BMC Question...

[FatTiresRollin]

Just a quick question for you body mount chop experts. Forgive me if this question sounds dumb...but, is there a functional reason for welding/capping off your bmc or is it just cosmetic? Every body mount chop I have seen on here is capped off and painted, so I can only assume there is probably a functional reason...just curious as to if this is necessary or could one simply make the body mount cut and leave it unfinished?

 

[thebwlife]

Yes because you really need the strength. Toyota put it there so you probably need it.

With your rubbing problem - you would be better served by getting some UCAs and setting them to 4* and that should take care of your rubbing. Lots of people have 17x8 w/ 0 OS w/ 4.5 BS and don't rub.

 

[FactoryRide]

The guy above is right about the strength. The only logical thing I can think of as to why they are for a head on collision. The body mounts would in my head are designed to prevent the wheels from being pushed rearward into the cab during a head on collision. So capping them retains some of the strength.

I did mine with only the cost of some spray paint to me. So for $10-15 I felt it was definitely worth my time. I do plan to add UCAs like stated and would be a great way to go about it, but for UCAs starting out at 450, I figured I'd do the BMC for now.

I did mine a little different from how everyone else has done though. There is a link in my build thread, but I can't get to it right now. I cut a 3/4" wedge out of the mounts, took a BFH and hammered in close together, and welded shut. At full compression and full lock I have about 5mm of clearance. I will revisit the BMC once I go up in tire size though. If you look at the link pay no mind to my welds.

 

[Jesse1983]

http://www.toyota-4runner.org/5th-gen-t4rs/125003-body-mount-chop.html

:cheers:

 

[FatTiresRollin]

The guy above is right about the strength. The only logical thing I can think of as to why they are for a head on collision. The body mounts would in my head are designed to prevent the wheels from being pushed rearward into the cab during a head on collision. So capping them retains some of the strength.

I did mine with only the cost of some spray paint to me. So for $10-15 I felt it was definitely worth my time. I do plan to add UCAs like stated and would be a great way to go about it, but for UCAs starting out at 450, I figured I'd do the BMC for now.

I did mine a little different from how everyone else has done though. There is a link in my build thread, but I can't get to it right now. I cut a 3/4" wedge out of the mounts, took a BFH and hammered in close together, and welded shut. At full compression and full lock I have about 5mm of clearance. I will revisit the BMC once I go up in tire size though. If you look at the link pay no mind to my welds.

I know nothing about metal working/welding, so no judgment from me on the welds. They are beautiful in my eyes.

Your BMC was one of the first I came across when searching. And you are right...all others seem to have just cut off the body mount at a 90 deg angle and capped it off. I like your logic for the purpose and it seems like your method would retain some of the strength and that original purpose...but it doesn't seem like welding a steel plate on the others would really add any additional strength? Plus once they are cut off, they certainly don't offer any protection in a collision.

Unless the overhanging portion of the body mounts are an overall structural support for the vehicle, I would think skipping the welding aspect wouldn't change anything other than the look. I know how to search this forum and others....and have read through all the BMC write-ups. I know what needs to be done and "how to do it"...just looking for a reason I guess. Similar to your reasoning, I am just looking for an inexpensive (free) alternative to UCAs. What can I say....I am cheap!

I haven't even felt any rubbing on the body mount, but there are obvious marks on the mounts and based on the pic I posted in the Level 8 MK6 thread...the wheel def touches at full lock. I can only imagine that the effect will be magnified in any offroad situation. I just don't think it has enough effect on my day-to-day driving to warrant $400+ UCAs + cost of alignment. That's a lot of money I can put elsewhere....

 

[FactoryRide]

I know nothing about metal working/welding, so no judgment from me on the welds. They are beautiful in my eyes.

Well I wish I saw what you saw. haha I've thought about grinding them and redoing them but it doesn't bother me that much.

Your BMC was one of the first I came across when searching. And you are right...all others seem to have just cut off the body mount at a 90 deg angle and capped it off. I like your logic for the purpose and it seems like your method would retain some of the strength and that original purpose...but it doesn't seem like welding a steel plate on the others would really add any additional strength? Plus once they are cut off, they certainly don't offer any protection in a collision.

The only thing I see is the end cap will prevent the open ends from being able to bend backwards. With the cap on it, it may solve that issue. Again this is assuming my reasoning for the BMs is correct.

Unless the overhanging portion of the body mounts are an overall structural support for the vehicle, I would think skipping the welding aspect wouldn't change anything other than the look. I know how to search this forum and others....and have read through all the BMC write-ups. I know what needs to be done and "how to do it"...just looking for a reason I guess. Similar to your reasoning, I am just looking for an inexpensive (free) alternative to UCAs. What can I say....I am cheap!

The force on the mounts from the body are from the actual mounting position and inward. There should be no force acting on the outer edges of the body mount. Harper7 just cut his out without welding it shut. If you decide to do that, make sure you round off the corners so you don't tear a hole in the tire in any situation where the tire might make contact with the BM.

I haven't even felt any rubbing on the body mount, but there are obvious marks on the mounts and based on the pic I posted in the Level 8 MK6 thread...the wheel def touches at full lock. I can only imagine that the effect will be magnified in any offroad situation. I just don't think it has enough effect on my day-to-day driving to warrant $400+ UCAs + cost of alignment. That's a lot of money I can put elsewhere....
If you're making some serious contact with the BMs, you'll know it. I can assure you of it. It may rub some hear and there. I don't think I would have even rubbed if I would have taken off my wheel spacers. I don't blame you on the not wanting to spend money on UCAs right now. I'm the exact same way.

Thanks Jessie for getting that link up!!

 

[Hawaiian4runner]

Thanks Jessie for getting that link up!!

Seriously now guys, not welding a plate is a huge compromise. That body mount is a structural mount made of high strength steel so you are just fooling yourself to "make up" all kinds of rationalizations on why it's OK. That being said, mine is cut and not plated. Chances are the cuts will not be the reason anyone dies if I'm involved in an accident but no, I'm not going to go around and say that it makes no difference when you chop up something like that. Just look at it, obviously it has been structurally compromised.