[Old w/2 many guns & bikes]

All speed readings from GPS as any change in front sprocket size
changes speedometer readings. 185 lb. rider. 87 octane NON-ethynol.

Flat test: 2385 elev. Windy

wind at back: 15 tooth - 58 mph ..... 14 tooth - 57 mph

head wind: 15 tooth - 48 mph ..... 14 tooth - 49 mph

Hill test: 1mile, 6% grade, base 3400 elev.

Down hill: 15 tooth - 62 mph ..... 14 tooth - 60 mph @ redline

Up hill: 4th gear: 15 tooth - 46 mph ..... 14 tooth - 48 mph

Up hill: 3rd gear: 15 tooth - 48 mph ..... 14 tooth - 47 mph @ redline

 

[Old w/2 many guns & bikes]

14 tooth sprocket MPH test conclusions.

The 14 tooth (or 13 tooth) is only helpful if:

1: you want to lift the front end easier.
2: you want quicker one or two block stoplight to stoplight times.
3: you need lower low to mid speed gearing because you are
well over 200 lbs. or ride two-up a lot.

For those wanting to gain (and be able to hold a higher speed) (55 uphill)
the 14 tooth appears to be of no use. A downshift to 3rd with the 15 tooth
equaled the best 14 tooth speed; and even if you do other mods, you are
already hitting redline with the 14 tooth, so there is no room for improvement.

I'll test again when I get a 16 tooth.

 

[mad8vskillz]

awesome info for street riders

 

[FXCLM5]

the bike makes so little power,

i feel like today it has 7hp out of the max 10

and yesterady it had like 10/10

i couldnt even make the bike accelerate in 4th gear today, i had to downshift it in 3rd and redline the bitch 2 keep it going then shift it into 4th and watch the speedo drop... wtf

 

[loaded]

Great post. These are my findings as well. I went back to 15T (stock) overall best.
Also with the 14t and lower you are just running the motor to death.

 

[GromGuy]

the bike makes so little power,

i feel like today it has 7hp out of the max 10

and yesterady it had like 10/10

i couldnt even make the bike accelerate in 4th gear today, i had to downshift it in 3rd and redline the bitch 2 keep it going then shift it into 4th and watch the speedo drop... wtf

That's weird, maybe the engines needs more of a break in? I know cars are like this, you have to keep driving them for some time till you start to get the power and MPG stated on paper.

 

[FXCLM5]

hope so, my grom is still under 100 miles with the original oil in it 2.

 

[Stray Dog]

I must say I'm a little surprised at some of your findings.
I'm not desputing them, but my grom has reached over 100km/h (60mph) on the flat without coming close to the red line, satnav verified.
Fyi I weigh 270lbs

Dog

 

[mad8vskillz]

I must say I'm a little surprised at some of your findings.
I'm not desputing them, but my grom has reached over 100km/h (60mph) on the flat without coming close to the red line, satnav verified.
Fyi I weigh 270lbs

Dog

Broken in vs new maybe?


Sent from Motorcycle.com Free App

 

[sicduc]

I'm 230lbs and the best I've seen with stock gearing is 59mph on flat ground with no tuck... lol

 

[Crashking]

Just curious, what was used for GPS numbers? Dedicated handheld GPS? Or cell phone?

 

[CiscoSanJose]

Just curious, what was used for GPS numbers? Dedicated handheld GPS? Or cell phone?

Getting Possible Speed

Getting Rid Of Money
:motorcycle2_smilie:

 

[Dodgerider26]

Just adding my .97... My Grom noticed no change in top speed with a tailwind or headwind, between the 15T and 14T sprockets. I did notice a significant change in ability to maintain speed up hills, especially with a headwind. Also, I'm still pulling speeds between 65-70 with my 15T and 14T.

Is your bike broken in yet? The engine is drastically different after 100mi and even more different after another few hundred. I'm over 1,000 now and this isn't the same bike I had at 300 or 400 miles....

 

[Lawdog78]

Just adding my .97... My Grom noticed no change in top speed with a tailwind or headwind, between the 15T and 14T sprockets. I did notice a significant change in ability to maintain speed up hills, especially with a headwind. Also, I'm still pulling speeds between 65-70 with my 15T and 14T.

Is your bike broken in yet? The engine is drastically different after 100mi and even more different after another few hundred. I'm over 1,000 now and this isn't the same bike I had at 300 or 400 miles....

You are saying after 1000 miles that your Grom picked up 10 to 15mph on the top end? That doesn't make sense

 

[Gromlin]

Its good to hear it gets better but yeah that is a HUGE gain or 15 mph

 

[turbo chris]

Its good to hear it gets better but yeah that is a HUGE gain or 15 mph

Exactly!!