How much pressure is normal to be put onto the SMC to move it forward enough...? Maybe my grip strength at that stretch sucks, but I can't fully "close" (retract, plunge, activate) the SMC with one hand, but if I add my second hand lightly, it's easy. I tried the one-person method but truly my left hand cant fully "activate" the SMC so my test is somewhat worthless.
I just went out and tried it for you.
Here is how I did it;
The bottom of the SMC piston is flat and is a perfect place to apply force in the correct direction. While lying on the floor next to the motorcycle, I push up on this flat spot with the thumb of my right hand while rotating the wheel by applying force against the tire with my right foot.
As a point of reference, this is being done by pushing with my thumb only. Using other parts of the hand, such as the palm for example, would allow applying much greater forces.
The result;
- The SMC just STARTS to move with very little force applied. There is no discernible brake application at this point, the SMC has just STARTED to move.
- The rear wheel becomes difficult to rotate with what I would refer to as moderate force.
- The rear wheel is locked at what I would call high force.
I always find answers like the above to be of only limited value. Is what I call moderate force roughly the same as what you call moderate force? Maybe I have been a brick layer for 30 years and have extremely strong hands while someone else has been sitting at a desk all of their life and has the same hand strength as my five-foot nothing wife. To negate this variable to some degree, I did this test a second time using a force gauge so I could measure the actual force that I was applying so as to give you some real numbers to compare against. I have a force gauge, so this was easy for me to do. How you will measure the force that you are applying so that you can compare your test results against mine is, unfortunately, a problem that you will have to sort out.
If you have no other means, you can always push your thumb against your bathroom scale to at least have an idea of what each level of force feels like.
If you desperately want actual numbers and you have no other option, and if you have someone to help you, you can actually use your bathroom scale with a piece of wood to push against the SMC. As silly as this sounds, the bathroom scale measures the same forces that a force gauge does, just not as easily or as precisely.
The result measured by a force gauge;
- The SMC just STARTS to move with about 7 Lbs. force applied. It may have begun a little sooner. It is to hard to tell without actually measuring the movement, but this gives you a good idea.
- The rear brake begins to apply with about 20 Lbs. force applied. I determined this by the change in the sound of the pads rubbing against the disc, so not scientific.
- The rear wheel is noticeably more difficult to rotate with 25 Lbs. force applied.
- The rear wheel is very difficult to rotate with 30 Lbs. force applied.
- The rear wheel can barely be moved with 35 Lbs. force applied.
- The rear wheel can not be rotated with 40 Lbs. force applied.
Keep in mind that the above is far from scientific because I have no idea how much force I am applying against the tire with my foot, and my foot has not been calibrated against your foot to ensure equal force is being applied in both of our tests. This is just to give you a more tangible idea of the forces required.
A couple of notes:
- As a point of reference, the forces being applied when the motorcycle is in motion and the brakes are applied will be much higher than this, and so will be the rear braking force.
- I have never read of this test being done before, and this is the first time that I have done it. As such, I have no idea if the results that I obtained are good, bad, or in the normal range.
And don't forget;
*** CAUTION ***
When you are performing this test it is possible to push on the SMC hard enough to push the motorcycle forward enough to allow the centre-stand up to fold up. This could result in the motorcycle falling on you. For safety, chock the front wheel and/or strap the centre-stand to the front wheel to make sure that it can not fold up on you during the test.
