Sprocket Question

[Motostar]

I have a question about sprockets. After researching different claims by different companies, i was wndering how exactly do sprockets help to make a bike go faster. I am completely clueless as to how they work (other than that they drive the chain) and was wondering if anyone could point me to any information to read up on.

For example, why does shaving a tooth off the front sprocket increase acceleration and decrease top speed?

[TooBuku]

if you're talking about messing with the front.. Usually the most you ever go is -1. That'll give you move low to mid range power, in exchange you'll lose top end, but when you do you need to go 180mphs anyways. if you do the front sprocket and still want to do more. you go up in the rear +2. It's the oposite, going down in the front is the same as going up in the back. -1 in the front about equal to goign +2 to +3 in the rear. Hope that makes some sense.

[dhdrider]

One way to look at it is to think about your bike w/o a chain on it.* When you pop it in gear and give it gas, and say rev it as high as it would go, your counter-shaft (and sprocket) would spin at the same rate no matter what size sprocket is on it.* The chain is simply a medium to transfer the counter-shaft spinning back to the rear wheel.

Case 1: If you put a really small sprocket on the front and a large sprocket on the rear, the front sprocket will have to rotate several times in order to rotate the rear spocket/wheel just once.

Case 2: If you put a larger sprocket on the front it has to rotate less times around to rotate the rear sprocket/wheel once.

So, in the first case, lets say you go 60 mph at 5000 rpms.* With the second case @ 5000 rpms, you would be going faster than 60 mph (it can also be said that if you were going 60 mph in the 2nd case you would be at less than 5000 rpms).* But you would have more "power" in the first scenario cause your bike has more grunt at 5K than it does below that.

Does that make any sense?

Here's good iinfo on gear ratios: http://science.howstuffworks.com/gear-ratio.htm
Make sense?

This is from an RC-51 website, but it shows you the different speeds & revs for differet gear ratios... http://members.aol.com/mwheele/RC51GearingCalc.xls

[Motostar]

thanx for the advise, as you can prob tell, im lookin for more acceleration versus top speed.

However, i am curious as to how much top speed i would lose shaving off a tooth in the front?

[dhdrider]

However, i am curious as to how much top speed i would lose shaving off a tooth in the front?


Not enough to matter.

On my RC-51 most guys go down 1 on the front and up one in the rear. 160 to 170 top end is plenty fast if you ask me...

[Patrick]

However, i am curious as to how much top speed i would lose shaving off a tooth in the front?

Typically 3-7 miles and hour depending on the bike, don't forget it will make your speedo and odometer even more inaccurate, typically 12 to 16% off (high)

Patrick

[Solracer]

However, i am curious as to how much top speed i would lose shaving off a tooth in the front?

Typically 3-7 miles and hour depending on the bike, don't forget it will make your speedo and odometer even more inaccurate, typically 12 to 16% off (high)

Patrick


unless you have a front wheel mounted speed sensor :tongue5:

[Prodigy]

also keep this in mind the smaller you go on the front sprocket the more wear and tear there will be on your chain.

Another thing if you decide on going -1 or -2 in the front the bike wont be as smooth as say running +3 or +6 in the back.

on my f4i stuntbike i run stock gearing on Vu's "Zx6r stuntbike" he's -1 +24 top speed of around 60mph redline.

And its best to replace your chain anytime you mess with the sprockets.

IF your wanting quicker acceleration have you thought about 520 conversion? Thats a lighter chain and sprocket lets you keep the same gear ratio but there is less hp lost

[Knightrider]

it works the same way as your multi-gear mountain bike

[dhdrider]

...don't forget it will make your speedo and odometer even more inaccurate, typically 12 to 16% off (high)

This guy makes a super easy unit to correct spped error. I have one on my RC. Plug it in and set the %error and you're done.

http://www.jahlmandesign.com/speedometer_recalibrator.htm

[Motostar]

I am mainly looking for increase in acceleration. I do not care about all out top speed, but i am concerned about losing any smoothness and reliabily. I will look into the 520 conversion. What other modifications are good for increasing acceleration without sacrificing too much reliability/smoothness.

[Din]

i thought aznstunta vu was runnign +60 in the rear?

[Solracer]

Dude, that would be like 100 or more teeth lol

[Capafool]

I am mainly looking for increase in acceleration. I do not care about all out top speed, but i am concerned about losing any smoothness and reliabily. I will look into the 520 conversion. What other modifications are good for increasing acceleration without sacrificing too much reliability/smoothness.


I dunno if you've mentioned this but I'd like to ask... what kinda bike u runnin?

and to answer your quetion as to why it is the way it is about losing and gaining speed...etc. I don't think no one has answered it and jason put it in about as simplest terms as you can get. I could explain it to you using physics but unless you're an engineer or a physics guy what I tell you would probably just go right over your head... :icon_thumright: