Questions about gearing for solely dirt riding

[mattygritt]

Hi everyone! I have a 2020 Bashan Brozz with pretty much everything stock. I have put about 500 miles on it. I really only ride on dirt roads. Pretty soft sand. I only seem to ride in 2nd and 3rd going pretty slow down these roads.

I would love a little more power in my bottom end. It looks like my stock Brozz has 17T front sprocket and a 46T rear sprocket.

This is my first and only motorcycle. I am not too sure about gearing and if it'll make a huge difference. But I really only ride the bike going up to at most 40 mph (and even that's a stretch; most of the time I am going 20-25 cause thats the speed limit on these dirt roads). Would gearing down to a 16T front sprocket, and going up to maybe a 50T rear sprocket give me more what I am looking for? Some more power in the lower gears?

I used a sprocket calculator and I really just don't understand the gear ratio stuff. Any advice is appreciated! Thanks!

[XLsior]

not a huge change from a 17t front down to a 16t.


try a 15t front sprocket. Shouldn't require a chain length link taken out with rear wheel adjustment/chain tension.


Front sprockets are cheap...rear sprockets not so much.


After that you can work out if you want a smaller front or if the 16t would be the sweet spot for your riding preferences.


46rear sprocket is fine. 1 tooth change on the rear is minimal effect.



the saying goes 1 tooth change in the front is like 3 in the back.

[Megadan]

Is it a standard brozz with the 17 inch rear wheel, or a RECON with the 18 inch rear wheel?

I do agree completely with the 15 front. The original Hawk has a 15 front and a 50 rear with the 18 inch rear wheel and it's geared perfectly for what you want. With a 17 inch rear wheel the 15 front and 46 rear would be very close to the same.

[mattygritt]

Thanks guys! It is the Recon but in 2020 it came with a 19" front wheel and 17" rear. I'll end up going with the 15T front sprocket then and give it a shot!! Appreciate the advice.

Maybe a dumb question... but how do you know if you have to remove a link from the chain? I am still rocking the stock chain the Brozz came with.

[XLsior]

if the back wheel is fully adjusted out and there is still to much slack in the chain you will need to take out a link if you're dropping down teeth in the front.

[Thumper]

Yes! Dropping a couple of teeth on the front will drop the ratio on every gear by about 11%


You will definitely notice 2nd and 3rd have a little more torque, and going 11% slower at a given rpm. Of course it also means 11% slower at same rpm in 5th on pavement!

It is actually amazing that you are still using the original chain, a 428. If the new gearing works for you, you might consider an upgrade to a RK Takasago 428H chain. Just $23. It will be quieter and stronger, and mate well during breaking in period on the new front sprocket.

I upgraded to 520 chain with sprockets on my Brozz (Bashan) Storm, but probably would have been OK with the better 428H chain.

By the way, I really like that original Recon. NICE bike! And I'll bet it's holding up well. My storm was identical, but black red and white colors. Correction: The recon came with knobbies. That's the only difference as I recall. I got dual sport tires that I got rid of within a month!

[red2003]

Gearing comes down to rpm. What rpm are you seeing when you feel you need more "bottom end power"? Changing the gearing isn't going to give you any more or less power, it just changes the rpm range of each gear. For example, if 25mph is currently 6000 rpm in your gear of choice, that's where your bike is prob building max torque. Changing gearing will have no effect for you. If 25 mph is only 4000rpm, then shift down a gear and bring the rpm's back into the torque band. To summarize, unless you are running out of gearing on the top end in 5th gear, or 1st gear isn't providing enough rpm at your slowest speed, changing gearing isn't going to help you at all.

[Thumper]

Originally Posted by red2003

Gearing comes down to rpm. What rpm are you seeing when you feel you need more "bottom end power"? Changing the gearing isn't going to give you any more or less power, it just changes the rpm range of each gear. For example, if 25mph is currently 6000 rpm in your gear of choice, that's where your bike is prob building max torque. Changing gearing will have no effect for you. If 25 mph is only 4000rpm, then shift down a gear and bring the rpm's back into the torque band. To summarize, unless you are running out of gearing on the top end in 5th gear, or 1st gear isn't providing enough rpm at your slowest speed, changing gearing isn't going to help you at all.

Not exactly what he is asking, and changing the gearing WILL help him.

His 2nd and 3rd gears are too tall for his riding conditions. The engine isn't revving high enough to be in the more powerful part of the powerband under those conditions. He wants a little more torque under those conditions. Increasing the rpm by 11% WILL give him more REAL POWER, ACTUAL TORQUE difference in those gears under those conditions, because the engine will be running at a higher rpm. This assumes that he won't change his choices and start running in 3rd and 4th under those conditions!

The real difference will be that he has more gears to select from that keep the engine higher in the rpm range that produces more power. 1st is too low geared, and 2nd/3rd are geared too tall for what he needs. That 11% change will help in the gravel/sand.

[mattygritt]

Originally Posted by Thumper

Yes! Dropping a couple of teeth on the front will drop the ratio on every gear by about 11%


You will definitely notice 2nd and 3rd have a little more torque, and going 11% slower at a given rpm. Of course it also means 11% slower at same rpm in 5th on pavement!

It is actually amazing that you are still using the original chain, a 428. If the new gearing works for you, you might consider an upgrade to a RK Takasago 428H chain. Just $23. It will be quieter and stronger, and mate well during breaking in period on the new front sprocket.

I upgraded to 520 chain with sprockets on my Brozz (Bashan) Storm, but probably would have been OK with the better 428H chain.

By the way, I really like that original Recon. NICE bike! And I'll bet it's holding up well. My storm was identical, but black red and white colors. Even the tires were identical!

