Chain

[carmanbikes]

Hello everyone, The std sprockets on my bike have been changed to 1 tooth smaller on the front and 1 tooth bigger on the rear does anyone know will the std 102 link chain will fit, Thanks

[VTRDark]

It should do, though it may depend on the chain manufacturer. When I fitted my new chain (all standard gearing) it did not adjust to least adjustment. If had known I would have taken a couple of links off beforehand. I have a theory that different manufactures have slightly different length links, so two different chains with 102 links could be different lengths. If a chain gets to it's max adjustment quicker it means people will purchase another chain sooner. Or maybe they do it so there is room for non standard gearing changes.

(:-})

[AMCQ46]

it will fit as the sum total of the changes back and front +1 -1 =0

and Carl, the pitch of a single link the chain should be the same for any manufacturer, otherwise it would not fit the sprockets and there would be very fast wear

[VTRDark]

and Carl, the pitch of a single link the chain should be the same for any manufacturer, otherwise it would not fit the sprockets and there would be very fast wear

That's me stupid again then.

(:-})

[carmanbikes]

Thanks I will get one ordered

[callam_nffc]

-1 front wont equate to exactly +1 rear though will it given sprocket size difference?

From a gear ratio perspective though, ive always been lead to believe "down one on the front is equal to two up on the rear"

[Pete.L]

Well I can tell you from experience that two up on the rear and you can still fit a standard chain. So one down on the front and one up on the rear should give no trouble at all until you twist the throttle fast

Pete.l

[AMCQ46]

-1 front wont equate to exactly +1 rear though will it given sprocket size difference?
"

callam,
I didn't do any sums, but in my quick estimate the change to the circumference of each sprocket is the same... One tooth pitch,

the chain length is required to span double the length of the spindle to output shaft distance (which isn't changing) + 1/2 the circumference of the front sprocket + 1/2 the circumference of the rear sprocket (that is a bit of an approximation as it is more that 1/2). Based n that the chain will still be the same number of teeth to go round the new sprockets.

I might haveto get a pencil out to prove it but that's my logic

[cheekykev]

Well I can tell you from experience that two up on the rear and you can still fit a standard chain. So one down on the front and one up on the rear should give no trouble at all until you twist the throttle fast

Pete.l

+1 on this, I'm the same 1 down on the front and 2 up on the rear, and I love it when you twist the throttle fast
If you go 1 down front and 1 up rear you will loose some of your adjustment on the chain

[callam_nffc]

Ahh I get you al

Id love to down gear my bike to turn it into a wheelie machine, but im just too much of a faggot to practice them lol

[8541Hawk]

+1 on this, I'm the same 1 down on the front and 2 up on the rear, and I love it when you twist the throttle fast

Or you could have stock gearing and run the bike 1 gear lower in the gearbox and have the exact same performance...... and still have a usable 1st and a O.D. 6th for cruising.

We have covered this before but I still don't understand the replies I get.

After showing, through the gearing commander site, that for ex. 15\43 in 3rd, has the close enough to be called the same, final drive ratio as 16\41 in 2nd ( and this works out for all the gears) the response has always been "It feels different" and "everyone likes there own thing" to paraphrase the common answers.

Ok I guess but it still baffles me.
IMHO it is the same as if I sat you down and gave you 2 pints and asked which one you liked better.....
Then after you choose,tell you they came from the same tap and are exactly the same....
Only to have you defend the one you chose by saying it tastes better or different...... Well Ok but it makes no sense to me, sorry.

It's the same with the gearing, the math says that by just running 1 gear lower in the gearbox with stock gearing you get the same final drive ratios as 15\43, so to me it is the same.
They "feel" the same and perform the same.... the math says so. I mean how can it be different? The same power, the same RPM and the same final drive ratio....how can it "feel" different?

So once again, IMHO, it is possible to go too far with the gearing. Just like you can raise the rear of the bike too high or pull the forks up too far in the triples.
The most you can go is either -1 in the front or +2 in the rear. This would depend on if you wanted a longer or shorter wheelbase.
We can cover the changes to the chassis geometry that will happen with either change but I'll leave it at that for now.
But if you go any farther with your gearing changes, you can get the same result by just moving your left toe and shifting gears....which is a bit cheaper than a set of sprockets.

To go any farther is counter productive. Track only, maybe I could see it but for a road bike you are better off saving your money for tires and petrol.

I'll end with, I am really not trying to offend anyone, I just don't get running the ultra low gearing. I would like to be convinced I am wrong but I just can't get past the logic of the math says they are the same.


Rant over.....Carry on

[rollingthunderx2]

Well said, Hawk.
And changes in circumference of sprockets can only be increased by multiples of the chain pitch (number of teeth)!!
Altering the sprockets by lowering the gearing by fitting a smaller front sprocket only moves the engine revs higher in relation to road speed, so the engine will be over-revving through the gears, and be under geared in top.

So instead of using a lower gear selection, altering gearing like that only takes away the potential top speed.
What it does do is add the number of gearchanges needed to get to a certain speed.Which may give the feeling of 'getting there faster' and will reduce the 'gap' between ratios so the revs will not drop as far between each gear potentially making keeping a wheelie up easier.
On a racebike, usually final gearing is a compromise between ultimate top speed on the fastest straight, and the need for the proper gear coming through some bends which may be of more advantage, either for exit speed or overtaking.

The small front/big rear sprocket believers in USA is usually accompanied by a 5 yard long swingarm, and is seen mostly sitting between traffic lights.

Think about it like this, mark inches on a ruler, then mark every 2 inches on a piece of elastic,stretched by around a third, say. Lay together, 12 inches on the ruler 12 on the stretched elastic. The marks on the elastic are your gears, the 12 inch mark on the ruler top speed, say 120mph.
If you relax the elastic, the number of gearchanges up to say 60mph will increase, but now the mark for 6th gear is no longer at the 12 inch mark on the ruler(120mph) but ..say.. 10 inches.(100mph) the engine cannot push the bike faster without over-revving.

If you do the opposite, stretch the gears(elastic) you can see that 6 th gear is now, say at 180, however the engine will not have the power to pull that gear, and adding extra gears only increases the number of gearchanges up to the limit of torque of the engine.

Add to that the problem of aerodynamic drag,....A bike at 50 mph may require only 10 horsepower to overcome air drag, but at 100 mph requires 80 hp . With a doubling of speed the drag (force) quadruples per the formula. Exerting four times the force over a fixed distance produces four times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, four times the work done in half the time requires eight times the power.

Tip...Remember..... if looking at available movement in the spindle slot in the swinger, remember, you can take 2,or 4 links out of a chain, but not 1 or 3.
Cranked links are not generally available for o ring chains.

[callam_nffc]

I thought the whole principle of dropping gearing was to give you a lower ratio in 1st? Therefore giving you even more drive in first....?

With the argument of "just change down a gear" you can always just change up with a downsprocketed bike, im very rarely in sixth when out for a blast anyway

[rollingthunderx2]

As I said, lower gearing between the traffic lights.
If your average top speed is below 60 and you're not worried by fuel consumption, enjoy.

[agentpineapple]

I ran -1/+1 for a year or so, it was fun, the only draw back is the speedo difference, I couldn't be bothered to buy/use a speedoheeler, I worked out that at 30mph I was really doing 24mph, which meant I never had a problem with speed cameras, also it slowed the mileage on the odometer...