Fun Guy Posted January 14, 2004 Report Share Posted January 14, 2004 Hey Fun Guy,What size Kumho's did you go with? BudchevySS, I couldn't find a Michelin the right size. I plus-three'd from 17's to 20's and got 305/50-20's for my Avalanche. Regarding tire pressure, you have to take into consideration vehicle weight. My Avalanche weighs in at about 5450lbs. I'm guessing that is a little more than an SS. Keep in mind that semi trucks regularly run their tires at 80-90psi - some of that is due to weight/load, some of it due to tire quality. Regarding tread wear, tread wear is a function of pressure, load, and driving habits. The best way to determine optimal PSI is to draw a line (with chalk or something else) and drive for a ways. If the mark is worn on the outside but not the inside of the tread, you have cupping, which means underinflation for your application. At Discount Tire here in CA, I was told to inflate the Kumhos to as high as I could stand them, as the tires would wear more evenly that way. At this PSI my AV is a little stiff, but handles great and is extremely sure-footed. I'm guessing the reason more people don't run them this high is that you lose the 'Cadillac ride' quality, which I don't care about. It also could be the individual tires. With the super-reinforced sidewall of the Kumho, it's entirely possible they have to be run higher to wear properly. I'm not completely sure, but I trust the guys at Discount Tire. Link to comment Share on other sites More sharing options...
BenKey Posted January 14, 2004 Report Share Posted January 14, 2004 I haven't bought many tires in my life, but have never heard a recommendation of more than 5lbs over the rated PSI for the vehicle come from any company that I have used. During certain evolutions maybe, but not for everyday driving. So are you telling me that Kuhmos have the cupping problem unless you inflate them 10-15lbs over the factory recommended PSI? If that's the case, don't know that I'd want them. Link to comment Share on other sites More sharing options...
zippy Posted January 14, 2004 Report Share Posted January 14, 2004 i'd go with nitto's or g-force ta's. Link to comment Share on other sites More sharing options...
Fun Guy Posted January 14, 2004 Report Share Posted January 14, 2004 I haven't bought many tires in my life, but have never heard a recommendation of more than 5lbs over the rated PSI for the vehicle come from any company that I have used. During certain evolutions maybe, but not for everyday driving. So are you telling me that Kuhmos have the cupping problem unless you inflate them 10-15lbs over the factory recommended PSI? If that's the case, don't know that I'd want them. The factory recommendations/specs are for stock 275/75-17's. Once the stock size has been so drastically altered (as in my case), I really don't think the sticker specs apply anymore. No one said you had to buy the Kumhos. As a matter of fact, given your aversion to deviating from specs, I really suggest that you don't. Link to comment Share on other sites More sharing options...
BenKey Posted January 15, 2004 Report Share Posted January 15, 2004 Not sure I know how to take the "aversion to deviating from the specs" comment. Factory tire pressure specs are based on the weight of the vehicle, from what I understand. All I'm saying is if you have done this cupping test on your tire and they required 10+psi over the factory spec, that there could be something to that. Link to comment Share on other sites More sharing options...
Fun Guy Posted January 15, 2004 Report Share Posted January 15, 2004 Not sure I know how to take the "aversion to deviating from the specs" comment. Factory tire pressure specs are based on the weight of the vehicle, from what I understand. All I'm saying is if you have done this cupping test on your tire and they required 10+psi over the factory spec, that there could be something to that. Sorry Ben, nothing was intended by that. It's just that those specs, while certainly possessing safety as a component, are really designed for an engineered spring rate and its associated ride. They are for people who do no modifications to their vehicles (i.e. stock-only applications) and want everything to stay the way it is. You are correct in that the vehicle manufacturer's recommendations for tire pressure are based upon the vehicles weight, but only at the stock size, speed rating, etc. Once you change that (i.e. as in my application) then again, the whole system is in play. I am willing to accept the repurcussions from my changing from stock size/rating/PSI, which may (but I don't think so) include uneven tire wear. For most people, I would recommend staying at stock pressure ratings. Link to comment Share on other sites More sharing options...
Dylan06SS Posted January 15, 2004 Report Share Posted January 15, 2004 I've always been a BFG guy myself. I don't have too many compliants about the stock wheels (compared to what some of the other manufactures put on their trucks I think we got a pretty good deal!) Link to comment Share on other sites More sharing options...
CraigW Posted January 16, 2004 Report Share Posted January 16, 2004 One other reason for running a higher air pressure than the manufacturer recomends is in the case of towing a large trailer or carrying a heavy load i fyou left the tires at 35# they will squat and heat up faster possibly to the point of failure. With a higher pressure the tire will actually run cooler and you mileage will be better do to less rolling resistence. Better to overinflate than underinflate! Link to comment Share on other sites More sharing options...
whitebowtie Posted January 16, 2004 Report Share Posted January 16, 2004 I have run GT II's on my truck for 2 years. Its also a 1992 X-Cab with 200K miles, but they work fine for me. Gotta remember guys: its a Chevy Truck, not a Enzo Ferrari. Link to comment Share on other sites More sharing options...
Fun Guy Posted January 16, 2004 Report Share Posted January 16, 2004 I have run GT II's on my truck for 2 years. Its also a 1992 X-Cab with 200K miles, but they work fine for me. Gotta remember guys: its a Chevy Truck, not a Enzo Ferrari. What part of the country do you live in? Link to comment Share on other sites More sharing options...
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