I am racing an EVO 9 and have had 2 rear hub failures in the last 2 races. The first one lasted 2 seasons and the second broke right away. The car is in stock config 350HP, Cusco 1.5 diff. Any thoughts?

 

something unusual going on, stock hubs should never break at 350 hp, even if they're old and abused. Assuming these are stock hubs. Is wheel width and offset stock or modified? Extreme width/offset away from stock can cause issues with stock hubs.

A little more info might help, where exactly are they breaking? Do you have any pics?

Are you changing the wheel studs or anything? Sometimes when you pound studs out and put new ones in it stresses the hub. Other than that I know of no common issues.

Just make sure everything else the hub is bolted to and contacts is straight and in good condition. A bent knuckle could be stressing the hub when it's bolted.

Put some anti-seize on all the threads except the wheel lugs, also put some anti seize on the axle splines. As I've said elsewhere the 160 ft-lbs axle nut torque spec should be maximum. If the cotter pin holes don't line up at 160 back the nut off to line up, don't tighten more.

 

Wheel are 9 inch and fit under the stock fender. I run Hoosier R6 racing compound. The breakage is at the radius where the hub flange and stub axle come together. I have longer wheel studs which were drwn in using a socket and lugnut, not a press or hammer. A slightly bent knuckle should not effect the hub if the camber, caster and toe are correct. Have you ever seen a bent knuckle that was not damaged by an accident?
I guess I will try being very careful when I torque the axle nut.

 

If the tire/wheel fits in the stock fender you would think it would be okay.

Why the longer studs? If it's because of spacers those could be the issue, changing the way the hub is loaded.

Have never seen a knuckle bend other than in a crash. Was thinking the bolt up surface where the hub mounts could be bent and bending the hub when it bolts, but it's breaking on the rotating flange 1/2 of the hub so that can't be it.

so it's breaking right behind the wheel flange?

pulling in studs with the threads is the best way, shouldn't cause any problem.

to get any further a pic might help, otherwise you need to find someone local with an engineering/racing background and give a hands on diagnosis.

 

Thanks man . Maybe it is just bad luck. 3rd time's a charm.

 

try again, personally i dont own an evo and a friend of mine who owns a 2g dsm broke his rear hub under launch stress and when we further investigated the bolts holding the hub/spindle to the knuckle was slightly oversized which caused more stress on the hub just my .02

 

I had that problem on my 2nd gen dsm.. No problem on the evo..

 

x2 Post some pic's of your setup, I'll see if I can give some $0.02

Unless you already fixed the issue.

 

Thats your best bet, whats the tq spec on that?