Why Five?
- Thread starter 5Runner
- Start date
5Runner
Adventurer
A quote from your thread in the first few sentences...
I guess I am not the only one to wonder this!
Thanks!
4Rescue
Expedition Leader
I've always thought of my 1St Gen Tunner as a "Mini Cruiser" this just proves it for me...
I'm willing to bet the increase in diameter of the studs is nearly the exact same as the smaller/6 Lugs... Each lug is able to hold so much force so either you make'm bigger or you use more of them. Although you could say to some degree having 6-Lugs gives just that much more saftey margin sould it be a nut failure/loss rather then a stud breakage
. Clearly 100's are plenty tough though so I think Toyota knew what they were doing... I'm pretty sure ny Mini-truck with early gen IFS is Hub-centric... although now that I'm thinking about it... I could be wrong.Cheers
DAve
Last edited:
ntsqd
Heretic Car Camper
Not in the slightest. Can't realistically get those here, so they do not exist in my book.Does this 5 lug LC change that theory
There is a LOT more to a bolt circle than just the size of the fastener. The radial distance of the fastener from the center of the hub is actually more of a factor than the size (within reason) of the fastener. A small increase in that radial distance is a huge change in torque transmission ability and a decrease in the leverage that the tire has against the stud.
AND the thing to always keep in mind is the surprisingly low amount of tractive force that the tire can generate even in the most ideal circumstances. 0.5 is a good cF for this situation, which means that a 50/50 distributed 10,000 lbs. vehicle can only put 1250 lbs worth of lateral force on any one corner before the tire slides. This is arm-waving, rough numbers, but it puts things in perspective.
Tucan viajero
Adventurer
The real reason is strength.
We have seen many cases of stud breakage particularly in 80 series vehicles. So many in fact, that we consider this, together with sector shaft breakage and exhaust pipe failure, one of the main problem areas of this model.
The problem with the 80 series studs breaking is so bad that I have seen dealers in Venezuela and Paraguay warning customers to tighten them only with torque wrenches.
Having five 14mm studs arranged in a 150mm PCD results in a much stronger assembly than 6 12mm studs in a 139.7mm PCD.
4Rescue
Expedition Leader
You said exactly what I was thinking and couldn't figure out HOW to say. One thing that I keep coming back to is that a stud needs sheer-strength due to a sort of "coast" and "load" side to the studs as they mount to the wheel. The larger diameter studs would have a greater shear-strenth so I'm sure 5 of them is as good as the smaller diam 6-studs...
Tucan V. I'm interested to hear this. We ran (in Australia) a few 80's along with the 45 ute and 75/76 Troupies and Utes ( :drool: ) with 6-6lugs and to say we abused those truck would be an understatement. WE were certainly carefull about not overtightening, but we changed wheels/tire combo's frequently for different uses. Never had an issue with any of them. Well except I tried to stash one in my suitcase to bring home.... It didin't fit, kinda like when a snake swallows a rat.... you could clearly see I had a large truck in my bag. Or maybe I just put my bag in the truck...Either way I failed
HAHAHAHAHAHAHA
ntsqd
Heretic Car Camper
Assuming that the lug nut is properly tight the stud isn't in shear at all. It provides a clamping force to hold the wheel's center to the wheel hub. The friction created by that clamping force is far, far stronger than the shear strength of the studs could ever be.
Think about a flywheel bolted to the rear of a crankshaft and why it is so important to torque those bolts exactly right. There is no way that those bolts could hold the engine's torque on pure shear strength alone. The only freeway speeds capable vehicle engine that I know of that drives the flywheel mostly by shear strength are air cooled VW's.
That the 80 lug studs are failing tells me that people are using too long of a tool to tighten them with. Going tighter is not the solution to failing wheel studs, it is a cause of that. You can yield a bolt or stud slightly and it will recover ("elastic deformation") or you can go further and stretch it beyond it's ability to recover ("plastic deformation"). Every elastic event is a fatigue life issue (it will only do it so many times before failing), but one plastic event results in a junk bolt or stud.
I always tighten lug nuts with the tool that I keep in the vehicle for changing to the spare.
Think about a flywheel bolted to the rear of a crankshaft and why it is so important to torque those bolts exactly right. There is no way that those bolts could hold the engine's torque on pure shear strength alone. The only freeway speeds capable vehicle engine that I know of that drives the flywheel mostly by shear strength are air cooled VW's.
That the 80 lug studs are failing tells me that people are using too long of a tool to tighten them with. Going tighter is not the solution to failing wheel studs, it is a cause of that. You can yield a bolt or stud slightly and it will recover ("elastic deformation") or you can go further and stretch it beyond it's ability to recover ("plastic deformation"). Every elastic event is a fatigue life issue (it will only do it so many times before failing), but one plastic event results in a junk bolt or stud.
I always tighten lug nuts with the tool that I keep in the vehicle for changing to the spare.
Tucan viajero
Adventurer
Precisely. The problem here is that for many people the tighter the better. Maybe out of fear that if they don't tighten them as hard as possible the wheels will fall off.
But the matter complicates further if we consider that undertightening the nuts can also lead to stud failure. This becomes a possibility when you stress the notion that the nuts should not be overtightened.
Which is why the recommendation to always tighten the nuts to the correct specification using a torque wrench makes so much sense and is the best way to solve the problem.
Last edited:
cruiser guy
Explorer
Nothing against mechanics in Latin America but in the five years we spent in Guatemala it got to the point where I would not let them touch my truck (even for an oil change which they do VERY inexpensively) because everything they tightened had to be "tight" to the point when I needed to check my diff oil I couldn't remove the fill plug. I rounded it off with the 24mm socket and a big breaker bar and that didn't work. I eventually welded a long length of steel to the bolt and broke it free that way. In my humble opinion, the mechanic put the bolt in just a little too tight! I don't recall seeing too many torque wrenches in my time down there other than the one in my possession.