I have had tough time this year. It's my last year of the PhD and my main supervisor has been largely unavailable. He had some personal issues but he also seemed avoidant of supervising me and almost stalling the whole PhD process. He knows how keen I am to submit by the end of the year. Keep in mind that he has been nearly perfect the first 2 years of my candidature. I am his first PhD student.

My second supervisor, who I barely see thinks that I should submit at the end of the year. She is a very experienced academic with tons of PhD students. The problem is that she can't understand 90% of my PhD due to highly specialized mathsy content. So she can't really judge how well my thesis is written. She is just there to offer some general guidance.

I haven't published anything from my PhD yet but I plan 2 papers from it. My main supervisor thinks that I should wait until after I submit to work on them. So no part of my thesis has been examined.

I have written up everything except for my last chapter. All my other chapters have been through 2-3 iterations with my main supervisor.

My second supervisor and me are now pushing my main supervisor to get things into shape for submission in a few months. He is STILL dragging his heels. He is not sure what standard of thesis is "good enough" and keeps saying that if I submit when I plan to, I am taking a gamble.

Of course, I am worried that I will submit and spectacularly fail. I am not sure whose advice to listen to. I am inclined to want to submit sooner, rather than later.

Thoughts?

Follow the advice of your main supervisor. Try to be patient.

I also advise you to wait and follow the advice of the main supervisor. Your main supervisor knows its topic better than the secondary supervisor.

I echo thoughts above. There is no rush to submit in three years and it's normal to write papers between submission and viva.