Changed my front sprocket to a 17, now back to 18

[flickmeister]

After all the good things I heard about the 17 tooth front sprocket, I did it and really tried to like it, but I just don't think it works for me. My biggest gripe is that it made first gear virtually useless. I could start from second every time, in effect, making it a five speed motorcycle. It did have a faster high gear roll-on, but since I paid for a six-speed tranny, I'd rather drop a gear and go and keep first as a viable part of riding. Oh, I also forgot how many non-related parts you had to undo to get to the front sprocket and change it. Cheers, Jack

[penno]

thanks for sharing Jack. this is something I was considering doing. Heard a lot of good things, mind you - but to me, what you're saying makes sense. 

[billincentraljersey]

If you are a touring guy, the lower RPM at top gear will be relaxing.  I calculated the gearing, -3 teeth at the rear sprocket, or +1 at the front sprocket, if it fits, will also fix the speedo error.  It is now a bit optimistic.  You may not get the top gear high speed roll as it was before the higher gearing.  It will be affected a little bit.  No problem down shifting one to pass a slow car.  At 5th, with the sligher gearing, will be much faster than 6th in stock gearing.  I don't see the higher gearing affecting the general  performance of the bike other than the 1st gear, for the red light drag race type.  Since I don't pull wheelies either, I am not affected.  I won't be changing the sprockets and the chain until I wear out the stock ones.  Too cheap and no time.  If I have a free day, I rather ride.

BTW, the stock speedo is optimistic, but the odo is accurate.  Correct the speedo, the odo will be pessimistic by the same percentage.

[terizius]

i haven't checked the odometer, but i'm not sure its accurate.  I use a gps on mine and keep track of fill ups at the pump.  When i showed 87 on the trip meter, gps showed 78.  Seems that if the trip meter is off, and the speedo is off, the odometer would be off too...

[billincentraljersey]

Terizius, thanks for the info on the GPS vs B1250.  Actually it is good news for me.  I had always thought the speedo was optimistic and the odo was accurate .... from various reading here and there.  Noe that you are saying the speedo and the odo are both optimistic, then a sprocket change to a taller gear ratio (that is what I wanted) would correct BOTH to be closer to reality. 

[terizius]

Glad to be of help :)  Question though.. i'm fairly noobish in terms of motorcycles, this being my second only and with only about 1 1/2 years of riding. Question is.. what would the sprocket change actually change in terms of riding feel, which sprocket and to what size.. and would a newbie like me tell a difference or care about it either way?  Thanks for your time.. i'm still trying to learn. :)

[billincentraljersey]

Question is.. what would the sprocket change actually change in terms of riding feel, which sprocket and to what size.. and would a newbie like me tell a difference or care about it either way? 

Just think 10 speed bicycle. 

Example.  At 80 mph or so at top gear, 6th gear, the rpm is at about 4000.  When I was traveling across the country, everyone travel at about 85mph, as indicated on the b1250 speedo.  I know it is a bit optimistic and the actual speed is about 77mph, according to what I read about the error of the speedo.  Anyway, I like to ride at lower rpm.  Noise, vibration, fuel saving, etc.  SO, I will be decreasing the rear sprocket by 3 teeth.  It will lower the rpm, for the same road speed.  Why 3 teeth?  the proportional change in gear ratio is the same as the error factor of the speedo.  I am not after drastic reduction of the rpm.  so 3 teeth is as good as any.  Actually better.  It cill correct my speedo.

MOST people want to INCREASE the teeth at the rear sprocket, for faster power delivery.  So, all the gears will be higher rpm per same speed.  Yes, even newbies will feel the difference.

[terizius]

bill, thanks for that simple explanation.  I seems like what you are after is more realistic as to what i would want.  If increasing the teeth will increase power though.. how much power would be lost by dropping 3?  I'm not an agressive rider.  I dont race, i dont even get on the motor very often.. but at the same time, i dont want to lose too much of what i have.  If you do get a different rear, can you let me know from where and what the price was, as well as a quick tutorial if you install it.  Thanks for your time

[billincentraljersey]

I look at it this way, if I need extra power and the increase in gear ratio make the bike more sluggish, then all I have to do is down shift by one gear.  All my previous bike have to do that.  The B1250 has plenty of power for me.  So, that is only a slight inconvenience for me.  I don't have any first hand experience in the difference in "feel" but we're talking 5% maybe?  I am sure you can "f-e-e-l" the difference, but I doubt it'll change the world for me.  I am no longer the stop light drag racer so the lower gearing don't do anything for me.  No wheelie for me either.  Dang!  I'm a pretty boring guy!

It'll be a while before I do the change.  Have to wait till the chain wear out.  If I have the time, I rather ride than wrench.

[billincentraljersey]

If canyon road peg scratching kind of ride is what you are after, perhaps a Bandit is not for you.  I recently went on such a ride.  I quickly found the gears are way too far apart.  I am constantly searching for the right gear, and not finding it.  It is either too high or too low.  I ended up using the brakes a lot more.  What I really like is a close ratio gear box.  1st gear to stay where it is.  2-3-4-5 tight and close together.  And 6th, very tall for the long distance touring. 

Hey, I know it ain't gonna happen.  I can dream about it.

Even as a touring bike, I don't get to use 2-3-4th that much.  There is so much power at 6th and 5th so 2-3-4 is sort of a waste.  Difficult to have a general purpose bike do everything.  The Bandit comes close.

[terizius]

hey, what you say makes quite a bit of sense to me.  Sounds like i'm in the same "boring" category as you :P  Thanks again for the time and info.

[bngboyd]

Nothing wrong with "boring". That is how you have a long and happy motorcycle life. I really should practice what I preach lol. 

[billincentraljersey]

Guys, hey eh, I heard that there is another Bandit forum and there is a thread on a rear sprocket change to 40T.  Aside from a slightly taller gear for a more relax cruise, it also corrected the speedo.  According to the person that made the change, 60mph GPS reading is dead-on at the speedo at 60mph.  At speedo 70mph, GPS reads 70 sometimes flickering to 69.  Speedo 80mph have a GPS reading of 79/80mph.

[dhcolesj]

Guys, hey eh, I heard that there is another Bandit forum and there is a thread on a rear sprocket change to 40T. 

Good to hear.  I'm more in the Touring / commuting set myself, so the lower RPMs sound good to me.  Besides the 1250 puts out close to its highest torque at around 3500 to 4000 RPM anyway.  My question is would going +1 on the front accomplish the same thing and be less expensive or about the same?  And, has anyone done this, or head of this being done with good success.  I'm thinking of MPG improvement as well as comfort and speedo correction.

I'm in the line with billincentraljersey, I'll have to wait until this chain set wears out before I find out. 

[billincentraljersey]

Some where between the two Bandit forums I read that a 19T front may have clearance problem.  +1 at the front is about the same as -3 at the rear. 

SPLITING HAIR here but it will be lighter, the chain will have less wear since the links don't have to bend as much to go around a bigger gear wheel.  All that and you'll get another 20ft more mileage for the higher gear ratio. 

In a practical point of view, none of that is significant.  To me, the slightly more relax rev and less engine noise plus correcting the speedo is what matters to me.  Even if the 19T front fits, I think it is a lot easier to swap the rear than the front.  That big ass nut is tought to loosen.  I havn't look, I havn't try, that is what I heard from a mechanic speaking in general.