2
$\begingroup$

There seems to be a very strong trend of the number of wheel lugs on cars and trucks increasing over time. For instance, many small cars in the 80s used 4 lugs, but have since switched to 5 (e.g., Honda Civic, Volkswagen Golf).

More stark examples can be seen in trucks. Consider the M35 series of trucks used by the US Army. The standard model weighs nearly 13,000 lbs empty, and is capable of carrying a load of around 5000 lbs. Its wheels use 6 lugs. (See top photo)

The latest version of the Ford F-150, a truck weighing about 4500 lbs with payloads in the 1500-3000 lb range, now has 6 lugs. (See center photo)

Meanwhile, a vehicle more comparable in weight and cargo specs to the M35 is the Ford F-550. It has a Gross Vehicle Weight Rating of 17,500-19,500 lb range. It uses 10 lugs per wheel. (See bottom photo)

Photo collage of an M35 variant, a 2017 F-150, and a 2017 F-550. (credits: Wikipedia & ford.com)

So why the lug inflation? This answer states "To some extent, the number of bolt studs depends on the anticipated torque on the wheel." While it's true that engine output and braking power have increased over the years, have they really increased enough to merit a 66% increase in the number of lugs in this example?

$\endgroup$
2
  • $\begingroup$ I'd speculate part of the picture is the proliferation of power tools. I'm sure in the field in WWII they were mostly fastened with hand tools. $\endgroup$
    – agentp
    Aug 22 '17 at 13:34
  • $\begingroup$ The number of fixings used is governed by the load / size etc not the advent of power tools : just look at the number of bolts on steam boilers etc when air guns or electric wrenches were not available... $\endgroup$
    – Solar Mike
    Aug 23 '17 at 8:51
3
$\begingroup$

As the diameter and width have increased so has the number of fixing points. Also, as many manufacturers use the same wheels across models then having the same fixings reduces component numbers...

Also, the type of wheel and its material have changed, older wheels tended to be thicker and could therefore use fewer studs.

$\endgroup$
1
  • $\begingroup$ And it's probably safer to drive with one of the nuts missing now than before. $\endgroup$ Sep 21 '17 at 13:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.