I've run a straight cut box in my roadgoing Clubbie Estate since 2007, and is IS noisier in gears 2 & 3 than a normal gearbox.  Nicely noisier mind you, and not ear-bleedingly noisy like straight cut drops are.

First is always SC anyway, and as soon as you get into 4th it's silent as there is no load through the laygear.

Fitting a SC kit to the ribcase casing is relatively simple, and if you're doing the bearings it's going to be in bits anyway.

So, you need to decide how much time you will be spending in 2nd & 3rd while competing.  On competetive stages I'd suggest it isn't a problem, and on the motorway between stages you'll be cruising in 4th which is as quiet as a helical box.

Me, I'd go SC.

Don't let people scare you away with the alleged noise of a straight cut box. It's not something I would advise for daily driving, but if you're already running a modified engine with performance exhaust modifications, the straight cut gears aren't going to be what drives you batty.

In a mini, I've found that a straight cut gearbox that runs with a standard helical drop gear set isn't noisy at all. The drop gears appear to me to be what make a mini straight cut set more "whiny". You don't have the drop gear arrangement with an inline gearbox anyway, so that's not going to be an issue for you.

And, again, don't let others parrot the "Straight cut gears are TOO LOUD" thing. They aren't.

Best bet I'd say is run what you have until it breaks. And when it does break, don't be afraid to "upgrade" to the straight cut gears.

Thanks for the comments and advice.

I have been in contact with the classic car trials club organisers and if I change major components such as the gearbox to say a ford item I will be placed in the modified class, meaning my Minor will be very much outgunned.

In relation to Straight cut gears I have been advised against them as classic car trials run upwards of 90 miles on public roads, some events being close to 300 miles and the noise will become a major issue.

Therefore I have purchased a 1275 midget ribcase gearbox and currently in the process of renewing the bearings etc to give it the best fighting chance.

Can anyone tell me if I can leave the bearing and bearing housing in position on the main shaft and remove the gears from the front end of the shaft?
I'm having issues with the 1st gear and don't wish to disturb the bearing and bearing housing so thought I would check if the gears can be removed from the other end of the shaft.

Thanks

Dermot.

I'd like to know more about that dog gear set up! MED in the UK has discontinued their excellent Ribcase gear set, so I've had to run the basic MiniSpares straight cut synchro set behind my multi web crank race engine. I have to say it's holding up well with 135+ BHP at the wheels! But on pavement!

I think you could get away with running a Ribcase with straight cut gears if you can deal with the close ratio. I happen to be resurrecting a 59 Morris Panel Van and have been eyeballing the knackered smooth case box Luckily My friends here have a dozen or more Ribcase units available to build...

I think when you see what these bits cost, the Ford route might be cheaper and stronger! The Morris Minor has much more room for a bigger gearbox that say the Sprite/Midget. I've just finished installing the Datsun 210 5-speed in my 71 Midget, but those are getting harder to find too.

While I have been doing trannys for the last 59 years starting with motorcycles and moving
on to cars a few years later. What tools I could not buy I have made over the years. I still
enjoy building mini trannys but have begun to pass on Sprite boxes. The last street box I
did received SC/CR gear set which seemed the only solution considering condition. I'm sure
they are all gobbled up by now but Datsun B210 trannys were the swap at one time.

If you are serious I think Webster on the west coast does a custom kit with dog gears.
Steve (CTR)

Heathrow Transmissions do all the Academy stuff, or Peter May Engineering.

It's probably cheaper to do a straight cut gearset rebuild.

Thanks for the comments and advice, its appreciated.
If I can get hold of a 1275 gearbox I may try it and see how I go on.

Now the issue is finding one for sale?

Any ideas in the UK?

Regards

Dermot.

I've got 90-odd going through mine, and it's only an Academy car not an unrestricted Speedwell class which will have 130+ at the flywheel.

70-80 should be fine.

The biggest obstacles you will face are traction with narrow tires and overcoming that, burning up the clutch. Ribcase transmissions do have success in racing, and are regularly put behind cars with more power - albeit on a smooth track. I would consider a stronger, larger diameter clutch to help with the increase in load and power.

Had to look this sport up!

Neat!

https://youtu.be/_Q1HegF4pG0

Midget /Sprite transmisions are pretty weak but peopel absolutely use them in vintage racing also .
 Ribcase Trans is the same across the board.  Stay away from Smoothcases.

havea  few spares around + be ready to pull and replace when things go Chonk.

Hi all

I have been a mini owner for many years having owned a few including a 1979 1275GT, 1996 Cooper spi, and a GTM coupe, my query today relates to the other car in my life namely my 1965 Morris Minor.

I intend to build my Minor into a car for use in production car trials, if you don't know what that is its basically driving your car up a grassy/muddy/rutted section of land and attempting to get to the top or as far as you can manage.

Whilst in normal use the Minor gearbox is suitable for the engine, I will be building a 1330 midget engine so I was thinking of upgrading the standard gearbox for something that could take the strain of pulling my Minor up said hill.

Would the 1275 Midget gearbox be strong enough to take the strain of say 70-80bhp?

I have been advised to go down the ford gearbox route but at £600 for just the box its an expensive option for a low cost motorsport (I know motorsport is expensive, but I like to try keep the cost down) then there is the conversion to think of hence my question regarding the Midget Gearbox.

Thanks in advance

Dermot.