PDA

View Full Version : Shifting w/o clutch


calegrant
10-24-2007, 10:28 PM
While driving home from work today my foot slipped off the clutch but I carried through with the shift and it popped right into 4th. I've heard of people shifting w/o a clutch before but I figured it was just idiots wrecking their cars. So like the moron I am I decided to experiment a little. By the time I got home I could smoothly shift through all gears including 1st-> 2nd. Is this going to damge my tranny in the long run? I didn't grind any gears, and it seemed to pop in really easly when I got the rev's matched properly. Is this a sign of wear that I'm not aware of?

Striker
10-24-2007, 10:55 PM
While driving home from work today my foot slipped off the clutch but I carried through with the shift and it popped right into 4th. I've heard of people shifting w/o a clutch before but I figured it was just idiots wrecking their cars. So like the moron I am I decided to experiment a little. By the time I got home I could smoothly shift through all gears including 1st-> 2nd. Is this going to damge my tranny in the long run? I didn't grind any gears, and it seemed to pop in really easly when I got the rev's matched properly. Is this a sign of wear that I'm not aware of?


I have been showing people for fun how it can be done, both up shifting and down shifting.

I can do it with any car with a syncromesh gearbox, just have to feel for the engagement. You are not really damaging anything if the gears are not grating or jumping into gears with a jerk, but it's not a good practice.

Back in the Caribbean we had many cars with cable clutch systems, no hydraulics so the cable would snap without warning. The easiest way to get home was to start the car in 1st gear (hard on the starter) and then shift clutchlessly home :D Good ol days.

It's not a sign of wear but don't do it, it takes lots of practice to get it right. I have shown people how it can be done on my e46 325is, they sometimes can't believe it can be done but I was doing this since i was like 15 over 20 years ago *wave*

calegrant
10-24-2007, 11:19 PM
Didn't take much practice for me. Didn't grind a single gear in the 15km drive home. Seemed pretty easy when you knew what rpm's the car had to be at for the up/downshift, then just had to feel it till it popped in. Almost shifts itself.

SamE30e
10-25-2007, 01:21 AM
It's not that hard to do. I think it's hard on the syncros though.

BigD
10-25-2007, 01:28 AM
You are not really damaging anything if the gears are not grating or jumping into gears with a jerk

This topic has been covered to hell and back but the short answer is yes you are. Synchromesh gearboxes are designed to be shifted with the inertia of the engine disconnected, period.

It's not that hard to do. I think it's hard on the syncros though.

Yeppers.

hadesm5
10-25-2007, 02:00 AM
i thought e30 trannys are only syncro'd between 4 and 5

Eurostyle
10-25-2007, 03:12 AM
This topic has been covered to hell and back but the short answer is yes you are. Synchromesh gearboxes are designed to be shifted with the inertia of the engine disconnected, period.



Yeppers.

Then how come all truck drivers dont clutch, and the transmission last over a million Km....?:confused:

Striker
10-25-2007, 10:22 AM
This topic has been covered to hell and back but the short answer is yes you are. Synchromesh gearboxes are designed to be shifted with the inertia of the engine disconnected, period.



Had a Ford Capri (1974 model) had a bad clutch and did shift without clutch for nearly a month whenever the clutch did not build enough pressure. I fixed the clutch, gave the car to my brother who used it for another 8 years until he crashed it in 1994. I NEVER had to replace the syncros in the gearbox.

I have been rebuilding gearboxes since 1985 and trust me, synchros are not damaged by shifting w/o clutch if properly matched, low and bad oil is the main reason why they do or pulling weight exceeding the max permissible weight of the vehicle.

I had buddy with the same car in 1987, he used to haul a trailer with his daily, had to do his synchros :)

I am not saying people should drive like that, I wrote it in all my replies, but they can last if done periodically.

Max_VQ
10-25-2007, 10:57 AM
The job if the syncro is to match the speed of two gears just before the engage.

If the driver can match the speed of the vehicle and engine RPM, you are doing the job of the syncro. No extra wear or damage.

BigD
10-25-2007, 11:09 AM
Then how come all truck drivers dont clutch, and the transmission last over a million Km....?:confused:

Truck drivers not only clutch but double clutch. And they don't have synchros, so the drivers skilled enough to rev match have no fear of wearing them out.

