How do people grind gears?

[Avery4]

I never have been able to figure out how people grind gears when shifting improperly since I thought the synchronizers were designed to not allow the gear to engage if the gear speeds aren't matched up, but somehow some people still grind when shifting.

There have been a few times I have accidentally attempted to shift without the clutch fully disengaged, once or twice I have even accidentally tried to engage 1st gear while stopped without using the clutch. Never any grinding though, it just wouldn't go into gear and I quickly realized my mistake and pushed the clutch with no damage done and no grinding.

The only thing I can think of is maybe some people try to force it into gear without the clutch fully disengaged they may grind it, but other than that I just don't understand how people do it and I wouldn't know about forcing it into gear since I never did that.

If someone could explain to me how people manage to grind I would appreciate it since that is something I am genuinely curious about. Thanks in advance!

 

[UncleDave]

Sometimes its talent - releasing the clutch before engagement is one I see in newbys.

Sometimes synchros wear out, this happened to my buddies porsche 928

Sometimes a hard fast 1-2 buzzes before engaging.

Sometimes clutch wear causes it (this is less common in the era of juice clutches, old cable clutches needed adjustment)

Other gearboxes have odd "personalities" like you cant shift into reverse without shifting into 1st gear prior without a buzz. (buddies jeep ploughing snow did this)

 

[PF52]

As the old saying goes: "If you can't find 'em, grind 'em!"

 

[Dave Sherman]

I've ground them in the MG if it's a little slow in a shift and my foot overtakes my hand before it's fully in the next gear. Reverse gears are usually not synchronized, so it's easy to grind reverse if you haven't fully stopped.

 

[sk_pete]

yeah, reverse is super easy to grind.

 

[JeffKeryk]

Very carefully...

 

[PimTac]

I have to laugh when I hear a newer car (last twenty years or so) getting its gears ground. The modern clutch and manual transmission is so easy to shift.

Now go back to the days of old with stiff clutches and non synchronized gears.

 

[Duffyjr]

The first vehicle I drove with a clutch was a 1939 ford pickup. You learned to keep a slight pressure on the shifter (with clutch in for me, the old guy I worked with could shift it without the clutch) and it would go into gear once the rpm's let it.

 

[PF52]

Reverse gears are usually not synchronized, so it's easy to grind reverse if you haven't fully stopped.

I used to have an S-10 pickup.... Even while stopped, I had to wait several seconds after pressing in the clutch before I could shift into Reverse. I quickly got used to and and I have to consciously think about it to avoid doing it now.

 

[Jimmy_Russells]

 

[Barkleymut]

When I was young and dumb my first car was an 82 Plymouth with a 5 speed. One day I decided to try and put it in reverse while going 50mph....had the clutch in and when it moved the handle towards R it let me know really quick that was not a wise thing to do. Luckily I put it back into 4th and just kept on going.

 

[DriveHard]

I have driven a few cars that don't have synchros on first gear...you have to literally be at a dead stop to put it into first without grinding. In my Fiat you have to put light pressure on the shifter and slowly let out the clutch to engage reverse...I know it is because I need to replace the shifter bushings (sitting on my work bench), but I have not gotten to it yet.

Otherwise, most modern cars I have driven, after you start off if you are skilled you don't even need the clutch to shift. After getting going, it is easy to go through all 5 or 6 gears without touching the clutch again.

Now motorcycles...if only cars had manuals like that. Powershifting a bike puts any car transmission to shame.

...and now I get the whole DCT arguments...still not the same as a manual motorcycle.

 

[Chris142]

1st in my f250 has a bad synchronizer. Sometimes it will clash when going into 1st. It's not synchronized at all going into reverse.

3rd in my Jeep is worn too. Ocasionally I will get a clack when going into 3rd.

 

[vavavroom]

In a synchromesh you can't grind gears since the gears are in constant mesh. The teeth on the synchros will make a grinding noise due to careless shifting or wear. An unsynchronized gear, frequently the reverse gear, may grind if operated carelessly.

 

[Avery4]

Thanks for the replies, greatly appreciated!

To clarify a couple things, I am specifically asking about reasonably modern cars with properly functioning fully synchronized transmissions as unsynchronized transmissions are obviously quite easy to grind.

I have seen the videos of people floating gears (shifting without the clutch) and I have came close to trying it a few times but I never did since I don't want to grind and ruin my transmission if I get it wrong.

Also, once I get the hang of it, I probably couldn't resist doing it all the time LOL. Took me a few tries to master shifting to neutral without the clutch, but once I did there's no going back since I frequently coast in neutral down hills and such. I always use the clutch when going back into gear though.

 

[DGXR]

Even the best driver will accidentally grind a gear once in a while. It's because of the human factor, we are imperfect creatures and mistakes happen.

 

[Oily_Thing]

Coast in neutral going down hills?

 

[simple_gifts]

The 5 speed in my B2300 the reverse is synchronized; not 1 sound putting into reverse, even when rolling forward

 

[Avery4]

Coast in neutral going down hills?

Yup, I'm a bit of a hypermiler. And yes I know about decel fuel cutoff. When people argue that coasting burns more fuel than engine braking because the engine is idling instead of being spun for free by the tires, that statement is true only when you want or need to slow down.

The fact that is almost always left out of their "coasting wastes gas" argument is that the vehicle will lose speed much more quickly engine braking than coasting since spinning the unpowered engine takes quite a bit of energy. And since combustion engines are very inefficient, staying on the throttle just enough to overcome the engine's friction to not lose speed while travelling down slight hills results in higher fuel consumption than simply letting the vehicle roll freely while the engine consumes a tiny amount of fuel idling.

And the safety argument against coasting is totally ridiculous. If I am cruising in 5th gear and need to accelerate, realistically I would need to downshift anyways to get decent acceleration. And no one with any brains would coast in neutral just to ride their brakes going downhill, so the brake fade argument is also totally ridiculous here.

 

[Chris Meutsch]

Beat me to it.