'79 GS750 - 530 conversion

[celtic.ink]

I imagine that there will be a loss in tensile strength with a lighter chain. I guess what I'm looking for are opinions on what my options are for faster than stock acceleration. Doesn't have to be crazy fast, but I do want a little something extra.

[allojohn]

I imagine that there will be a loss in tensile strength with a lighter chain. I guess what I'm looking for are opinions on what my options are for faster than stock acceleration. Doesn't have to be crazy fast, but I do want a little something extra.

No loss in strength but gains in maintenance and longevity.

[celtic.ink]

Awesome. I think I will be looking into doing this swap over the winter. As you can tell, I am very new to all of this. That being said, if I went with a 17t 530 front, what would be a good choice/range for the rear if I want a bit higher than stock acceleration?

[mmattockx]

i am comparing stock 630 to the modified 530 larger gear front and rear=longer chain on the 530.
do you see my point?

Just in case you are thinking the 530 sprockets are physically larger than the 630 ones because they have higher tooth counts, have a look at this site: https://www.rbracing-rsr.com/calcsprocketdiam.html

630 pitch is 0.750" and 530 pitch is 0.625". From the calculator, we get:

15 tooth 630 sprocket pitch diameter = 3.607"
18 tooth 530 sprocket PD = 3.599"

42 tooth 630 PD = 10.036"
50 tooth 530 PD = 9.954"

As you can see, the 18 tooth 530 front sprocket pitch diameter is 0.008" smaller than the 630 and the 50 tooth rear is 0.082" smaller than the 42 tooth 630 rear. The reason the rear is smaller is that 50 teeth is not the correct equal size replacement, but is the closest full number of teeth. The correct number of teeth is actually 50.4 (6/5 x 42) but we have to make sprockets with complete teeth.

I imagine that there will be a loss in tensile strength with a lighter chain.

There will be no loss in strength, current 530 chain has been developed to the point that it is stronger than the old 630 that was around 30 years ago. MotoGP bikes run 200+HP through a 520 chain under severe conditions, so your GS will be more than OK with a quality 530 chain. The newer O- and X-ring designs also last much better, going 30,000+km for me on two bikes with very minimal maintenance. Keep it clean and rust free and your chain will go for years.

That being said, if I went with a 17t 530 front, what would be a good choice/range for the rear if I want a bit higher than stock acceleration?

If you want to use the 17 tooth then I would suggest a 50 or 51 tooth rear. It is often suggested to avoid sprocket combinations that provide even ratios though, and 17/51 = 3.00:1, so I would say the 50 tooth is the better choice.


Mark

[blowerbike]

As I said, the 530 will have 20% more links in it because the pitch is 5/6 of the 630 pitch. Having more links is not the same as being longer. I do agree with you that the weight savings won't be very significant.

Edit - After re-reading your post it seems that you think the 17 and 50 teeth 530 sprockets are physically larger than the 15 and 42 teeth 630 sprockets. Is that correct?


Mark

i will reply once i compare the sprockets we are speaking of as i do have all of these on hand and i can make a direct comparison on diameter.

[celtic.ink]

17/50 530 sounds like a good way to go, then. Now is there somewhere that I can go to calculate the number of links I would need for that chain, or can I trouble you for the info? lol

[mmattockx]

17/50 530 sounds like a good way to go, then. Now is there somewhere that I can go to calculate the number of links I would need for that chain, or can I trouble you for the info? lol

Have a look at Z1 Enterprises, they have kits with the correct chain length for your bike.


Mark

[blowerbike]

why not a 16/45 combo...less chain...less weight...less cost.
and the Canadian with the mathematical skills is correct....
after laying a larger tooth count 530 over a smaller tooth count 630 as per discussion...they seem near the same diameter.

[btbarb]

go here

Go to http://www.gearingcommander.com/ .

Pick you bike model, the stock info will load.

You can change the pitch and sprocket sizes and have all your questions answered. There's even a way to calculate number of links IIRC.


FWIW, I went 18/47 and 114 links. I'm mostly city. Seems opposite with more highway-like gearing, but for me it's easier and more comfortable keeping up with traffic in this setup than stock.

[mrbill5491]

When I did the conversion, I just ordered a 118 link chain and cut it down to the size I needed. Better to have too much then not enough. Don't want to add links.

[celtic.ink]

So taking all of this advice into consideration, and checking the websites posted in the thread, I'm feeling fairly confident about a 17/46 530 setup. z1 has a 116 link x-ring chain which should only need one or two links removed, if I have figured correctly. Thanks for all of the input. I am really going to enjoy being a member of the site.

[blowerbike]

So taking all of this advice into consideration, and checking the websites posted in the thread, I'm feeling fairly confident about a 17/46 530 setup. z1 has a 116 link x-ring chain which should only need one or two links removed, if I have figured correctly. Thanks for all of the input. I am really going to enjoy being a member of the site.

send me a pm if your interested in my 46 tooth vortex rear...she is perty

[mmattockx]

So taking all of this advice into consideration, and checking the websites posted in the thread, I'm feeling fairly confident about a 17/46 530 setup.

Before you do that, you do realize that 17/46 is taller gearing than the stock 15/42, right? If you are still after snappier acceleration this is going in the wrong direction.


Mark

[celtic.ink]

Oops...lol I meant 16/47. Good catch, Mark.

[mattfeet]

I went 18/52 and the improvement in acceleration is very very nice. I'm a big fan of that combo.