Wheel Backspacing and Offset Info

Heh. I have a similar issue but I think I'm pretty close to figuring it out... I need a little help getting over the hump...

I have two sets of wheels currently (17 Tacoma wheels) and (17 inch ProComp Helldorado) The Tacoma wheels have a backspace of 4.75" (i believe) and the Helldorado are exactly 4.75" backspace.
I am running 285/70/17s. On the Procomp wheels I have no rub (I have winter blizzak and summer Procomp tires/same size)
I have a 2.5 inch lift using spacers and blocks. I will be upgrading that with an Icon Stage 3 kit which includes the UCAs. I am planning on exactly the same lift.
Currently my Tacoma wheels rub the lower control arms on a hard turn in reverse and forward. I do not have this issue with my Procomp wheels.

Procomp:

• Wheel Size: 17x9
• Bolt Pattern: 6 on 5.5
• Backspace: 4.75
• Max Load: 2500
• Finish: Flat Black
• Offset: -6

Tacoma:

• Wheel Size: 17x7.5
• Bolt Pattern: 6 on 5.5
• Backspace: 4.75
• Finish: Aluminum/Platinum
• Offset: 30mm

I believe the Tacoma wheel / tire rubs because its narrower but I scratch my head as to why if the backspacing is the same. Is it because the other is wider and the spacing is such that its all in the Offset?

The recommendation from Icon is: aftermarket Wheels: 8" - 9" Wide Wheel With 5" Backspace. Tires: 33 x 11.50 Tall

Clearly my Tacoma wheels will have to go..

First:
I would like Some TRD Pro wheels to replace them. I believe I will just need to make sure that the TRD Pro wheels are at least 8" wide, with a 4.75 backspace. (Can anyone confirm this for sure?

Second:
How in the heck to I convert tire size from 285/70 to 3? X 11.5 Tall? Can I continue to use the same tires with no issues if the wheels are similar in size to my Procomp?

Last for fun:
Which Correctly sized TRD Pro wheel would you recommend as far as appearance? (My Taco is a 2015 DCSB that is MGM in color.)
If you have links to a similar Taco with TRD Pro wheels that would be cool and/or if you have a link to the TRD Pro wheel for best price that would be rocking!


Thanks

 

I'm assuming you have the '17 TRD Sport wheels, even though your avatar says '15 Offroad.
The TRD Sport wheel is a 17x7.5 +30mm/5.5" backspace.

Backspace is mounting surface to outer rim edge; 7.5" is inside rim edge. You're not accounting for the thickness of the rim flange. Industry standard is 1/2" x 2...
The math would look like this:
(7.5 + 1)/2 + (+30mm) = 5.5
I believe this is a big part of your confusion.
How did you come up with the Pro Comp backspace?

33x11.5R17=295/70/17
Here's a link to LT metric vs LT flotation:
https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=53
or...
Here's a calculator to compare different set-ups. I will warn you; the backspace it gives are wrong. They do not account for flange thickness either; so, just add 1/2" to what they give you.
It also allows you to input a metric tire size and toggle it to an equivalent LT flotation.

I have no opinion on the looks of wheels...

 

That makes more sense because when I tried measuring the ProComp it looked to me like it was a little.over 5" inches. (Plane across the back across the wheel with a string to the center, then measured the string) I can measure the Tacoma wheels because they are on the vehicle. (And yes they are not original, I picked them up used from another Tacoma owner locally) so for both I just pulled the data online for the measurements figuring the vendor data was more accurate than my measurements.

 

Their data should be accurate then. I just didn't want you to make the same mistake if you were calculating using width and offset.

 

The recommendation from icon is: aftermarket Wheels: 8" - 9" Wide Wheel With 5" Backspace. Tires: 33 x 11.50 Tall

I'll likely swap my Tacoma wheels for a set of TRD Pros. I just have not seen any that meet those specs.

Thanks for your input.. I will use those links.

 

Tacoma Pro or 4runner Pro?
FN FX Pro are 4runner knock-offs and measure 17x8 +0/4.5" backspace,

I'm sure they mean 5" or less on the backspace as well.
Here's a chart to help you shop.

 

Just for clarity

What I have:


What I am thinking (typically the 17s are from the FJ or 4 runner)

 

What size and Brand tire you got on the truck?

 

This stuff is going right over my head. I would like to run 285 but do not want to add spacers or have to change out the UCA's. I want to get the Fuels Ripper rims but getting confused on the backspace/offset. I am trying to get 16X8 and run the Falken Wildpeak AT3 285/75/16. The two options for the rims are: offset: 01 mm backspacing: 4.50" or offset: 20mm backspacing: 5.25". I have a 2016 Tacoma OR with Bilstein 5100 at the second to highest setting. Which option is better/best and will they clear the UCA's and how much cutting or other issues will I have if any? Thank you for the help

 

A positive offset will being the wheel closer to the UCA. For 285s, you'd be better off with the 01mm offset wheel.

 

FWIW, I have a 2014 with those specs on my KMC rims and those tires with foxes dialed up to about 2" and had to cut a lot of fender flare, body mount, etc to make mine not rub all the time.

 

There are some helpful links above that can give you good links to see the differences tire size and offsets make. I found it helpful

Here is one: The other link is in the quote below. If all else fails find a tire shop that sells the wheels you want and you can ask a bunch of questions. They should (if they are reputable) be able to get you on the right track.

The key is to not get discouraged. We all learn in different ways. Keep asking questions and meeting people and you will find the answer you need. This forum is really great for it.

 

So:
18 Off road
Stock suspension (for the first year)
Want to run FJ TRD 16x7.5 15mm offset

Can anyone tell me if a 265/270 will get me even with the fender and rub or not?

 

The rim will stick out 16mm more than stock.
A 265/75/16 will stick out 10mm more than stock.
Shouldn't rub in everyday driving.
It might rub plastic or mudguards if locked and stuffed; depending how much caster you have.

 

Thank you for the answer. I would have been backward. I was under the impression positive offset tucked the tire into the well more. Glad I asked.

 

The stock Offroad wheel is a 16x7+25mm...
Here's a calculator to help you out. Scroll down for clearances.

 

Ahh. So I was right, just not in comparison to he stock wheel. Thanks again.

 

Yes; if your reference is zero offset...but, it also depends on width, too.

For example; a 16x9 +12mm offset will stick out further than a 16x7 0mm offset

 

I have 2 sets of wheels. Stock 2017 OR with 25 offset.... And stock 2005 FJ 17 inch wheels with 15 offset. I am using 1.25 spacers with both.

I'm about to move to 285s from 265s on my lifted OR. I have read of situations where too much poke and too little poke both cause running in different ways.

I see three options for running the 285s.

The OR wheels with the spacers +25 offset +1.25
The FJ wheels with the spacers +15 offset + 1.25
The FJ wheels without the spacers. +15 offset.

Which sounds like the best option to hit the sweet spot.

 

Not sure this is the best thread, but I'm trying to figure out what brand/style and — more importantly — what offset/backspacing the wheels in the pics below are. I just picked up a '99 T4R SR5 (what can I say, love 3rd gens) and was hoping you guys can help me figure out.

They have pretty decent stance, especially considering they are only wrapped in 265/70R16 AT's right now.

Looking to go up to 285/75r16 (and some SCS wheels when they get back in stock) but would love to figure out what these wheels are and what the specs on them are. Honestly, they look pretty good. I might keep as a backup set and paint with some Graphite Duplicolor!

I figured if anyone knows it'd be the guys on this thread, so please let me know if you have any ideas.