For most individuals, changing a tire means taking out the nuts holding down the present tire, eradicating the tire, mounting the brand new tire, after which re-tightening the lug nuts. These nuts are essential for securing the tire to the wheel hub; utilizing the improper torque and failing to tighten them appropriately are widespread errors individuals make when altering tires. Nevertheless, an rising variety of automobiles at present wouldn’t have these lug nuts; as an alternative, they use lug bolts, which each connect the wheel to the hub and in addition safe it in place.
Lug nuts seem to be a neater, foolproof technique, so why the swap? A giant a part of the reply is geography. German manufacturers like Audi, BMW, Volkswagen, and Mercedes-Benz, and different European marques have relied on lug bolts for many years. With their platforms being offered globally, which means Individuals typically find yourself with automobiles constructed to European engineering requirements, just like the now-discontinued Mercedes-based Chrysler Crossfire. The primary benefit with bolts is that it lets automakers skip urgent steel into the hub in the course of the meeting course of, thereby decreasing the variety of components within the wheel system. It would seem to be a small distinction, nevertheless it provides up for tens of millions of automobiles.
Other than shaving off some manufacturing assets, some engineers argue that lug bolts might present extra constant clamping pressure by creating a decent connection. The additional stability and wheel steadiness matter once you’re going quick at limitless autobahn speeds. Nonetheless, it is a trade-off: because the wheel must be held in place whereas the bolts are began, it may be tougher for the typical driver or mechanic to deal with.
Lug bolts generally is a ache, however there are methods to mitigate it
The primary headache with lug bolts turns into clear once you cease for a roadside tire change. With studs, you merely slide the wheel onto the rods and spin on the nuts, however bolts imply that the wheel must be held in place when you line up the holes and thread the primary bolt. Think about having to do this within the rain or on the shoulder of the interstate — not enjoyable. In some circumstances, the brake rotor itself may also shift when the wheel is eliminated, which implies you might must align each the rotor and the wheel earlier than the bolts can go in.
You’ll be able to resolve a few of these issues should you use a information pin or alignment software that comes within the manufacturing facility toolkits of some automobiles, like BMW. This small threaded rod screws into the hub briefly, letting the wheel grasp on it when you begin the bolts, basically recreating the comfort of studs. Whereas not as handy, some hubs and wheels even have matching grooves or dowels to assist seat the wheel correctly earlier than placing within the bolts.
In the event you’re an fanatic commonly swapping wheels, there are aftermarket stud conversion kits. These add everlasting studs to a hub initially designed for bolts, which makes wheel modifications faster and reduces the chance of cross-threading (and ruining) the hub’s inside threads. Specialist suppliers like BimmerWorld and ECS Tuning market these kits for BMW and Audi automobiles.
