Honda CBR 500 Riders Forum banner

1 - 20 of 39 Posts

·
Registered
Joined
·
45 Posts
Discussion Starter #1 (Edited)
I'm thinking of changing the sprocket sizes when it's time for me to install a new chain and sprocket set. I've done some research on the forums and internet but still, I'm not certain if deviating from the stock teeth count will give me what I want from my CB500F. I would like some advice from others who have made this change and what you think.

I ride my 2015 CB500F to commute to work on congested city roads with slow-moving traffic on somewhat rough and uneven roads, reaching up to speeds of 40/50 MPH but mostly on speed limits of 30 MPH. I also take my bike out to bigger and faster roads with speed limits of up to 60 MPH. However, this is not done very often and I rarely ever use the motorway (highway)

I've found the gearing range to be very short with the stock sprocket ratios and having to work through the gears a bit too much to my taste. I often find first and second gear to be too responsive and jerky, very small throttle inputs give drastic acceleration or engine braking effects. I feather the clucth at slow speeds but i still find it to be jerky often. Third gear in traffic seems to lug the engine, be less responsive which does help reduce the throttle jerk, however, the bike just feels wrong and unhappy in this gear.

I was wondering if changing away from the standard sprocket sizes would allow me to stay in gear for longer and not work through the gears as much, while still having enough torque with slower speeds and RPM's while also being responsive enough but not so jerky in responsiveness nor be lugging the engine? Am I asking for too much or is this possible to achieve with sprocket teeth changes?

I think back to the 2017 Honda NC750S I learnt to ride on, obviously, it's not the same bike as the CB500F, but I could comfortably reach 20-30MPH in second gear on this bike without it screaming, nor did it have any jerky responses from small throttle inputs.
 

·
Registered
Joined
·
225 Posts
I was wondering if changing away from the standard sprocket sizes would allow me to stay in gear for longer and not work through the gears as much, while still having enough torque with slower speeds and RPM's while also being responsive enough but not so jerky in responsiveness nor be lugging the engine? Am I asking for too much or is this possible to achieve with sprocket teeth changes?
I have a " Sprocket Calculator" link below. You can plug in your original sprockets' sizes, then insert your desired sizes to see the how they change the bike's torque and speed. It also tells you the proper number of links the chain has increased or decreased by the sprocket changes. Hope this helps. Good Luck :nerd:
https://sprocketcalculator.com/
 

·
Registered
Joined
·
36 Posts
I have '16 500F and the best mod ive done aside for gear indicator was to change the gearing... (stock gearing sucked IMHO)

JT Front Sprocket [JTF1381.16RB (55-138116R) steel 16 teeth with rubber damper](factory part has 15 teeth)
JT Rear Sprocket [JTR1303.39 steel 39 teeth] (factory part has 41 teeth)

I felt the factory gearing was too close.... i use my bike as daily commuter on crazy congested CA freeways and surface steeets. Before id often hit rev limiter on freeways and often feel gears were way too close together i could nearly take off from dead stop in second. I didnt like it at all... now the bike rides great - things are a bit more spaced out and since i have always driven a manual transmission vehicle - it feels way more natural in its current gearing configuration. Granted this mod did sacrifice a little acceleration but makes it purr a bit smoother, get better gas milage , and a tad more speed without hitting rev limiter. I still have plenty of torque but if i need more i can always downshift (like one should). Overall the bike so much more fun to ride.... would def recommend this mod to anyone... was so thinking about selling the bike before i did this mod and now i dont want to ever give it up. Id def add a DID Chain 520VX2-112FB (520 x-ring) & 12oclockLabs SpeedoDRD as well to complete the job.


I was wondering if changing away from the standard sprocket sizes would allow me to stay in gear for longer and not work through the gears as much, while still having enough torque with slower speeds and RPM's while also being responsive enough but not so jerky in responsiveness nor be lugging the engine?
YES!


is this possible to achieve with sprocket teeth changes
YES
 

·
Registered
Joined
·
45 Posts
Discussion Starter #4 (Edited)
I'm very interested now, but I have more questions!

Steve77, If I change the front sprocket to a 16 tooth, will this fit without any issues on my 2015 CB500F? Also, If I change the rear sprocket to a 39 tooth, along with the 16 tooth front, will this still give me enough power to climb hills, as my commute to work does involve some semi-steep hills?

Considering perhaps only changing the rear sprocket to a 38 tooth or the front to a 16 tooth, not sure if this will give me what I want however. As mentioned in my first post, I'm not really looking to increase my top speed, I rarely ever do more than 70 MPH, 90% of the time i'm in 30/40 MPH zones, and I dont use the motorway. I want the gears to be taller but still have enough power at low speeds / RPM's to keep me going on flat ground and hills (nothing too crazy) without the engine bogging down, I fear this will happen if I change to a 16/39 tooth set but I have no idea if this is true

I used the SprocketCalculator airhead83 linked, If I change to a 16 tooth front / 39 rear sprocket set, It says I loose around 12% torque and gain 12% speed. I really dont care about the speed but the torque loss concerns me. Would losing 12% cause issues with hills?

