Honda Grom Sprocket Upgrade Everyone Should Do - Can gearing down increase torque and speed?

[@MatthewRooney-qn7ej]

I have a 2020 Honda Grom. My only performance mod is a Chimera Cold Air Intake. I weigh around 195lbs. The fastest I've ever had my Grom is 68mph GPS verified. I hit my rev limiter. The gearing I'm running is 15/36.

[@poisondragon5670]

@@MatthewRooney-qn7ej I hit 70 down hill full tucked

[@Disorientation_]

As a 115 pound rider that can full tuck, it is hilarious watching these 180+ pound men struggle to hit 60 on a grom. I kept stock gearing on mine and top out at 73.

[@DiogenesOfCa]

I weigh 270 pounds, my poor grom struggles to go 55!

[@HashMaster1776]

lol… you’re below the average weight and height 🤣 you must be like 5 foot 4 also lol so… no surprise there

[@jesseparsons5701]

They really rip that quick with a lighter rider? I'm about the same 120 if I don't take a shit.. been thinking about snaggin a grom but have been looking into speed upgrades. But if it rips at 70 with you on it i think I'd be good

[@mzgarage]

They take quite awhile to get up to those speeds

[@Disorientation_]

@@jesseparsons5701generally you won’t be hitting 70 for long at all. You will be uncomfortable and the bike will hate you. Expect to cruise around high 50’s the majority of the time

[@Johnbon555]

Good explanation near the end

[@mzgarage]

Glad you think so!

[@rivit7615]

These determine speed electronicly so you will need to install a speed correction unit to get your speedo to display the TRUE speed if you have altered the sprockets gear ration. Try using a GPS speedo with both sprocket setups so that the electrinics cant skew the results. You will surely increase the acceleration since the larger rear and smaller front provide more torque but top speed maybe not.

[@poisondragon5670]

If the bike says it’s going that fast it’s going that fast same reason as to why when you push the bike in eureka it still goes 1 2 3 mph

[@user-co6ww2cm9k]

wouldn't the newer ABS grom use the abs disc instead of the RPM

[@Disorientation_]

@@poisondragon5670 thats not at all correct. messing with gearing throws off the spedo.

[@rivit7615]

@@user-co6ww2cm9k Good point. I'm not sure.

[@supericeman1]

@@poisondragon5670 after I got the grom tuned with dhm stage 1, when I drove past one of those signs where it measured your speed, I've noticed it's 2mph off than what it says

[@silvercrxsi]

It doesn’t reduce your top speed because in this case you aren’t hitting the rev limiter because the motor simply doesn’t have the power to do that , in theory the gearing would reduce the overall potential top speed

[@graemegeorgeharrison2468]

Just clocked 72mph on my stock Grom I’m about 82kg

[@joeyformoso3066]

I prefer to go one tooth bigger in the front and save my motor,

[@baseballfanatic110]

I’m new to biking and needing a little bit of help! I have a 23 grom and I have an exhaust, air intake, and currently waiting for flashed ecu. Would upgrading the sprockets help even more with speed? I keep seeing people saying 14t front and 40t rear sprockets so I’m wanting to try that. I just didn’t want to hurt the performance I’ve already dropped in to the bike

[@mzgarage]

I cannon speak to the 23 models. They have different gearing and are 5 speed instead of 4. From my experience, you will appreciate the increased low end on these bikes even if you did lose a little top end. The sprockets for these are very inexpensive compared to a regular bike and easy to swap back if you didn't like it. It should be possible to swap gears without replacing the chair or taking it off depending on how much bigger you go in the rear.

[@orionsanford4440]

13 front 42 rear and see what happens trust me. I race groms professionally for reference.

[@NJreellife]

@@orionsanford4440does this hurt top speed by a lot? wouldn’t care if the top speed is hurt a little, i just want more torque on take off

[@orionsanford4440]

@@NJreellife yes quite a bit I definitely do not recommend for every day riding only if you are going to race or stunt

[@NJreellife]

@@orionsanford4440 what would you say the best rear sprocket size would be for a 14 front?

[@irongoatrocky2343]

did you use a 420 or 428 chain?......what length....100 ? 104? 106?

[@mzgarage]

I put links to what I purchased in the description. It was a 420 and a bought 110 link and removed 2. It is available in 108 link.

[@irongoatrocky2343]

@@mzgarage thanks for the reply

[@theethoughtschannel]

What about vibrations?

[@mzgarage]

I didn't notice any change.

[@monsanto1984]

14x40 the best accelaration. Rather than 15x37 becuase this gearing is made for high speed but no power up hill accelaration

[@pneumonical]

so for wheelies would 14 40 be better

[@friktionrc]

@@pneumonicalin short, yes. Better the acceleration the easier to pop a wheelie

[@xzander4311]

will i need to get a new chain? if so how do i know what chain to get for the gearing i want to use?

[@mzgarage]

I was able to use the stock chain with the sprockets I purchased by moving the rear axle all the way forward. I ended up getting a new chair because the stock one has some rust on it. There are sprocket calculator websites that will tell you the number of links you will need based on the number of teeth on both sprockets.

[@Wanderin73]

Have a link for that calculator you used?

[@mzgarage]

I will take a look and see if I can't find it. There are many sites out there. If you Google search "sprocket calculator" you will find many.

[@rodneysweetnam8653]

Hi - its Big Rodders in Ireland. Check out Gearing Commander. It has stock bikes on file and enables you to change sprocket sizes and tyre profiles to give you altered speed and revs. I find it extremely useful. The two top gears in both the the 4 and the later 5 speed speed models have identical top speeds at max power - I've seen a lot of rubbish spouted on KZbin about the 5 speed being faster.

[@daynuhbraps]

So the gen 3s are 15/38 stock... would you leave the rear on this or go up to 40? More into stunt riding and this gearing is okay, but my girlfriends gen 2 after the 14/37 upgrade, hers actually goes faster than mine now 😅Dont wanna lose a whole lot of top end either 🤷‍♂️

[@mzgarage]

What you are topped out, are you hitting the rev limiter or just not able to go any faster?

[@daynuhbraps]

@mzgarage never hit the Rev limiter in 5th. Top speed varies. Calm day flat road 65 is pretty manageable. Almost touching red line with that

[@mzgarage]

If it seems like there are some more revs to go, I don't think it would hurt to try. The sprockets cheap compared to large bikes. Just remember the speedo may still read faster regardless depending on where the sensor is.

[@ss_whole]

I have a 2023 Grom, 5'th gear was a joke, seemed like the bike was coasting, I couldn't even use 5'th, (I weight 210 lbs.), I put a 14 tooth up front and got noticeably better acceleration and could now shift into 5'th but the bike still can't pull redline in 5'th, I think I should go up to a 40 tooth in the rear.

[@monsanto1984]

All this gearing are for high speed. If you are looking for fast accelaration. I mean more power up hill. Use 14x40 sprocket like mine now. To much power already going up hill.

[@Emcipio]

Groms have the speedometer sensor on the front wheel. Changing the gearing will not affect the accuracy of the speedometer.

[@mzgarage]

What year do you have? Mine definitely does not have that.

[@saulopena9840]

Does anyone know the correct grom rear sprocket size in diameter? I have a 17 tooth front (420)

[@mzgarage]

Are you asking for a diameter measurement or tooth count?

[@saulopena9840]

Many 30t sprockets diameters vary. I just need the right sized 30t

[@ProDigit80]

2:00 You did the wrong thing. Should've gone +1 to +2t up on the front, and -3 to -9t in the rear. Reach top speed in 3rd gear instead of 4th. Save acceleration time shifting only 3x instead of 4x. Also, your perception of acceleration is flawed, not reality. It FEELS like you're accelerating faster, just because the engine revs through the gears faster, but what really happens is you're only going faster from 0 to about 5 or 6k rpm in first gear. Second, third, and fourth gear are not really faster than stock; a rolling start should prove that.

[@mzgarage]

I disagree with pretty much everything you said lol

[@user-co6ww2cm9k]

wack

[@jonahill6440]

Does anyone know a good place to get get tail bars for wheelies that arent £300 plus

[@mzgarage]

All of the ones that were recommended to me cost that or more. If you find something good, please share a link.

[@GarrettGrensteiner]

Everything should be geared so the transition always has the advantage. Fact is allll transmissions are designed by the same pple .. and thers only a few different kinds in hundreds of different kinds of vehicles.. and there's week links built into all of them.. hence nothing can reach its full potential. The world we live ..the powers that be hold back technology trickling it down to us. I enjoyed the experiment thank you😊. It's a sweet bike! What you need is another double sprocket. In between the engine and the tire 21 tooth in 29 tooth to the tire So you can keep the output sprocket small and the rear larger lol. Too bad they don't just use taller gears in the transmission with slightly faster ratios. When I worked at Polaris, I asked an engineer.Why don't we design our own transmissions and engines? And alternators. He informed me that's not how it works.. Look at all the different lawnmowers out they are all the same thing.. lol ..With Different seat mower deck and fenders... Can't make this s*** up. A model T got 25 mpg. And it's still the standard for cost per mile.. sorry for the rant😅. Peace be with you

[@jonahill6440]

My 21 grom is stock and can reach these speeds, i am very light tho 😅 8:17

[@mzgarage]

Yea, I dont know how the comparison would be. I know they have different gearing in the 20's and up, I believe.

[@jonahill6440]

@@mzgarage yh my groms top speed usually sits at about 66mph but depending on whether and tire pressure and other variables it's been known the get up to 70 so I can't wait to kit it out n see what it gets to

[@jonahill6440]

​@@mzgarageoh shit I only just realised your the creator of the vid, it's really cool that you acc interact with ur viewers you've just got urlsef a new subscriber 👍

[@stefanie_m466]

it shifts gears like a truck, also the speedo meter is attached to the counter shaft. also it hates high rpm. well. it runs faster on gps with a 16/34. the 14/34 was like more shifting than driving. the throttle doenst give enough fuel and air for high rpm.

[@orionsanford4440]

Is anybody running a 13/42 on a 23?

[@jeffbullock2212]

I'm running 13t and stick rear. It's quick but bounces limiter at around 62is speedo says 71 but not corrected.

[@orionsanford4440]

@@jeffbullock2212 I run 15/42 now along with Aracer mini X and wideband O2 sensor a.k.a. AF2, racing Bros rear mono R chican shock, 10w front fork oil 225ml in each fork, the speed shop cam chain tensioner and cam cover, chimera intake and Vance and hines exhaust

[@franklinfocus]

13T in the front 40T in the rear for me 🙏‼️💯👑 Top speed: 53mph 2018 grom

[@mzgarage]

Wheel happy!

[@stratblacknosugar.5125]

This is a slow bike, if you want more speed get a different bike..

[@mzgarage]

I have two faster bikes, don't worry!

[@cooliipie]

0:58

[@bnolsen]

The sprocket change does work. I think I have this same set, but also a stage 2 with chinera, full yoshi exhaust and tb parts cam, and also a kitaco clutch cover kit. Speedometer is wildly off.

[@Casey_E]

​@@bnolsenDid the clutch cover make a noticeable difference?? I've got a 2020 and thinking about getting the Kitaco..