5" rim conversion on OEM FS570 hub

Howdy Folks,

I've got a 2011 FS570, and I'd like to move to a 5" rim. Bunches of folks here just buy a whole new wheel, and I'd rather avoid that expenditure to ease approval by the wifey.

My theory is that if I buy the 5" Excel rim, (PN ENJ412N or EMK422N are 32 and 36 hole, respectively) that I could undo the current 4.25" rim, and lace the new rim using the same spokes and nipples.

Can anyone think of why this wouldn't work? The bike certainly has the clearance along the chain and drive for it. I would be saving the cost of the spokes, nipples, hubs, and retaining the OEM cush drive. Though I hear there is much skepticism as to whether that's of any value.

If I priced this out right, it's under $300 and maintain the same quality as OEM, rather than the $600 for a Warp 9 spare wheel setup. -Which I really don't need.

Thanks Pollo, I saw that posted in the marketplace. Tempting, but I'd like to stick with the OEM black rims. Yours is silver. Nothing personal, you know. I'm just a prissy b!tch.

@HusaBELGfs570- You've hit the nail on the head. I bought this bike as a track beast, and the 4.25" rim isn't cutting it. I've got connections on Metzelers, and they do start at 160, which would be a very wrong contour on the current rim.

As I was digging around the interwebs after posting, I found the error in my OP. The OEM is a Behr sAXESS.

@LeDelmo- that is looking pretty good! Any idea what shipping to California might be? Did you do just what I am proposing? Place a 5" rim on an OEM hub? Or was this the original setup on your stolen (SORRY!!!) KTM?

@LeDelmo- Let me know if/when you get figures, I won't be offended if you find someone local first. The tubeless/not thing isn't a problem. Folks have published ways to seal them up.

Hey Roger, you definitely raise valid points. I've attended the University of Youtube and was instructed that prior to dismantling rims, measurements of the offset must be recorded and likely pictures of the lace pattern, so that it can be properly repeated. I'm going to do a bit more research on both the ID of the rim, which would affect spoke length, and the nipple penetration diameter and angle. I'm not sure if those are published figures, but someone has to have that info... somewhere!

I did some reading over at Supermotojunkies and Thumpertalk. Folks actually suggested that the offset may need to be adjusted a bit for chain clearance, and the chain guide modified to reduce the inner surface. I figure that if I'm going through the hassle of lacing, making some minor adjustments is doable, and I actually enjoy cutting crap apart.

Some quick measurements on the bike last night though, and I think I've only got about 1/2" clearance either side right now. The fit will be tight, but doable. I plan to mount the Metzeler Racetec SM, which I understand has far less rim overhang than would a DOT tire. This should minimize chain and/or swingarm rub from folks forcing street tires into this application. I think I'm going to get to ordering stuff soon, and keep my fingers crossed that it all works out.

I'll start this update with a big thank-you to Pollo, who shipped me the rear wheel he was selling in THIS THREAD. It looked like some youngster learned how to change wheels on it, but with a little love, TLC, some 320 grit sandpaper, and about 2 hours of scrubbing off that F'ing duct tape excuse for a wheel strip, I managed to clean them and prep them for powder coating.

I picked them up from a local shop yesterday. Took them home to inspect, and I am thrilled with the results! These things look terrific. I'm hoping that the spokes from my OEM hub are long enough to work with the non-Saxess Behr wheel. As I begin lacing this weekend, I'll let you all know whassup.

See the results for yourself:

Hiccup: The Behr rim I picked up from Pollo is drilled for a different lace pattern than the OEM hub is designed for. Allow me to get all geometry up in this be-otch.

These rims have 36 spokes, which means that each spoke is 10 degrees apart from the next. Each side of the hub (left/right) has 9 pairs of spokes that pull the hub toward the rim in a single radial direction. This is advantageous for a number of reasons that I won't get into now. Each pair of spokes will consist of one that connects to the leading edge (front) of the hub and one on the trailing edge (back). The result is that each pair of spokes is roughly 40 degrees from the next pair [9x40=360]. Yes, these pairs will criss-cross each other from where they anchor on the hub, but they will not cross where they anchor to the rim.

If you break that down another way, that means that the nipple pattern can be clustered into groups of four nipples, each with a specific orientation it was intended to hold. This pattern will describe the lace it will support.

If I were to begin at the valve stem, and work my way up the rim, as looking down into the channel, we could record a pattern for the rim. Note that the rim will be symmetrical if we were to rotate the plane of the rim 180 degrees around the axis created through the valve stem to the middle of the hub, and beyond. Below, I will use letters to describe the direction of each spoke, as seen by the rim, based upon descriptions above.

The OEM 4.25" Husaberg FS570 Behr Saxess rim has the pattern of
Vv-FL - FR - BL - BR
Vv-FR - FL - BR - BL
Above is for the 5" Behr rim I got from Pollo. Markings on the rim suggest it is 2002 era.

As you can tell by that pattern, I can lace one side of the hub just fine (sacrificing 30+ minutes of work) by shifting the hub one spoke in either direction. The result is:
Vv-FL - FR - BL - BR
BL-Vv - FR - FL - BR
The Front Right and Back Right line up, so I could do the whole right side. But then when I try and lace up the left side of the hub, the spokes are coming in at opposite directions from where the rim is drilled.

This is, clearly, a problem. I'm going to place some calls to a few spoke shops and see if there's a single-side spoke solution. Might not be a possibility.

If all else fails, I can replace the non-cush hub back in the 5" rim that it was shipped with. Not my preference, as that would negate my goals stated in this thread....

Hey Pollo, no stress man. I didn't mean to insinuate that this was in any way your doing. This little experiment is all on me.

I am very impressed with your Google ability. I tried doing some research on the topic, and couldn't find anything about spoke angles, but maybe I just quit my searching early.

Yes, I will likely just put it back on the standard direct-drive hub for my upcoming event, and see how it feels. I'll investigate a cush alternative later. I have, though, reached back out to LeDelmo to see if he'd be comfortable shipping that rear wheel he has.

Cheers!