RC51 Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
44 Posts
Discussion Starter #1
Alright guys it has come time to change AT LEAST my rear sprocket and chain on my 2003 rc51, but I am not really sure as what to get. right now it is stock gearing. I have been trying to do some research but am still confused on whats right for me. I live in missouri, and alot of my riding is in town riding, but I still ride on the highway when commuting to work and other places. I am running the stock tire size.

Can anyone point me in the right direction as what to get for either both sprockets or at least the rear and chain. From what I have read the stock gearing is really tall on these bikes, I am just not sure where to go with it so it fits my riding style the best. No i dont ride wheelies, I just like crusing.

Thanks,
Bryan
 

·
Premium Member
Joined
·
2,697 Posts
Bryan,
Use the "search" function; I've seen some threads on Zilla and a write up on ROGUE. But anyway here is my $0.02
I'm running a 15/40; 530; 190/50-17 setup right now. Stock is 16/40; 530; 190/50-17. All I have done is street ride with the bike so far and it works well for me. This winter I'm going to a 190/55-17 and also be looking into a 41 tooth rear. I don’t want to give up chain life of the 530 for the performance benefits of the 520. Don’t see that it's worth it for a street bike. Fuel mileage I really can't tell you anything about, never really paid attention to that. With 15/40 and 190/50 I was about 3.5-4k rpm at hwy speeds in 6th (if I remember right). I also need a speed-o healer. I've read that our bikes are meant for a 15/41 or a more spirited 15/42 setup. I have done the flapper and pair mod this winter and I'm hoping to get a pc3 and tuned before spring. So a write up after really wouldn’t valid for just a gear change. IMO no one can tell you the right set up for you, just the right one for them.
Good luck, have fun, Ride Safe,
James
 

·
Registered
Joined
·
728 Posts
15/41 is what I have always heard for track but if your just cruising stick with stock or even go smaller in the rear 16/38, not sure if there is room but try 17 front.
 

·
Registered
Joined
·
105 Posts
I've got 15/41 on mine. I really like it so far.

Once the weather warms up, you can take it for a spin to see what the diference is from yours.......
 

·
Registered
Joined
·
44 Posts
Discussion Starter #5
Is there any sprocket I can put on just the rear that will make it like a 15/41 setup so i dont have to spend the extra money on the front also? Gish man did u ever figure out your electrical problem? I just got my stator in yesterday and am thinking about tackeling it this weekend? I never heard back from you on kcsportbike, not sure if it was on your part or the new forum setup??
 

·
Registered
Joined
·
105 Posts
The general rule is going down/up one tooth in the front is the same as three in the rear. And, going down in the front is the same as going up in the rear. Soooo, Going up four in the rear would be similar to down one in front/up one in rear. Problem is that you would need a longer chain for that much larger rear sprocket. (I think).

I think my electrical issues are solved.....or at least they didn't show up on my last ride. I'll see what happens once I get out more in the Spring.
 

·
Registered
Joined
·
728 Posts
Agreed with Gish, you can go up 2-3 in the rear to get same effect as going down 1 in the front but didnt you say you didnt want to wheelie.... so why wouldnt you go down in the rear or up in the front? If you go up in the rear more than likely you will need a new chain especially if you dont go down in the front but this kind of configuration basically reduces your HP (top end) and increases your torque (bottom end) causing you to wheelie easier and lose top end and essentially decrease your fuel efficiency at cruising speeds as your engine will be at a HIGHER RPM to achieve the same speed. So if you go down in front, up in rear, or both you are decreasing your highway rideability of your RC51
 

·
Registered
Joined
·
145 Posts
The are no rules, just exceptions :)

There is no general rule, these are numbers we are talking about. As far as steet bikes go the ratios are never too far from each other.
16/40 = 2/5 or 40/16 = 2.5
So to maintain the same with a 15 that would be a 37.5 ... no such sprocket and having a broken tooth on a 38 doesn't count.
So with 16 you might want to go to 43 to be close to the 15/41 ratio and it is more efficient to have larger sprockets with more teeth than having smaller ones but you are having a longer chain which weighs more.
With a 16/38 and a 190/55 you will not need a speedo healer as you are getting closer to real speed but you will have a hard time in traffic and be wearing your clutch trying to keep it smooth.
You shouldn't judge gearing by what your buddies have on other bikes as primary ratios and overall gear ratios vary from model to model. I heard some silly comments of people saying their buddies on a GSXR runs a 15/43 so they want the same on a ZX14 .... !
If you are traveling at legal speeds and 6th is too high, try 5th. Nothing wrong with 5th, is it? Much better than lagging the engine.
 

·
Registered
Joined
·
44 Posts
Discussion Starter #11

·
Super Moderator
Joined
·
6,481 Posts
I bought my '02 RC51 back in '08 it had a 15/41 combination.
The rear sprocket was Driven 520 unit and it was worn out.
So I replaced my 15T front with a Renthal, the 41T rear sprocket with a Vortex F5 hard anodized aluminum unit, and the chain with an RK XSO x-ring chain. All 530 type.
I was concerned about the possible lifespan issues with the aluminum rear sprocket, but those fears have evaporated.
I've probably put over 18,000 miles on that rear sprocket and it's not even close to requiring replacement.
Every time I clean and lube my chain, I check the rear sprocket teeth for wear.
I've got many thousands of miles to go.
Of course the key is keeping the chain clean, lubed, and properly adjusted since a worn chain is what wears out sprockets.
 

·
Registered
Joined
·
210 Posts
Dont forget that changing your sprockets affec the speedo and odometer too. Im waiting on a speedo drd right now to correct a 16/42 gearing. Anyone know what the speedo is off on average from factory? Im guessing about 5%.
 
1 - 13 of 13 Posts
Top