Changing overall gearing

[Citroenjunkie]

Greetings

I thought there might already be a strand about changing the gearing on a RX3 but couldn’t find one. So

Has anyone significantly changed the overall gearing on a RX3 with any success. I have covered nearly 5000 km with my bike this year and am starting to long for a higher overall ratio. While I’m sure my bike will do the next 10 000 at 8000 I think, if I could do the same thing at lower revs it would be great.

My bike will happily rev right to redline in top on a flat road, as an indication, so I think it will pull higher gearing.

Thanks in advance.

[fjmartin]

I know the folks at CSC offer various sized front and rear sprockets. 14T is front stock and they offer a 13 but not a larger one though I could have sworn I saw something about a compatible manufacture that had one on a thread a long time ago. JT sprockets if I remember right. The rear is a 44T stock but CSC offers up to 46 and down to 42. If you wanted a higher end speed you could stay with the 14T and go to a 42. This calculator will help with what you'll get doing the various combos when it comes to speed and torque: http://www.sprocketcalculator.com/ Personally I'd think that the bike would be very luggy in 1st gear by going down to a 42. I don't know of any internal transmission gearing that is available. Going to a 14/42 would increase top end speed by 4.8% but if you could get a 15/42 combo that would increase it by 12.2%.

Joe

[rtking]

FWIW, I went to a 42T rear gear after adding my Akopovic muffler. This gives the bike “longer legs” so you won’t need to shift to 3rd gear t the end of an intersection, but acceleration will be tempered a bit. The bike won’t rev as high on the highway, but it also will give up a couple of MPH (lower top speed) since you’re dropping the bike further away from it’s power peak, and aerodynamic drag increases exponentially the faster you go.

[AdventureDad]

I wouldn’t do it. Stock was bad enough with slipping the clutch starting on a paved road, much less off road. It just doesn’t have the low end power to do it.

[Jay In Milpitas]

I read this about an hour ago and didn't think about it much, then it struck me that you bought the bike used, if I recall. It is possible the first owner changed the gearing, do you have the stock 14/44 sprockets or something else?

[Citroenjunkie]

I havent checked the sprockets to see how many teeth they have so I'll do that this weekend.

Our open road speed limit in New Zealand is 100kph and this is policed pretty strictly, so Im not really looking for huge top speed. I do hear what you're saying about the high first gear so I'll have to give the whole thing a real think through.

On a slightly linked topic does fitting a 19" front make the speedo more accurate? mine is well on it's way to being 20% over.

Have a great day

[jbfla]

Originally Posted by Citroenjunkie

.....

On a slightly linked topic does fitting a 19" front make the speedo more accurate? mine is well on it's way to being 20% over.....

That seems quite a bit more error than most.

My speedo error at 60 mph was about 7 mph off.

With the 19" wheel and tire, it was about 4 mph off.

http://www.chinariders.net/showpost....9&postcount=34

jb

[Jay In Milpitas]

Originally Posted by Citroenjunkie

On a slightly linked topic does fitting a 19" front make the speedo more accurate? mine is well on it's way to being 20% over.

Have a great day

I know that you are in NZ, but in this situation I think an Australian phrase is best used.
A 19" will make it less fucked, not make it fully accurate.

I know many folks have smart phones (I don't) that can be used as GPS speedometer. If you have that ability it may be the way to go.

[pyoungbl]

The 19" front wheel made my speedo darn near 100% accurate. The bike was shipped with the 19 installed and the 18 as an extra. I rode the 19 for a while and then swapped back to the 18 just to burn up that rubber. If/when I finally wear the 18 down to the wear bars i'll go back to the 19". With all that said, I was struck by the fact that the 19" wheel was tracking so closely to my GPS mph, much closer than any bike I have ever had. I think I was about 1% off. Now with the 18" it's at least 10% off (reads faster than reality).

As for changing the gearing, a 13 tooth front sprocket will tend to accelerate wear on the chain only because it makes the chain go through a tighter arc. If you go to a 15 you'll be forced to slip the clutch a lot just to get started. In my mind the stock 14 tooth sprocket is the best compromise. Play with the rear sprocket if you want to change the gearing.

[fjmartin]

I ran the stock chain for 5000 miles and then replaced with an EK o-ring chain. Didn’t change the 13 countersprocket or the 45 rear. Ran that EK chain 10000 miles. They are $45 USD. Both the 13 and 45 still look great so I put another chain on it and will replace the whole thing before my Alaska trip. And I do both big freeway runs and tough off-road

[sqwert]

Carefully check the clearance between shifter bolt and chain before running a 15 tooth countershaft.