If I change just the front sprocket to a 16 tooth and keep the 41 rear, I loose around 7% torque. This seems more reasonable to me but I'm unsure.
 

·
Registered
Joined
·
1,412 Posts
I recommend the 16T front sprocket change. I did that and liked it.
I tried also changing the rear sprocket to 39T with the 16T front.
It worked fine for my riding. Just remember that 5th gear acts much like the original 6th gear in that arrangement... so you don't loose out at all.

I went back the std on the rear and remained pleased with the 16T front. sprocket
 

·
Registered
Joined
·
36 Posts
Steve77, If I change the front sprocket to a 16 tooth, will this fit without any issues on my 2015 CB500F? Also, If I change the rear sprocket to a 39 tooth, along with the 16 tooth front, will this still give me enough power to climb hills, as my commute to work does involve some semi-steep hills?
I dont know... how steep we are talking like San Francisco steep ? I seem to have plenty of power and do take my bike on mountain runs on some weekends without issue. Sure i have to downshift sometimes but its not like a super dramatic maneuver. And didnt require any mods - although i did elect to install a new chain and a speedohealer.

I was pretty apprehensive when i was in your shoes (although for different reason).

But yes ExTex is right when he says..
Just remember that 5th gear acts much like the original 6th gear in that arrangement...
With my setup its almost like you have wider spaced gears and a new overdrive 6th gear (which is great as for my long commute it helps save fuel).
When i need more torque i can simply drop into 5th and go.

The setup works good at slow speeds (20-50) as well, as my commute isn't all on freeway. You wont be able to do a wheelie but doesn't seem like thats your jam anyhow. :)
 

·
Registered
Joined
·
45 Posts
Discussion Starter #7
After doing more research about the speedo being offer with non OEM sprocket sizes, I've been put off making the change. Unless changing the front to a 16 tooth would not cause the speedo to be too far out. However, the whole thing seems like a bit of an investment to try, which I'm not keen to make at the moment. Maybe sometime in the future, if I hang onto the bike for the long term. Just have to put up with how it rides stock for now.
 

·
Registered
Joined
·
43 Posts
I have got a 16 tooth on the front and like it. No chain change. With 39 on back if it gives a 5th that feels like 6 then it must also give a 1st that feels like 2nd.
 

·
Registered
Joined
·
5 Posts
Steve77, what RPM does your 16/39 setup run at 65mph? Also do you have to give it much throttle to start from a stop without stalling?
 

·
Registered
Joined
·
97 Posts
After doing more research about the speedo being offer with non OEM sprocket sizes, I've been put off making the change. Unless changing the front to a 16 tooth would not cause the speedo to be too far out. However, the whole thing seems like a bit of an investment to try, which I'm not keen to make at the moment. Maybe sometime in the future, if I hang onto the bike for the long term. Just have to put up with how it rides stock for now.
$20 for a front sprocket

Ride for a few days and if you like it buy the speedo correction module.
Not too much of an investment
 

·
Registered
Joined
·
5 Posts
Would someone be kind enough to point me in the right direction as to what I would need to buy to correct my speedo on a 2017 CBR500R? I seem to only be finding modules for 13-15 year models. Also how easy is this to install or is it just a calibration tool that you plug in and reflash the ECU?

Thanks
 

·
Registered
Joined
·
134 Posts
With the conversion to a 17T counter shaft sprocket, my bikes speed is about 5-6 mph faster than the "true" speed. The OEM speedometer is about 10% fast. I just add 5 mph to whatever speed shows and leave it at that. I only worry if I am passing cars with regularity. I am not worried about going 2-3 mph faster than the posted speed. Police will not stop you for that. The rpm reduction at any speed for a 16T sprocket just did not strike me as sufficient. With the 17T, I definitely feel the difference. My '17s mileage consistently is in the 70+ range (converted from odometer reading being 13% low after the sprocket change).

There was enough adjustment available even with a new bike's chain to nor require a longer chain. I just moved the rear wheel as far forward as possible and then had enough slack to run the wheel back a bit for proper chain tension.

Ralph
 

·
Registered
Joined
·
5 Posts
It appears that a 17/41 and 16/39 are roughly the same gear ratio. Ralph can you tell me what your RPMs are at 65 MPH? Or can anyone tell me what their sprocket combination os in relation to their RPMs at 65? My whole reasoning for even thinking about the change to 16/39 is to bring the RPMs down in 6th gear on the highway. Stock gearing is running around 5300 rpm at 65 mph. Any insight as to how far this will drop with the above sprocket change is very much appreciated.
 

