What is the purpose of the hub on a car?

I've been told my hub is going bad and needs to be replace. Of course I will do this but I'm curious how long can I put it off? What is the importance of a hub? Thanks!
Also...
I first found out when I had to replace the struts and the bearings on my car and I did replace them on both sides. All the mechanic said afterward is the hub is going bad. He said I'll know it's bad when my car drives really loud (makes a roaring noise). A month later my tie rod (I kept calling it the tire rod, lol) broke on the passenger, front side of the car. I went to a different mechanic and he said the same thing...just that the hub is going bad and estimated it to be about $250 (this is at Tuffy) to replace (whereas the other place (Midas) said I would be paying around $600)! Now it sounds like from the beginning when my struts were bad, every time a go over even the smallest bump, everything sounds loose. Again, I will get this replaced, I know I can't put it off much longer but no one explained to me what a hub is. Thanks for all the feedback!

2010-10-12T19:27:04Z

The bearings were replaced in the back and I have a Dodge Stratus. Thanks!

justin plainold2010-10-12T18:11:29Z

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a hub is what the wheel attaches to on the front of the car, so all those lug nuts hold the hub on the tire, there are bearings inside the hub, I am giving you a general description of a hub, if your car is front wheel drive (and in the future, it is extremely helpful if you tell is the year make and model of the vehicle) front wheel drive hubs, are set up different, than cars with rear wheel drive. On a rear wheel drive car, the front hub has the brake rotor and the brake caliper attached to the hub, inside the hub are usually two sets of bearings, an inner, and an outer, the inner bearing is usually much bigger, it gets more stress. the hub sits on an axle which is a strong round piece of steel with a nut on the end, the hub slides onto the axle, and then a big nut holds the hub on the axle. It is filled with grease to lube the bearings, and a dust cap is put on the end to keep dust out, and grease in, (this usually pokes through the center of the wheel a inch or so.usually if a hub had been damaged its usually related to the bearings wearing out, and then disintegrating and grinding up everything, you can hear it sounds like something howling, (or roaring) but the howling noise is the bearings grinding themselves into broken pieces. If can eventually if driven long enough, ruin the axle, and heat can cause things to crystallize, and then get brittle and the axle can break, and the wheel will pass you on the freeway. This is however a worse case scenario, and it takes a lot of heat, and abuse to get that far. (the longer a trip, the more heat if things are not rolling right. So it kind of depends on what damage the hub has, (ask the mechanic next time) hope this helps.

clncarplz2010-10-12T18:09:15Z

The hub is a part that has the bearings so the tires can rotate. It will also have the brakes. It really sounds like the brake drum is worn out if they replaced the bearings. The older cars with the drum brakes had this problem while the newer ones with disk brakes simply replace the rotor. If the problem is not the brake part then it might be that where the bearings fit is worn so bad that the bearings are loose & the mechanic should have replaced them at that time.
BTW Midas is know for overcharging & not really fixing the parts that needs to be repaired so you will come back. Did they tell you that their guarantee is only good for that place (& not nation wide)? I had experience of that & was told by another Midas shop to take it back to the Midas shop where it was worked on even if that place was 1,000 miles away! I will never again use midas.

jim t2010-10-12T18:21:07Z

A hub is what sits behind the front or rear wheel and consist of the spindle and bearings if the bearings become dry they will make a roaring noise and eventually seize up causing the wheel to possibly come off I would not let this go for to long due to the fact I had a grand prix do that exact same thing and I remember seeing my wheel go across the highway after the spindle broke, needless to say it did some pretty good damage to my front fender and scared the heck out of me. If you can find someone with basic knowledge of mechanics it's pretty easy to change Chilton makes very good manuals for all makes and models of all cars available at almost any auto parts store and they show you exactly what to do.......good luck

p3200tmz2010-10-12T18:51:34Z

"Hubs" don't go bad. Wheel bearings wear out.

You need to mention what kind of car you have and which bearings were replaced (front or back).

A "hub" would technically refer to the older type of wheel bearings today most commonly found on some Pick-ups and SUVs.

wurze2010-10-13T11:52:02Z

if it's the wheel hub you are talking about, it contains the brakes and sometimes gets grooved inside due to brake pad or disk wear, even when fitting new parts the car still will not handle that well until the new ones have bedded in