trialsman Posted January 30, 2006 Report Share Posted January 30, 2006 Hope I'm not repeating a post. Most of you young guys can't relate but I'm 58 with a bad back. I will be dropping my '06 2/2 very shortly because it looks better and because climbing up in and getting back down bothers my back. My question, could I not get another inch or so closer to the ground with a different height tire? If so, what size and what would the ramifications be? Thanks Link to comment Share on other sites More sharing options...
2drTahoe Posted January 30, 2006 Report Share Posted January 30, 2006 Jonmalibuss is running lower than 2/2... 3/4 maybe can't remember check his topics. With a tire size change you may have to program your computer http://www.silveradoss.com/forums/index.ph...rofile&MID=5778 Link to comment Share on other sites More sharing options...
orion :: SS Posted January 30, 2006 Report Share Posted January 30, 2006 My question, could I not get another inch or so closer to the ground with a different height tire? If so, what size and what would the ramifications be? <{POST_SNAPBACK}> If you're running stock wheels...275/45-20 would be ~2.2" shorter overall diameter as comapred to stock tires, so it wold bring the truck down ~1". Without a drop, this would look REDICULOUS...so lowering is a MUST. Ramifications: Basically, it would be like going to a 4.33:1 gears in the front and rear diffs...faster acceleration, higher RPM on the highway, drop in gas mileage. - Brian Link to comment Share on other sites More sharing options...
ArizonaSS Posted February 1, 2006 Report Share Posted February 1, 2006 ive got some 295/45R20 BF GOODRICH T A KDW 'S Link to comment Share on other sites More sharing options...
ArizonaSS Posted February 1, 2006 Report Share Posted February 1, 2006 with stock wheels Link to comment Share on other sites More sharing options...
misterp Posted February 1, 2006 Report Share Posted February 1, 2006 If you're running stock wheels...275/45-20 would be ~2.2" shorter overall diameter as comapred to stock tires, so it wold bring the truck down ~1". Without a drop, this would look REDICULOUS...so lowering is a MUST. Ramifications: Basically, it would be like going to a 4.33:1 gears in the front and rear diffs...faster acceleration, higher RPM on the highway, drop in gas mileage. - Brian I am doing the same thing, McGaughy's drop (2/3) and 295/40ZR20's (1.5-inches shorter than stock). So in my case the door sill of the cab will see a 2.75" drop (2-inch from the kit, .75-inch from 1/2 the difference in tire size). I did the math, in my case the truck will behave like it has 4.33 gears which means a 6% increase in torque multiplication but at the cost/requirement of 6% increase in RPM - it will require another 175 RPM to sustain 80mph. I have no problem winding up the motor, it doesn't have enough stroke to matter. This will cost mileage and require PCM reprogramming to account for change in tire size. But I am betting that where economy is concerned it will still be be an overall improvement, because lowering a truck 2" gives 1-1.5mpg improvement (typical) and I think that will outweigh the loss in economy due to change in tire size. Another VERY important benefit of using shorter sidewalls is that the weight of the tire drastically changes - a stock-sized Goodyear tire weighs 42 pounds, versus a Pirelli Scorpion which is 2" shorter (best/lightest I could find) only weighs 38 pounds; multiply by 4 and you get 16 pounds of rolling weight off the truck, it will actually measure a 10hp increase on a chassis dyno. Plus not wear our your suspension *and* the wheel will less dribble like a ball against the pavement when you hit a pothole. Post pics of your lowered truck when you can! Mr. P. Link to comment Share on other sites More sharing options...
wkeil Posted February 1, 2006 Report Share Posted February 1, 2006 Tire calculator Link to comment Share on other sites More sharing options...
Holty Posted February 1, 2006 Report Share Posted February 1, 2006 If you're running stock wheels...275/45-20 would be ~2.2" shorter overall diameter as comapred to stock tires, so it wold bring the truck down ~1". Without a drop, this would look REDICULOUS...so lowering is a MUST. Ramifications: Basically, it would be like going to a 4.33:1 gears in the front and rear diffs...faster acceleration, higher RPM on the highway, drop in gas mileage. - Brian I am doing the same thing, McGaughy's drop (2/3) and 295/40ZR20's (1.5-inches shorter than stock). So in my case the door sill of the cab will see a 2.75" drop (2-inch from the kit, .75-inch from 1/2 the difference in tire size). I did the math, in my case the truck will behave like it has 4.33 gears which means a 6% increase in torque multiplication but at the cost/requirement of 6% increase in RPM - it will require another 175 RPM to sustain 80mph. I have no problem winding up the motor, it doesn't have enough stroke to matter. This will cost mileage and require PCM reprogramming to account for change in tire size. But I am betting that where economy is concerned it will still be be an overall improvement, because lowering a truck 2" gives 1-1.5mpg improvement (typical) and I think that will outweigh the loss in economy due to change in tire size. Another VERY important benefit of using shorter sidewalls is that the weight of the tire drastically changes - a stock-sized Goodyear tire weighs 42 pounds, versus a Pirelli Scorpion which is 2" shorter (best/lightest I could find) only weighs 38 pounds; multiply by 4 and you get 16 pounds of rolling weight off the truck, it will actually measure a 10hp increase on a chassis dyno. Plus not wear our your suspension *and* the wheel will less dribble like a ball against the pavement when you hit a pothole. Post pics of your lowered truck when you can! Mr. P. damn dude, good post, i enjoyed reading that even though none of it relates to me, it might in the future!. Link to comment Share on other sites More sharing options...
misterp Posted February 1, 2006 Report Share Posted February 1, 2006 damn dude, good post, i enjoyed reading that even though none of it relates to me, it might in the future!. Thanks. Dropping unsprung weight, and even more importantly rolling weight, makes MAJOR differences in vehicle dynamics well beyond what you would expect with just the simple weight reduction. In other words - I bought lightweight aftermarket rims and tires for my SS, the final weight will be 62-lbs per wheel; and since the OEM cast 20s and Goodyears are 88-lbs per wheel the *total* weight reduction realized will be 26-lbs x 4 = 104-lbs. That simple choice of parts will already make the truck .10-sec faster. But there's more - because the overall height of the new tires is 1.5" shorter in my case the truck will have an effective rear gear ratio of 4.33 instead of 4.10. These LQ9 motors love to wind-up and this puts the motor even more into the RPM range where it likes to make power, and a chassis dyno will measure a 6% increase in torque at the rear wheels due to torque multiplication. ...so lessee, an additional 6% of 380 ft-lbs would mean an additional 22 ft-lbs delivered to the pavement... BUT there's even more - because the rolling weight is being reduced there will be less effort 'invested' in putting the wheels into motion, more of the motive force will be available to propel the vehicle - the truck will be quicker yet. If it were only 20-lbs difference I would not be all that excited, but in this case we're talking a reduction of over 100-lbs in rolling weight. I'm hoping for a .15-sec improvement, we'll see. Mr. P. Link to comment Share on other sites More sharing options...
2drTahoe Posted February 2, 2006 Report Share Posted February 2, 2006 what a nerd interesting reads misterp Link to comment Share on other sites More sharing options...
misterp Posted February 2, 2006 Report Share Posted February 2, 2006 what a nerd interesting reads misterp Thanks, I think? Mr. P. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.