Gearbox pic's

Derek can you repost on here brians 3 speed cluster pics again pls...

What I've noticed with this method of using all road gears you can make a pretty decent c/r cluster
that gives some differences to the std c/r box - that is if my maths in right??

Std c/r gears for bottom gear is 28(driven) over(divide) 19(driver) = 1.47
times output pair 24(driven) over 23(driver) = 1.04 = 1.53 to 1
Std c/r gears for 2nd 25 over 22 = 1.136
times Output pair 24 over 23 = 1.04 = 1.182 to 1

Or to put it another way Top 1:1 Second 1:1.182 Bottom 1:1.53
Or another way (1divided 1=) 1 Top. (1divided 1.182=) 0.85 Second. (1 divided 1.53=) 0.65 Bottom.

Now assume in do 100mph at 12k with a std c/r box then in the gears you should have 85mph 12k 2nd and 65mph 12k 1st

With counting and guesstimating gears in pic I reckon ratio are Top 1.1 second 0.78 bottom 0.46 now if the bottom gears were changed from 28/19 to 26/21 bottom would be 0.54....


Which is nearly the same as running a c/r box with snell output pair... quite a usable box!!

Mike

Steve Frayne runs one of the converted boxes and has been doing so for a few years with no major issues, that said he did swap the output pair back to a CR set I believe as he found the gap from 2 to 3 a little wide.

Its certainly a route worth taking if you cant find a CR box as they do seem to come up less often these days

Hi James think Steve has a more conventional box where the two sliding gears have not been swapped over as
in the pic which shows a layshaft slider on the main shaft and vice versa, notice also the 'flag' becoming 'two flags' on the selector....

Brian is a clever chap....