Gearing Question: Front vs Rear...

[SoCal Blur]

A co-worker and I were having a discussion the other day and the topic of gearing came up. We agreed that lowering the front sprocket by one tooth was pretty close to increasing the rear sprocket by three teeth.

Setting aside the fact that a smaller front sprocket can put more stress on the chain, what are the advantages/disadvantages of choosing one method over the other, in other words, removing teeth from the front sprocket vs. adding teeth to the rear sprocket?

Or does it even make a difference?

 

[Tufbusa]

Chain pull in relationship to the swingarm directly affects anti squat. A smaller front sprocket robs HP. Not much but it takes more HP to wrap the chain it a tighter circle as well as more ware on the chain.

 

[dane789]

If your swingarm is stretched, a larger rear sprocket will help increase the gap between the arm and the rotating chain.

 

[dadofthree]

Rear sprockets are much, much easier to play with.

 

[BusaFbaby]

Rear sprockets are much, much easier to play with.

agreed!

 

[The Big Red One]

It also depends on how much you want to change the gearing. I went 1 down in front/2 up in back with only a few thousand miles on my bike. I don't think the stock chain would fit all 5 up in the back.
I went 1 down in front first because the front sprocket was way cheaper to try, then realized I needed more gearing so 2 up in the back it was BTW that combo also brought the chain adjusters back to the stock position.....1 down in front alone put the wheel back far enough that with only a couple thousand miles on the bike I was getting pretty short on chain adjustment room. The gearing changes will definately move your wheel forward or back, which will probably affect handling and wheelie tendencies slightly.

 

[Dennis]

If your swingarm is stretched, a larger rear sprocket will help increase the gap between the arm and the rotating chain.

Conversely, a smaller front gear will give you chain slap on a stock arm. If money is no object, I prefer the larger sprockets (go up in back vs. down in front) and a new chain.

One of my bikes is -1, +3 and the other is 0, +2.

 

[SoCal Blur]

I put +3 on the rear on my Gen 1 which is how the discussion started. I wasn't sure if I missed out on something performance wise by not going -1 on the front instead as my co-worker suggested. The wheelbase shortened by almost 2 inches which does help in the twisties. So far I'm liking the change.

 

[karnage]

I went 5 up in the rear to a 45 tooth.

 

[sixpack577]

I usually get beat up on this debate, but here goes anyway.
-1 front doesn't equal +3 rear. The gear ratios are similiar on paper, but the feel is very different.
I know some disagree with this and say that they can't feel it. Well, that's their opinion.
I wheelie, I stunt, I've changed sprockets, and on many bikes.
I prefer bigger rear sprockets over smaller front ones, and I can tell the difference.
Rear sprockets are easier to change, but front sprockets are only around $20.
Buy a rear sprocket, and get a front too. Switch them around and see what YOU think.

 

[Dennis]

I usually get beat up on this debate, but here goes anyway.
-1 front doesn't equal +3 rear. The gear ratios are similiar on paper, but the feel is very different.
I know some disagree with this and say that they can't feel it. Well, that's their opinion.
I wheelie, I stunt, I've changed sprockets, and on many bikes.
I prefer bigger rear sprockets over smaller front ones, and I can tell the difference.
Rear sprockets are easier to change, but front sprockets are only around $20.
Buy a rear sprocket, and get a front too. Switch them around and see what YOU think.

I thought we settled this the last time? It really is as simple as torque multiplication.

 

[sixpack577]

I thought we settled this the last time? It really is as simple as torque multiplication.

Sir, let me respectfully ask you this. Can you stunt a motorcycle? Dirt, street, cruiser?
I can.
I do not say this arrogantly either.
I can also feel the difference in a -1 as opposed to a +3.
I never argued the math, I said what it "feels" like.

 

[JGGUNS]

Sir, let me respectfully ask you this. Can you stunt a motorcycle? Dirt, street, cruiser?
I can.
I do not say this arrogantly either.
I can also feel the difference in a -1 as opposed to a +3.
I never argued the math, I said what it "feels" like.

