Sooooo, the other day I decide to clean rear tire spokes and notice some stress cracks in the rim around several. Yikes! The rig is a Hannigan Classic/Suzuki S83 (VS1400), and my trusty dealership (really good shop) says that in in the whole 20+ year history of the bike they haven't seen this problem even when the bike was used to tow sidecars or trailers. They suggested I have the car installer check for proper alignment. Given that I know the skill of Hannigan's shop, particularly our wonderful friend Dave, I didn't think that misalignment was the cause and decided to do some research. I found quite a few Suzuki C50 owners complaining of rim cracks (and they weren't towing anything!), but absolutely no S83 owners were among them. Hmmmm... Then, I found a fellow with a Guzzi rig who was advised that his rear rim cracks were due to side load that the rim just wasn't designed to handle. This theory interests me, and I wonder what you guys think of it. And, if you think this is the answer, what company can provide me with the stronger design I need?
I've seen cracks like those in some old BMW spoke rims that had seen alot of miles & potholes. There was no consensus on the exact cause in the BMW wheel, though it was noted that the rims weren't heat treated like some later wheel rims were. I cannot say for certain, but if you think that a customized wheel might work for your needs I'd check into Buchanon Spoke and Rim - I think chances might be fairly good that they could make a wheel to fit your needs if you provide them with your hub and info, though it won't necessarily be cheap.
"Old timers" have told me that the spoke wheels can handle side loading better than alot of the cast alloy wheels - I don't know if this is true or not?
I ask myself if your rim some when got regalvanized... that would explain a lot.
Generally extra thick spokes are needed for a rig. and the steel rims last better then aluminium casts.
Sven
If the rim was chrome-plated, there's a possibility that it was made brittle when plated. The problem is known as hydrogen embrittlement. In order to avoid the unnecessary hardening of the base metal of the rim, it's necessary to place the rim in an oven at something like 300 deg. F. for a prescribed number of hours. Unortunately, few manufacturers perform this procedure.
It's common practice tp perform heat treatment in aerospace manufacturing. The manufacture and rebuildng of aircraft landing gear shafts for example, requires that they be striped and replated with hard chrome and reground to size. At some point in the process, they are then given a heat trearment to drive out the free hydrogen atoms which cause the hardening. I've seen numerous cracked rims on older Harleys and Trumphs.
Beyond that, it could also be caused by loose spokes and the passage of time. I don't necessarily think that sidecar use would cause this since it also happens on solo machines.
One thing that helps a great deal is the relacing of the wheel with stainless steel spokes. Besides their nice appearance, they tend to stay tight and this helps to avoid wear and stress in the dimples where the nipples enter the rim.
On Inox just never forget the thread lubrication. I use Chesterton 785 assembly cinc paste. Best stuff I have used in my profesionall life.
Why I say that? ...I have quite a few scars in my face because I had to break siezed inox screws at the valve factory I learned at.
Eating wrenches taught me to keep focused on the important things.
The devil is in the details....
Best wishes
Sven
definatly get your spokes through buchanon's they are stainless and they will make any length you want if not in stock. stay away from the cheaper chrome spokes. I've pulled two sets out of my cb750 before the side car. the threads are pressed on and very poorly done. many of the nipples just slide over the thread never touching, or just barely, very easy to break.
Thanks for the input, guys. I've checked out all the spokes and they're good and tight all around, so this really is a rim issue. I've decided to take the rig in next week for a new OEM rim since I have a ride scheduled for early October and there's no time to get a custom order completed in time. I'll be watching the new OEM closely and not loading up any more than I usually do to see how it holds up. That plan wipes out my original intentions to bring along camping gear-- a bummer-- but I really want to test another OEM under normal load just to see if my original rim was a quality control fluke. If this second rim goes bad I'll turn to Buchanan's for a steel rim w/stainless spokes. I see they have a great reputation.
CeSalt - 9/25/2010 11:21 AM
Thanks for the input, guys. I've checked out all the spokes and they're good and tight all around, so this really is a rim issue. I've decided to take the rig in next week for a new OEM rim since I have a ride scheduled for early October and there's no time to get a custom order completed in time. I'll be watching the new OEM closely and not loading up any more than I usually do to see how it holds up. That plan wipes out my original intentions to bring along camping gear-- a bummer-- but I really want to test another OEM under normal load just to see if my original rim was a quality control fluke. If this second rim goes bad I'll turn to Buchanan's for a steel rim w/stainless spokes. I see they have a great reputation.
That's a good plan except it sounds as if you are going to reuse your old spokes. That's not something I would do.
Not to worry. Old mixed with new components don't make sense in this instance. The new rim will be matched with new spokes. Let's see what happens!
Great ending to this story! So like I said, I have a great shop to deal with, and when I arrived to pick up my rig the owner asks, "Who does the detailing on your bike?" While showing me my old rim, he explained that what absolutely does look like cracks around the spokes (see pic from original thread message) is actually the result of the chrome having been scrubbed away. Sure enough, in bright light I was able to inspect each "crack" close up and personal, and I saw rock-solid metal beneath. What a hoot! So now we know FOR SURE that there was a quality control problem, not with the Suzuki rim but with an overzealous detailer--ME!
I have been a perfectionist since childrenhood....
And had excellent vision......
I never understood why so many people overlooked fatal damages in their machines.....
Now since my telescope arms do not work anymore and my eyes need double traction....
I understand!
Including your shout: "Wolf!"
Congrats to the lucky analysis result.
Once upon the time my NSU-Supermax rims lost crome in the same spots like your rims.
Best luck
Sven
