Greetings from Munich!

My son just hit his license and was driving my 914 this evening with me as passenger. He grinned 1st gear about 4-5 times. I never grind it but have had the habit since I was a kid with my 2nd 914 and still have today with ANY car I drive with a manual transmission, to shift into another gear first and only thereafter into first.

My son asked me why that works to prevent grinding when putting the car into first and I couldn't answer it definitively.

After looking online to no avail, here I am posting here in hopes of getting an explanation.

Thanks!

With best regards,

Mike, and Nicholas, in Munich

It stops some bits from turning. Someone else will surely explain it better, but that's the nutshell.

So the gear sets are always engaged, and they spin freely on the shafts. When you select a gear, you move a thing that effectively locks one gear to its shaft. But if the shaft is spinning and the gear is not, there are some bits that have to speed the gear up to whatever speed the shaft is turning.

Those bits are the synchros. They wear quickly, especially on 1st gear if the clutch is not adjusted correctly. (When the clutch disk is always dragging on the flywheel the shaft never stops turning, meaning more work for the synchros to do.)

Note that the locking of the gear to the shaft happens no matter if the clutch is engaged or disengaged.

If you put the transmission in 3rd, you have made sure the 3rd gear and the shaft are spinning the same RPM. Then you take it out of 3rd, but the shaft is still spinning for a little while. That means that the 1st gear which is still spinning is closer in RPM to the shaft. Less work for the synchros on 1st to do, so ones that are worn but still sort of working can work well enough to keep the grind from happening.

The above skips some things, and oversimplifies others, but it should convey the general idea.

--DD

Dave always over-simplifies everything.



Kidding of course, and exactly the follow-up I hoped for.

awesome! Thanks Dave!!

M.i.M.