Could someone explain this? Always wondered what it was, since I heard it in the first Fast & Furious..."Granny shiftin not double clutchin like you should". Whats that mean, how do you do it, whats the advantage, etc?

Sorry if its a repost...couldn't find anything.

Thanks!

 

THe basic idea is to relase the clutch between taking the car out of gear and putting it back in. Examples:

Most people:

1st gear, decide to shift.
Depress Clutch and hold
Take car out of first gear and put into second gear.
Release cluch while bringing up RPM to match.

Double Clutchers:
1st gear, decide to shift.
Depress Clutch and take car out of gear.
release clutch
depress clutch and enter 2nd gear.
release clutch again.

It's my understanding that this was VERY common before syncros. The general idea now is to reduce dammage to syncros.

Personally I don't see the benefit in a modern car. YMMV.

This is my understanding on the subject. I am sure someone will correct me if I am wrong.

 

ruexp67 got it...here's more: Check out this article for help.

Mendii

 

Great link Mendii.

Well worth the read. Typically on a downshift I will match RPM with the clutch out. I don't downshift much, but can see where this would be very handy in say a racing situation.

 

The article is correct. Ruexp67's explanation is a bit inaccurate.

It's true that double clutching is not required in modern cars. However, it's a useful skill to have and will save wear on your synchros over time. This is particularly true if you do a downshift where there is a large engine speed differential, i.e. from 4th into second at 50MPH. For the most part, just normal heel and toe is enough for just about every situation.

The only time in my driving experience that I've ever *needed* to double clutch was on the track in my M3 at Summit Point. The shifter would not go smoothly into 2nd unless I double clutched.

Dave

 

dngo has a good point - on the track tends to be when we use this technique

 

Ok...thats what I thought it was..but please tell me why Vin says that in the movie? Did he honestly expect him to do that during a drag race!? That would have to be the SLOWEST way to shift...I know many ppl that dont even life off the gas when drag racing...

 

If you're taking car advice from Fast and Furious...




-Matt

 

It's sad but true! Some people actually think that F&F is a serious and accurate recounting of automotive fact. This whole double clutching part in that movie had to be one of the most of all the parts in the show.
In "real" life, double clutching and rev matching and heal/toe has its biggest advantage and widespread use on the track. For the street, about the only time you would benefit or even need to do this is to gain access to 1st gear on a high speed downshift. This is pretty much required to get past the 1st gear blocker ring. Under ordinary street downshifting circumstances, rev matching is quite adequate.

 

I wasn't taking advice from the movie...or thinking that it was accurate...I was just questioning why Vin said that...cuz I didn't think it was right.

Thanks all