The 5.5" rear wheel conversion saga

By: Charles Raasch

Hey Everyone. After weeks of measurments and CNC machining, my rear wheel conversion is done. I did quite a bit of research and found out many people have done it and most of them have used different methods. I think this is the best and safest way to do it. Here are some pics of all the parts I either had custom made or modified.

Ohhhh...I thought this was going to be an easy thing too....but as I got into it, I said to my self..."self....lets do this the right way so we don't have to worry about the new wheel at 130mph." Needless to say it snowballed, bigtime!

Use as much as you can from the donor wheel, so as not to mess with the bearings. I believe that the bearings should ride in and on what they were designed to. This method requires quite a bit of custom work, but hey, thats okay with me.

The things I did were
1.) modified swing arm holes out to 20mm using highspeed grinder and carbon bit
2.) modified SV brake hanger.(drilled out hole to .790" and faced off one side)
3.) had 3 spacers custom CNC machined, 2 were machined out of ultra high quality 304stainless steel and one out of T6 6160 Aluminum.
4.) modified swing arm/axle spacers to fit gixxer axle (aprox .790")
5.) MFG, custom made axle w/ .790" diameter but length of SV axle. That too was made from 304 stainless.
6.)modified wheel washers, (the square ones that are outside the swingarm).

Through out this whole process I used a dial caliper to measure out to .001". There are other ways to do this project but I feel this is the safest. It wasnt cheep to have all of these parts made from billet 304 stainless or T6 aluminum, but its the only way to insure a safe conversion. I believe that hand grinding doesnt give you the accuracy you need to be safe. A CNC machine does. If you are off a few .001" on one side that will put uneven presure on your bearings and it could lead to catastrophic failure. We wouldnt want that, now would we.

If you are thinking about doing this conversion, take the time and do it right. Its not a simple conversion, but when its all done, it looks great and really helps to put the power to the ground, and i'm wrestling with almost 87bhp to the rear wheel.

The total cost of all the custom machining was over $240 That includes the raw billets of T6 and 304. Like I said, its not cheep to have a +$90,000 +5 ton machine make one-of-a-kind pieces.

I have all the measurments and drawings of what I gave to my machinist, if anyone is interested, don't hesitate to drop me an email

The shop that did the work was Romax Engineering and MFG. in Willits, CA (707-459-0780). The guy to talk to is Clay Romero. If you are seriously thinking about doing this, contact me or him directly but tell him Charles Raasch the motorcycle guy sent you. He is awesome w/ a CNC machine, fast and accurate. The longest part of this project was taking all the measurments. That part took a few weeks. The actual machining time was about a week.

Cheers everyone and be safe!
Charles Raasch sv700rider@hotmail.com