+1 up front = great!
- Thread starter Pizz
- Start date
Time for physics 101....
If you take a car with rear wheel drive and put a tire one size over stock to gain approx. 1/2" in ride height or what ever, your speedometer is no longer accurate. If you take a four wheel drive and add taller tires to gain ground clearance and the 'look' that will attract the babes, your speedometer is no longer accurate. You will find that approx. 1/2" height increase due to the larger tire will throw the average vehicle's speedometer out 4-6 kms/hr and you will actually be travelling faster that your speedometer reads.
To prove this, cut the 28" tire and stretch it into a straight line then do the same with a 33" tire. Suprise!! The 33' tire is longer in a straight line therefore in one rotation of each tire, the taller tire travels further. To extend that thought,by increasing the tire height, you will find your rpm is down when travelling the posted speed limit of your favorite road.
So when you add a tooth to your sprocket, the actual circumference increases a tiny bit and your rpm at a set speed WILL BE LOWER and people will write about less buzz in their handlebars etc. If you had a sprocket that added a tooth but had the same circumference, THEN there would be no difference, but who in blazes makes a sprocket with different teeth counts that is the same circumference as stock??!!
And just to mess with you some more, if you play with the rear sprocket, it is all backwards to what I just said about the front. That is why 'trial' and 'trail' bikes etc have such large rear sprockets.:thumbup:
If you take a car with rear wheel drive and put a tire one size over stock to gain approx. 1/2" in ride height or what ever, your speedometer is no longer accurate. If you take a four wheel drive and add taller tires to gain ground clearance and the 'look' that will attract the babes, your speedometer is no longer accurate. You will find that approx. 1/2" height increase due to the larger tire will throw the average vehicle's speedometer out 4-6 kms/hr and you will actually be travelling faster that your speedometer reads.
To prove this, cut the 28" tire and stretch it into a straight line then do the same with a 33" tire. Suprise!! The 33' tire is longer in a straight line therefore in one rotation of each tire, the taller tire travels further. To extend that thought,by increasing the tire height, you will find your rpm is down when travelling the posted speed limit of your favorite road.
So when you add a tooth to your sprocket, the actual circumference increases a tiny bit and your rpm at a set speed WILL BE LOWER and people will write about less buzz in their handlebars etc. If you had a sprocket that added a tooth but had the same circumference, THEN there would be no difference, but who in blazes makes a sprocket with different teeth counts that is the same circumference as stock??!!
And just to mess with you some more, if you play with the rear sprocket, it is all backwards to what I just said about the front. That is why 'trial' and 'trail' bikes etc have such large rear sprockets.:thumbup:
Husband thought of this...
To give you a home made example of this theory....
Take a four wheel drive or pickup (large wheel openings) and mark the stock tire on one portion of the circumference. Jack the rear end off the ground slightly and mark the drive shaft with chalk or tape. Turn the wheel one revolution and count how may times your mark on the drive shaft passes a given point.
If your shaft mark passes 4 and bit times, you will have close to 410 gears.
Now put a larger tire on and mark it in the same way as the first. Again turn one revolution of the tire and you will see the shaft mark only travels about 3.7 turns instead of just over 4. Without changing your gears, you have now made your rearend ratio approx. 370 gears. As such, your engine rpm will be lower at the same set speed of your local favorite road.
So going back to your drive sprocket, if you increase the circumference your rpm will go down.
Further, if there were more teeth on a sprocket and the circumference was not increased to accomodate the chain spacing, would you not have a grinding mess in very short order?
Cheers!
To give you a home made example of this theory....
Take a four wheel drive or pickup (large wheel openings) and mark the stock tire on one portion of the circumference. Jack the rear end off the ground slightly and mark the drive shaft with chalk or tape. Turn the wheel one revolution and count how may times your mark on the drive shaft passes a given point.
If your shaft mark passes 4 and bit times, you will have close to 410 gears.
Now put a larger tire on and mark it in the same way as the first. Again turn one revolution of the tire and you will see the shaft mark only travels about 3.7 turns instead of just over 4. Without changing your gears, you have now made your rearend ratio approx. 370 gears. As such, your engine rpm will be lower at the same set speed of your local favorite road.
So going back to your drive sprocket, if you increase the circumference your rpm will go down.
Further, if there were more teeth on a sprocket and the circumference was not increased to accomodate the chain spacing, would you not have a grinding mess in very short order?
Cheers!
