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RIM LOAD STANDARDS?

RIM LOAD STANDARDS?

RIM LOAD STANDARDS?

(OP)
IS THERE A STANDARD THAT REGULATES THE LOADING THAT CAN BE PLACED ON WHEELS?  

RE: RIM LOAD STANDARDS?

NOT SO FAR AS I KNOW BUT YOU MIGHT WANT TO LOOK IN T&RA.

More specifically, if a light truck is on a 15x6 rim, and a small hatchback is on the same size rim, the loads will be different and so will the wheel design.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies  http://eng-tips.com/market.cfm?

RE: RIM LOAD STANDARDS?

(OP)
THANK YOU FOR THE REPLY. THAT WAS KIND OF THE SAME CONCLUSION I CAME TO. IT SEEMS LIKE TRA REGULATES THE CONTOUR OF THE RIM, BUT NO STANDARDS ON LOAD REQUIREMENTS. I JUST THOUGHT I WOULD POST AND NOT PAY FOR THE STANDARD TO FIND OUT THEY ONLY REGULATE CONTOURS. I GUESS I WILL JUST LEAVE IT UP TO THE VENDOR TO EVALUATE MY SPECS AND LOAD REQUIREMENT. THANKS AGAIN FOR THE REPLY.  

RE: RIM LOAD STANDARDS?

A couple of thoughts:

First is that vehicle manufacturers typically have different bolt pattern between cars and trucks to distinguish between wheels designed for each - with the obvious difference being the load.

Second is the use of the term "vender".  This term is usually used in the trade to describe a supplier of goods or services to another business - and not to describe the relationship between an individual consumer and a retail outlet.  

So if your intention is to buy a large number of the same part for your manufacturering process, the term "vender" would be appropriate - and you will need to describe the service conditions to the vender.  They, of course, will check to be sure that the parts they make are suitable for those conditions.  But if you are going through a wholesaler, the that wholesaler should check with the manufacturer for such info.

But if you are a consumer doing your personal car or truck, then it is quite likely that the bolt pattern will determine what is available to fit and you can be reasonably sure the wheel manufacturer considered loading in the design process.

But if you are doing a modification - particularly if you are doing something along the lines of increasing the load carrying capacity of your 1/2 ton pickup - well, there are many more issues involved than just the wheel (and tires). Frames, suspension pieces, brakes, etc.  would also need to be upgraded -something usually not considered.  If this is the case, my personal advice would be upgrade the whole truck.

And lastly, use of the CAPSLOCK is considered shouting in internet postings.  It should be done sparingly if you want to be treated like a resonable person.  The first impression you leave with a posting with all caps is that you are a jerk.  It'sobvious the group here looked passed that, but other groups are not so forgiving.

RE: RIM LOAD STANDARDS?

(OP)
Sorry about the caps lock, I do not post on forums very often and was unaware of it indicating an intention to shout. No, this is not for a personal application. We design and build machinery in the railcar mover industry and are introducing a new model larger than anything we currently build. I am a new engineer, and kind of thought that the wheel and tire vendor would verify that the design was acceptable, but I just didn't want to take it to my boss and look like an idiot if there was a standard that I should have been using. Part of being new I guess. Again, sorry for the "shouting". It was not intended.

 

RE: RIM LOAD STANDARDS?

Wheel loads are usually derived from axle load ratings or tire load ratings (if the axle ratings are not available) and are used in durability test load calculations.  The end goal being that the axle or tire fails before the wheel, if overloaded.

Tim Flater
Senior Designer
Enkei America, Inc.
www.enkei.com

Some people are like slinkies....they don't really have a purpose, but they still bring a smile to your face when you push them down the stairs.

RE: RIM LOAD STANDARDS?

(OP)
Thanks, I do have axle load ratings. The piece I was missing is that you would want the axle to fail before the wheel. Sorry for the seemingly stupid question. I'm still new at this. Thanks for the advice.  

RE: RIM LOAD STANDARDS?

It's a little unclear, but it sounds like you will be using OTR type tires - and if that is the case, you can be sure that the rim manufacturer will be designing the rim to accommodate the worst case tire loading.  Many in this area supply both the tire and the rim - which helps assure compatibility.  At any rate, you, as an engineer, should contact the supplier to get their published specs, but you don't have to worry about anything other than making sure you've accurately described the operating conditions.

You should also be closely working with the tire supplier to make sure the tire is compatible.  If I am reading this correctly, this kind of specialty application requires a tire guy who is familiar with the operating conditions and can select a tire that will work.  He should also be able to direct you to rims suppliers that they've worked with before - and they have confidence in.

RE: RIM LOAD STANDARDS?

The only stupid question is the one that is not asked, correct?

Wheel and tire design methods are a bit of a dark art....not much info out in the public eye for people to readily use.  About the only way to get the entire scope is to actually work in either industry for a few years....or ask here.

For passenger cars and light trucks (typical pickups and lighter), rims must only fit into an "envelope" of sorts which really isn't for durability or strength but mainly for tire fitment and installation.  The strength of the rim is in the wall thicknesses and processing of the metal (roll forming or spinning for example).  This does not mean that you only concentrate on the design of the rim area....but rather that you only focus on meeting the dimensional requirements of the rim area, using a wall thickness of say 6mm minimum would be sufficient for most passenger car and light truck applications.  Heavier loading may require a thicker wall in the rim area.  The wheel strength is usually in the spoke and hub areaa for aluminum wheels.

The rim standard organizations (T&RA and JATMA - Japan) books usually have tire load ratings as well as fitmnt charts based on rim sizes (15 X 7 rim fits specific tire sizes).  It wouldn't be uncommon that if the axle load ratings were not available to take the highest load rated tire that would fit the given rim and use that tire load to calculate wheel loads (durability test loads).

In this case, one could take 1/2 of the axle rating and plug that number into the SAE equations for rotary, radial and impact for test loads.  Wheel must pass those test loads at given number of cycles.

Tim Flater
Senior Designer
Enkei America, Inc.
www.enkei.com

Some people are like slinkies....they don't really have a purpose, but they still bring a smile to your face when you push them down the stairs.

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