classic motorcycle forum

Motorcycle Discussions => British Bikes => Topic started by: dicky-yrrep on November 12, 2009, 09:58:26 PM

Title: Types of BSA gearboxes RRT2, STD,STB,etc.
Post by: dicky-yrrep on November 12, 2009, 09:58:26 PM

Hi, can anyone give me some info on the various types of boxes and what they stand for? I have a Super Rocket and i have removed the box today, i thought the stamp read ST3 but after getting onto the bench it actually reads STB, What is the difference between this and a STD ? also some info on RRT2 etc would be great, I'm learning something about these great machines every day!

Title: Re: Types of BSA gearboxes RRT2, STD,STB,etc.
Post by: L.A.B. on November 12, 2009, 10:21:02 PM

http://victorylibrary.com/graphics/A10-ratio-chart.jpg

Title: Re: Types of BSA gearboxes RRT2, STD,STB,etc.
Post by: L.A.B. on November 12, 2009, 10:29:28 PM

And, apparently, STB was a US model A10 Spitfire scrambler gearbox?

Title: Re: Types of BSA gearboxes RRT2, STD,STB,etc.
Post by: Goldie on November 16, 2009, 10:39:27 PM

A genuine RRT2 gearbox is a close ratio racing box with a very high first gear and has a reverse cam plate plunger which is situated on top of the gearbox and not below as the STD box.

If you live in a very hilly environment and the bike is for road use then I would not advise the RRT2, unless you have a very good clutch and be prepared to replace the plates on a regular basis depending on the amount of milage you do.