Thanks all for your input.
Bed Engine Trans GVWR GAWR (front) GAWR (rear) Curb wt Curb weight (front) Curb weight (rear) Payload
SB Diesel A4 9900 5200 6150 6895 4170 2725 3000
--My rear axle load is: 2200# tongue, + 400# full aux tank
--I've tried running 90+psig to help alleviate this apparent underinflated symptom when towing, to no availcold
--tire temperatures after running 2 hours towing, pretrip cold press. @ 90psig. , ambient temp. 82deg. , temps were 110deg shade, 120deg sun
--regular tire rotation & alignment chks biennually.
--3195# tire load max. rating I find is typical for all USA, LT truck tires, E rated, except possibly NITTO?
--calls to manuf's resulted in identical reports of: "All we can recommend is what the vehicle was equipped with OEM. "
--the Michelin 285/70 is strangely rated as a 'D' load rating, no help there
Further data mining resulted in:
--Nitto Dure Grappler sku 205-070: LT285/70R17 E 126R, OD=32. 80", 3750# @ 80PSIG
--Nitto Dure Grappler sku 205-370: LT285/75R17 E 128R, OD=33. 86", 3970# @ 80PSIG
Now 2 quandaries emerge:
1-Did Michelin alter their design 5 years ago, resulting in current evidence of lower than advertised load capabilities? I'm making a warranty claim, if only to determine what's changed. My maintance records are pretty good.
2-Is Nitto for real, or just Dura Grappler hype? I'll be posting this forum to hopefully find some real world experience using Nitto highway tires.