Good to know! I am really excited to see what the bike feels like when I make the change. I think that sounds like a good idea. I'll test things out with the stock chain and I'll upgrade to the chain you linked when. I feel like I am satisfied with the 15T front sprocket!

Thanks too! I love the look of the Recon. Really love the brown and black combo! It's been such a fun bike. Perfect for what I needed! I am really happy I got it. I'm still using the stock nobby tires it came with too, they've really outperformed my expectations I had of them lol!

[Megadan]

Originally Posted by red2003

Gearing comes down to rpm. What rpm are you seeing when you feel you need more "bottom end power"? Changing the gearing isn't going to give you any more or less power, it just changes the rpm range of each gear. For example, if 25mph is currently 6000 rpm in your gear of choice, that's where your bike is prob building max torque. Changing gearing will have no effect for you. If 25 mph is only 4000rpm, then shift down a gear and bring the rpm's back into the torque band. To summarize, unless you are running out of gearing on the top end in 5th gear, or 1st gear isn't providing enough rpm at your slowest speed, changing gearing isn't going to help you at all.

Gearing does change the amount of torque at the rear wheel. That's what gear ratios do, divide rpm and multiply torque. Horsepower doesn't change because it is a function of rpm and torque. Changing gear ratios just alters the relationship between those two on their side of the equation.

[ProDigit]

Totally opposite of what I'd do, but, yeah, go with a 15t, and if you want more after that, get a larger rear sprocket. But I'm fairly sure 2 teeth on the rear will do a lot, allowing you more flexibility. It's just that, for loose sand, a 250 is kind of overkill. A 150 would've had the power you need, and you could've geared it to reach 5th gear, and still spin your wheel in the first 3 gears.
It's be a lighter weight bike as well, which helps when you fall.

[ProDigit]

Originally Posted by Megadan

Gearing does change the amount of torque at the rear wheel. That's what gear ratios do, divide rpm and multiply torque. Horsepower doesn't change because it is a function of rpm and torque. Changing gear ratios just alters the relationship between those two on their side of the equation.

Hp rating of the engine doesn't change, but changing to taller gears, definitely changes HP to the wheels.
Not only because one can now reach top speed at hp peak, rather than at redline (where the bike has lower HP), but also, by increasing the load on the engine, you can extract more energy out of it.

Hence, lower gears, net more torque, but lower HP.

The results of torque can be seen by how fast it accelerates,
The results of HP can be seen by how fast the bike can get.

[Thumper]

Originally Posted by ProDigit

Totally opposite of what I'd do, but, yeah, go with a 15t, and if you want more after that, get a larger rear sprocket. But I'm fairly sure 2 teeth on the rear will do a lot, allowing you more flexibility. It's just that, for loose sand, a 250 is kind of overkill. A 150 would've had the power you need, and you could've geared it to reach 5th gear, and still spin your wheel in the first 3 gears.
It's be a lighter weight bike as well, which helps when you fall.

OP can drop two teeth on the front sprocket for a 11% gearing change, and probably won't even need to remove a link. Adding two teeth on the rear would drop rpm 2/50 = about 4%. He probably won't need a new chain with the larger new rear sprocket, but removing a link would be the opposite... Dropping 1 tooth on the front sprocket would give OP a 5% drop in speed at same rpm, with the same/similar gearing advantage to adding two teeth on the rear sprocket.

Front sprockets are less expensive, and OP wants to explore this gearing change. It may be the opposite of what you would do, but it is a low cost option/test. I was amused at your suggestion to use an ethernet cable to rewire a harness in another thread. Talk about opposite...Now that is a bold and fascinating proposal! Clearly you have novel ideas for motorcycle maintenance and repair. I recently wired up an isolated lighting system on my KTM. I used spools of 12, 14 gauge wire and brass end connectors with insulation. I guess I went a little more boring and "conventional".

[Megadan]

Originally Posted by ProDigit

Hp rating of the engine doesn't change, but changing to taller gears, definitely changes HP to the wheels.
Not only because one can now reach top speed at hp peak, rather than at redline (where the bike has lower HP), but also, by increasing the load on the engine, you can extract more energy out of it.

Hence, lower gears, net more torque, but lower HP.

The results of torque can be seen by how fast it accelerates,
The results of HP can be seen by how fast the bike can get up to.

I never said HP rating changed, nor is anybody talking about at the engine... So your reply is confusing. We are strictly talking about sprockets, so the engine isn't even a factor here since this is about gear reduction between the counter shaft of the transmission and the rear wheel.

Gears do not affect horsepower. Period. Sorry, but you are wrong.

Torque does affect acceleration, nobody argued that. Again, not sure what your argument is here exactly.

Horsepower is the result of calculating an equation involving both torque and RPM. It's a measure of energy from Force over distance and time. That's it. Torque is the measured force. The Distance and Time is the Revolutions per minute of the rear wheel (in this instance). Since the gear ratios multiply AND divide said force and the rpm by the same ratio, the resultant horsepower figure remains unchanged.

This is algebra 101 stuff and I won't argue this further. I am correct on this. If you want to argue more, go hit up google and do some more studying. I have little time for know-it-all arguments.

[Thumper]

There are thousands of webpages on torque multiplication using gear reduction.
Here is one:
https://bauergmc.com/4-major-advanta...r-reducer.html

OP will gain significant torque increases with a 11% reduction in gear ratio. This is what he needs. It will allow his 14hp engine to power him through high friction surfaces like sand/gravel with more torque. Chaindrive systems are actually more efficient than gearboxes, but they need more maintenance. This really is simple math.