14 replies to this topic

[neil_g]

right, now i know drop gears are a touch on the weak side if you try and put alot of torque through them.. but at miniworld last weekend there were quite a few engines running No2..

how come theyve got away with it? is it just the A series box and would they of upgraded/strengthened the box somehow?

Note: question is relating to gearboxes not No2 :tongue:

[bluebottle]

not heard of weak drop gears before, its usually the diff that gives up first, thats why 4 pin diffs are so popular.

[siggy]

Drop gears are not weak, read KC's comments in the mags.

Diffs and gearboxes are much weaker.

Siggy

[neil_g]

oh right.. i must of mis-read something :erm:

im sure there was something that wasnt great under higher torque, maybe it was the box?

[Bluemini]

Its the diff that will go first, drop gears are probly one of the strongest parts of the box

[neil_g]

*scratches head*

so what the hell am i talking about then??! lol

[Wil_h]

I don't think that drop gears themselves are week, the main cause of failure is the bearings.

Early boxes and flywheel housings has much smaller bearings and it's these bearings that have a reputation for poor reliability.

Later engines used larger bearings which are much better. I've never had them fail and I've got 120 ft lb torque. I have blown the diff up though.

Wil

[bluebottle]

are you back on the hills again this year will?

[Wil_h]

Yep. Doing at least 10 events. Done Silverstone already

I'm off to york for Mini Vs Beetles on monday to bed my new tyres in and the Wiscomb park on the 24th for a start.

Wil

[bluebottle]

probably see you at prescott if your there, i'll be with my mate, ian davies' mini,(silver with a black roof), he's trying for an entry on may 1/2nd

[Pavel]

You must be thinking of drop gears because people replace them first to S/C.

This isn't due to weakness, but because helical (standard) drop gears create a LOT of loss of power in the gearbox (the most significant loss is from there, a few percent I believe, up to 4-5).

[Telejmp]

This might sound liek a stupid question, but what are drop gears? Ive heard a few people talking about them.
Ive seen a couple of modified minis around here, and apparently they have them installed, I just cant figure out what they are/do. I heard them refered to as 'straight cut, drop gears' im assuming they are the same.
thanks alot,
pEaCe
Dom

[siggy]

The drop gears or the transfer gears are the ones that drive the gearbox.
One on the end of the crank, the second is an idler gear and the other on the gearbox input shaft.

Standard gears have a helical tooth pattern.

Siggy

[Wil_h]

The only Prescott I'm doing this year is September 25/26.

I know Ian, he beat me last year. I've been working hard over the winter to try and make sure it dosen't happen again.

Wil

[bluebottle]

he's been working hard as well!....good luck anyway!