Gear Chart

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MotoPsycho

MotoPsycho

Well-Known Member
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Location
WY, Ooosa (USA)
I'm sure this has been done already, but I thought it could use an easily searchable title for anyone interested.

Gear ratios explained



HIGHER GEAR ratio "number" (ex. 4.08:1) = Lower Gearing - EX. 13t cb/53t spur = 4.08:1 ratio-LOW GEARING!
(High gear ratio number = great bottom end, lower top speed, and less heat generated)

LOWER GEAR ratio "number" (ex. 2.20:1) = Higher Gearing - EX. 20t cb/44t spur = 2.20:1 ratio-HIGH GEARING!
(Low gear ratio number = bottom end suffers, high top speed, and more heat generated)

Keep in mind, you can't fit all of these combinations in your truck! I run a 18/52 and had to modify the engine mount to achieve proper mesh!
 
Why would you go 18/52 and have to modify the engine mount/plate when you could run 17/49 and have a very very simular Gear ratio? Unless you are looking for more gear surface area.
 
great idea moto to post the gear chart as there always seems to be alot of questions posted about what gearing to use, should help alot of people!!:cheers: some reps for the effort!!!!!
 
larsenracing said:
Why would you go 18/52 and have to modify the engine mount/plate when you could run 17/49 and have a very very simular Gear ratio? Unless you are looking for more gear surface area.
Click to expand...



I have done this .. I did it in a pinch .. I stripped out my last 49 tooth and only had a 52 tooth on me .. I used washers to space out the tvp ..

I have ran 17/49 .. I like the all around power you get w/ 18/52 .. Looking foward to them pic moto :Xfingers:
 
So of the above mentioned table which combinations cannot be used in a savage without modification? I think this might be a good add on to the table.
 
well this can't be used w/o mod

13/47/ 14/47 17/52 18/52
 
So other then issues with the gears fitting. Would there be any advantages to say a

15/45 vs. 16/48 vs. 17/51? all are a 3.00 gearing
 
For me, it was about future setup changes I could make with the easily changable "X 4.6" spur gear.

2.89:1 was about the lowest I thought I would ever want to go, but with a "quick and dirty" spur change (to a 46 tooth), I could gear as high as a ratio of 2.56:1 in about 3 minutes (good parking lot race gearing).

That high of a ratio (2.56:1) is not available with any CB smaller than an 18.
 
MotoPsycho said:
HIGHER RATIO = Lower Gearing - EX. 13t cb/53t spur = 4.08:1 ratio-LOW!
LOWER RATIO = Higher Gearing - EX. 20t cb/44t spur = 2.20:1 ratio-HIGH!

Low gear ratio= great bottom end, lower top speed
High gear ratio= bottom end suffers, high top speed
Click to expand...

I don't mean to be picky but these 2 things seem to contradict each other. I understand what you mean by both of them but the wording seems to be confusing.

If we put engine rpm in front of wheel rpm this wouldn't be a problem.
 
MTBikerTim said:
I don't mean to be picky but these 2 things seem to contradict each other.
Click to expand...

Is this better wording? Gawd, I love people that are as anal as I am!
Thanks Tim!
MotoPsycho said:
HIGHER GEAR ratio "number" (ex. 4.08:1) = Lower Gearing - EX. 13t cb/53t spur = 4.08:1 ratio-LOW GEARING!
(High gear ratio number = bottom end suffers, high top speed)

LOWER GEAR ratio "number" (ex. 2.20:1) = Higher Gearing - EX. 20t cb/44t spur = 2.20:1 ratio-HIGH GEARING!
(Low gear ratio number = great bottom end, lower top speed)
Click to expand...
 
So if I want to keep my same gear ratio (3.00) but lower my RPM's then I would go from a 15/45 to a 17/51?
 
Kingsuv said:
So if I want to keep my same gear ratio (3.00) but lower my RPM's then I would go from a 15/45 to a 17/51?
Click to expand...

That, my friend, is an EXCELLENT question! It seems that way because you are increasing the CB diameter and tooth count, causing a slower working rotation - but you are also equaling that effect with the Spur gear.

But alas, the answer is NO! You will not change RPM at a defined speed.

In a 15/45 the CB turns 3 times for every 1 turn of the Spur; hence 3.00:1
Or, 45 divided by 15 = 3

The same is true with a 17/51.
51 divided by 17 = 3

Basically, 17 teeth have to rotate 3 revolutions to mesh with 51 teeth, as 15 teeth have to rotate 3 revolutions to mesh with 45 teeth.
 
So is there any benefit from doing one combo over the other?

I have a 15 and 18 CB and tried the 18 with a 52 spur and didn't like it, too tall for my likings.

I have an OS30 and want to get more top speed out of it without loosing too much low end.

I'm also looking at picking up a 3 speed tranny so I can get a little more out of it.
 
Kingsuv said:
So is there any benefit from doing one combo over the other?

I have a 15 and 18 CB and tried the 18 with a 52 spur and didn't like it, too tall for my likings.

I have an OS30 and want to get more top speed out of it without loosing too much low end.

I'm also looking at picking up a 3 speed tranny so I can get a little more out of it.
Click to expand...

The only thing either offers, is more direction to go higher, or lower. With the 18/15 about your only option is to gear higher with smaller spurs, (more speed)

With the 15/45, about all you can do is go lower - less top end.
 
MotoPsycho said:
The only thing either offers, is more direction to go higher, or lower. With the 18/15 about your only option is to gear higher with smaller spurs, (more speed)

With the 15/45, about all you can do is go lower - less top end.
Click to expand...

Ok Thanks.
 
ok stupid question. I'm runnign 15/49 right now. if i want to get a little more low end what should i go with. i also have an 18 tooth CB but i am placing an order so i can get whatever.
 
parkermarsh said:
Looks like a 13 or 14 tooth CB and a 52 spur is about as low as you can go bud. Are you trying to remove stumps or something? LOL
Click to expand...

top end is pretty damn good with the combo I'm running. i was just hoping to get a little more low end out of it.
 
Your 15 and a new 47 would be slightly lower (3.13:1), or you could use your 49 with a 13 for a pretty extreme drop (3.77:1)

Remember, any change to bottom end will affect bottom inversely, and vice versa...
 
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