Grom gearing/speedometer

Where does the Grom speedometer pick up from? Is it accurate all the time, or affected by gearing?

I’m trying to figure out if I can trust the speedometer or not on the street.

 

I remember reading that gearing did affect the Grom speedometer. Couple places had a speedometer correction device. I sold mine a couple years back but I do remember asking the same question.


Hard racing has them for sale

https://store.hardracing.com/cart.p...id=30021&xid=AQhGoSJTvXgSkgMyQHxh5wkhIevsm404

 

this one would be very accurate for you
https://www.swimoutlet.com/p/sporti...MIufn8m--P5QIVjp-fCh1uRADhEAYYAiABEgIyz_D_BwE

 

True. I am just looking for a ballpark figure, within 5-10mph or so.

 

I would pay good money to see the Johnson City police chasing you on the Grom.

 

Anybody know how to figure how much?

FWIW - I am +2f / -2r from stock, and in 4th gear at 7000rpm I am reading 60mph.

I know down in the front and up in the rear makes you read a lot faster than you are actually going. I assume going up 2 teeth in the front and down 2 teeth in the rear would make it read slower than I’m actually going, right?

 

Agreed. I have a Garmin on the Multi and I was surprised at how the speedometer and GPS will be damn near identical.

 

It is amusing blowing past people on a littleass bike.

 

But that takes effort. It’s easier to just beeboogle that shit.



Actually, I was playing on The Grom for a few hours earlier, I shoulda thought about that.

I have nowhere to mount it though. I reckon I could start a “trip” with it in my pocket, then reach a particular top speed (Speedo), then take the Garmin out and compare it to the top speed of the trip.

 

so you're saying the R6 i saw on Craigslist won't do 215 mph ?

 

Here is a calculator that might give you the answers you're looking for.

https://www.12oclocklabs.com/sdrd_calc.php

 

Well. Shit.

I reckon pimping The Grom is the only viable option.

 

Buy an eBay garmin watch and strap it to the bars. I have only taken cycling GPS readings into the low 50’s, but i see no reason it wouldn’t remain accurate to highway speeds.

Only disadvantage is that you will have to start an “activity” every ride, but my battery lasts like 5 days without any activities and like 20 hours when tracking GPS.

 

RAM makes an awesome little quick clamp mount for the handlebar.

 

Can't you just have someone ride next to you or behind you in a car? Close enough.

 

Find a cop and ask him to run a radar on you