Textar has launched a conical adapter ring set to help workshops improve runout measurements when working on vehicles.

To prevent brake judder, every brake repair should include a check of whether the runout of the brake disc is within the vehicle manufacturer’s tolerances. Even small deviations, such as 0.05mm, can lead to vibrations that cause noise and/or brake judder.

Most garages are aware of this and therefore routinely measure runout. Nevertheless, the proportion of motorists who complain about juddering brakes is relatively high. Measurement errors are often the reason for this and even the most precise runout gauge cannot provide accurate values if the disc behaves differently during measurement and driving. This is because of how the brake disc fits on the hub; after all, the hub is only fixed in place by the mounted wheel. However, the wheel must be dismantled for the runout measurement.

If the wheel bolts are screwed in without the rim, they are almost always too long to provide a firm hold. Garages often use nuts as spacers but this solution has two disadvantages: firstly, most wheel bolts have a conical collar so a uniform holding force cannot be applied even when tightened crosswise and, secondly, the contact surface of the disc bell can be damaged when using steel nuts. The first of these two disadvantages in particular can be enough to provide an unrealistic measurement result with low tolerances.

Textar now offers a solution that is simple and reliable in the form of conical adapter rings which serve as both spacers and holders for the wheel bolt collar.

Thomas Beier, Junior Product Manager at TMD Friction, said, “During our test series with our adapter rings, we found that when the brake disc is bolted crosswise and a torque of 80 Nm is applied, meaningful measurement values are obtained. During measurement, the brake disc then behaves as if it were being held by the wheel. It’s an efficient option that garages can use to offer the highest level of assembly quality.”