The reason the employer match is always pre-tax is because the employer is the one getting the tax deduction for that part, not you. If you go with Roth you pay more taxes, but that doesn't mean your employer wants to pay more taxes.
As it has been noted, the true max is $53,000. This includes up to 18k pre-tax/roth from you, the employer match, any profit sharing, and after-tax contributions.
I'm eligible for a pre-tax contribution rate, an after-tax contribution rate, and a Roth Contribution rate.
What I'm about to tell you about is very rare, but it is worth asking about. Some companies, I know Google is on the list, will allow you to contribute to the "after-tax" portion, and then later convert that to the Roth portion all within the 401(k)!!! Even if you can't do that you can contribute to after-tax now, and then when you roll it into an IRA you can roll the after-tax portion into a Roth IRA. That means you can contribute the full 53k(including the employer match) and then later roll all of it into IRAs(trad+roth).
If that sounds too good to be true, it is. Whether you could roll after-tax money into a Roth was a long standing question. Investment firms, 401(k) providers, and most CPAs assumed no, but the IRS didn't specifically say that. Then in 2014 the IRS said you could. I don't think they realize what they were doing at the time, but they effectively increased the tax advantaged limit on a 401(k) to $53,000!!! :D
Downside to this: if your company doesn't let you do it within the 401k then you have to wait till you leave to complete the rollover. The IRS could change it before you leave/retire.