5/8 offset sprocket measure question

Hollywoodmx wrote:

wireman wrote: Use a piece of aluminum or steel for your straightedge

The light bulb just turned on for me. This is super simple. You don't need strait edges, rulers, lasers to determine the front sprocket offset. I feel like doc from back to the future and just hit my head on the toilet and invented the flux capacitor! :lol: :lol:

You guys tell me if I'm wrong in this theory.

Stealing part of zeds technique, to find the offset needed all you have to do is this;

1. Measure from the center of the rear tire to back/inside rear sprocket. My case 117mm

Now Zed says 101mm is the true centerline of the chassis using the 5/8 offset sprocket.

5/8's is 16mm.

2. Minus 16mm from 101mm that's 85mm (stock).

3. Use your measurement from step one and minus it by 85mm. Using mine; 117mm - 85mm = 32mm.

4. Answer I need a 32mm offset front sprocket which equals 1 and 1/4 front sprocket. FAK! :pinch:

So in my case what I can do is machine 5mm of the rear hub and that will give me a 27mm/ 1 1/16th front, subtract the conversion to 530 then that's 1" offset. Where is the crying emoticon? Cause 1" will hit the frame for sure..

I think the only thing I can do is get a custom 520 5/8 offset front sprocket made and take off 8mm then of the hub and find a skinny non o-ring yet high strength chain and accept the slight miss in 100% alignment.

Who's on first? :lol:

Good Fortune!

Patton wrote: Who's on first? :lol:

Good Fortune!

Gets worse.. man this offset issue really has me computing..

520= 5.8mm
525= 7.05
530= 8.74
630= 9.5 (estimated)

That is with me measuring sprockets in stock which they are vortex sprockets.

Taken from the DID website, a 520 VM2 X-ring chain has a 22.95mm outside pin width, while their 520 VT2 X-ring chain is only 18.70mm.

Divide that 520 chain /2 thats 9.5mm, 18-9.5=8.5

the difference of the 520 rear 3.mm that would put me at 114mm .

Minus the 8.5 I can allow before tire rub that would put me at 105.5

105.5 - 85 = 20.5 = 51/64"

4mm over 5/8ths..Doh!

BUT since the 520 chain is thinner I can run 3mm closer to the frame than the 5/8s 530 offset sprocket so if I go with a 19mm offset 520 sprocket I will be 1mm of true which is good enough because I have done some rounding as well.

Leon where are you??? I need a 19mm offset 520 sprocket! :whistle:

The only way it will work in a stock frame is if you use a 530 5/8th's front and offset the wheel which i have ocd problems with :laugh: so can't bring myself to do it.
3/4 min offset is needed for a 6" rim but the frame gets in the way and would need trimming or tunneling and you need to use a 180 tyre.
For all the hassle i changed my zx10r 6" rear for a z750 5.5" on my cafe project.
I really want the zx12r flat spoke style wheels for my Moriwaki project and am considering tunneling the frame but would happily use a 5.5 rim if they did one in the same style as the wide rubber is not really a benefit and a 170 section tyre is best for quick direction changes.
Don't bother with one-off sprockets as it will cause problems again when wanting replacements or gearing changes.
Just use a 5/8th's 530 and work around it,wether by offsetting the wheel or sourcing a 5.5" rim.

zed1015 wrote: The only way it will work in a stock frame is if you use a 530 5/8th's front and offset the wheel which i have ocd problems with :laugh: so can't bring myself to do it.
3/4 min offset is needed for a 6" rim but the frame gets in the way and would need trimming or tunneling and you need to use a 180 tyre.
For all the hassle i changed my zx10r 6" rear for a z750 5.5" on my cafe project.
I really want the zx12r flat spoke style wheels for my Moriwaki project and am considering tunneling the frame but would happily use a 5.5 rim if they did one in the same style as the wide rubber is not really a benefit and a 170 section tyre is best for quick direction changes.
Don't bother with one-off sprockets as it will cause problems again when wanting replacements or gearing changes.
Just use a 5/8th's 530 and work around it,wether by offsetting the wheel or sourcing a 5.5" rim.

Sourcing a 5.5 is not an option, I have already bought the tires and mounted them, and I have sanded the rims. I'm in Canada so ebaying and shipping rims with tires wont sell well. Unfortunately I am committed to the 6 with the 190 tire.

What do you mean by the OCD? Are you scared you wont get it right?

Hollywoodmx wrote:
Sourcing a 5.5 is not an option, I have already bought the tires and mounted them, and I have sanded the rims. I'm in Canada so ebaying and shipping rims with tires wont sell well. Unfortunately I am committed to the 6 with the 190 tire.

What do you mean by the OCD? Are you scared you wont get it right?