·
Registered
Joined
·
97 Posts
It appears that a 17/41 and 16/39 are roughly the same gear ratio. Ralph can you tell me what your RPMs are at 65 MPH? Or can anyone tell me what their sprocket combination os in relation to their RPMs at 65? My whole reasoning for even thinking about the change to 16/39 is to bring the RPMs down in 6th gear on the highway. Stock gearing is running around 6300 rpm at 65 mph. Any insight as to how far this will drop with the above sprocket change is very much appreciated.
According to an old post on the site I found, 65 should be around 5100 rpm in 6th
The image from that post is below

And I'm pretty sure mine with factory sprockets runs 6000-6200 at 75ish
The previous owner of yours may have gone to a 14T sprocket
 

Attachments

·
Registered
Joined
·
5 Posts
Slevin you are right that was a typo on my part. Anyway still looking for input on what others RPM is after converting to 16t front 39t rear or a 17t front.
 

·
Registered
Joined
·
15 Posts
Gear Up

Slevin you are right that was a typo on my part. Anyway still looking for input on what others RPM is after converting to 16t front 39t rear or a 17t front.
Matt2911, I just did the 16T change this week (staying with 39T rear). In 4th gear 60kph (37mph) is around 3700 revs. If that helps. I found the bike much better around town from standing starts into turns at intersections I'm not grabbing 2nd halfway through anymore and in the curves I find it's comfortable now staying in 4th and revving up to 5 or 6 or if the curves are wider grabbing 5th and settling around 4/4500. Of course 6th is now also taller but I find the bike will comfortably cruise in top gear around 3500 revs on 70kph or 45mph. JT Front Sprocket 16T
 

·
Registered
Joined
·
19 Posts
I went up one tooth on front sprocket on my '13 CBR500R. Good change to ratios. Now top gear feels right, yet bike maintains enough power for steep hills in top gear. Speedo error is almost 0, (GPS'd), and no change required in drive chain length.
 

·
Registered
Joined
·
134 Posts
It appears that a 17/41 and 16/39 are roughly the same gear ratio. Ralph can you tell me what your RPMs are at 65 MPH? Or can anyone tell me what their sprocket combination os in relation to their RPMs at 65? My whole reasoning for even thinking about the change to 16/39 is to bring the RPMs down in 6th gear on the highway. Stock gearing is running around 5300 rpm at 65 mph. Any insight as to how far this will drop with the above sprocket change is very much appreciated.
I could say, "I'm old. I never go that fast" which largely is true on both counts. I also live in a rural area of Texas where deer are VERY prolific and pose a constant threat to vehicles. I generally cruise at 50 mph (indicated; about 58 true due to 13% gearing increase) When I "did the math" some months ago, after the upgrade to a 17T sprocket, my rpm at any speed dropped by 13% and was much more pleasant at any speed. I hate "buzzy" engines! At least the CB-500 appears very serene at any rpm.

The OEM speedometer readings likely are "optimistic" by several percent so I never really can be sure how fast I'm going. I ride on a mostly rural, secondary roads and I go at whatever speed feels pleasant. I think the rpm drop at 60 mph was about 600, allowing for a bit of optimism in the speedometer readings. Someone with a GPS and a 17T sprocket fitted to his CB-500 could give us true data. Anyone??

All in all, I'm delighted with the 17T conversion. Bottom gear is still very strong for me.

Ralph
 

·
Registered
Joined
·
57 Posts
I'm glad to see that a bunch of riders have responded with their feedback here. I have been contemplating a 16T up front since I've noticed that 1st and 3rd gear are too short in town but 4th is a bit too long. Also, I find that down shifting to 5th on the highway is basically not worth it since 5th will only go to about 90 MPH (at stock redline) and speed limits around here allow for cruising at 80 MPH. I'm hoping that the gear change will make 5th a bit more usable in my area.
 

·
Registered
Joined
·
97 Posts
It appears that a 17/41 and 16/39 are roughly the same gear ratio. Ralph can you tell me what your RPMs are at 65 MPH? Or can anyone tell me what their sprocket combination os in relation to their RPMs at 65? My whole reasoning for even thinking about the change to 16/39 is to bring the RPMs down in 6th gear on the highway. Stock gearing is running around 5300 rpm at 65 mph. Any insight as to how far this will drop with the above sprocket change is very much appreciated.
I could say, "I'm old. I never go that fast" which largely is true on both counts. I also live in a rural area of Texas where deer are VERY prolific and pose a constant threat to vehicles. I generally cruise at 50 mph (indicated; about 58 true due to 13% gearing increase) When I "did the math" some months ago, after the upgrade to a 17T sprocket, my rpm at any speed dropped by 13% and was much more pleasant at any speed. I hate "buzzy" engines! At least the CB-500 appears very serene at any rpm.

The OEM speedometer readings likely are "optimistic" by several percent so I never really can be sure how fast I'm going. I ride on a mostly rural, secondary roads and I go at whatever speed feels pleasant. I think the rpm drop at 60 mph was about 600, allowing for a bit of optimism in the speedometer readings. Someone with a GPS and a 17T sprocket fitted to his CB-500 could give us true data. Anyone??

All in all, I'm delighted with the 17T conversion. Bottom gear is still very strong for me.

Ralph
Nearly everyone has a GPS. Use Google maps on your phone and enable gps speedometer.

16T = ~6.6% lower so about 300-400rpm at 60-70mph
 
1 - 20 of 39 Posts
Top