the od of the tire can be seen at the address I mentioned earlier, I could not post proper links till I had 5 posts.
it's 23" OD for the 125 and 23.57" for the 135's. stock od's are 23.75".
as to handling and safety concerns I imagine it would be a trade-off where wide tires would equal good handling and low economy while narrow ones would give low performance and higher economy.
the results of metrompg's tests with the spare tire donuts baffle me, i cannot understand how the doughnuts performed so awfully on his RR tests.
4 vehicles would have been in for the mod if this was proven to work, the lightest of them 2500 lbs but the heavier ones would require slightly higher loading capacity. however I don't think these 125mm tires are really what is needed for this type of job.\
http://store.cokertire.com/catalogse...sult/?q=125R15