[endo]

Alrighty, I did a search for this and went through 17 pages of threads and couldn't find what I'm looking for (as well as regular google searches).

Joe and I both picked up VFR750 (1990) rear ends, for way less than we should talk about publicly and we're starting to brainstorm. I have a stock rim with mine, so worst case scenario I can run that, but I would like to run a 17x7 rim a la Mighty Mod Scrappy and Hybrid 929.

What is the best way to decide offset and such? Should I find a rim I like and make everything fit, or should I decide which bike I'm putting this in, get the swingarm in straight and aligned, and then do it? I'm thinking slingshot GSXR for the next buildoff...

I'm thinking the latter, but then how do I figure out my offsets and spacing requirements? I've never had to deal with offsets before, nor have I ever retrofitted a SSSA to anything. Please excuse my ignorance to this subject.

Hook a couple brotha's up with info!

 

[dogbreath]

No!

 

[endo]

:rock:

 

[skr00zloose]

offset is gonna be dependant on how the arm is mounted, if it's mounted dead center of the bike, then you need a rim that'll let the rim be centered (obviously), but if the arm is offset to one side or the other, then that will change the offset needed on the rim. in any case, you're looking at a FWD rim, as most RWD rims don't have anywhere near the offset needed to work. i'm helping build a friends bike with a SSS, with a 20" spoked car rim, and the offset is nuts. i mean, it will work, but it's gonna take alot of fabrication. you may not have so much of an issue with a 17" rim that's not 8" wide.

in all honesty, at least on this forum, scrapyard is probably the best brain to pick.

and FWIW, getting the arm in the frame is the easy part, making the suspension work properly is a whole 'nother story.

 

[Smokey74]

Here you go..

http://www.wheelsmaster.com/rt_spec...=45&bd2=17&rd2=17&rw2=8.0&et2=25&text1=&text2

 

[Scrapyard]

If it's going in a slingshot, your first hurtle is going to be lining up the shock. Actually, this is going to be a problem with most bikes. As the shock mount on the VFR arm is offset to the left. This is a little easier to handle then the wheel alighnment. Basicly, once the arm is fited in the pivot you'll need to measure for a few spacers in order to line up the linkages. Pretty straight foward.

Moving on to the wheel. Joe had PM'd me earlier and stated that the pivot width of both the GSXR frame and the VFR swinger are 9" wide. That being the case...

My CBR is 10" wide at the frame. The swingarm is fitted all the way to the left side with a 14mm spacer taking up the slack. My wheel is 17x7 with a 38mm offset. The adapter between the swingarm and wheel is 1" wide.

This website was a huge help in figuring out the offset I needed.
https://www.rsracing.com/tech-wheel.html

This one is even better. You can plug in your measurments and it will give you all the measurments and a diagram.
http://www.wheelsmaster.com/rt_specs.jsp?item=Wheel-Tire size comparer&showRim1=1&showTire1=1&sw1=225&ar1=60&bd1=15&rd1=15&rw1=7.0&et1=20&showRim2=1&showTire2=1&sw2=245&ar2=45&bd2=17&rd2=17&rw2=8.0&et2=25&text1=&text2

The way I went about it was I measured the back spacing of the stock VFR wheel. If I recall the VFR has a backspacing of 4" and is 4.5" wide rim. Now if we take the center line of that rim we get 2.25". Now subtract your 4" back spacing by 2.25" centerline.

4-2.25=1.75
so you have a 1.75" offset. Now multiply 2.25 by 25.4 to convert inches to millimeters.

1.75x25.4=44.45

so the stock VFR wheel has an offset of 44mm.

Now if we look to move up to a 7 inch wide wheel. Take a look at the quick reference chart on the web site above. or plug in your measurments on the other.

It's kind of like the theory of plus sizing the wheels on your car. the bigger the rim the lower the tire profile to get the same wheel diameter. In this case instead of going up we want to go out. So the wider the rim the less back space we want and less offset.

So theoreticly we would want a 17x7 with a 12mm offset in order to make up the difference.

A lot of times it's difficult to find a wheel with the correct offset we need, so we have to find a wheel that we like that is close and then use adapters take up the gap.

This how I came upon the use of a 1 inch adapter for mine. I found a wheel with a 38mm offset and started pluging away at the numbers and figured out I needed to make up a 1 inch gap in the backspace in order for it to work.

Hopefully this points you in the right direction.

 

[endo]

Awesome thanks a tonne! Those three websites are kick ass.

:cfrocks: HUGE!!! The wheel I found that I really like is a 40mm offset, so I should be able to make it work. This is gonna be both fun and frustrating...

(PS* Just to say it, 4-2.25=1.75 )

 

[dogbreath]

dude endo
so seriously do this

 

[Britjoe]

Im not the sharpest tool in the shop, this has totally confused the crap about of me though I have just got in from a 12 hour night shift,
Ill work on it over the weekend, I think the problem will be fairly easy, I have seen it done on busas and Ks and srads,

 

[Britjoe]

endo for now for mock up if I though your 1000 motor in the frame I have we can work on it, chain alignment and shock mount fabrication etc over the weekend. that way we wont be guessing at all.

 

[Britjoe]

standard VFR RIM

 

[Britjoe]

so to get the same spacing so the inside of the wheel is in the same place as the VFR rim, I would do this, I would need a 24mm 0.9inch spacer......
38mm minus the 14mm, am I right or have I got it all arse upwards

apparently there would be trouble getting a rim for this bolt patern with a 38mm offset, so the next nearest thing would be a 40mm offset, and you would need a 1inch spacer.

 

[endo]

That's fine 'cause the rim I think I want is a 40mm offset.

 

[Scrapyard]

Sounds about right to me.

 

[Scrapyard]

Awesome thanks a tonne! Those three websites are kick ass.

:cfrocks: HUGE!!! The wheel I found that I really like is a 40mm offset, so I should be able to make it work. This is gonna be both fun and frustrating...

(PS* Just to say it, 4-2.25=1.75 )

You're right on the math. Sorry, it was late. Fixed now.

 

[endo]

It's all good dude!

 

[chandler]

links dont work for me