Pop up gearing advice

[Katfish]

Hi guys,
just fitted a pair of 17" wheels into the pop up. Does anyone know how many teeth sprockets are best, speedo is Reading a little optimistic at the moment

[Pop-Kat]

Not much you can do about the speedo reading due to the bigger front wheel, you could try grafting a teapot speedo into the popup clocks ?.

re gearing, have you put the old and new rear wheels side by side ?, it'll give you an idea of how far to go, assuming the new 17" rear wheel (with tyre) has a smaller diameter then the std gearing will give more acceleration, if you want to get it back to where it was go smaller rear sprocket, can't see there being too much difference so i reckon 1 tooth should be pretty close.

[Katfish]

Cheers Mal, currently running a 13 tooth front & a 42 tooth rear from a slabby, bike doesn't feel to bad but just thought somone may have done this already and got things spot on.

[bobster]

Personally i'd just go 1 bigger on the front sprocket..........cheaper than a rear sprocket and quicker to change! Less exceleration and better fuel economy............

She1te......... did i just say that

I must be getting old!

[Pop-Kat]

Whats std gearing ? 14/42 i think ? yours must be a bit revvy, would have thought if you go back to a 14 front you'll have a little extra omph over std and not be too revvy.

But if you like it as is then leave it.

I did it years ago but had a 152bhp 1230 engine in it, so don't think my gearing would help

[Katfish]

14/43 standard I think I now have 13/42 but to be honest I don't know how bike should feel as standard as it was running 13/45 on the standard wheels as it was when I got it.

[bobster]

This may sound strange ........but 14/45 is probably about the same gearing as 13/42........

The usual rule for gearing is 1 more tooth on the front is equivelent to 3 less teeth on the rear sprocket!..........or visa versa.

hope this helpd

[fossie]

So you changed a 17" rear for a 17" and need to alter the gearing !

[Katfish]

Yeh Fossie lol, what I was getting at is that gearing as never been right and the only sprocket I had to fit the new carrier was 42 teeth but I do have 13 & 14 teeth fronts so i was after was knowing which was best or long term does it need standard size rear sprocket?