According to the firm that I had research and draw the Reider coat of arms:
Province of the Rhine and Bavaria. Created a noble of the Holy Roman Empire, 24th November 1760.
Arms: Per fesse, 1st, argent, St. Martin and a horse statant, all proper;
2nd, bendy of eight argent and azure, over all three annulets interlaced fessways or.
Crest: Issuing from a crown or, a horse sable, bridled gules.