As far as I understand them, dog teeth spin the next cog at the same speed as the one currently transferring the drive, so instant clutch-less shifting is possible.

In my mind, this works fine with a sequential box, but I don't understand how it could work for a standard H-pattern box.

If anyone could clear this up, I'd be grateful

On a similar note, has anyone heard of Tranex gearboxes?

Thanks,

Ralph.

 

Maybe the Q isn't clear enough:

How does a Dog Box work when it is in an H-pattern format?

 

Dog gears dont spin anything up, they simply replace the syncro rings in a standard gearbox and rely on the engagement slamming into each other one side has a castliation the other is machined to accept the castleation with a degree on elonagation to help enagement, unlike a standard syncro cluster which slows the hub down before carrying out a smooth enagement.

There are numerous configuarions of dog boxes and some work better than others....as an example quaife used a large 3 dog change then evolved to a 6 dog to try and improve change quality....number of dogs, quality of material, design of the cluster all go towards improving the operation of a dog box.....

They operate in exactly the same way mechanically whether they are sequential or H pattern.

Dog boxes require a high level of maintenance as the dogs wear, but they provide substantially less loss of engine power transfer than a standard as the change is carried out without having to slow the box down to change gears...

HTH

Ian

 

That does help, thanks

As the shift time in an H-pattern is longer than if in sequential format, do you have to reduce the throttle to avoid the engine and gearbox spinning up quickly whilst between gears, which would wear the dogs faster?

I've searched for Tranex boxes but have found little

It needs a crown wheel and pinion, and I don't want to find they went under years ago...

 

Yes and no....with the dog box we never clutch going up the box and with the FFD I never usually clutch going down....even with sequential, without gear cut, flat change (torque reduction) software/hardware you would still need a small amount of off throttle time to allow a change...

Tran-ex are a small company you produce excellent gear kits....they are still in existance...

http://www.tran-x.com/gearboxHTML/gearboxHome.html

Ian

 

Thanks very much for your help