40 tooth sproket review

**CRUISER** · #1 (**permalink**) 12-24-2007, 08:42 AM

i recently changed my 44 tooth to a 40 tooth on my 70cc 2 stroke. sounds like a small change but it makes a heck of a difference. i get about 5 mph more on the top end and on the bottom end i can tell no difference. still climbs hills nice. i think the best part is the engine dosn't have to work as hard. to run at 25 mph it purs and is not pushing the engine hard at all which means less vibration and a longer life. top end is 35 mph however i like to cruise at around 27 to 30 mph. definatly a modification that was worth every penny.

ChrisHill · #2 (**permalink**) 12-28-2007, 09:51 PM

Do you ride around any hilly areas Cruiser?
Are you able to easily do any type of no peddle take-offs, or do you need to give it a little help to get going?
What type of material is the sprocket made out of?
Is it milled, flow jetted, or stamped?

I have used sprockets ranging in size from a 44, a 48, 50, and 56. I am usually pulling a trailer, and my (personal) bikes get used for daily transportation, irregardless of weather or hills. I am somewhat lazy, and don't care to peddle much anymore, lol.
About a month ago, we received about a foot of snow overnight, and I was the only person who was able to make it into work the following morning. That's a nice feeling, when you ride a bike and other people drive huge, gas guzzling 4x4's, lol.
I have a custom 36 tooth sprocket on order as I write this, and will definitely let everyone know how it goes. This will be for a custom touring bike which will be homebuilt for a long highway trip thru Northwestern Ontario next summer.

**CRUISER** · #3 (**permalink**) 12-28-2007, 10:09 PM

lol you got me their Chris. the sprocket is the cheapest thing i could find. not sure what it is made of. i bought it before i learned about kings sprockets but it works. the sprocket is not chrome just ugly metal. now you got me wanting to ride in the snow. we got another 5 inches today. my main concern is all the salt they use on the roads here and it is the only thing that has kept me from going out. i did have a day the car wouldn't start and it was 29 degrees so a little below freezing and i bundled up good and it did a nice job and got to work on time. i did buy fenders for it the next day though. only reason i got cold was i got wet. as far as hills its fairly flat here but their is some good hills that with my electric bike the only way i could make it up them was to pedal assist. the gas bike goes up them like nothing and the only time i peddle is to start the motor. yes i am lazy. it goes from a stand still no problem just giving it the gas.

Andyinchville1 · #4 (**permalink**) 12-30-2007, 04:22 PM

FWIW - I live in a fairly hilly town and I have been using a 36 T sprocket on my bikes and love it....at low speeds and low throttle openings I get some jerking (up to about 11-14 MPH)....but when you get to 15+ MPH she runs real well with lots of pulling power too....As far as hill climbing, I can ride up Bellview ave (a steeeeeeep street that is long too) and still pull the hill faster than the stock 44T setup (in all fairness though I am running a tuned pipe / expansion chamber exhaust).....when the bike was using the stock exhaust it did bog up the same hill but made it none the less...I may try gearing with a 32T Rear sprocket soon.....I weigh about 160 and the bike is a Trek 7000 with a Dax 70.
Andrew

PS - 36 T is about 6300 RPM for 34.4 MPH on a 36 " wheel
(hard to read the digital tach and speedo while riding but I got the max figures from the respective units when I stopped the bike)