Increasing tire to 42" on new 2017 F550

[MJL]

I work with a company that wants to increase the Tire size up to 42" on the new 2017 F550 for custom trucks.

They have worked with a US company that makes lift kits that is recommending a 2" lift kit and modifying the frame slightly at the front and back of the wheel well.

The 42" Tires are desirable because they are each certified to carry 8,000 LBS.

My concern is modifying the steel structure just in front and behind of the wheel well. I am an Engineer and can do static load calculations on modifications but I do not know what standards they have to be designed to or what loads these frames are subject to. The one behind the wheel well ties the floor to the sidewall I believe. The front modification should be similar to one the company had done on an earlier model but I need to figure out what loads I need to subject the design to.

 

Does anyone have experience with modifying these areas that can point me in the right direction?

 

Thanks

 

Edited January 30, 2017 by MJL

[NLPRacing]

These guys seem to have experience in putting big tires on F550's. I have no first hand knowledge of their work, but it seems to be a step in the right direction.

 

http://www.startrackstrucks.com/index.html

 

[MJL]

I believe these are the guys that are supplying our fender extension and lift kits. Those would even be the tires we will be putting on I think. I just need to be able to put some accurate numbers to the design modifications. Well they suggest putting in heavy enough steel to ensure it is strong enough, they do not have any numbers calculated to back it up and I want to be able to show the before and after strength of the modified area.