I know of one company that produces ROPS for older tractors. The company is:
Saf-T-Cab Inc.
3241 South Parkway Dr.
P.O. Box 2587
Fresno, CA 93745
559-268-5541
You will probably not like the price, retro 4 post for 550 $1921, SAE 2 post $1355.
I assume the high price has a lot to do with liability.
I don&#039;t ever recall seeing a ROPS on an agricultural 550 but some of the 550 backhoe-loaders had over head protection.
There are many good machinists that can fabricate a ROPS much cheaper however most ag safety engineers frown on this practice.<!-- s:( --><img src="{SMILIES_PATH}/icon_sad.gif" alt=":(" title="Sad" /><!-- s:( -->