Striker: I agree that in the short term it probably won't make any difference, especially if the person is skilled and dilligent enough to get the revs matched closely. But in the long term, they will still wear because no one's good enough to match them 100% perfectly, which is why non-synchro boxes have wider windows for the dogs right? And I don't know about you but I'd much rather change the clutch than rebuild or buy a transmission. Besides, if you shift properly, the clutch will last longer than you'd probably keep the car.

Eurostyle
10-25-2007, 11:26 AM
^^^Yes they do have syncros, and good drivers dont clutch other then when taking off...*th-up*

everlast
10-25-2007, 11:44 AM
What's the point? Rev matching under full acceleration is not faster since you need to wait for the revs to drop, and that's the only time you'd benefit from any decrease in shifting time. Freeing up a foot is only worthwhile if you can't heel-toe, and in an e30, heel-toe is simple with practice.

I suppose it might be handy to shift while holding your coffee and steering with your left leg. Which I do. ;)

El Gato Liso
10-25-2007, 11:45 AM
so when u get the perfect revs

do you have to come off the gas when u shift without the clutch
or do u just keep the gas when u shift
if u get the correct rpm and u come off the gas, wouldnt it drop a bit thus not getting the right rev match? or do u rev beyond that point so when u shift the rpm drops to that correct point

BigD
10-25-2007, 12:25 PM
^^^Yes they do have syncros, and good drivers dont clutch other then when taking off...*th-up*

Prove it. Here's mine:

http://en.wikipedia.org/wiki/Manual_transmission#Truck_transmissions

No they don't, not here. In Europe or wherever they don't have weight limits and uber strict policing, maybe.

Heavy duty trucks utilize unsynchronized transmissions in the interest of saving weight. Military edition trucks, which do not have to obey weight laws, usually have a synchronized transmission. Highway use heavy-duty trucks in the United States are limited to 80,000 pounds GVWR, and the lighter the curb weight for the truck, the more cargo can be carried, and with a synchronizer adding weight to a truck that could otherwise be used to carry cargo, most drivers are simply taught how to double clutch.

Furious
10-25-2007, 12:38 PM
Prove it. Here's mine:

http://en.wikipedia.org/wiki/Manual_transmission#Truck_transmissions

No they don't, not here. In Europe or wherever they don't have weight limits and uber strict policing, maybe.

nothing beats real world experience in which it looks like the only person whos had enough of it is striker.

i dont believe everything i read on wikipedia.

Blades
10-25-2007, 12:49 PM
Then how come all truck drivers dont clutch, and the transmission last over a million Km....?:confused:

LOL your talking apples and oranges here buddy .. they have way many more gears and a high low setting. If you use the clutch driving a truck then your a newbie. There transmission is different and you dont need to clutch or double clutch like you did in the old days.

Arash
10-25-2007, 12:51 PM
^^^Yes they do have syncros, and good drivers dont clutch other then when taking off...*th-up*

No, they don't.

Axxe
10-25-2007, 12:58 PM
Europe: Trucks have synchros, because they have to chang gears all the time and have small output engines. Also, most of the driving is in the city and/or rush hour traffic. They also have weight restrictions as severe if not more severe than in North America, it's just easier to drive with synchro's.

North America: Long haul. Non synchronized transmissions have less internal shit to go wrong, and they have less internal drag. Once you get on the highway here, you put it in top gear and through the cruise on, the current engines have so much power and torque that the only way you need to grab a lower gear is if you are hauling a heavy load through the mountains.

njansenv
10-25-2007, 01:18 PM
I've yet to meet a (north american) trucker that uses the clutch when shifting. I know a LOT of them. None of them have had to replace the transmissions for 'shift related' purposes with trucks exceeding WELL over 1.5 million km.
Not that relevant compared to a car trans, mind you. :)

Striker
10-25-2007, 03:46 PM
Striker: I agree that in the short term it probably won't make any difference, especially if the person is skilled and dilligent enough to get the revs matched closely. But in the long term, they will still wear because no one's good enough to match them 100% perfectly, which is why non-synchro boxes have wider windows for the dogs right? And I don't know about you but I'd much rather change the clutch than rebuild or buy a transmission. Besides, if you shift properly, the clutch will last longer than you'd probably keep the car.

^^^ True

BigD
10-25-2007, 04:21 PM
i dont believe everything i read on wikipedia.

I don't believe everything I read on web forums either.

everlast
10-25-2007, 04:28 PM
I don't believe everything I read on web forums either.