Looks like your your best option is to offset the wheel then now that you are committed.
As for the OCD, it just means that things for me have to be perfect and having the wheel off center would be too much to live with.
It would bug the hell outta me :laugh:

i run my rear rim offset 3/8" with no ill effects.

i also get away with running a 3/8's offset 520 countershaft sprocket with no cush drive machining.

which adds up to verify what zed is saying, 3/4" if it was on center.

the funny thing is that my 2000 r1 rear wheel has the hub centered in the frame,the rim is offset from the hub.

so,when i built my swing arm i assumed the rim was centered with the hub.

it wasn't.

by the time i figured it out it didn't matter.

lottsa bikes come from the factory (sport and cruiser)with the rear wheel offset with no ill effects and the consumer never knowing it.

is it perfect?
no.

is it a compromise?
yes.

will you be able to tell that it is offset by riding it?
no.

if you ever meet zed1015 and he walks up to your bike,will he be able to tell the rear rim is offset just by looking at it?
yes :lol: .

in the end you have to satisfy yourself,because you are the one that has to sleep with yourself :woohoo: .

hth,

leon

Hollywoodmx wrote:

zed1015 wrote: The only way it will work in a stock frame is if you use a 530 5/8th's front and offset the wheel which i have ocd problems with :laugh: so can't bring myself to do it.
3/4 min offset is needed for a 6" rim but the frame gets in the way and would need trimming or tunneling and you need to use a 180 tyre.
For all the hassle i changed my zx10r 6" rear for a z750 5.5" on my cafe project.
I really want the zx12r flat spoke style wheels for my Moriwaki project and am considering tunneling the frame but would happily use a 5.5 rim if they did one in the same style as the wide rubber is not really a benefit and a 170 section tyre is best for quick direction changes.
Don't bother with one-off sprockets as it will cause problems again when wanting replacements or gearing changes.
Just use a 5/8th's 530 and work around it,wether by offsetting the wheel or sourcing a 5.5" rim.

Sourcing a 5.5 is not an option, I have already bought the tires and mounted them, and I have sanded the rims. I'm in Canada so ebaying and shipping rims with tires wont sell well. Unfortunately I am committed to the 6 with the 190 tire.

What do you mean by the OCD? Are you scared you wont get it right?

:laugh:

I agree with Leon, don't assume the rim is centered and just do the math. Probably won't work out. Measure, measure, measure. I had to offset my rim 0.170" to get 3mm clearance to the tire. I did that based on Leon's assurance that I would never know the difference. Now I've never met Leon, but he seems like he wouldn't tell a lie . Certainly can't tell it's offset. We'll see how she rides when she's all back together, but I have no worries.

hey thanks for the vote of confidence there sir haybus :whistle: :lol: !

i am open,honest and up front.

that is how i live my life and i don't have to remember any bs.

if i don't know i will say "i don't know"i won't bs anyone.

if i tell you something i believe to be the truth and later find out i was wrong,i have no problem coming back and goin"hey man,it seems i was full of sh!t,sorry about that.i know have new information that i have found to be true."

people don't always like to hear what i have to say,but they can't say i lied to them.

and,

that's all that matters to me.

leon

Haybus wrote: Here's what I did. Clamped a straight piece of aluminum angle to the inner face of the rear sprocket, making sure to contact as much of the sprocket face as I could. Then measured the offset from the inner face of the front stock sprocket. Can't change where the sprocket meets the transmission so figured that was a good base. Came up with something larger then 5/8. Machined the cush drive hub to make the offset 5/8. Then made a spacer that was 5/8 minus the thickness of the 630 sprocket. Clamped it all together, back to the straight edge, and laid the chain on to verify alignment before making the offset sprocket. (Offset the wheel a few mm cause I have a 6" wheel, but don't tell anyone :sick: ).

Doesn't matter what sprockets you're using as long as you measure from the mount surfaces. If you're using different sprockets than you intend to use you'll need to account for that.

This is how I did mine also, written above....worked out great for me. Centered rear rim/wheel, clamped on angle iron and set spacing on rear rim to center or line up sprockets.

Here's what I did. Clamped a straight piece of aluminum angle to the inner face of the rear sprocket, making sure to contact as much of the sprocket face as I could. Then measured the offset from the inner face of the front stock sprocket. Can't change where the sprocket meets the transmission so figured that was a good base.

Ya my wheel is centered "currently".

This is the plan. Leon's going to make me a 19T 520 18mm (safest bet I figure, feel free to comment) sprocket. I'm going to run the skinny racing chain 18.5mm and I will tunnel the frame a little, f*ck it. I will then see how that lines up.

Say run 19/41 @520 for teeth? Thats close enough to stock and should get me extra swingarm clearance on both the front and the back that others have been worried about. I was thinking with the 57mm carb I probly could afford to reduce the gearing as I figure I will lose some throttle response in the initial RPMs but I'm a bit worried running the 40T due to clearance.

Hollywoodmx wrote: Ya my wheel is centered "currently".

This is the plan. Leon's going to make me a 19T 520 18mm (safest bet I figure, feel free to comment) sprocket. I'm going to run the skinny racing chain 18.5mm and I will tunnel the frame a little, f*ck it. I will then see how that lines up.

Say run 19/41 @520 for teeth? Thats close enough to stock and should get me extra swingarm clearance on both the front and the back that others have been worried about. I was thinking with the 57mm carb I probly could afford to reduce the gearing as I figure I will lose some throttle response in the initial RPMs but I'm a bit worried running the 40T due to clearance.

Sounds like a pretty good plan.
I run 19/40 with 530 (same pitch as 520), there's plenty of swingarm clearance and the bike accelerates like a rocket.