I got a set of 348wheels for my 84 Mondial (hooray) I measured the bolt in the old wheel and the new wheel and calculated that the new bolt should be 58mm on the shaft (cone edge to end) The 348 bolts are listed as 55mm. A thread said that I should have 6 good turns which I do on my old wheels but dont think I would have on the 348 bolts, is this and issue? Your opinions would be most welcome before I spend anymore hard earned cash. cheers Frank
Is your stock situation exactly 6 turns or more than 6 turns (like 7~8 turns)? IMO what you want is full thread engagement over the thickness of the hub flange + ~2 mm more to account for any end chamfer/shape. If you work this backwards and assume the hub flange is 10mm thick at 1.5 mm pitch you get 6 2/3 turns -- which quasi-matches your 6 turn min reference, so no room to fudge even further under that IMO (if your flange is 10mm thick -- but having only 6 turns of 1.5 mm pitch into a 10mm thick hub flange doesn't thrill me). Can't Paul Hill (Sponsor -- Hill Engineering) provide the extra length you need for about the same cost as the stock length 348 lugbolts? You don't have a better source than Hill Engineering do you?
I had a hell of a time with the people that supplied my New Rims for my 328. The stock bolts were not onlt going to be too short but their heads would not fit into the holes they drilled in the blanks with the 108 pcd required for the car, or if they would the socket would not fit in there to tighten it up. They found slimmer heads but alas the same length. After much pressure from me for them to provide a solution, they machined the tapered base back thereby lengthening the shank. Does anyone think this is dangerous ? I keep wondering if the machining has left microscopic score marks that could act as stress risers and allow the bolt heads to snap off like one would score and cut glass.. Back to the topic, I'ts my understanding that a bolt must seat as deep as the thickness of the shank to achieve full strength. ie a 10mm bolt should seat 10mm deep. Skin
On the other hand, you don't want bolts that are too long. Look at bolt holes in your hubs, specifically, insert a screwdriver through the bolt holes. You will find that the holes bottom out not too far behind the end of the hole. If your bolt is too long, you will hit bottom and you'll think you've tightened the wheel, but it will still be loose on the hub. You must measure the depth of the holes in the hub very carefully, both to get minimum depth but also for maximum as well. Then, insert your bolts in the rim and determine the projection. You want to slightly exceed the min. but not reach the max. I have an '84 Mondi also, so ask me how I know. Regards, Steve
My bolts currently do 6 1/4 turns exactly. Good point about the maximum, I hadnt thought that the holes might be blind but assumed they would go through a plate. I will check the max depth with a screwdriver verses the dimension of the original bolt shaft.
Frank, If you are doing 6 1/4 turns, it sounds like you are fine. Torque the bolts to 72 lbs/ft. and you're in business. Steve
I'm probably just over-estimating your hub flange thickness (and the rears might be less than the fronts -- my TR front lugbolt is just under 8 turns of engagement). So if your original question is can you drop down to 4 turns (6mm total engagement length) on a 14mm lugbolt -- still sounds not too good to me -- JMO.
On the 328 the holes dont bottom out but pass right through the hub and a too long bolt will hit the rotor.. Skin.
