Originally Posted by Surfn54
I do not mean to interupt the thread, but I need a question answered regarding my new TW.
The tw200 comes with a low geared transmission. Most of my research shows that those who want better top end speeds need to go from a stock 50 rear to a 47 tooth and in addition go from a stock 14 front to a 15.
That is fine, but can anyone explain why not go to a 45 rear or 43 or 41 etc.....as well as a 16 or 17 front? Can anyone explain what happens as you keep going and why the 47/15 seems to be the best improvment?
RUle-of-thumb seems to be 1 or 1 1/2 mph per rear sprocket tooth.
If you off-road in rocks and up steep hills you will get so much gear-lash/chain snatch you are going to thin you are goig to knock the bottom end out of yoru T-Dub.
Also, lugged down gets em' HOT at very low speeds. (NOT "IMO", jsut fact...)
You've got a close ratio gearbox and if you went ONE tooth larger on your counter-shft there would be a BIG difference. (Also, keep in mind that 1st is about where you would want it to be, even on the street already...Make several "starts" from dead stop in SECOND gear before you radically change your stock ratios.)
If you have no problems startign in 2nd, take your pocket calculator and figure IF your gearing change is going to put 1st where 2nd is "stock", where will that put 5th?
If you are very light, like around not over 125 lbs. you can probalby pull taller gear ratios better than a 200 or 250 lb. rider.
"Given" the small engine, large tires(heavier/harder to turn), close ratio 5 speed, good-but-not-state-of-the-art suspension, if you REALLY "need" more speed don't you think you'de be happier with one of those six speed 225 or 250's (or larger)?
My old BSA 441 one would do and indicated 90 mph only when I laid flat on the tank and grabbed the fork tube with my left hand to lower wind resistance, and those old Brit. singles were "TRACTORS".
A small displacement bike being jammed into increasing wind resistance is like going up and increasing gradient, steeper & steeper.
You just are not going to be able to pull extremely tall ratios like you are talking about unless you are going downhill.
You will have to split your cases to change counter-shaft sprockets, and your rear hub needs attention since the bolts are "rattle-fit" to the sprocket/hub holes. (Read previous posts....)
Also, your stock chain and sprockets are not "of the best".
Personally, I have decided to "get along with" the stock counter-shft sprocket, but have replaced rear sprocket and chain.
IF speed is paramount to NOT use O-ring chain as there is more drag to it.
Lots of gearing change info. over on tw200forum.com
Serioulsy, try THERE for more info. BEFORE you burn some bridges behind you.
(Probably no higher than 45 tooth rear and stock 14 counter-shaft is practical, and then only for "street". or a 15 tooth counter-shft sprocket and 'stock" 50 tooth rear sprocket.)
Paradox Pete (aka Old N' Tyred over on tw200forum)