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-   -   pic: Problem with IFI Wheels (http://www.chiefdelphi.com/forums/showthread.php?t=66640)

RogerR 06-04-2008 16:42

Re: pic: Problem with IFI Wheels
 
Quote:

Originally Posted by Aren_Hill (Post 731433)
so wait...how many bearings did you have between the wheel and the axle? because with 2 bearings supporting it i don't think this situation has a likelihood of occurring.

actually, because of the way that they are mounted, the bolt on sprockets (if left unsupported) can create a fairly large load on the wheels. this cyclical loading can cause major problems. this used to be the main cause of failure among the skyway wheels (see also: 1902's 2006 exploding wheels), and while i'm not sure about the new kit wheels (they are much more robustly designed, as they have the bearings mounted farther apart), i've seen some pictures of failed wheels that look suspicious.

further more, if you at look both the sprockets available from ifi and am.biz, you'll notice that they both are made to accept a 3/8 in bore flanged bearing.

s_forbes 06-04-2008 17:03

Re: pic: Problem with IFI Wheels
 
I noticed some similar wear on one of our IFI wheels from last year (the 6"x1" version), but it wasn't worn that badly. Also, the wear seemed more like it came from the bearing turning against the wheel rather than being wollered out due to a deformed wheel plate.

...My theory is that the bearing wasn't tightened down enuogh when our wheels were put together. The supporting evidence: when I was playing with one of the wheels that was laying around the shop, I noticed that one of the bearings was actually able to turn against the wheel! The screws seemed tight enough, but it was still able to turn. It's my guess that the little white standoffs that go between the plate and the screws were too thick and didn't allow the screws to clamp down tightly on the bearing.

I didn't think much of it at the time, but it's my guess that this is what happened to your wheels (though I may be wrong...). We've never had any deformation of any kind on our plates, and we were using the 6"x1" wheels last year (we were being pushed sideways for a good part of our matches, too).

Aren_Hill 06-04-2008 17:04

Re: pic: Problem with IFI Wheels
 
Quote:

Originally Posted by RogerR (Post 731528)
actually, because of the way that they are mounted, the bolt on sprockets (if left unsupported) can create a fairly large load on the wheels. this cyclical loading can cause major problems. this used to be the main cause of failure among the skyway wheels (see also: 1902's 2006 exploding wheels), and while i'm not sure about the new kit wheels (they are much more robustly designed, as they have the bearings mounted farther apart), i've seen some pictures of failed wheels that look suspicious.

further more, if you at look both the sprockets available from ifi and am.biz, you'll notice that they both are made to accept a 3/8 in bore flanged bearing.

I wasn't being specific as to the locations and knowing Richardmcc2 from his posts i know he is knowledgeable enough to not put one bearing on a wheel, it was just a quick check.

having the sprocket bolted to the wheel with both bearings in the wheel does create a high stress cantilever that i can see being enough to round out that whole, especially if there were any nonconcentric sprockets in the drive to pulse the chain from tight to really tight. putting a bearing in the sprocket should stop it because if relieves the cantilever

GBIT 06-04-2008 22:36

Re: pic: Problem with IFI Wheels
 
Quote:

Originally Posted by mark johnson (Post 731524)
You must doing something wrong because we have been using them for the past two years and there industructable. Last year we competed in six competitions between first and off season events . also before the off season events we loged many hours of pratice time for the new drivers and not one failure.

They are not indestructible. We broke a wheel last year. and we had bering problems as well...... PRESSING A BERING INTO THE SPROCKET WILL ELIMINATE this problem...... it has worked for us....

daltore 09-11-2008 17:56

Re: pic: Problem with IFI Wheels
 
Well, he forgot to mention that the wheels were rotating at about 1000 rpm. To do this with #25 chain means that you could play a tune with all the tension we have on the chain. We put bearings in the sprockets and haven't had any problems since.


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