The Spike Gear deals 45% of melee damage done to the wearer at to the player who dealt the damage.
Below is a damage table. On the left damage done. On the right, damage reflected by the Spike Gear.
The Corrupt X Wings reflect 25% of damage done to the player wearing it, so combining the Corrupt X Wings with the Spike Gear will allow you to reflect 70% damage back to the player hitting you. Assuming you have lots of food, this can make outlasting the opponent very easy because there is no way he can hurt you without greatly hurting himself.
Keep in mind that you cannot rely on the Spike Gear + Corrupt X Wings build without actually fighting the other player, because in any event they'll still be able to kill you before the gear kills them.
Theoretically combining the Spike Gear, Sawblade and Shield can be extraordinarily effective because if a player hits you he may actually receive more damage than he inflicts as the Sawblade always inflicts a solid 5 damage points on players who hit you.