Q: What would make me want to buy a Bench-Pro over any other tester on the market?

A: Just about every aspect of our Bench-Pro tester is different than any other tester on the market. In the beginning there were two main categories that we wanted to improve upon. The first and most important is accuracy. The two main factors causing inaccuracy are friction and deflection. We incorporated a linear roller bearing on the base main shaft which has a very low coefficient of friction and also allowed us to hold a close .0015" fit. Figure 1 below shows an exaggerated example of why the tolerance on the bearing is crucial to the overall accuracy. If a spring would stay square as it was compressed this would not be a great issue, but you won't find many springs that do.  When the spring is compressed it will load one side of the spring perch more than the other side thus causing the perch to go out of square. Most testers measure the height out on the edge of the perch, this only multiplies the problem. The example shows a shaft to bearing clearance of .020", by the time this clearance travels out to where it is measured you have an height measurement error of .046". Remember that the example below is exaggerated but it shows you how a little turns into a lot.  Lets just say for instance you had only a .020" error, on a typical roller cam spring this would be a ±13 lb error meaning that two springs that are actually the same could show a 26 lb spread.

 Another improvement is that we have added a needle thrust bearing on the spring perch allowing it to rotate freely. On most other testers the perch is fixed solid where it cannot turn at all. We have found this to cause error also. Springs have a tendency to rotate as they are compressed and if they are not allowed to do so they will bind thus causing an invalid reading.

Q: Why the lever design instead of the standard rack & pinion or screw type ?

A: This gets into the second major category of improvement. We wanted to make something easier and faster to use. The rack & pinion design is good but it has several drawbacks, one being the handle is never in the right spot to obtain good leverage.  We found the screw type very cumbersome and time consuming. After trying several different designs we ended up going with the lever type actuator. The first advantage is that the handle lever is always in the right spot to get the most leverage. The second advantage is that the leverage ratio starts out at around 9.0:1 and ends up at about 32.0:1. This means that the more you compress the spring the more leverage you gain. This makes it nice for checking the open pressure on those big ones.

Q: Dimensionally what is the biggest spring the Bench-Pro will accept ?

A: We designed the tester to accommodate all passenger car and light duty truck springs including aftermarket racing springs. The max spring dims are 3-7/16 x 1.750.

Q: Does the dial indicator and bracket come with the tester or do I have to purchase it separate ?

A: Yes, the unit ships complete with indicator and bracket.

Q: Do you make a left handed version ?

A: The testers are universal. They can be changed from right to left in a matter of seconds.

If you have any other questions please don't hesitate to ask.