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General Category => Bike Help => Topic started by: boatwhiskers on February 04, 2013, 11:22:02 AM
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As my bike closes in on 20k I am thinking of changing the sprocket ratio. I really don't have any complaints on power or acceleration but I have top end that I never use and I was looking for feedback on what others have done and what are the upside/downside some of you may have experienced.
Also, my bike comes standard with 190/50 rear tire I changed to a 190/55 and It did seem to be a little lighter on initial turn in, or change of direction, although it could have been the tire compound difference from the stock Bridgstones BT 015 to the Michelin PR2/ PR3 (third set) I have also read some folks are running 200/50 or 200/55. Pros/Cons thoughts?
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You have a 17T c/s sprocket-so you could go down to a 16T without too much strain in the way of making the chain turn around a tighter circumference and create more friction/resistance and wear components faster. But I always prefer if making gearing changes to make them in the rear. Add some teeth 2 perhaps to the rear sprocket when ordering your new parts.
As far as the tires go;
A 190/55 vs 190/50 regardless of who's tires they are will have a steeper profile (more triangulated) and aid with turn in. Of course typically sport tires are more aggressive in this nature than sport touring tires.
On you question of going up to a 200.....consult your tire manufacturers website for proper fitment. I am not sure Michelin offers either of the Pilot Road II or III in a 200 series?
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Don't forget that gas mileage drops proportionally to your steeper gearing change. If you have any buzzing that bothers you at cruising speed, that buzz will move relative to speed over ground. I agree that it is easier on the bike to go up in rear, but if you are not replacing chain and the original chain is not long enough to handle the +2 then modifying the rear is quite expensive. Modding the front sprocket is cheaper and lets you know that your existing chain will fit. Also it is easier to go back and forth on the front one vs. rear sprocket. I can do the front on my bikes within 5 - 10 minutes. Rear is slower.
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I changed my gearing from +4 in the rear back to stock on my sv1000s. I like the acceleration but cruising rpms were way too high. After I changed it back, it felt like I had a whole nother gear to shift into.
If I rode more track I'd gear up more.
Looking at your profile it looks like this is gonna be done on a busa. Good luck keeping the front end down if you change gearing lol
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Leave it alone Weedhopper!! I thought you had a project bike to mess with. My Fut's similar to your bike and at 40k+ I won't change a thing-It might go 150+ but it can get 50mpg. So many folks(including me sometimes)think they know better than the factory guys. Leave it be or put a girder & hardtail on it-then post it on Ebay with a $30,000 reserve and watch the bidding war. GJ ::)
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I rarely understand what John says but yes id have to agree.
..I think
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Increasing the number of teeth on the rear sprocket and/or dropping a tooth on the front sprocket will reduce your top speed and improve your acceleration. It will decrease your fuel mileage and make your speedometer read high. You may need to get a longer chain in order to use a rear sprocket with more teeth, especially if you don't drop a tooth on the front sprocket.
Increasing the size of your rear tire will slow your steering, decrease your effective gearing and make your speedometer read lower. It will also increase your cornering clearance and your seat height. Of course it will also give you that fat rear tire look, favored by many urban riders.
Given the abundance of power your Busa generates at all rpm levels, unless somehow you find the performance of your bike lacking, I wouldn't touch the gearing. Given the size, weight and wheelbase of the Busa, going to a 55 profile tire makes sense to me, but going to a 200 size is probably going to be a backwards move with respect to handling.
At 20K, my guess is freshening up or reworking the suspension will probably give you a noticeable improvement in ride/handling if your suspension is still stock.
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Thanks for the replies! I do like the fact that 45+mpg is possible on this bike, also the rpm at 75mph (slab speed) is comfortable. I may just go with a stock chain/sprocket ratio, fiddle with the suspension (er.. hire someone that is) and try some BT-003's
After all I do have a transmission, and as my experience grows on this bike, the more I like just riding in 3rd gear for the twistes
BTW. looking for a set of used wheels to fit a gen II busa.
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The power on that bike is going to fry a 003 fairly fast. I'd go with the rear 20's mated to a front 003 instead or perhaps a pair of 20's.
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OOPS?? Sorry guys,somehow my aged noodle thought JVS started this post. The winter was getting me down but I got the plastic off the Fut for winter R&R plus went xc ing in the new snow today. I'll try to pay better attention. ???
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I'd keep the stock gearing and step up your profile of your tire to a 55. Give you a bit more raise to your rear and they have and the profile will also aid a lighter turn in feel.... the tire will be taller, a steeper roll off.
From your comments about enjoying being in 3rd in the twisties, you might enjoy a lower gearing so you could stretch that gear out a bit longer and ease up it's midrange. And give you better mpgs for the slab ride home!!
Enjoy the ride :)
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Keep in mind your speedo will change also.
i.e. Your speed is 65 but your speedo says 55
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you can look at this http://www.speedodrd.com/ (http://www.speedodrd.com/) to fix your speedo issue, do to regearing and tire size change
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Wow - That speedord thing looks cool!
Here's site for rpm/speed/etc calculation information:
http://www.gearingcommander.com// (http://www.gearingcommander.com//)
Steve ;)
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I have used that Speedodrd on my FZ1 when I changed the gears on it. I am going to put it on the R1 now.