Got this question:
"I have a question regarding interply shear or scrubbing common
on double or triple axle fifth wheels. I have a double axle and try to
avoid sharp turns and U-turns as much as possible, but I see visible
signs of scrubbing on the tread of my tires.
It looks like flat spots on the edge of the tires. After a turn, I can
go back and see the rubber I've scrubbed and left on the road. It's
frustrating. I have the axles aligned and tires balanced once a year and
have individual wheels weighed occasionally.
I try to keep side-to-side and front-to-back weights within a couple
hundred pounds. I currently carry 85%-90% of load capacity, or about
3300-3400 lbs per tire.
"My question is: Would going to the next load range up (from G to
H) or going to a harder compound tire reduce this problem? I currently
use Goodyear G614RST tires, size LT235/85R16. I've heard in the past
that Michelin uses a harder compound in their tires,
which makes for a little stiffer ride, but might this overcome some of
the effects of scrubbing? I feel I could get a lot more miles out of my RV tires if I could reduce the flat spots or sculpting caused by
Axle alignment or wheel balance isn't the problem. There is a sketch in this post
on interply shear that shows why the tire tread scrubs. The center of tire rotation is
not pointed to the center of the turn radius so the tires are always
being dragged around every turn. It is just worse on tight turns.
the percentage of max load capacity is a good idea. Don't forget that it is the
air pressure that determines the load capacity not the Load Range (G to
H). You will gain nothing from a Load Range change if you do not also
increase the air pressure. You do need to confirm the wheel max psi
capacity which, for some wheels, is not easy to do as some wheel manufacturers do
not have high pressure ratings easily available.
Regarding tread compound: Sometimes it isn't just the hardness of the rubber but also the tread pattern that can affect scrubbing wear.
In general, the tread scrub is a function of dragging a trailer around.
Send your questions to me, Roger, at Tireman9 (at) gmail.com
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