gear ratio?

What makes a heavy vehicle like a bakkie, truck, or van get into motion so
easily? You have to change gears very quickly but you can release the clutch
right after it starts moving.

What I am trying to say is it is easier to pull away with a vehicle that has
this close gear configuration.

What do you call this?

Something to do with gear ratio?

 

short gearing?

Pete

 

can you elaborate on that please?

Thanks

 

Yep, it's low ratio. Of course you hit the rec limiter at 4mph though.

 

Who uses a clutch? For other than the initial start and final stop, I mean.

Close ratio

 

Nope.
Close ratio refers to the the difference between all the gears.
That is, the ratio between 1st and top is closer than usual.
In a close ratio box this usually gives a relatively high 1st
gear.
Meaning you have to slip the clutch more to pull away.
A low 1st gear ratio is all that's needed to enable an easier
pull away from rest.
Most HGV vehicles only need 1st gear when fully laden.
Mike.

 

Okay, I'll stand corrected. But, the gears are close together in a 13, 15 or
18 speed transmission. I only bump the throttle a couple of hundred of rpms
between shifts.

That's true, enough.

 

mean.

Well, it depends on what you drive and how quickly you want to change gear.
In my car the revs don't drop quickly enough to get anything approaching a
quick change without the clutch. Obviously, the clutch takes a little more
hammer helping to slow the engine down. Probably better to break and replace
my clutch than the syncro rings. If your car has a lot of engine braking
(mine doesn't, something to do with emissions or helping stupid people
change gear, revs don't drop quickly at all) or a light flywheel, or a very
close gearbox, clutchless changing becomes simpler. In many cars I expect it
would be royal pain in the arse.

 

Talking of which.

Any HGV drivers favourite gearbox out there ?

I haven't driven for some years now but mine was a Fuller
rangechanger.

Well fast.

 

I like either an eighteen or thirteen speed. Pretty easy for driving around
in the city, and not much shifting on the highway.

 

Eaton Twin Splitter, virtually a clutchless vehicle if you know what you're
doing. Certainly sorts the noobs out!