cooperess wrote:
SOUNDS like I need to think about the noise output, thanks guys.
Ha, ha - nice play on words. Well done.
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| C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-ratio https://www.ausmini.com/forums/viewtopic.php?f=2&t=100771 |
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| Author: | cooperess [ Tue Feb 16, 2021 10:11 am ] |
| Post subject: | C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-ratio |
Attachment: 417.jpg Is there any advantage in the above purchase and should I also get the straight cut drop gears.
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| Author: | winabbey [ Tue Feb 16, 2021 10:58 am ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
If you do then be prepared for increased transmission noise, and straight cut drop gears make it even worse. Have a look on YouTube for "mini straight cut gearbox" or similar. Here's an example - https://www.youtube.com/watch?v=3UP-CRlKEeI and with S/C drop gears - https://www.youtube.com/watch?v=i5IyYfS7EhM |
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| Author: | Stuwey [ Tue Feb 16, 2021 10:59 am ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
Whats the rest of the vehicle spec? For a cruisey road car? Definitely not. For a hot weekender? Maybe. I have straight cut gears and drops and it's obnoxiously loud. In my car if you have the window down, the noise echoing from the car next you is so loud you can't hear your passenger speaking. Interestingly, the big-dollar gearsets are quieter. |
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| Author: | IndigoBlueCooperS [ Tue Feb 16, 2021 1:27 pm ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
I run the MED version of that - noise is sweet, not loud. I like the close ratios, but I don't think there are any other advantages of the straight cuts for the road car. This is with standard drop gears. Mini Spares gears may, or may not be louder than the MED. |
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| Author: | cooperess [ Wed Feb 17, 2021 10:07 am ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
SOUNDS like I need to think about the noise output, thanks guys. |
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| Author: | winabbey [ Wed Feb 17, 2021 11:01 am ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
cooperess wrote: SOUNDS like I need to think about the noise output, thanks guys. Ha, ha - nice play on words. Well done.
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| Author: | Stuwey [ Wed Feb 17, 2021 11:47 am ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
Also be mindful of the ratios. A longer first gear isn’t great on the street if you’ve got a hot motor that doesn’t work under 3000 revs. |
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| Author: | Bill B [ Sat Feb 20, 2021 8:42 am ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
Out of interest, would this straight-cut gear set be considered mainly for performance reasons or because the early 4 synchro helical gears are becoming harder to find? |
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| Author: | simon k [ Sat Feb 20, 2021 9:57 am ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
I'm gonna stick my neck out and make some statements that may be incorrect... If I'm wrong please correct me because I'd like to know Straight cut gears are weaker than helical cut, this is because there is less contact between the meshing teeth. However they may be made with better material than the factory helical. Straight cut gears are cheaper than helical because helical are harder to make. Aftermarket close ratio headsets are only available as straight cut because they'd be uneconomical to make helical. Straight cut gears transmit more power from the engine to the wheels because the gears do not push sideways against each other the way helicals do. This probably means they run cooler too How wrong am I? |
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| Author: | fuzzy-hair-man [ Sat Feb 20, 2021 9:58 am ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
Bill B wrote: Out of interest, would this straight-cut gear set be considered mainly for performance reasons or because the early 4 synchro helical gears are becoming harder to find? Straight cut gears AFAIK have advantages for performance, they are more efficient at transfering power as helical gears impart a side thrust, they are also considered stronger although I can't exactly remember the mechanism. The downside is noise and I hesitantly add perhaps wear as the mesh of the teeth isn't as smooth as with helical. Helical gears are more difficult to make but I doubt that's the reason, I'd guess more people just want 'racer' noises, or it was originally developed due to demand of racers. |
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| Author: | pdpsing [ Sat Feb 20, 2021 10:09 am ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
To add to those comments, here is an extract from the Car Throttle website. "The main advantage of using straight-cut gears is that they produce no axial load. This ‘thrust force’ is generated by the sliding contact between the teeth of helical gears. This lateral force is applied to the input shaft of the gearbox, which in front-wheel drive configurations will then convert through to the driveshafts. This greatly restricts the amount of torque that can be applied through the gears before failures on other components occur. So straight-cut gears effectively allow much larger powertrains to be placed in a vehicle without risking the output shafts and other bearings tearing themselves apart, producing a larger safety factor within the transmission itself" Sent from my SM-A305YN using Tapatalk |
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| Author: | timmy201 [ Sat Feb 20, 2021 11:07 am ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
Close ratio gears won’t have much extra noise in 4th gear, but straight cut drops are noisy all the time Close ratio gears are definitely available in helical, this type have wider gears for more strength http://www.minispares.com/product/classic/C-STN48.aspx |
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| Author: | drmini in aust [ Sat Feb 20, 2021 1:56 pm ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
Some people I know have put the SCCR gearset in with a 1330 or bigger and used a 3.76 diff to shorten the gearing. With straight cut drop gears too it sounds like a street bound race car. Too noisy for me, even though I'm half deaf now. 
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| Author: | Bill B [ Sat Feb 20, 2021 2:06 pm ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
timmy201 wrote: Close ratio gears won’t have much extra noise in 4th gear, but straight cut drops are noisy all the time Close ratio gears are definitely available in helical, this type have wider gears for more strength http://www.minispares.com/product/classic/C-STN48.aspx I am aware of those MS gearsets as an alternative to to the original factory parts, but since they are currently Out Of Stock and original parts are less available, that was what prompted me to ask my question. I probably should have asked if people were being forced to look to the straightcut sets as an alternative. |
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| Author: | drmini in aust [ Sat Feb 20, 2021 2:45 pm ] |
| Post subject: | Re: C-AJJ4014 Gear-set, 4 synchromesh, straight-cut, close-r |
If you want Cooper S ratios in a 4 syncho remote or rodchange box, you could consider a diff swap instead. Going from a 3.44 to a 3.1 diff will give 1-2-3 ratios the same as an S, with a taller 4th gear. It's a good combination, and better for freeway cruising. Much cheaper than putting a Cooper S 1st motion shaft and a 22G1040 cluster gear in. |
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