09/10/2013 Ask Mike! Archive
What is causing the uneven nose tire wear?

Good Afternoon.

I am currently working on a Beech Bonanza Model S35 that has been wearing the nose tire out mostly from the right side.  Not even.  Gone through 2 nose tires and when sitting on ground appears as if the axle was slightly bent. 

It has had nose strut rebuilt and new wheel bearings/races installed.  Neither has helped.  The strut and the nose tire have been properly serviced full.

The steering has very little play.  Running out of ideas as to why this has started to happen with the last two tires.  Been looking for the obvious, but all we have found is while measuring the axle to the strut, the outboard side measures about 1/8 inch further than the inboard side.  Some mechanics say this is normal, but not sure that will be the case.  Any ideas from your past experience?  Would appreciate feed back.

Thanks,
Armando

Armando,

If the axle is bent, usually the nose gear will not retract properly and fit the well; this can be observed with the door linkage disconnected and gear retracted.  Also, there would have to be an 'event' that would have caused this.  Were there any 'events', such as this is happening after a nose gear collapse?  How fast are you gong through the tire?  (Approximate number of landings.)  Is it cupping or even wear?  Same pilot?  Regular crosswinds?  And, brand of tire?  This all will give me more data to think about.

Mike

Thank you for responding....OK... Got a chance to talk to Tech. Rep. at Beech after I emailed you... Good info found.  He told me this was normal.  The axle is supposed to be 2 to 3 degrees lower on that end (axle nut side) by design.  "Reason for it is for tracking down the runway related to the V-tail effect on it.  They figured the speed and time it ran down the runway, would help it stay centered counteracting the side roll produced by the prop and v-tail."  I didn't know this.  Anyway, good information.  He told me he got 1 call per month on the same issue.  Said most notorious on the Goodyear tire brand which is what we have on this Bonanza.  Told me Beech is now using Michelin tires and they seem to help.  Secondly, told me that tire pressure would make it more notorious on the wear.  My client doesn't monitor it very well either.  Anyway, put my mind at ease.  There is a second Bonanza on my field that is doing the same exact thing.  That owner was concerned as well.  Anyway, thought I would share this with you in case you run into it.  I had thought that maybe the bearings which are fairly new in this case might have had the cup crooked, but was not the case when I took the wheel apart.  My guess was the bushings in the strut itself, but this strut was rebuilt or replaced a few years back.  The strut had no signs of being crooked.  Just the axle looked and measured 1/8th inch bent at the end.  The explanation the engineer gave me put that idea to bed.  Anyway, thanks again for following up on this.  Now we have learned a new thing I guess...