts.

[Bill Douglas]

Adapters can be used as spacers if you remove the studs. Then use suitably long studs on your hub that go trough the adapter.

[sandiego]

Your photos are not of what you actually have on the car. Look on your car to see if you already have a brake rotor. If so you dont need to source one. If you do have a rotor then you wont see any 1/4” holes, just studs sticking out.
Longer studs can be sourced to accommodate most combinations of spacer and rim offset.