Just found this board last week and glad that I did as it has help me with several questions. However, I haven't found a string discussing going to larger diameter rims on the stock ride height Lightning. I am interested in any feed back on 20 inch diameter rims and tire sizes. I want to to go to 20 x 10's with Nitto 305/50/R20 but am not sure they will clear everything. There also are several 295s either 40 or 45 profile in other brand tires (Dunlop, Goodyear or Toyo). Any info would be appreciated.

 

The following sizes would keep you within the recommended 3% band from oem spec overall diameter:

- 295/35R20 (-1.13%)
- 305/35R20 (-0.17%)
- 315/35R20 (+0.80%)

I assume you don't want to get tires that are narrower than stock, right?

The 305/50R20s you mentioned would be 12.5% off! (Remember, the OEM tires alone have a 45 aspect ratio, and that's from a 295 width tire)

Hope that helps...


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Thunder
rainmaker@attglobal.net

Black 97 Expedition EB 5.4L 4WD

Mods: Lightning front fascia, Lightning Wheels, Pirelli Scorpion Zero 285/55VR18, K&N Gen II Kit, JET Chip

Brembo 14" disc brake kit coming right up!!! And hopefully a Lightning engine too!!!

Audio: McIntosh MX406, McIntosh MCD4000, Zapco SX-SL, Zapco EQ30, Genesis Monoblocks (3), Genesis Dual Mono, Dynaudio System 340, Dynaudio System 220, JL Audio Stealthbox

 

Hrm, Whats the equation to find out total heights with wheels and ires, i vaguely remember it but not sure, you convert it to metrics, do a cpl other things and add the rim height . Also on the subject of 20" wheels I ahve seen tires totally bald, like evenly worn that came from 20's, not sure if this happens to everyone but theese were perfectley bald after only about 8k miles. I was thinking it had something to do with the very large rim pushing down with allot of force on the slim tire.

 

This is a good calculator http://www.cs.fredonia.edu/~stei0302.../tirecalc.html

those 305/50/20's are pretty tall (32+")

 

Most 20in. tires dont last at all... ur lucky of u get 12-15k out of them.. This has to do mostly with the tread compound (Z rated). Pirelli i think wear out the fastest. I had them on my Porsche C2 and they lasted 10k
I have Yokos on mine and expect about the same, maybe a little more.
305x50x20 r really big tires. i mean BIG. Thats alot taller than the stock. If u go too skinny tho, it rides pretty bad (not to mention bent rims ). Only reason i can stand mine is cause the bags smooth it out a bunch.



[This message has been edited by CptReKaHo (edited 02-29-2000).]

[This message has been edited by CptReKaHo (edited 02-29-2000).]

 

Here you go...

Given, say, your 305/50R20 tires

305 is the width in mm
50 is the aspect ratio (sidewall height as a percentage of the tire width)
20 is the wheel diameter (not tire dia.)

- convert the width into inches by dividing by 25.4 [305/25.4=12.01]
- multiply the width by the aspect ratio to get the height of the sidewalls. [12.01*50=6.005]
- add the wheel diameter to twice the sidewall height to get overall diameter. [20+6.005+6.005=32.01]

If you give me your email address, I can send you a simple template I made in ms excel.

[This message has been edited by Thunder (edited 02-29-2000).]

 

I use Goodyear runflat 295-40-20's on 20X9 rims and put a little over 10,000 miles on them before I took them off for the winter and they still look like new, lots of meat on them. Could be bec they have a stiff side wall and don't wear like the others? Now that I said this they'll probably be bald by summer.

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99 Expedition 2wd 5.4L, Silver w/Dark Grey Int, Billet Grill, Door sills, pedals, brake cover, ant, wiper covers, fender badges, rear view mirror. Shaved roof rack & tail gate, fog light bumper color matched. Clear front corners, WMS intake, directional mirrors. Front and Rear Airbag suspension with 4 wheel
independent control, 20in CEC's w 295-40-zr20, Alpine CVA 1005, 12 disc changer, Alpine speakers, subs, amps. Alpine 8081 alarm w/pager and remote start.

 

What's the speed rating for those Goodyear's, Slammed Expy? And how much do they cost? I am seriously thinking about 20" for my Lightning. That black F150 is tight!

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99 Black Lightning
created 8/17/99, bought 9/25/99
#3681/4000
CD changer, Tow package, factory tonneau cover
100k mile warrantee, bed/under liner, paint protected

 

The 295x40x20 might be different. The r a much taller tire than most. Maybe they have a harder tread...

 

They are Zr-Rated so no problems going as fast as you like. I do have a pic of them on my truck but only with the 4in drop. As soon as I know that it's won't snow again, I'm putting on the 20's and getting pic of them tucked in the fender. Airbagged it this winter. Plus the height is just a bit smaller than stock and they don't hit the lip, they tuck all the way to the top of the well. I have no idea how to put a pic here like the one above (nice truck BTW) e-mailing is the only way I know.

 

Oh, as for price, I don't know bec I got a deal on the wheels and tires (so he claimed) and I put an Alarm and Remote Starter in the guy's truck. But I paid under $4000.00 for the CEC 169's in chrome with tires about a year ago. I do remember seeing in the mag somewhere the price and I know they were under $400.00 a tire.

 

Thanks for the info, Slammed. About as much as these Lightning tries, $300-$360 a pop

 

Thanks for all the info from those who replied. I haven't heard that the 20's have such poor mileage as compared to the 18's that came with the Lightning. As far as the 305's and size, I went to the Nitto web page and the diameter they give is 31.89 and 12.28 wide. This compares to 30.45 diameter and 11.61 wide for the stock F-1's. I haven't given up the idea yet and am trying to hook up with a local tire/wheel dealer to work with me on this fit and choice.

By the way, CptReKaHo, that black F-150 has a nice look with the chromes and in the weeds stance. I am also considering dropping the Lightning after I figure out the wheel and tire combination. Who/what did you use for your bag sit-up?