Trouble maker!

 

[sixpack577]

Trouble maker!

I know it

 

[SoCal Blur]

Sir, let me respectfully ask you this. Can you stunt a motorcycle? Dirt, street, cruiser?
I can.
I do not say this arrogantly either.
I can also feel the difference in a -1 as opposed to a +3.
I never argued the math, I said what it "feels" like.

This has me very curious. Can you describe how it feels different? When I opted for the +3 rear, I just had a gut feeling that the -1 front wouldn't feel like it would produce as much torque. Now maybe it does but I imagined that it wouldn't feel the same.

 

[sixpack577]

This has me very curious. Can you describe how it feels different? When I opted for the +3 rear, I just had a gut feeling that the -1 front wouldn't feel like it would produce as much torque. Now maybe it does but I imagined that it wouldn't feel the same.

Personally...personally, I agree with that statement.
To me, a -1 front on a busa makes it feel more like a 1000.
Where as a +3 rear just makes it feel all the more torquey.
As I said before some people don't share my opinion, and no disrespect to them either.
Maybe I'm just more in tune to small changes like that given my riding style, I don't know???

 

[JGGUNS]

I would describe it like this:

-1 spins up faster through the RPM range but doesn't feel like it pulls as hard as +3 rear.

 

[Dennis]

Sir, let me respectfully ask you this. Can you stunt a motorcycle? Dirt, street, cruiser?
I can.
I do not say this arrogantly either.
I can also feel the difference in a -1 as opposed to a +3.
I never argued the math, I said what it "feels" like.

I've never tried to stunt a motorcycle. I can reliably adjust my 1/4 mile time by .03 seconds when trying to hit an index, can you? The correct answer isn't determined by who has the most motorcycle skills, it's all physics and is independent of the rider.

I explained the last time why it is the same, and I know you are smart enough to calculate the ratios so you understand what I'm talking about. I do not accept subjective "feel" as proof. I'm not saying you don't believe it, but it's all in your head. You really need to explain the physics behind your claim if you want to have any credibility. Normally you give decent advice, but you really are off the mark on this one.

 

[SoCal Blur]

I've never tried to stunt a motorcycle. I can reliably adjust my 1/4 mile time by .03 seconds when trying to hit an index, can you? The correct answer isn't determined by who has the most motorcycle skills, it's all physics and is independent of the rider.

I explained the last time why it is the same, and I know you are smart enough to calculate the ratios so you understand what I'm talking about. I do not accept subjective "feel" as proof. I'm not saying you don't believe it, but it's all in your head. You really need to explain the physics behind your claim if you want to have any credibility. Normally you give decent advice, but you really are off the mark on this one.

Have you considered that the "feel" has something to do with the fact that, given the same chain length (112 links) the +3 rear sprocket shortens the wheelbase by at least 2 inches over the -1 front sprocket arrangement? The shorter wheelbase increases the likelihood that the front wheel will rise given the same throttle input over the longer wheelbase of the -1 front sprocket. Yes, the gear ratios remain mathematically the same but the geometry is altered. This is also basic physics.

 

[Dennis]

Have you considered that the "feel" has something to do with the fact that, given the same chain length (112 links) the +3 rear sprocket shortens the wheelbase by at least 2 inches over the -1 front sprocket arrangement? The shorter wheelbase increases the likelihood that the front wheel will rise given the same throttle input over the longer wheelbase of the -1 front sprocket. Yes, the gear ratios remain mathematically the same but the geometry is altered. This is also basic physics.

Undoubtedly wheelbase is a factor. Note I stated buying a new chain, that is to keep the wheelbase the same. If that is the only "feel" factor we are discussing then we agree. If you are going to tell me you can feel the extra friction of the chain wrapping tighter on a -1 gear or the extra friction of 4 more total teeth with a +3 gear on the back I won't believe you. I also don't believe a +3 gear shortens the wheelbase by at least 2".