Hello
In the 68/69/70's Porsche racing cars bolts where holow in order to minimise final load on their prototype cars .
On some "factory" cars bolts where hollow "and" titanium material !
Diameter of suspension bolts are linked to diameter of spherical bearings diameter and the thread being installed into the whihsbone welded bushing
A sample ; if you have an 1/2 "spherical bearing and you do not use a reduced diameter ball you need an 1/2" bolt !!! plus 1/2 washer and nut !! these are far too big ( even for a 1500kg car ) specially if you are using hight grade steel bolts. in this case there is absolutly no problem to use reasonably hollowed , Why ?
Because for most of these suspension bolts ( beside the transmision bolts !!) the working load is not at all in torsion but in "perpandicular cut load"
( apologise I don't remind the right english word!!)
For such effort the center " neutral fiber" is not for use because it does not enter in the calculation
So it's better to have a big diameter with a hole than a smaller diameter ; this one being possibly bended much more quickly
Again this is not the case for transmisson bolts ; because they are submited mainly on torsion failure ( this is why Factory Porsches used titanium hollowed due to the very higth tensile and torsion ratio this material carry)
Another sample ; in some aeronautics application the bolts are hollow, not only, but nuts are in aluminium !! They are in place just to tighten the bolt and the arrangement and they do not suffer any lateral load
Torsion or "trench" calculations are different , in the formula's calculation , material thickness is used differently ; this is why ( after considering the situation of that bolt) you can take off the center off these .
But there is an important advise to remember ; those hollow bolts are done very industrially , means the hole is done very clean and not "badly drilled"
so there is no on the inside surface any circular mark that can be the start of crack failure !!!!!!!!!!!!!!!
So using already aero and race hollow bolts YES, but drill your own standard bolts HUMMMMMMM !!! I will not be confident offff !!!!!!!!!!!!!!
Hope this helps ( beside my so bad English !!)
And if you want some more "formula's" information just click on there ( but beware of any head sick LOLLLLLLLLLLLLL!!!!!!!)
https://www.google.fr/search?q=shea...niv&sa=X&ei=FVfDVPbMH8fXavaGgMAC&ved=0CC4QsAQ