Mucking with the gear ratios...

[raven]

Folks,

Was wondering if anyone out there has tried playing around with their gearing - I've been reading through my shiny new Haynes manual of late and it LOOKS pretty straigh-forward, but wanted to know of anyone had any 1st-hand advice.

Wondering my motivation? Basically, I'm going to be touring a lot in the next little while and it'd be nice to increase the ratio on 6th for when I'm booting along at >120kph.

From what it looks like, it SHOULD be as simple as popping off the cogs and replacing the 6th but... well, I choose to assume that these things will be harder than they innitially look...

R.

[Blueknyt]

with stock 16 tooth front, and 39 tooth rear on a 130 series rear tire, you should be plenty good for cruiseing, you dont want to raise the gearing too much cuz then it will need more power to turn eveything, play with tires, 130/70.  140/70 or 140/80 you can even squeeze a 150/60 on(i find more stable under load and speed) but your choices of rubber for the 150 will be more sport and less tour so you wont get the miles out of it. the 140 will be lower revs for 120 kph in 6th, i wouldnt muck with gears in tranny any unless they break

[Kerry]

Blueknyt is right, in my experience.  With

* A stock-sized 110/70 BT45 front tire
* A stock-sized 130/70 BT45 rear tire and
* The stock 16/39 sprocket ratio[/list:u]my RPM needle tracks close to 2 notches lower than my speedometer needle in 6th gear.  Of course this is with a speedometer dial marked in MPH rather than KPH.

Anyway, when I'm doing an indicated 80 MPH (~130 KPH) my tach shows a little over 6,000 RPM.  That's a cruising speed if I ever saw one.  And the bike is already plenty gutless at those speeds in 6th gear.  I wouldn't want to stack the deck against it even further....

What size is your rear tire?  That can make a big difference, as

Blueknyt pointed out.  I replaced my original Exedra 130/70 with a Cheng Shin Hi-Max 130/90 (because I didn't know any better at the time) and all of a sudden my tach would read 1,000 RPM lower than before (at a given speed in a given gear).  It took me while to figure out what was going on!

That tire very nearly scraped a suspension-related bolt directly in front of it, so it was the maximum diameter that will fit.  And, like Blueknyt said, I sometimes had trouble starting up from a stop.  I had to rev the engine appreciably higher than usual to get the bike to move.

Bottom line?  Like Blueknyt, I would tweak the sprocket ratio or the diameter of the rear tire before I would tweak around with the gearing.

Is there something extra that you haven't mentioned?  An additional, overriding reason to adjust the top gearing?

[werase643]

tranny gear ratio's are a pair of gears
and
I don't think you will find any alternate ratios
and
if you can find....75-100 a gear


rev the bike a little and you will notice it can be a completely different bike
fun actually  
my street GS live between 7k-10k
all day long

[raven]

OK - my concern with changing front or rear sprocket was that doing that would change the characteristiscs of the whole gear-set. I don't particularly want to kill my low-end acceleration just to lower the revs on my occasional touring, which is why I was curious about changing just the 6th gear. I rarely use that around the city, so it would suit me well to increase the size of that a little, leaving the rest of the set unchanged.

Of couse... I COULD just have 2 front-sprockets - one for the city and one to whack in when i'm heading out of town.

Will check my treads and reference from previous - I've currently got what I understand to be stock tyres. Again with the not wanting to change the characteristics of the whole bike.

I like the idea of making the bike "ideal", but if it's going to be too much work then I might just have to live with the swap-out...

Cheers for the suggestions!

R.