Rear mudflap position measurement (International)

[musigenesis]

Current state of my bus:



My first step is going to be to add cross-members behind the wheel wells that run from my new steel angle pieces to the walls, which I'll be attaching my replacement mud flaps to. Problem is, I don't know exactly where the original mud flaps were attached (in terms of how far behind the wheels they were positioned); I asked the guy going the demo to mark the position for me before he started cutting but he didn't do so (should have marked it myself, obviously - should have done the whole job myself, in fact).

Could anybody give me this measurement, basically how far back from the joint between the wheel well and the floor?

[Rochey6957]

Bluebird body?

ill try to grab it tonight for you

[Brad_SwiftFur]

For something like this, I'd just eyeball it. As I recall, the mudflaps hang off the crossmember behind the wheel wells. This isn't a critical measurement and you could, in fact, hang 'em off the rear bumper (some RV's do this).

[musigenesis]

Originally Posted by Brad_SwiftFur

For something like this, I'd just eyeball it. As I recall, the mudflaps hang off the crossmember behind the wheel wells. This isn't a critical measurement and you could, in fact, hang 'em off the rear bumper (some RV's do this).

Well, I'm more concerned about being too close to the wheels than too far away from them. I'm fitting a step tub right behind this that projects through the floor, and I need to have sufficient clearance on this new beam to allow the tub plus 2" insulation around it to fit in the hole, but this may mean bringing the beam too far forward towards the wheel. The location of the existing flaps is more to give me an idea of what the minimum clearance needs to be.

[o1marc]

On mine the flat space from in front of the mudflap to the back of the wheel well is exactly 5"

[Brad_SwiftFur]

Originally Posted by musigenesis

Well, I'm more concerned about being too close to the wheels than too far away from them. I'm fitting a step tub right behind this that projects through the floor, and I need to have sufficient clearance on this new beam to allow the tub plus 2" insulation around it to fit in the hole, but this may mean bringing the beam too far forward towards the wheel. The location of the existing flaps is more to give me an idea of what the minimum clearance needs to be.

Don't be afraid to install whatever mods you want to make right behind the wheel and hang the mudflap(s) from that, assuming you make it strong enough to hold them. Mudflaps aren't sacred! Cut 'em as needed to make the project work.


Sure, there's laws dictating how long they should be (typically this addresses how low they should extend) so try to get the bottom edge to the same height as it began. On trucks, mudflaps are a common violation but I've not seen it enforced as strictly on buses, I doubt many officers are going to get out a tape measure over them as long as they "look" right.


(After a quick check, there are no federal laws requiring mudflaps but most guidelines want them to hang low enough to "cover" 2/3 or so of the tire, to hang within 6-8" off the ground but not so low as to drag. Most laws are set by individual states.)

[Sehnsucht]

DOT standard for semi trucks is that the mudflap should be within 6 inches of the ground when at travelling height. I say 'travelling height' because some trailers and many motorcoaches/buses/RVs dump the suspension air when parked so I don't want that measurement to be the one you use to base it on. As Brad mentioned, this seems hardly ever enforced anyways and even when I asked a DOT exam instructor he couldn't cite the reg which shows how little its a priority. As long as the mudflap is present and secure enough not to fall off, and that it's not torn or worn through (I see that in dump trucks a lot) then there's very little chance of a mudflap attracting undue attention on its own. Distance from tire and overall length is entirely a function of the vehicle's design so if you construct some lower hanging structure and then cut down a standard length mudflap to length you're fine so long as it still secures effectively to the body or frame. If you're really OCD about it the biggest issue may be using an unbranded mudflap so that some image or logo isn't cut in half!

[Brad_SwiftFur]

Originally Posted by Sehnsucht

DOT standard for semi trucks is that the mudflap should be within 6 inches of the ground when at travelling height....

I did a quick Google search of this when I posted and each state's requirement differs (quite a few states had no requirements at all!) The DOT "standard" is more of a guideline than it is a federal law (most if not all state laws will follow this fairly closely, or be less restrictive.)




Some have distance-to-ground rules measured in inches, a couple used tire height formulas, GA has a ground-to-centerline-of-axle rule, some use a 22.5 degree angle rule (basically measure a 22.5 degree angle from the bottom of the tire, toward the back of the vehicle and the mudflap must reach this zone.)

[musigenesis]

Originally Posted by Brad_SwiftFur

Don't be afraid to install whatever mods you want to make right behind the wheel and hang the mudflap(s) from that, assuming you make it strong enough to hold them. Mudflaps aren't sacred! Cut 'em as needed to make the project work.

I definitely don't think they're sacred, just trying to make really really sure I don't weld something up and then have to cut it out. I'm going to do like you suggest and just frame things up to fit my tub as necessary, and then attach a cut mud flap on the underside of that

Originally Posted by Brad_SwiftFur

On trucks, mudflaps are a common violation but I've not seen it enforced as strictly on buses, I doubt many officers are going to get out a tape measure over them as long as they "look" right.

It would be amusing to me to get a ticket for missing mudflaps while the officer ignores the 8 foot square section of missing floor - which I'm sure is illegal for some reason.

[musigenesis]

Originally Posted by o1marc

On mine the flat space from in front of the mudflap to the back of the wheel well is exactly 5"

Perfect, thanks.

[Brad_SwiftFur]

Originally Posted by musigenesis

It would be amusing to me to get a ticket for missing mudflaps while the officer ignores the 8 foot square section of missing floor - which I'm sure is illegal for some reason.

Sounds like a plan. I ... have no idea about the floor rule without looking it up, since you're presumably not intending to leave it that way indefinitely. I would consider it a violation and safety hazard if you had any passengers but not so much if driving it to the welding shop for work to be done.


Another weird tidbit. There's no federal rule (and the same is true for most states) requiring doors! The only rule I can find says that doors must be secure (they don't even have to be closed! Only that they must be secure!) Jeeps often have doors removed in warm weather, and UPS/Fedex drivers often do their routes with doors open.

[o1marc]

Originally Posted by Brad_SwiftFur

Sounds like a plan. I ... have no idea about the floor rule without looking it up, since you're presumably not intending to leave it that way indefinitely. I would consider it a violation and safety hazard if you had any passengers but not so much if driving it to the welding shop for work to be done.


Another weird tidbit. There's no federal rule (and the same is true for most states) requiring doors! The only rule I can find says that doors must be secure (they don't even have to be closed! Only that they must be secure!) Jeeps often have doors removed in warm weather, and UPS/Fedex drivers often do their routes with doors open.

Reminds me of the arguement I had with officials on my race car that had operating door hinge and opening method (from inside). I was told they needed to be welded or chained. I'm sorry, but the car was manufactured with doors that are secure when closed by Federal standard. I don't believe your rules differ. I ran with opening drivers door.

[Sehnsucht]

Originally Posted by Brad_SwiftFur

The DOT "standard" is more of a guideline than it is a federal law (most if not all state laws will follow this fairly closely, or be less restrictive.)

Exactly. I suppose I need to learn to just get to the point!