Straight cut gears

General Chat with an emphasis on BMC Minis & Other iconic cars of the 1960's. Includes information on MK1 Action days.
BLACKJACKф
Posts: 69
Joined: Thu May 27, 2021 9:10 pm

Straight cut gears

Post by BLACKJACKф »

I'm considering switching to straight cut gear box and drop gears I heard it's quite loud. But what is loud mean? So my silly question I guess is which is going to make the louder sound just changing the gearbox only or just changing the drop gears only.? Obviously doing both together would be the loudest.
User avatar
timmy201
Posts: 1758
Joined: Mon Jun 10, 2013 9:57 am
Location: Australia

Re: Straight cut gears

Post by timmy201 »

Here's an idea of the noise for you:
https://youtu.be/gW3W0LMdU_Y?si=Vl2mXgsrw9V_O8ky

On all gearbox gearsets first gear is straight cut

On a straight cut gearset the noise will be similar to standard in first gear, then 2 & 3 will be much louder. 4th gear shouldn't be as bad as 2/3, as the power isn't passing through the straight cut gears

The straight cut drop gears are noisier, and are loud in every gear
CooperTune
Posts: 1180
Joined: Sun Sep 22, 2013 1:47 pm
Location: Coastal VA USA

Re: Straight cut gears

Post by CooperTune »

I have had good experiences with REM treatment of all gears. I think Swiftune offers gear sets called super finished? I have read it reduces drag 2 HP per 50 HP produced. I have CWP, drops and all gears REM and cryogenic treated. It works. Steve (CTR)
User avatar
Pete
Posts: 10816
Joined: Fri Jun 25, 2010 10:47 pm

Re: Straight cut gears

Post by Pete »

Some straight cut gear sets are barely any louder than standard, depending on if your car has any soundproofing, trim etc but most straight cut drops are significantly louder. Some might say they’re a bit of an unnecessary expense on road car but I actually quite enjoy the sound of mine (both) albeit it’s no motorway car!
User avatar
Exminiman
Posts: 2462
Joined: Tue Jan 17, 2017 8:59 am
Location: Berkshire UK

Re: Straight cut gears

Post by Exminiman »

Years ago Vizard did an article in CCC about straight cut gears, I am sure he talked about topping the gears to make them quieter ……might be worth looking up...but it’s quite possible I could be imagining it 😀
EMOKID
Posts: 45
Joined: Sun Mar 29, 2020 10:39 am
Location: UK

Re: Straight cut gears

Post by EMOKID »

If you want the noise without the full expense then sc drop gears are the way to go. A+ series are quieter then the original A series.
and.rs1800
Posts: 101
Joined: Tue Feb 04, 2020 11:45 pm
Location: Herts

Re: Straight cut gears

Post by and.rs1800 »

On the cars I’ve had with straight cut drops and gearbox the noise didn’t bother me at all,the induction roar from twin SU’s was louder
MrNoo
Posts: 153
Joined: Sun Aug 02, 2020 8:25 pm
Location: Cirencester

Re: Straight cut gears

Post by MrNoo »

Drops and gears are not at all bad, certainly to my ears, it's when you have a SC final drive that makes a fair bit of noise.
User avatar
Andrew1967
Posts: 7773
Joined: Thu Jun 24, 2010 6:35 pm
Location: Usually in my garage on the east coast of Norfolk, UK

Re: Straight cut gears

Post by Andrew1967 »

Following this with interest as I'm thinking of doing something similar with 9748KO .. to get the desire for the the sound out of my system :o :lol:
kit of bits
Posts: 1806
Joined: Tue Feb 09, 2016 11:30 pm
Location: South Northants

Re: Straight cut gears

Post by kit of bits »

I just love that noise..
I’m about to fit a sc box to the S I can always change it back if/when it drives me mad..
D
You do not have the required permissions to view the files attached to this post.
Post Reply