Author Topic: 17 inch CBR Front Wheel Conversion ( ST1100 ) *  (Read 5527 times)

Offline KoTAOW

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17 inch CBR Front Wheel Conversion ( ST1100 ) *
« on: May 18, 2008, 02:20:25 PM »
This article was taken from web page.  It was originally submitted and written by Dennis Martin in December 2004

The original conversion - as far as I know - was done by Alan Barbic, to allow the use of a more standard tire size, and for weight reduction.

I saw mention of it, with a pic of him, in a Rider Magazine story about the Iron Butt ride just finished, perhaps the one before last. I was able to contact him and he explained it, for which I am thankful. Here's how, courtesy of Alan:

Find a front wheel from a CBRF2 - the 3 1/2inch wide rim, NOT the 2 1/2 inch one.

Make up spacers with thickness exactly half the difference between the hub widths of the two wheels, 12 of them, to place the discs at the same width as they are on the ST wheel.

The ST discs will bolt right on, but you will need Suzuki disc bolts - Part #09106-08082. They will bolt up the disc to the hub, and are longer than the Honda ones, which will compensate nicely for the thickness of those spacers you made.

If you're really anal about these things, you'll drill the spacers to fit tight to the Suzuki bolts, and size the spacer's thickness exactly so that the disc does not wobble. I made them within .001 inch........Took a while.

The wheel will mount into the ST forks with only the need for a spacer on the axle on each side of the new wheel. Axle size is the same.
To center the wheel, I installed the calipers in their normal position(more on this later) and carefully positioned the wheel so that the discs run exactly centered in the calipers, without moving them from rest position on the slide pins.
If your calipers are perfect and slide easily, you can do this by simply clamping the calipers to the disc using the brake lever. New pads of course!

Having done this, you must very carefully tighten the axle just enough to get it in the finished position, without pulling the fork legs together at the bottom. I was able to do this better after I fitted the fork brace we all bought.

Then, you must carefully measure the thickness of the space remaining on the axle, on each side of the wheel, with the original spacer and the speedo drive gear in place. You'll need to make spacers to these measurements - they're different each side - to restore the cumulative width of the ST wheel and spacers, so you can tighten the axle nut, and keep the fork legs parallel.

Let's get back to those calipers now. After the wheel is fitted, because it is 17 inches only, there will not be quite enough room to get the calipers over the disc, and inside the rim. You will need to carefully trim off some of the excess body on the inside corner of the caliper. It sounds bad, but it's really not, they are alloy, and there's some fat there anyway. I trimmed them very carefully with a large "bastage"(courtesy Craig!)file until they would just slip in with the brake pads in place. Once in, there's plenty of room.

The last thing left to do is to change the speedo drive gear to one that works with the new front wheel(CBR again).

Now, I can use 120/70-17 front tires like everybody has in stock! Then Metzeler changed the rear size on my favorite tire, but that's another STory.......

So go to it, but remember, you're on your own - in uncharted waters. Be careful!! Dennis M.

Correcting Speedometer with 17 front wheel by Dennis Martin

When I finally ran it for a while, I discovered a 10% error in the speedometer, both in indicated speed and the odometer reading.

I tried changing the driving gear, do better.

Finally, I changed the speedo drive to one from the same donor bike CBR600 F2. The Honda part number is 44800-MV9-003.

The speedo and odometer are now within acceptable limits.
« Last Edit: December 09, 2012, 05:09:58 PM by Tom Melnik »