Quick Q: Front Sprocket

[Meuryn]

Hi everyone,

Just wondering, if I drop a tooth on the front sprocket, do I need to 1. change the length of the chain (add or remove links) and / or 2. change the rear sprocket?

Main reason is that I can afford a new front sprocket, but I can't be forking out for another new chain

As a matter of interest, will this make long distances / touring uncomfortable? I realise that at a given speed the RPMs will be higher if I drop a tooth, but is it going to outweigh the benefits of increased acceleration and make touring hard work?

Cheers!
Meuryn.

[twocool]

If you're low on dough...don't waste your cash on something like a different front sprocket.  You will have some real maintenance issues in the future...like eventually you WILL need a new chain...new tires etc...save your $$$  for that stuff.

As for "improved acceleration"...dude...you're not gonna see it.....maybe, just maybe, in first gear off the line, the bike will be microscopically faster...but since the GS has 6 gears...after the dead start, it all depends on where you make the shift points, not the size of the front sprocket.  And to get any real acceleration off the line, you gotta really rev the engine...are you drag racing this bike, or just driving around town like most of us?  On a long road ride, you only start from a dead stop, what once or twice?  This is not a "performance bike" no matter what mods you do...

Yes at continuous high speed cruising, in top gear, the RPM will be higher and that might be annoying.  Many use this argument to go to HIGHER gearing....

Remember, about 1/2 the posts on this group say lower gearing gives improvement, while the other half say higher gearing gives improvement

But...for someone short on doneros, jack rabbit starts are the last thing you want to do....And prolonged cruising at very high speeds is the second worse thing.  Drive smooth, and keep the speeds reasonable...and you'll save 20% on the fuel bill, easily...and have cash to buy stuff you really need...

If that smaller sprocket is the only thing standing between you and inner peace, something that you just gotta have, can't live without, life will be complete...go for it!

One tooth means you just have to reset the rear wheel, back, to take up slack in chain....there should be enough range in the frame slots....

Cookie

Hi everyone,

Just wondering, if I drop a tooth on the front sprocket, do I need to 1. change the length of the chain (add or remove links) and / or 2. change the rear sprocket?

Main reason is that I can afford a new front sprocket, but I can't be forking out for another new chain

As a matter of interest, will this make long distances / touring uncomfortable? I realise that at a given speed the RPMs will be higher if I drop a tooth, but is it going to outweigh the benefits of increased acceleration and make touring hard work?

Cheers!
Meuryn.

[gsJack]

Stock chain OK, will only move axle back .148"
http://gstwins.com/gsboard/index.php?topic=44849.msg502495#msg502495

You will get different opinions on touring affect, some change to a 17T front  to reduce high speed revs but I had a 15T front on my 97 GS for over 40k miles back when we were doing 400-500 mile interstate days at higher speeds and it never bothered me  a bit.

I put it on to help steep uphill restarts in the mountains and never felt a need for it on my 02 GS for that purpose.  Have used a 15T off and on with the 02 to keep revs near stock when running bigger rear tires.  I like stock gearing on the 02.

See we got a differing opinion already while I was typing.   

[Meuryn]

Interesting points Maybe I gave the wrong impression, but I'm not that low on money, I can budget for a front sprocket without delving into my generous 'maintenance' fund. I've looked over the stuff about performance gains - I'm under no illusions here, I know that the GS isn't going to be transformed into a supersport regardless of how much money you spend on it.

I suppose my point was rather that although I'm comfortable trying out a 15t front sprocket, provided I don't have to buy a new chain, I still don't want to undermine my ability to ride motorways for extended periods. I think you're right about prolonged higher RPMs putting a strain on the motor, but again, that's something I've considered Thanks for chain info by the way

GsJack - thanks for the info! I'm doing a bit of touring in the summer, so if I find it's too buzzy at motorway speeds, it won't be too much of a pain to switch back. I just read a thread on a conversion to 14t which sounds tempting

[cWj]

How far are you into the life of the chain?

Is it something that can wait until it's time to change the chain, or is the need for speed irrepressible?

[Meuryn]

Chain has about 1000 miles on it, as do both front and rear sprockets. Installed in September; can't ride as much now as my uni doesn't allow personal vehicles within 12 miles of 'campus'

Also the need for speed is absolutely irrepressible, after all, that's why I bought a GS in the first place 

Looking online I can get a 15t front sprocket for about £15, so if it's not going to destroy my bike I'll order one and see what's what.

[CraigR]

You can run the 15t without changing the chain. I did works fine.

When i dropped it down to a 14T I had to punch a link out of the chain as it was at full adjust, it was just simply too long.

I ran the 15t for 6 months commuting to work before putting on the 14t.

Chain is still fine apart from now its too short to go back to the a 16 or 15t without putting in a second joiner.

[dinkydonuts]

I ran a 15t briefly and while it certainly had more "get up" than the 16t, I was shifting constantly. It seemed like, at the time, that 1st gear became damn near useless.

Now I'm running a 17t and I can get up to 40MPH in 1st gear. For 45MPH roads, I use 3rd gear which keeps me at 5500RPM which is right where the torque is sweetest. 2nd gear is useless now. On the highway, I can do 80MPH in 6th and my mirrors are still functional and not vibrating like crazy. That being said, at times it feels like I could use a little more acceleration.

Maybe the 16t is where it's at...? 

[Badot]

I like my 18t front and 130/90 rear tire because they keep the engine between 4k and 5k RPM at highway/interstate speeds in 6th, and that's where the bike feels smoothest to me. Outside of the change in shift points nothing else makes a difference to me.

I rarely go near WOT so if I ever want more speed out of my bike 99% of the time I just open the throttle a little more. 

[cWj]

Is there any mechanical advantage to changing gearing via the front versus the back (or vice versa)?

obviously the size in the rear is limited by the sprocket bolt hole pattern on the wheel...

But does it matter which end you change to get your desired effect?

I'm going bigger on the back tire to relieve some buzz (though that's partly due to Chaparral having had 140 80 BT 45Vs for 95 fricken bucks a few days ago).

[radodrill]

It's cheaper to change the front.  Rather than going down 2 teeth on the front, you can co down 1 in the front and up 3 in the rear for about the same gear ratio without needing to cut the chain.

[twocool]

Smaller gears wear out faster.

Smaller gears wear out the chain faster.

Smaller gears have more mechanical friction.

Smaller gears are slightly lighter.

You gotta check the chain line and make sure it doesn't come to close, or hit anything
Cookie

Is there any mechanical advantage to changing gearing via the front versus the back (or vice versa)?

obviously the size down in the far is liked by the sprocket bolt hole pattern on the wheel...

But does it matter which end you change to get your desired effect?

I'm going bigger on the back tire to relieve some buzz (though that's partly due to Chaparral having had 140 80 BT 45Vs for 95 fricken bucks a few days ago).

[CraigR]

I wouldn't go 14t on the front again, 1st and 2nd are pretty useless. Though I've gotten real good at clutchless shifting so it's less annoying now :p

When this chain wears out I'll probably go back to the 15t or maybe the 16, I'll decide on the day