settypeblocksize does not change the textwidth

I'm new on using the memoir documentclass and I've been trying to implement a page layout with a large side margin, so I can have margin notes and margin figures, but I've been trying to create an environment that, for specific pages, I get rid of this margin. The code is as following:

\LoadClass[twoside, 11pt]{memoir}

\setstocksize{11in}{8.5in}
\settrims{0pt}{0pt}
\settypeblocksize{7.5in}{4.3in}{*}
\setlrmargins{1.5cm}{*}{*}
\setmarginnotes{20pt}{6.2cm}{0pt}

\checkandfixthelayout[nearest]

\newenvironment{fullwidth}{%
\settrims{0pt}{0pt}
\settypeblocksize{7.5in}{6in}{*}
\setlrmargins{3.2cm}{*}{*}
\setmarginnotes{0.01pt}{0.01pt}{0pt}

\checkandfixthelayout[nearest]
}{%
\settrims{0pt}{0pt}
\settypeblocksize{7.5in}{4.3in}{*}
\setlrmargins{1.5cm}{*}{*}
\setmarginnotes{20pt}{6.2cm}{0pt}

\checkandfixthelayout
}


It seems to work well, since the layout —visualized using \usepackage[showframe,pass]{geometry}— gets changed propertly, but the textwidth does not. How can I solve this issue?

• Note that that env will not work as you cannot change the page layout mid page. May 7 at 13:38

As @daleif says you can't change the layout mid page, but perhaps memoir's adjustwidth environment is what you can use.

% textwidthprob.tex  SE 643343

\documentclass[letterpaper]{memoir}

\usepackage{lipsum}

\begin{document}
\lipsum[1]

%%% reduce local margins by 1cm and 2cm
%%% (increases local textwidth by 3cm)

The adjustwidth environment can cross page boundaries.