Need Advice "gearing"

[holes41]

Hey guys, I ordered a new chain and my 89 came with a set of new sprockets when I bought it. The seller gave me both a 17 and 18 tooth along with a 40 rear. I was thinking about putting the 18 on until I went to remove the old front one and it just so happens I have a 16 tooth on there now. No wonder first gear seemed useless, I swear by the time my wrist was at wfo it was redlined and at 60mph I was over 4k rpm in 5th. My question is if I go from a 16 to an 18 will I only lose that 0-20 insta-thrust, or will it seem less quick everywhere? I know the later xjr1300 had 18-39 and they look like they scoot just fine. My friend was telling me once the revs are up it should feel the same just a broader powerband, kinda like comparing a Banshee to an RZ350 same motor, way different gearing, banshee will win off the line but to 80 the RZ will take it cause the banshee is shifting like crazy, sorry if that is a bad comparison but it kinda made sense. So I am either going 17-40 or 18-40 , if you guys can give me any thoughts from experience id greatly appreciate it. thanks ... John

[oldktmdude]

    Gearing is a personal choice you have to make for yourself. It depends upon many variables and all you can do is ask for suggestions. Think about the style of riding you do, traffic conditions, the terrain you spend the majority of your time riding and loads of other questions that you can only answer for yourself. Going from a 16T counter to a 18t will be a fairly big jump, however, try the 18 first, that way you can always shorten your chain if you decide to go with the 17T.
   I'm running 18/42 and this suits the type of riding I do perfectly. I like the quicker acceleration and closer gear ratio's for the twisty mountain road style of riding around this area. Others like 18/39 for a flatter, more hwy oriented style of riding. It's easy to change, so experiment until you find a combination that suits you.  Pete.

[TexasDave]

I also run an 18/42. I still have good acceleration in town but have dropped the rpms slightly on the highway.  Dave

[yamaha fj rider]

As Pete said try it to see what you like. When going to the ice cream shop, I may know what I want but this doesn't keep me from sampling the other flavors.

This post inspired by Capn Ron's deboning a chicken. 

Kurt 

[holes41]

My biggest gripe is the unusable 1st gear , I don't even like to try and launch like a pro, I prefer to nail it from a roll when i wanna get my kookaloo on so I bet the 18t will be to my liking. Heck I may be able to take it on the interstate without getting numb fingers, my only concern is if the pull will feel like I lost 10 horsepower

[Sabre093]

I'm running 18/38 combo...no problem at all bike has so much torque it pulls everywhere.

[andyb]

It definitely loses that thrust imo, but rather less than you'd think.  The motor doesn't mind at all working against a longer gear.

Go up a tooth and see, if you have 16/17/18 available.  Personally I like nearly stock gearing, just seems like a nice compromise.  If you go straight to a 18 from a 16, it's going to feel like you have a heatsoaked engine and a passenger all at once

[movenon]

You are on the low side. Good for street racing but not to good for the freeway.  Front sprockets are inexpensive and easy to change so don't think you are locked into anything.  The only thing I can add to check and make sure your chain is in adjustment range,  which it probably is.

I had a stock setup then went to an 18/38 combo and recently have dropped the front back to 17T.  I think one tooth up front is equal to 2 on the rear or around that ratio.  With what you have I would go with the 18T for a start.  At least you will get a feel for the extremes you have with your front sprocket gears.
George

[aviationfred]

Sprocket gearing is a personal choice, just like windscreens. As with anything, different people like different things. 

I use a 18/38 sprocket set. I am not in to stop light to stop light drag racing, and the engine has plenty of torque for accelerating from a stop, and significantly lowers the rpm's at highway speeds.

Fred

[FJmonkey]

Sprocket gearing is a personal choice, just like windscreens. As with anything, different people like different things. 

I use a 18/38 sprocket set. I am not in to stop light to stop light drag racing, and the engine has plenty of torque for accelerating from a stop, and significantly lowers the rpm's at highway speeds.

Fred

+1 on 18/38...

[bigbore2]

I use 18/38 for trips as it lowers the RPM nicely, but still has good pull. Even with that gearing, stop and go traffic is no problem. I use a 17/42 for around town cause I like the hit with the lower gearing for on ramps or whatever. And most of my in town riding is 20 miles total distance or less. On the highway, the 17/42 is way too high a gear for me for any distance.  Last trip I took, I was getting over 50 miles to the gallon at 75-80 mph with the 18/38.

[FJmonkey]

Last trip I took, I was getting over 50 miles to the gallon at 75-80 mph with the 18/38.

Ha!!! Another getting 50MPG. Is your FJ still stock, pipes, air filter???

[Burns]

"My biggest gripe is the unusable 1st gear"


there you have it.  The 16T winds up too quickly for your taste. My guess is that it gives the bike a very nervous personality in the lower gears.  Also, in stoplight competition having the shift point up 10 or 15 MPH higher is a major advantage. Not that I advocate that sort of thing.

I'll go against the collective wisdom here and suggest that you go to the most teeth you can stuff on that front sprocket.  You will trade a little punch for  'longer" gears (usable over a broader range of road speeds in any given gear) and as a bonus will get maybe 20% longer chain life.

  I'm suggesting that you make a big enough alteration so that the change in riding characteristics is very clear.  If you want to split the difference once you ride it a bit drop a tooth.

You'll find your sweet spot

[aviationfred]

I didn't mention the mileage per gallon on my previous post. With the 18/38 sprocket set, I easily get 225 miles on a tank while riding around town. On my trip to Colorado last year, I had two legs where I got 53mpg. I had 258 miles showing on the odometer with just over a gallon still in the tank, I was very tempted to push and see if I could hit 300 miles on a tank. I was riding solo and had no spare fuel tucked away in case I ran out.


Here is a photo of the bike during one of the 53mpg runs.




Yes, I got that kind of mileage fully loaded.

Fred

[Pat Conlon]

I think 18/40 is about perfect for me...

The larger countershaft sprocket puts less stress on the chain.

You guys, that is some amazing mileage.....stock jetting Fred?