Advice needed for a sprocket ratio of 16 / 45

[Hokano12]

I’m currently running 17/45 on my 79 gs425. It’s in a nice in between from the stock 16/45. Still has plenty of power off the line. I do a lot of high speed (65-80mph) cruising and definitely helped lower the rpms while still having enough general power.

[Mat]

Yeah I am looking into a sprocket around 48 to try on the rear but can't find one that fits

Lots of abrupt hills around here in the city (9 -12 percent being common) and I can imagine needing more with a passenger on

[Suzukian]

Always do the changes with the rear sprockets. Making the front sprocket smaller will eat up the chain and front sprocket quicker from the chain having to tame a smaller wrap around. Putting a larger rear sprocket will give you more oompf at the sacrifice of top end, which you won't need with a passenger out, just riding around.

[rphillips]

eats front sprockets, yep, each toot on fronts are pulling (rubbing) on/off chain link 3 times to every 1 time for rear, plus pulling the chain into a tighter bend.

[Cipher]

Can you get a 420 conversion?

[Cipher]

My bike is 47/14 stock and eats front sprocket teeth

[Mat]

My bike is 40HP only... At the end of summer I will probably install a luggage carrier and have a passenger on occasion. I was thinking more about oooumph at the start and less about top speed so if I do I'll experience with the rear sprocket only. Thanks to you all that gives a good idea.

[rphillips]

Agreed, to me, 2 teeth either way on the front is kind'f extreme, appx same as 6 teeth on rear, also kind'f extreme.

[Rijko]

From what I've noticed. If someone secretly changed your rear one tooth, you would never notice the change. For the front, you would notice immediately...Also "I've" not heard of clearance problems, I'd think would have to be a pretty extreme change in size.

i have seen that on several bikes .. lately on a GSX1100F with 140HP.
Front sprocket 2 teeth oversized, he had to remove 1 sprocket cover stay to be able to fit.

And for a 140HP bike i was surprised it would not reach top speed.
That would be even worse with a bike with less HP ...

Clearance issue is not strange when going down on front sprocket size, but not many people
go down more than 1 tooth so you may not hear about it that often.

[rphillips]

From what I've noticed. If someone secretly changed your rear one tooth, you would never notice the change. For the front, you would notice immediately...Also "I've" not heard of clearance problems, I'd think would have to be a pretty extreme change in size.

[Rijko]

Thanks
Am I right to assume it's always okay to go one teeth less or one more and not expect any clearance trouble and such? Any rule of thumb for this?

That assumption is not good i'm afraid.
Especially with the front sprocket you could run into issues : with a smaller sprocket you could get the chain rubbing/slapping on the rear swingarm at the pivot point ; a tooth too much and it might get clearance issues with sprocket cover or other parts.

And with a heavier sprocket ratio you may discover the bike will not pull properly from the start or not reach top speed in the highest gear.

Rule of thumb is 1 tooth at the front equals 3 teeth in the back, so a change of 1 tooth on the front sprocket is a big change.

If you check the manual, parts list or online references for sprockets you often see valid alternatives.

[Mat]

Thanks
Am I right to assume it's always okay to go one teeth less or one more and not expect any clearance trouble and such? Any rule of thumb for this?

[LAB3]

I'm no math guy, what would be the effect or feasibility of putting a 44 tooth sprocket on the rear or a 17 tooth sprocket on the front? any ressources you recommend to understand the basics here?

Going from 16/45 to 17/44 would result in a higher top speed at the expense of low end acceleration, it would give you slower take off speed. If you went with 15/46 you'd accelerate faster with a lower top speed.

[Mat]

I heard good things about the sunstar sprockets, they supposedly last long. I ordered one on fortnine for the front. JT on order off ebay for the rear.

I decided to order the DID chain cutting and rivetting tool even if I trust myself with a dremel/punch and hammer. Some spare rivet links to go with it too...

I will just keep adjusting my old chain weekly until theses parts all show up to install them all at the same time.

I'm no math guy, what would be the effect or feasibility of putting a 44 tooth sprocket on the rear or a 17 tooth sprocket on the front? any ressources you recommend to understand the basics here?

[zuluwiz]

When replacing sprockets, that's the time to replace the chain as well. Sprockets and chain all wear together: Worn sprockets will quickly wear out a new chain. Vice versa: a worn chain is not good for new sprockets