Re: World of Sprockets!

But why? Modifying your internal gear ratios would be detrimental unless you really know skin deep what you're doing about. Manufacturers take a lot of things into equation creating the primary and final drive ratio. Screwing them up on the internal would lead to seizure induced due to improper power delivery, etc etc etc.

You can go for a smaller rear sprocket or a bigger front sprocket for improved top end.

Cheers!
VJ

Re: World of Sprockets!

Avoid all this.

There are "n" number of problems you might encounter, including false neutrals, hard gearshifts, noisy gearshifts, internal jamming, etc, etc.
Remember, even a big group like Mahindra couldn't solve the Pantero gearbox issue till now. It was in Stallio too.
Internal Gearing is not DIY stuff. Like B7ACKTHORN said, Avoid it.

Read very carefully, as you might get confused... If you're looking to achieve a target speed in least amount of time, you'll have to think carefully and then under/over gear. Say, if you're looking for the best 0-80 timing only, I suggest you try noticing the best speeds you can get in each gear.

If you're getting 80 kmph speed all out in the 3rd gear (for example, it can be 2nd or 4th gear also), then don't change anything. Its the ideal setup.

But if you're getting 75 (or 72) kmph in 3rd gear then you should try to get to 80 kmph in 3rd gear itself, then overgear it. By this way you'll reach 80 kmph in 3rd gear itself without locking in the 4th gear at all. You will get better timings in 0-80 kmph despite overgearing!!

If you're getting 84 kmph in 3rd gear, then undergear it so it touches 80 kmph only. Here, undergearing becomes an advantage.


Gearshifts take up time and secondly, they are actually a time zone of "Almost Zero Torque". Less gearshifts are an advantage to any rider.

Our member Joel K Raju had tried a 43 teeth sprocket on his P220, undergearing it by a huge margin. You think acceleration should increase, right? Read on...
Its 0-100 timing instead of quickening up, slowed down by 0.5 seconds or so. Why? Because the bike required 5th to reach 100 kmph. Earlier it was not so.


Another example, CBR 250R has better torque spread than Duke 200. Both make 25~ bhp. But Duke has lighter weight, and so, better Power2Weight ratio. Duke is undergeared too compared to CBR!
Still, CBR and Duke are almost equal in 0-100 timing... Why? Because CBR does 100 in 3rd gear, Duke does it in 5th gear due to its comparatively undergeared setup.
That means the Duke rider goes through 2 more gearshifts... and he loses time.... Getting my point?
Inside the city, Duke might feel peppy, but 0-100 timings are a different matter.

Re: World of Sprockets!

thanks a lot for this wonderful insight. you got it right, what i want. i meant to get best 0-80 timings only by modifying chain and sprockets. Finance is a constraint, hence not touching cylinders, reed valves,carb, etc.
please note my Rx has an expansion chamber too. With the current setup the bike shows 90km/hr on speedo in 3rd gear and goes till 110 in 4th gear. So may be as you say under gearing is needed for me.
The bike will be mostly ridden in city and inside roads, hence acceleration is what matters to avoid crossing the legal speeds of 40, 50 or 70.
I have seen moto cross bikes having huge rear sprockets, isnt it for acceleration?
need to know what to be done for my needs. thanks.

Re: World of Sprockets!


Tell you what, RX series are really good for city driving. Undegearing makes acceleration quicker and overgearing, taller spread. Now two strokes usually start slow and then gain speed, as you know. You need to take into consideration, as Sam rightly pointed out, speeds at different gear. Because you use particular sprocket for a particular speed, you timings will get affected someway or the other in topspeed or low end.

Just try undegearing it for most part, as two strokes have a wide RPM to achieve power, and then based on that UG or OG accordingly.

Personally I'd just stick to the stock setup, which more than suffices for the bike.

Cheers!
VJ

Re: World of Sprockets!


yes yar, its UG that i want as i want best possible 0-80 timings. Being frank i have felt upgrade from stock can give more acceleration leap in Rx 100. Im not saying it isnt enough, but for 0-60 timings a P220 can easily take over my Rx. Hence Im just interested in 1st 3 gears giving best output through sprockets.

Re: World of Sprockets!

Then simple go for a smaller rear sprocket, with losing the low end performance as all two strokes are meant for. And I understand, even a quite a few of my friends have RX 100s and they are mad at it. And they always prefer stock settings and with stock at certain times, they just blast off, and I had to rev hard to catch them up on my bike. You can definitely OG/UG but just make sure they fit your category.

Cheers!
VJ

Re: World of Sprockets!


are you sure what you said? in my knowledge it is

Smaller front gear: faster acceleration, lower top speed.
Bigger front gear: slower acceleration, higher top speed.

Smaller rear gear: slower acceleration, higher top speed.
Bigger rear gear: faster acceleration, lower top speed.

so i must be getting a good bigger rear sprocket and a smaller front sprocket. now what i need is, inputs on number of teethes and how to under gear it?

Re: World of Sprockets!

Precisely. Now you have something called gearingcommander.com. Go to this website, I've already posted a link few pages back. But just Google, gearing commander and you just test whatever sprocket you need, and speed at a particular gear etc.

The reason I said *small rear is* it's good to have higher top speed in two strokes as opposed to sheer fast start..

Basically yes, your understanding is spot on.

And remember custom sprocket set up is always a DIY.

Cheers!
VJ

Re: World of Sprockets!

i need input precisely, ie, which rear sprocket and which front sprocket? and how many teeth?

Re: World of Sprockets!


Check out the website called gearingcommander.com. Here you will have boxes with respect to speed RPM and everything. As you asked, which speed in which gear and how many teeth for which sprocket. Just throw in the inputs needed in and you'll speed, at which gear with respect to your stock setup and the website will automatically give you all the details you needed.

Cheers!
VJ

Re: World of Sprockets!

finding it tough yar. version is only Z. no 100 option. and dont know to set other options.

if anyone has done it please get the numbers and size. i will try to buy it. please.

Re: World of Sprockets!

Did you check the RX 100 thread here in xBhp. If no, have a look at it, I think I read somewhere about the sprockets there long back.

Cheers!
VJ

Re: World of Sprockets!

Rx 100 is terribly short geared with 15/39 teething

Other series of Rx has;

15/37 for RXG
16/34 for 135 4S and
15/38 for 5S

Anything lesser on the rear will make it taller gearing and anything lesser in the front will have it more stressed. Remember every teething in front corresponds to two teeths at rear..:-)

Re: World of Sprockets!

Glad you popped in Ram about time.

Cheers!
VJ

Sent From My Phone Using Internet.

Re: World of Sprockets!

i didnt understand by shorter gearing. you mean in stock 15/39 it has low acceleration?

i need inputs on increasing 0-80 timings ,ie, best acceleration possible with sprocket modification.