- Tue Nov 01, 2016 9:23 am
#241770
under discussion, no real solutions yet
but some findings that relate to tire wear and steering effort
Tramling can be defined as the car shaking its head.
rapid movements back and forth that can be violent
after much experiment and discussion
we find
as wheel width increases, track increases and traction increases
we get to a point of instability
some useful indicators are center of tire rotation and the resulting scrub radius changes
if the tire doesn't rotate on center
one part of the tire must move more than the other side
it scrubs
this affects tire wear as well as tamlining
looking at the following tire, we see its center of rotation is far from center
resulting in the inner edge of the tire scrubbed clean
even though wear every place else is even
20161017_153914 by yogib777, on Flickr
center of rotation was determined simply by turning the wheels in place
several times, rolling back a bit and observing the results
as the center of rotation moves toward the outside of the wheel [my case] steering effort increases exponentially
Small changes make big differences
closest solution is brocks short track car
9" wheels, 35mm et, 235/40/17 r-comps
center of rotation moved in about 1/4" from mine
DSCN1606 by yogib777, on Flickr
DSCN1604 by yogib777, on Flickr
compared to mine
1309488 by yogib777, on Flickr
DSCN1090 by yogib777, on Flickr
back to 2jr, tomorrow
we try smaller tires on the same wheels
but track tires not street tires
will report back on new alignment specs and track dyno tune
[faster turbo spool, more low end, less top end hp]
real test will be Sat. Nov 5th
can it run wot at AMP
tuned at 361hp, 371 tq, it turned 91mph in the 1/8 mile
shaking so hard, i would not have been able to hold it in lane had it been a 1/4 mile
but some findings that relate to tire wear and steering effort
Tramling can be defined as the car shaking its head.
rapid movements back and forth that can be violent
after much experiment and discussion
we find
as wheel width increases, track increases and traction increases
we get to a point of instability
some useful indicators are center of tire rotation and the resulting scrub radius changes
if the tire doesn't rotate on center
one part of the tire must move more than the other side
it scrubs
this affects tire wear as well as tamlining
looking at the following tire, we see its center of rotation is far from center
resulting in the inner edge of the tire scrubbed clean
even though wear every place else is even

center of rotation was determined simply by turning the wheels in place
several times, rolling back a bit and observing the results
as the center of rotation moves toward the outside of the wheel [my case] steering effort increases exponentially
Small changes make big differences
closest solution is brocks short track car
9" wheels, 35mm et, 235/40/17 r-comps
center of rotation moved in about 1/4" from mine


compared to mine


back to 2jr, tomorrow
we try smaller tires on the same wheels
but track tires not street tires
will report back on new alignment specs and track dyno tune
[faster turbo spool, more low end, less top end hp]
real test will be Sat. Nov 5th
can it run wot at AMP
tuned at 361hp, 371 tq, it turned 91mph in the 1/8 mile
shaking so hard, i would not have been able to hold it in lane had it been a 1/4 mile