LCGB Forums

Hi, currently running Indian gp 200 gearing with 46x19 sprockets giving a 4.84 4th gear ratio, coupled with this is a 30mm dellorto carb & a bgm clubman ,this set-up runs great uphill ,against headwinds etc but im thinking of trying 47x20 to give me a 4.70 4th gear ratio . my question is I'm i best leaving as is or are other people running this set-up successfully with no drop's in performance? many thanks for any info al

try it

My gut feeling is that you already have about as good as you are going to get. I was running mine with 17 x 46 on an Italian Li 150 box which I think is 4.6. Mine is optimized for touring and has a Franspeed Supertourer fitted but really struggled on that gearing. I rode it like that this year on a 1000 mile tour of Germany in company with a bog standard Vespa Rally 200 and really struggled to keep uo with him on hills I've since dropped the front sprocket to 16 which is 4.9 and it is totally transformed and is a pleasure to ride now.

The BGM bow is said to be torque so a 4.7 ration might work but the only way to find out is to try it

It can depend on a lot of things. Your weight , if you going to carry luggage etc. I've heard or of people say the bgm pipe does give good torque. Nelly on here has a jet 200 Dsc tuned with bgm , atomic reed valve. He has just gone to 20 tooth from 19 on the same gearing setup and it pulls like a train. I've had ago and I'm nearly 16 stone it pulled me no problem. In fact I was very surprised how well it went. With no struggling in top. All you can do as previously suggested is give it ago.

It's usually a compromise between easier low down power (short gearing) OR a potential higher top speed (IF THE ENGINE CAN COPE) at the cost of performance lower down (tall gearing).

I always gear as high as I can get away with, but this can and in the past has caused excessive use of 3rd gear, that's if you settle for a fourth gear ratio that the engine just cannot reliably pull.

But as already said "try it" and see what it's like, it's what I'd do as It's only a couple of sprockets that'll need changing to put it back to right.

Good luck

You could always try a larger diameter rear tyre first.