Need help: Fith wheel to high with 11R/24.5 tires

Well, I thought I was doing the right thing but I may have a problem.I found a great truck and committed to buying it. pete flex air suspension 11R 24.5 tires..was gonna do tanker work but that is on hold for awhile.instead I signed on for intermodal van work. now the 5th wheel is 49" high and I will be operating in the north east where there are lots of 13.6 bridges.....will sucking up the cost to replace them with 24.5 low pro tires solve my problem? can I just change the drives? what will this lower it to? I have a clean record and don't need to start scraping the tops of trailers.. Thanks for any advice. GP

 

The revolutions per mile on the 11R 24.5 is 476 the 24.5 lo pro is 501 or 25 turns per mile by the road speed calculator that is usually bout 100 engine rpm diff at 60 mph. As far as real data I have never swapped from low to tall or vise versa so I cant say, all I can give you is the on paper version. Hope this helps

 

Thanks wore out. I'm right now mainly concerned about the overhead trailer clearance especially this winter with snow and ice on the ground. I still want the truck and plan on doing tanker later on but not right now. Now I imagine I can have the speedo tire size parameters adjusted through the ECM so read correctly. I guess the fuel economy is what it is. Seems like i'm already learning the hard way as a new owner op. i'll have to straighten this out before I start pulling for the company in 2 weeks.

GP

 

off the top of my head 11r 24's are around 4in in dia taller than lp's so you would drop 2 inches from the ground to the top of the trailer. if you went all the way to lp 22.5's you would bring the top of the trailer down around 4inches with tires 8 inches shorter.

 

2 in. will drop from 11/R 2 lo/pro. ck. 4 air bags set to hi. adj. rod down till vib. starts measure 1ST then reset as Ulike

 

Ya definitely have tire size changed in ecm I have found that to be biggest fuel gains for my customers, I did roll a lo pro 24.5 up next to my 11R while ago looked like just short of 3 inches total course tread depths didnt match but you may get 1.5 inches of diff in the swap

 

Maybe if someone added 24.5's after the build spec, maybe they didn't change out the fifth wheel to a lower mounting height design. But that wouldn't be a cheap fix either unless someone would give you a decent credit for your 5th wheel. Plus you'd have to insure you have sufficient clearance now between the tire and the trailer to allow a reduction in that gap. You could also perhaps lower the bag height slightly but not sure if that's a good idea either if you're frame is currently level.

 

Yeah, frame pretty level.Fw looks normal,don't wana mess with the air bags if I don't have to. I wonder if the tire shop will take my 11R 24.5's on trade for Lp's? I assume I have change the steer's as well?......If I can get it down close to 47" fw height i'll be happy.my buddy told me not to worry about it but that's easy for him to say.he's running 22.5's....wow. new job, new truck woes and I didn't even pick it up yet...thanks for all the replies.keep em coming. being a company driver for so long I never had to worry about these things....

GP

 

We lowered our overall trailer height 2" by switching to lower profile 5th wheel. Get your specs and search junkyards on newer model wrecked trucks.

 

How high are the risers for the 5th wheel? Google the manufacturer for your 5th wheel. They will have info on different heights are available. I have a Fontaine, they call it an "Air Slide Bracket". http://fontaine.com/pdfs/literature/LT-135_PartsCatalog.pdf

Flex Air is a great suspension- very light weight, rides like a Cadillac, handles like a Corvette & has a really low ride height. I suspect you have really tall 5th wheel mounts & changing them would be cheaper than doing all your tires. Make sure you set the ride height in accordance with Peterbilt specs- effing with it will just cause problems.

If you have the rear end ratio to permit it, I would get to LP 22.5's as soon as convenient for fuel mileage alone.