pressure of 75 pounds the strain gauge of the sae no 2 apparatus measured the torque as a deflection of a pointer high brake chatter compositions gave a series of wide deflections whereas compositions of low brake chatter gave essentially no deflection to the pointer satisfactory compositions are those giving less than 5 mm of deflection the above described test was run on a noncompounded midcontinent paraffin based mineral oil citcon 350 n the deflection was 36 mm indicating a very high brake chatter lubricant then sufficient alkane 1 2 diol to give a concentration of 1 5 by weight and comprising about equal weights of pentadecane 1 2 diol hexadecane 1 2 diol heptadecane 1 2 diol and octadecane 1 2 diol was added to this base oil the resulting composition gave a 2 mm deflection to the torque gauge of the above apparatus indicating no noticeable brake chatter a hydrocarbon oil composed of 75 parts of the base stock of example 1 and 25 parts of a similar but lower viscosity oil citcon 200 n was compounded with about 4 of a conventional lubricating oil additive package containing dispersants detergents zinc ep agents and hydroxyesters this compounded oil was then tested in the modified sae no 2 apparatus the results are given in table i then various blends of alkane 1 2 diols were added to the compounded oil in the indicated quantities table i and these were also tested in the same apparatus the results are given in table i table i______________________________________effect of alkane 1 2 diols uponlaboratory brake chatter simulationrun maximum deflection mm sup 1 no alkane 1 2 diol at 40 pounds at 75 pounds______________________________________1 none sup.