LOL

El Gato Liso
10-25-2007, 05:21 PM
LOL

i dotn believe that LOL was genuine:cool:

Arash
10-25-2007, 05:26 PM
:cool:

I don't believe that you're really cool!! :D

El Gato Liso
10-25-2007, 05:37 PM
I don't believe that you're really cool!! :D

i dont believe you mean that *th-up*

Axxe
10-25-2007, 05:43 PM
i dont believe you mean that *th-up*

I don't believe you.

Arash
10-25-2007, 05:51 PM
I don't believe you.

I don't believe YOU!!


<object type="application/x-shockwave-flash" data="http://www.collegehumor.com/moogaloop/moogaloop.swf?clip_id=1781938&fullscreen=1" width="640" height="360" ><param name="allowfullscreen" value="true" /><param name="movie" quality="best" value="http://www.collegehumor.com/moogaloop/moogaloop.swf?clip_id=1781938&fullscreen=1" /></object>

Eurostyle
10-25-2007, 11:38 PM
Prove it. Here's mine:

http://en.wikipedia.org/wiki/Manual_transmission#Truck_transmissions

No they don't, not here. In Europe or wherever they don't have weight limits and uber strict policing, maybe.

I dont need to, i've been around the trucking business for 15+ years so i know they dont clutch...

As for the syncros, last time i drove a truck 7 or 8 years ago, i dont remember grinding gears, so it must have syncros...

Eurostyle
10-25-2007, 11:44 PM
LOL your talking apples and oranges here buddy .. they have way many more gears and a high low setting. If you use the clutch driving a truck then your a newbie. There transmission is different and you dont need to clutch or double clutch like you did in the old days.

My dad is a driver, i have spent some time in a truck, and driven one myself...so i'm not totaly clueless about the # of gears...*th-up*

El Gato Liso
10-25-2007, 11:46 PM
18wheel trucks have like 13 gears and/or 18gears i believe

and today after this topic i said alright i want to try this in my e30

and i did it! 1 into 2 into 3 was rough but 3 into4 was so smooths, and 4 into 5.....didnt workout too nice :(

Axxe
10-25-2007, 11:51 PM
My dad is a driver, i have spent some time in a truck, and driven one myself...so i'm not totaly clueless about the # of gears...*th-up*

Take a refresher before spreading mis-information. Non-synchronized. 100000% guaranteed (class 8 trucks only, does not include automated transmissions).

Some class 6 and 7 trucks are synchronized, but not all.

BTW guys, most common transmissions: 10, 13, 15, 18 speed. 15 and 18 speeds are now obsolete, 10 speeds are bullet proof but crap (wide spread) and 13's are the most common. I can explain the ranges and half gears later if anyone is interested.

Striker
10-26-2007, 12:27 AM
Guys, stop experimenting on your cars, if you don't want to clutch there is a better way.............. an AUTOMATIC :D

Seriously, don't try doing crazy things with the gearbox, it's not worth the risk of chipping a gear or doing other damage. The e30 gearboxes are very strong but don't abuse it, not easy to find and not cheap or easy to fix.

I am looking into equipment to begin repairing the older BMW gearboxes, you don't wanna know repair equipment cost and the time it takes to do it not forgetting cost of parts.

You wanna play or experiment with some kewl gearboxes, go get yourself a girl *wave*

Eurostyle
10-26-2007, 12:55 AM
Take a refresher before spreading mis-information. Non-synchronized. 100000% guaranteed (class 8 trucks only, does not include automated transmissions).

Some class 6 and 7 trucks are synchronized, but not all.

BTW guys, most common transmissions: 10, 13, 15, 18 speed. 15 and 18 speeds are now obsolete, 10 speeds are bullet proof but crap (wide spread) and 13's are the most common. I can explain the ranges and half gears later if anyone is interested.


All i said was that truck drivers "dont clutch", wich i'm 100001% sure they dont! ;)

The technical reason behind it, i cant say much, i'm not a truck mechanic....
Altho one mechanic i asked today told me they have syncros, but thats his word, dont know what trucks he works on...

Axxe
10-26-2007, 11:54 AM
All i said was that truck drivers "dont clutch", wich i'm 100001% sure they dont! ;)

The technical reason behind it, i cant say much, i'm not a truck mechanic....
Altho one mechanic i asked today told me they have syncros, but thats his word, dont know what trucks he works on...

Pick up trucks? Hino's? Mitsu-Fuso's? Those have synched boxed. I know they don't clutch, I don't either :P