Two teeth down?

[Cos]

So, when they put on my new sprockets the other day, i discovered that they put a 44 rear instead of a 46. No biggie, i thought about gearing it a bit taller anyway. I was telling somebody today and he goes "No, it's really bad if you change the rear and keep the front as is."

Huh??? Since i've never heard of this, can anyone tell me if it's true or some kind of urban legend?

[Mustang]

pheh! urban  
3 teeth down on the back is =to 1 up on the front
and vice versa

[JetdocX]

DO NOT RIDE THAT BIKE.  IT WILL SURELY 'SPLODE!

Definitely not going to be any better onfroad, but you might like the reduced revs at freeway speed.

And your wheelie-abilities will surely suffer.

[Cos]

Pretty much what i thought.

Bike's still doesn't feel like it's lost any power down low.

As for wheelies Doc, not my strongest point to begin with.  :lol:

[Mustang]

Here's a handy chart that shows what gear ratio (final drive ) diff. combinations of gears will acheive .
front sprocket size across the top rear sprocket down the left side .
Gear Ratios - Motorcycle Front/Rear Sprocket Combinations
 
      14    15    16   17    18    19
49 3.50 3.27 3.06 2.88 2.72 2.58

48 3.43 3.20 3.00 2.82 2.67 2.53

47 3.36 3.13 2.94 2.76 2.61 2.47

46 3.29 3.07 2.88 2.71 2.56 2.42

45 3.21 3.00 2.81 2.65 2.50 2.37
 
44 3.14 2.93 2.75 2.59 2.44 2.32
 
43 3.07 2.87 2.69 2.53 2.39 2.26
 
42 3.00 2.80 2.63 2.47 2.33 2.21
 
41 2.93 2.73 2.56 2.41 2.28 2.16

40 2.86 2.67 2.50 2.35 2.22 2.11
by webBikeWorld.com

[John Stenhouse]

Mustang, would you know how to convert those ratios to give revs in top gear at a set speed? Say 70mph?

[Mustang]

no but on my steamer , I can tell you that 1 tooth change on the front sprocket equals 500 rpm change either direction in top gear .
ie. 18 tooth front 65 mph rpm is just over 4500
17 tooth at same speed is 5000

[John Stenhouse]

OK that's good to know.

[blacktiger]

I can confirm that with a 19 front with standard rear you get :-
50mph@3000rpm
65@4000
80@5000
95@6000
etc. So you're looking at 15mph/1000revs.
Only God and someone in the Triumph design office knows why they fit an 18 front on the Tiger when every other model has a 19.

[John Stenhouse]

Only God and someone in the Triumph design office knows why they fit an 18 front on the Tiger when every other model has a 19.

Because it wont pull on the steep alpine tracks without that 18 tooth front, you need to slip the clutch even then  8)

[FullMonte]

They should've made first lower and sixth taller.  I thought about going up a tooth or two on the rear but when 90mph equates to 6k rpm and 30 mpg, I'm glad I didn't.

[Stretch]

They should've made first lower and sixth taller.

Word.  I would love for some enterprising adventurer to chime in about how the 'first and sixth gearsets from a Triumph ________ will drop right in with no modifications'.

I'll wish us up a cure for cancer while I'm at it.

[mff]

checked my 02 Tiger- it has 18 front - 46 rear
if I go to 19 front - 43 rear- what will it do to my mpg / performance?

[Mustang]

checked my 02 Tiger- it has 18 front - 46 rear
if I go to 19 front - 43 rear- what will it do to my mpg / performance?

In theory you will get better gas mileage ...................but your performance is going to suffer horribly .
It will be like dropping 6 teeth from the rear , you will slip the clutch alot in 1st and  you will be downshifting a lot when you want to pass , it will take forever for rpm's to climb  in any gear .
Too drastic of a change in my opinion .
A KLR will probably be able to spank you  :shock:

[Cos]

Yep. Either go 1 up in the front or drop 2 in the rear. We went on a two-up day trip on Sunday and i'm happy with mine.