Power Loss do bigger tire or more agressive tread?

[ugabiged88]

Hey guys just moved up from the stock Rugged Trials on my Excursion to 285/75/16 Cooper S/T's and was very suprised by the amount of power I lost, especially on the highway. I have a DP 80hp tune and finally was able to get out on the highway for a good road trip and was shocked. I knew around town in would take a good bit more to get rolling, but I thought that on the highway the effect would be less noticable. It's kind of hard to describe the feeling, but I don't think it would be unreasonable to say 60 to 70 mph takes about twice as long as before. I'm a little worried to even try and tow the trailer.


Enough of my rambling. My real question is whether this is more the effect of a larger tire or the more aggressive tread. I guess my next move is going to be going down a size in the same tire to gain some power back.... would this solve my problem. Do more aggressive tires have significantly more rolling resistance?


Thanks guys,
Ed

[browningbuck225]

what it is you are feeling is a higher final drive gear ratio. the same thing happened to me, i went from stock 265/75/16 to 35x12.50x18 and its a little slower and less pick up speed

[boomboom]

I did the same size tire swap but with BFG muds that you did before my DP tuner and noticed a little change in performance with the bigger tires. Then I put the tuner in and WOW !!! When I ordered the tuner the 285's were listed on order sheet so maybe with yours configured to 265's at the time you got the tuner might be the problem. OR there is a differant issue all together going on and it just happened at the same time you got the new tires ?? I have NO problem with power NOW.I would contact DP and ask them