Can a video be made to give good reasoning and explanations that will convince a persons significant other that a new expensive gearbox is both needed, practical and a smart purchase for the family.
That's easy -- if the top gear reduces rpm, that would reduce engine wear, noise and gas consumption. Maybe the other person is smart and says, let's just put in a lower final ratio. The problem there is that many modern cars don't have optional final ratios.
Dual clutch's generally provide more speed and better economy. I would presume the same could be said for a straight cut or dog box since they're more efficient than a normal manual. So not only will it save you money in fuel but it wil also mean you can get places faster which allows more time to spend with the family/better half. Hows that?
This video was exactly what I was googling for. The basic of what I wanted to know about all the different manual gearboxes. Presented in a clear and concise manner as well. Well done. Thank you.
A "taller" 1st gear might also be used to downshift in very tight corners instead of trying to crawl out in 2nd to avoid blowing your engine in smithereens with a normal 1st gear.
I remember meeting Andrew when he did a feature on one of mi mates cars for ignition, been around along time mate glad to see you as one of the main faces in this industry, keep on going strong mate well done
Ive been searching for a good explanation of why people call synchro teeth or splines, dog teeth, when they are not the same. This was a great breakdown!
Should have mentioned that a motorcycle cycle gearbox is sequential and dog clutch as a good example of this type of 'box. Like {Kroberter} said below, well spoken.
I got a rally inspired 07 ford focus with a straight cut 5 speed from massive speed Racing. Its my Daily driver and my car for scca events. I love my straight cut baby.
Awesome video. Super informative for the enthusiast thats not an performance technician. Pros and cons layout was superb and just what i was looking for. Thanks.
Have to point out a straight cut gear is actually weaker than a helical gear. Its just they dont generate axial load which forces to 2 gears aparts and causes teeth to get munched off.
Peter Donaldson mate you might want to check your facts if size is equal helical gears are stronger because they are longer contact patch because theyre angled. Most straight cut gears replacing helical take up less room therefore can be made larger in same space. Its not to say they're stronger only that bigger teeth are stronger than smaller teeth. Once again my point is that its the axial load that causes helical gears to fail not that they are weaker
Swings and roundabouts... For the same tooth count, a helical gear is thinner in the loaded direction - approximately 90 degrees to the tooth face helix. A helical gear is point loaded, with a sliding action, whereas a spur/straight cut gear is loaded across the full width of the gear - so it has a higher stress on a smaller load bearing part of the tooth - you can verify that with a simple vector diagram. A helical gear has a higher axial force on the end thrust faces/bearings, which increases with the helix angle, and 'may' increase case loading and distortion. Despite the common misconception (even seen here) there is still a single tooth contact for most of the rotation of the gears, except the very small period when the load is transferred from one pair/set to the next. Where a helical gearbox has a big advantage is in reducing the backlash/chatter/shunting as torque is transferred more smoothly between the loaded teeth as the shafts rotate, which means they are much, much quieter - spur gears can be made relatively quiet ( I have known an instance where it sounded just like any normal helical type - but that was a single example), but the tooth design and manufacturing is expensive as the tolerances and design has to be right.
I hate it when you start to get on the car really hard and try to force it in to 3rd and your transmission tells you "no way dude, I'm giving you 5th!". I owned a '92 240sx that was that way.
Robert D Way back in the day, I swapped a 5 speed close ratio in place of a 4 speed in a diesel rabbit. Those things are soooo slow, rated 52hp. Dropped like 5 seconds off the 0-60, felt like a comparison of it picking up 15-20hp. Way over on the other hand, I put a close ratio behind a late model diesel and while it would rip trees out, a buddies stock model was quicker.
Helical gears are always stronger compared to same straight cut gear but generate a side thrust. This is why herringbone gears are used where high loads and tooth velocities are high. Helical gears have a huge advantage is one important area. By changing the helix angle you can produce a mathematically perfect gear. Pitch circles that are thru the middle of teeth instead of on the outer portions. Not having to compramise this aspect is important when many ratios must share the same shaft centres. No point in having an expensive transmission if it has a compromised gear pair.
Very cool, think gear ratios is much simpler then people make it out. You basically want, the most granular gear ratios that means more gears as possible, but add's weight as literally more gears jamming into transmission. So like you said, you really don't have to worry about lower ratios cause your not in them ever on race track (except quarter mile). So by making the lower gear very long, you can be more granular on the top end, and that means you have more phases where you can be in the power band or torque band of the engine, and be faster.
I agree with everything you said but one thing, helical cut gears are generally stronger than strait cut due to the fact that there is more surface area of the teeth in contact with one another at any given moment. Strait cut gears are used a lot in racing applications because they are more efficient with less friction because there is less surface contact between gears.
Straight cut gears put the whole load on a single tooth. They aren’t inherently stronger, but they can be built to be so, the main benefits are that they reduce friction and don’t put a thrust load through the shafts.
That's me. I need and want car education anywhere anytime. Learned and corrected a lot of the things from MOTIVEDVD. Huge thanks for that. Keep up the good work Andrew 👍
Great video. I was excited when I saw the screen showing gears for the 6 speed until I saw that it was for a GT-R. I was looking for a sequential shifted, dog engaged, helical gear transmission that is rated for 900-1000 hp and had enough gear spread to allow 4.11 rear ratio and not have huge revs at highway speed. Think pro touring. I can find 3 out of 4.
There is something important you could have covered with your straight vs helical cut gears. Helical cut gears have a sideways thrust that straight cut gears do not have. Most helical cut transmission use taper bearings to transmit this thrust to the case, a straight cut transmission can use roller bearings instead and that reduces the size and weight of the case.
Did you read my last comment then !? ,this video seems like a quick response then to me . Great explanation and footage love that getrag transmission with housing cut out
Thank you! This article synchronized my ideas about gearboxes. Q: is there a way to identify if a gear teeth is broken? Bcs a loose piece of metal can destroy the entire gearbox.
description on synchro engagement is slightly off. refer to bork rings and what they actually do, prior to synchro action. there is also a debate on material strength of helical vs dogbox strength. RE total surface area contact on the gears.
You can clutchless shift with synchros as well. Disengaging a gear is easy when you time the throttle release appropriately but engaging a gear without the clutch doesnt feel good but can be done haha!
I use to have a 95 s10 i could clutchless shift thur all the gears at rolling at idle or reving it out as high as it would go before i let off and it always shifted perfectly fine never grinded or was upset
I dig a really close ratio gearbox. First time I let a friend drive it, he missed the 2-3 shift cause the linkage is slightly sloppy. He went went 2-5 instead 🤣🤣 It barely mattered, it pulled away just fine
