Hi, new to the forum, been riding since I was 8, have owned 5 Kawy's one CR, and a KTM.
I just bought a 2005 KX 125 and need to replace the front axle nut. Does anyone use titanium nuts and bolts on their bikes? Or is aluminum a better metal type to use?

 

A titanium nut would cost twice as much as a steel or aluminum one. Steel is least expensive and can take a beating that aluminum couldn't, it will last as long as titanium and cost about half as much. The only way titanium is good use is if you are using enough to matter. One nut isn't worth the cost. All it would really do is allow you to brag that you saved a few ounces on an axle nut. I'd buy a steel replacement and spend the extra money on something of more benefit. I did a quick check, if you can get the right 18mm thread nut the titanium one would cost around $20, where the OEM nut costs around $10 depending on where it was bought.

If you buy a titanium or any other kind of nut do not buy a locking nut with the metal tabs, the tabs can embed in the axle and not come off. You have to cut it off. Yamaha used that kind of locking nut on some of their bikes and in some cases the lock tabs bed into the axle requiring the nut be cut off. I replaced my axle nut with a steel nylock nut (the kind with the nylon insert.

do not buy one of these

If you buy a locking nut buy one of these


Or buy a plain flange nut.