6 Speed Gearbox Variants

[Martin7H]

What are the differences on the 6 speed gearbox when fitted to various engine combinations, Caterham list x3.  Are the ratios all the same, are the input shafts different, etc. Also what about the CRB? Is there anything else to look for or to beware of, or need? I have a 1.6 K engine. Thanks

Martin

[Graham King]

Martin, I'm pretty confident that all 6 speed boxes fitted to K-Series cars had the same ratios. I've got the ratios listed somewhere if you need them, but sounds like you've got them anyway. Similarly for the CRB, the manufacturer of the bearing did change a few years ago but only one CRB as standard. There are other options for the CRB, notably from Burton Power, that are perhaps more robust but these do require modification to fit properly. 

If you do a search for CRB you'll find loads of threads on it.

Is there a specific reason for asking? 

Graham.

[Martin7H]

Hi Graham, I maybe replacing the 5 speed box currently in my 21. It should have a 6 speed unit. Caterham have three units listed: CSR/R400, Sigma and a close ratio one. If I was to buy a s/h one would there be any problems with installation or compatibility? Hence the enquiry. Thanks

Martin

[Graham King]

Martin, ah ok, I have no experience of the 21, but I would have thought provided you got a 2nd hand unit that had come from a k-series then you should have no problems as everything is the same. I can't comment on the other variants I'm afraid. Perhaps a call to Road and Race transmissions (nr Sevenoaks, Kent) may help as they know everything there is to know about these boxes. 

Not sure how easy they are to come across 2nd hand, but again Road and Race may be able to help.

Graham.

[Dave J]

no doubt there are different versions for different input shaft lengths . K series is a longer shaft than duratec of using compact bel housing etc 

[7 wonders of the world]

First motion shaft lengths differ depending on engine choice, all ratios are the same

K Series

Duratec

Sigma

[Martin7H]

Does anyone know the dimensions of the input shaft on a 6 speed box for a 1.6 K engine? Length from main casing, diameter and position of spline. I understand there are long or short shafts. Any data for all the variants would be helpful. Cheers.

Martin