I just installed a 17 tooth (+1) front sprocket (thanks to Pizz for the detailed instructions).
I really like what it did for the riding experience - all the gears are a little taller. It may not have as much flat out acceleration, but it does not feel off by much and it is less buzzy at freeway speeds.
I really like what it did for the riding experience - all the gears are a little taller. It may not have as much flat out acceleration, but it does not feel off by much and it is less buzzy at freeway speeds.
flyingminno
New Member
Just got my kit from indysuperbikes, and due to a slight stock mishap that was settled over the phone, I now am getting driven sprokets +1 for both front and rear, long story. But we shall see how it works out! I've got nearly 17k miles on my bike with stock chain and sprockets so I'm sure it will feel smoother and have just a small amount of rpm improvements. The speedo will likely still likely be a bit optimistic but that's all right.
+1 front and +1 rear? That's only -300 RPM at 70 MPH...
Need some clarification/help. I dropped 2 in the back attempting to lower my RPM's.
Stock gearing: 6th gear at 6k rpm's =70mph
-2 in back:6th gear at 6K rpm's = 70mph (same as stock)
So what's the deal. Was my speedometer off with my stock gearing and I was really only going 65mph at 6k rpm's? and now taking two from the back has made my speedometer accurate?? I'm kinda confused. Gear guys plz help me out... If there is no change then I'm putting my 46 tooth back on!
Stock gearing: 6th gear at 6k rpm's =70mph
-2 in back:6th gear at 6K rpm's = 70mph (same as stock)
So what's the deal. Was my speedometer off with my stock gearing and I was really only going 65mph at 6k rpm's? and now taking two from the back has made my speedometer accurate?? I'm kinda confused. Gear guys plz help me out... If there is no change then I'm putting my 46 tooth back on!
There was a change... the speedo sensor is on top of the gearbox, not on the wheel. If you check your speed with a GPS you will see a difference.
Does anyone in Australia (Melbourne) know where to get a new front sprocket with 17 teeth, the mechanic I go to said his regular suppliers can't find one, don't think they look beyond their own products however & I don't want the mechanic spending too much time searching for one for me..
Hoping I can get one from somewhere in Melbourne city...
Hoping I can get one from somewhere in Melbourne city...
I agree... Feels natural.
Getting more technical...
From a chart that can be found on the attached link (you may have to type the link)....srs6.com/gearratiochart
Our OEM Fornt sprocket is 16 and the oem rear is 44 tooth. This provides a gear 'ratio' of 3.143. I you add one tooth to the front you will get a 'ratio' of 2.933.
The qoute clearly states how to interpret the results.
"Bigger number = Shorter Gearing = Higher RPM's"
Smaller number = Taller Gearing = Lower RPM's
For those using various sprocket combinations, you will find this chart will explain your results.
Cheers!
From a chart that can be found on the attached link (you may have to type the link)....srs6.com/gearratiochart
Our OEM Fornt sprocket is 16 and the oem rear is 44 tooth. This provides a gear 'ratio' of 3.143. I you add one tooth to the front you will get a 'ratio' of 2.933.
The qoute clearly states how to interpret the results.
"Bigger number = Shorter Gearing = Higher RPM's"
Smaller number = Taller Gearing = Lower RPM's
For those using various sprocket combinations, you will find this chart will explain your results.
Cheers!
Last edited:
16/46... I run 17/44. (Stock 6th = new 5th.... 1 gear overdrive)
It's alright. 95% of the time I don't have to downshift to pass on the freeway. 6500 rpm get me 78 mph... this is where I cruise usually on I95. 6K=73, 7K=84.
Maybe without the pipe/PCV combo you will need to downshift but still good enough. Worth the benefit of smoother cruising IMO.
It's honestly 1 gear overdrive. The first gears is so short that you won't see much difference in take of, even 2up.
haha I could so be inappropriate right now. I'll be good.
I went back to stock gearing because I noticed I ran out of power before I hit the rpm limiter on the autobahn. I could only hit 200kmph on flat ground with the 17T, but I could hit 215kmph with the 16T. I'll take the acceleration between the two for about the same top speed....I thought I'd gain a few mph's with the larger front sprocket, but nope. Old dudes in 330 Mercedes still roll past me while I'm pissed that I can't go faster. I'd be happy in the US, don't get me wrong, but with the unlimited stretches here in Germany, I'm disappointed in the XJ6 (but other than that happy).