How to Measure Spring Eye Bushing Diameters

Showing an easy way to measure what size spring eye bushing will fit a particular spring. This is a common question we get from our customers.

Using a dial caliper, it's easy to measure the thickness of the main leaf in the spring pack along with the outer diameter of the spring eye you want to size a bushing for. From the outer diameter, subtract 2 times the leaf thickness and that will be the inner diameter of the spring eye. Round that number to the nearest standard size bushing for that type of leaf spring. For the Toyota pickup, 4Runner, T100, Tacoma, Hilux, Hilux Surf models those diameters are 30mm, 36mm and 40mm.

Realize that you may have different spring eye diameters on each end of the spring. Also, with the ability to swap springs between various Toyota models, you can't just go by a chart, it pays to measure and confirm the size bushing(s) you need. On the above vehicles, spring hanger bushings are typically all 30mm outer diameter and either a width equal to the spring eye or wider than the spring eye.

For other vehicle makes, you'll have different diameter spring eye and shackle hanger bushings. This same technique will work for obtaining the measurement but realize that the bushings may be sized in imperial units.

Also, do not get hung up on getting the dimensions to 0.01mm or 0.001". You just need to get within a few mm or 16ths of an inch in order to choose between common bushing sizes for your vehicle.

Dial calipers:
https://amzn.to/3EfTob5
https://www.harborfreight.com/hand-tools/measuring-marking/calipers-micrometer/calipers.html

Web page link for more information:
https://www.4crawler.com/4x4/ForSale/Shackles.shtml

Photo album with more information:
https://photos.app.goo.gl/2nZceJMFsYMzvoyq5