2nd Gen Non-Engine/Transmission Behavior / Performance of Cooper Discoverer HTs

[arthr31]

Hi there,



About 500 miles back i got new tires - Cooper Discoverer HTs. Size 265/75R16. I think stock, the truck had 245s... but I've never had those on the truck... Previous to this set, I had BF Goodrich All Terrain TAs. They were good, kinda loud, and too aggressive for my driving.



So, my question is, with the new HTs, I am getting a lot of "sway" while travelling at speeds 70+mph. Is this normal? While spinning down the highway, sometimes the truck seems to drift a lot more than it did with the BF Goodrich's. I had thought the opposite would be true with the new tires.



During my last trip (400mi), I was running 80psi in the rears, and 75 in the fronts. I've since changed to 75psi in the rears and 70 in the fronts. Indoor panel of the truck says 80/65 (rear / front), but the HTs call for 80psi. Which is correct? I used to run 65psi in the goodrich's, but that's what the sidewall called for...



Also, one last thing to consider in my riding performance, the HTs are load range E, BF's were D. So, again, is my performance "normal"? Thanks. Sorry for the long ramble...



-arthr

 

[SnoKing]

If you are running around without a load, let the rears down to around 42-45 and you will get a much better ride and improved handling. 80lbs in the rear is for max GAWR of 6084 or two times the max of 245's which is 3042 each. The 265 are E rated, so you only need around 70 lbs to carry the max 6084 of the rear axle, as they are rated to 3415 each.



Try 65 in front and 42 is rear empty for a good ride and good handling.



SNOKING

 

[J.BURCHFIELD]

Don't know how many miles are on your shocks but when they need replacing they will allow your truck to sway. With the 265's you will only see 100 miles on your odometer when you have gone 104. Thats only 4% but it does make a difference on your speedometer. Assuming your speedometer is accurate you will be going 52 when it says 50. The Federal Gov. mandates that speedometers be manufactured to show slightly more than actual for safety reasons. As if that would help, what a crock. Good luck with your Coopers, one of mine separated after 30K and damaged my truck ($2,000) and Cooper paid for it. What a surprise. The tire did not loose any air, just the tread all came off on the interstate at 60 MPH. I said no more chances and put on Michelins all the way around ("E" rated)

 

[bmoeller]

My boss has 265s on his GMC. Doesn't seem to matter on the brand either, but is probably the squirrrelest (if there is such a word, lol) handling truck I have driven. Likes to find the big truck ruts in the road really bad.



Had H/T tires on the Ram when I bought it (albeit 215s), and they were just fine. Have Cooper S/T in 235s now.

 

[Hammer]

Define Sway. .



If the feeling your experiencing is the truck feeling like the way ones hand would move when having a dusting towel and you twist it by moving only your wrist,then I would say its tire related. Proper pressures could cause this feeling but I am confused how it would show now and not with the lighter rated 8ply D series tires. If anything would happen with this change you describe it should have been a complaint about the stiffer ride and firmer feel on the road. Look inside your trucks owners manual packet and see if it still has the update sheet from Ma Mopar with the tire pressures on it. If it does then adjust your accordingly and see what happens.



I suspect you will find instead what you did now by going to the stiffer 10 ply E tires is to show a weakness in your front suspension you may have been overlooking all along. Think about it,when your driving down a interstae with decent surfaces do you find yourself constantly rowing the wheel to compenstate for front end problems. We have all been there at one time and didn't even know we were doing it until we changed something out. Listening to what your tellin us here tells me you have one or a combination of things happening. It could be a bad trac bar,tie rod ends loose,steering stabilizer bad,worn shocks on all corners and/or bad ball joints. Any of the itmes above get overlooked alot by owners and when told of them failing I have seen them say "Not my truck,no way". I'd suggest that you hook up with one of the NE guys and have one of them drive your truck and offer you their opinion. Most any of them can and will help you or take a ride south of Boston and allow Scott Hovey of MassDiesel Performance to drive it as he will put you on the right track.



As for the Coopers being the problem,I'd highly doubt it with the description you gave. If they were problematic they would show you in other ways first... ... . Andy



http://massdiesel.com/

 

[arthr31]

Thanks for the responses, guys. i'm gonna try different pressure values first to see if that changes the ride at all... As far as checking other things out, i changed the trac bar 1 yr ago, ball joints 1. 5 yrs ago. . shocks might be suspect, they are looking kinda tired... Also just had an alignment so that should be okay...



btw, hammer, already a customer of MassDiesel, was interested in what i might expect wrt performance/ride from the Coopers before really digging too deep.



I'm putting 400 miles on tomorrow with different pressures, so I guess I'll see after that... Thanks again for the input, i'll let you know the outcome...