New 20's rough ride question

Discussion in 'Lifted & Offroad Suspension' started by hunky, Jul 28, 2009.

  1. hunky

    hunky Rockstar 100 Posts

    What air pressure are you guys running in your 20" tires. Shop that mounted the tires recommended 42psi but ride seems a little rough to me. Tires are 275-55-20 so I still have about the same sidewall as the stock tires.Truck is an '07 silverado classic,reg cab,8' bed
    Last edited: Jul 28, 2009
  2. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    What kind of truck, and what are your sidewall numbers? xx lbs at xx max psi.
  3. 5speedsilverado

    5speedsilverado Epic Member 5+ Years 1000 Posts

    im guessing the truck came with 17's, and you went to a bigger rim, and kept the original tire diameter?
  4. lerbud

    lerbud New Member

    I have 275/55R20's and I run mine at 34 in front and 32 in the rear. It rides much smoother than when the pressures are higher.
  5. adampaul1964

    adampaul1964 Epic Member 5+ Years ROTM Winner 1000 Posts

    Actually you have less side wall than stock tires. 275/55/20 is 31.9 inches tall, 265/70/17(stock tire on my Z71) is 31.7 inches tall. The height is the same but the difference in wheel diameter means your sidewalls are 1.5 inches smaller, which will give a slightly stiffer ride because there is less "cushion", you can try airing them down but I would watch them very closely for uneven wear.
  6. lerbud

    lerbud New Member

    the silverado ss tire pressure on the door says 34. they come equipped with the same size tire.
  7. hunky

    hunky Rockstar 100 Posts

    How long have you had them? Notice any wear problems?
  8. grimreapersshadow

    grimreapersshadow Rockstar 100 Posts

    you should go what off what your doorjam sticker says which is proalby 35 psi even tho you changed rim size you dont wanna change your air pressure
  9. 2ToNe04

    2ToNe04 Epic Member 5+ Years 1000 Posts

    of course its going to be a rougher ride you went to a bigger sized rim, with less side wall for cushion.
  10. hunky

    hunky Rockstar 100 Posts

    Dropped the air pressure 6psi,down to 36 and took it for a ride. Big diffrence,still " stiff" but not like riding on wooden wheels like before. I'll keep an eye on tire ware just in case.

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