1973-1974 RM21 vs RM23

RR Fan Dan · Oct 24, 2025

I was shopping for replacement glass and they had different quarter glass listed for a RM23 Roadrunner. My 1974 is a RM21 Roadrunner with fixed quarter glass. I believe that it is a coupe. My understanding was you could only get roll down quarter glass with power windows. Does roll down glass make a RM23 HT and fixed glass a RM21 Coupe? What is the difference between RM21 and RM23? Confused.

YY1 · Oct 24, 2025

23 is roll down rear windows.

They do not need to be power.

21 is fixed rear windows. That changed through the years, from posts around the door windows and a completely different roofline, to simply different glass and no mechanism.

IIRC "all" 71/72 RRs were 23 body and "all" 73/74 were 21 body.

rm2173! · Oct 27, 2025

I have a 73 roadrunner with fixed rear windows could not find new glass all they had was for rollup window I orderd them anyway if u narrowthe bracket and make it shorter they fit

YY1 · Oct 27, 2025

I have a "rollup conversion" for my "21 body" 73 Satellite.

They are definitely different.

I wonder if the glass could go the other way?

My sedan glass is near perfect, and the glass I got with the mechanisms is scratched up pretty bad in a couple areas.

RR Fan Dan · Oct 27, 2025

rm2173! said:
I have a 73 roadrunner with fixed rear windows could not find new glass all they had was for rollup window I orderd them anyway if u narrowthe bracket and make it shorter they fit

I can’t find the rear qtr glass either. Do you have pictures of how you did this?

YY1 said:
I have a "rollup conversion" for my "21 body" 73 Satellite.

They are definitely different.

I wonder if the glass could go the other way?

My sedan glass is near perfect, and the glass I got with the mechanisms is scratched up pretty bad in a couple areas.

I am having the same problem maybe @rm2173! can show us how he did it,

rm2173! · Oct 28, 2025

i do not have apic but i will take pics tonight

rm2173! · Oct 29, 2025

this is modified bracket to make roll up window work

RR Fan Dan · Oct 29, 2025

rm2173! said:
this is modified bracket to make roll up window work

View attachment 1939437

What did you do to it? Is that picture with the bracket installed? Can you take a picture of the whole window with the mounting holes shown?

rm2173! · Oct 29, 2025

That pic is with bracket installed if u get new windows and see them side by side it will make sense you have to narrow bracket to fit holes in glass and then shorte bracket because holes are higher up in New glass

rm2173! · Oct 29, 2025

If uwant to all me with questions 508 864 7572 mike

1973-1974 RM21 vs RM23

RR Fan Dan

If it ain’t broke, fix it till it is.

YY1

Well-Known Member

rm2173!

Well-Known Member

YY1

Well-Known Member

RR Fan Dan

If it ain’t broke, fix it till it is.

rm2173!

Well-Known Member

rm2173!

Well-Known Member

RR Fan Dan

If it ain’t broke, fix it till it is.

rm2173!

Well-Known Member

rm2173!

Well-Known Member

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