Shifting straight cut gears

B

Big hammer

Well-known member
FYI this weekend nascar race cars are using straight cut gears in their transmissions! They aren't using the clutch to change gears 4th to 3rd and back to 4th! So a learning how to change gears with straight cut gears watch the race and learn!
 
I ALWAYS watch NASCAR!!!!
Never saw a cut away of the trans. They must have synchronizers that are like DOG CLUTCHES???
Bill Fan
 
No synchronization, just straight cut gears, fs1 showed a cut away and then how a driver was shifting! It blew me away, off the gas then bang into gear so quickly almost hard to see I know not much change in ratio 3rd to 4th but I was amazed!
 
Recently a couple of cars got stuck in gear. When Jr. inadvertently shifted to second, instead of fourth, it over-reved, blew the engine & damaged the trans!
They shift a LOT, without the clutch, when running the ROAD courses.
"Wonder" if a NASCAR box could be stuffed in a Model A???
Bill Watcher
 
Years ago as a teenager I used to shift my Model A coupe from 1st to 2nd and 2nd to 3rd without using my clutch.

No grinding. I could "instantly" feel the immediate thrust forward like someone bumped my car from the rear.

Figured it may break a transmission gear tooth so I stopped doing it.
 
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Yes Bill, they are dog boxes, like the old Harley gears with the dog teeth on them. I'll try and post a picture of a gear.
 
Thanks Art for the u-tube link! FS1 with Larry Mac didn't explain it in detail, only to say straight cut gear transmissions are stronger transmissions! It was cool seeing the drivers shifting.
 
It's the same type of transmission design that is used in just about every motorcycle from the 60's on. Nothing new.

 

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Y-Blockhead said:
It's the same type of transmission design that is used in just about motorcycle from the 60's on. nothing new.
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We call them "Constant Mesh" gearboxes. All gears are engaged all of the time. changes are done using the big dogs on the side of the gear.
 
My father 'float' shifted a model A like butter...only used the clutch to take off..been 40 years for me,I got the hang of it as a teenager. Looks like I'll master it again,brought a 50A home yesterday.Double clutching is the same thing,the pause in the middle of the double clutch is to allow the input shaft speed and the output shaft speed to match through the cluster gear..a syncronizer does the same thing,it 'forces' the meshing gears to match speeds..
 
I never "Double Clutch" in my 1928 Roadster Pickup and it has the AA 4 Speed Transmission. I wait about 2 seconds between gear changes and its smooth.
Double Clutching is ok but you are wearing out the Thrust surfaces of your Babbitt quicker and same goes for your Pedals, bushings and clutch linkages.
Something to think about.
 
Fullraceflathead said:
I never "Double Clutch" in my 1928 Roadster Pickup and it has the AA 4 Speed Transmission. I wait about 2 seconds between gear changes and its smooth.
Double Clutching is ok but you are wearing out the Thrust surfaces of your Babbitt quicker and same goes for your Pedals, bushings and clutch linkages.
Something to think about.
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Yup, That's fine when changing up but i think a double de-clutch is necessary when changing down. Like Jim said, it is because there is no synchro in the box.
Might be worth remembering that these racing drivers don't care about the longevity of the gearbox - it's all about the win. Things are a bit different on the road (well, for most of us.:D)
 
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