I just finish doing the whole brake service on my wife's 2010 TL (CPO car) with new rotors/pads/hardware/fluid for the front and rear.

I bought a kit from RockAuto, the Power Stop Performance Brake Upgrade kit, with comes with everything including brake pads, new caliper hardware/clips, etc..

I finished doing the front, and when I went to the replace the rear rotors, I found to my surprise that the rear rotors in the kit do not fit my wife's car:



obviously the bolt pattern is not correct for my car:



Here is the original/OEM rear rotor:



And here next to each other:



So I carefully measure the bolt pattern in the rear of the car, and it comes to about 4.5", which matches the 5x114.3 mm some Acura's have:








If I check that bolt pattern with the rear replacement rotors that I got, I find that (as I noted above since they don't fit), it is different:






If I open up the caliper until I approximate the actual bolt pattern on the replacement rotors, it comes to about 4.75" inches approximately, which matches the 5x120 mm that some Acura cars have:






Per what I can find out, I expected the rear bolt pattern to be 5x120mm, not 5x114.3mm. What is going on? Anyone else has that happen in their cars?


Will

 

as you suspect, rock auto sent you the wrong rotor for the rear.

put on the factory rotor, as I'M SURE it has plenty of life left.

send the rear back

 

Ah, and of course, I should have mentioned, the bolt pattern on front is also 4.5", since I have rotated tires front <-> back for 2 years now every 4-5K miles. So both the front and rear bolt pattern is 5x114.3mm.

So the kit I got had front rotors what where 5x114.3mm and rear rotors that were 5x120mm.

I just need replacement rear rotors with the 5x114.3mm so that I can complete the brake job.

Thanks much,
Will

 

I thought all if the 4G TL's were 5x120?

 

My 2010 TL definitely isn't.

Either way, the kit that I got has 5x114.3mm rotors for the front, and 5x120mm rotors for the rear. Weird, right?

 

Extremely weird. Every search I've looked at after reading this states 09+ Acura TL is 5 lug 115mm which is 5x120. Even when I look up your wheels.

I don't understand how your bolt pattern would be 5x114 unless you have hub adapters from 5x120 to 5x114. But strange that they would send you two different lug pattern rotors in a set.

 

I can't explain it either, but my car has no adapters of any kind. Here is the front, driver side new rotor installed: 4.5" bolt distance:

 

Baffled by this,certainly a strange one.Perhaps the dealership may have some info to offer you.

I have seen some charts that listed 2009 at 114.3 and 120 mm,but i figured it was a typo mistake since the 2009 + should all be 120 mm.

 

your stock wheels are 5x120 and so your lug bolt pattern cannot be 5x114... that is physically impossible.. your measurements must be wrong.

also i am 100% sure that all 4g tl come in 5x120 bolt pattern.

m14 lugs use 5x120 bolt pattern... absolutely no way your stock wheel will fit on a 5x114..

 

Wow - I never said my wheels are 5x120. Another forum member said that above - I didn't. I have measured and re-measured 5-6 times, and the bolt pattern in my car is "not" 5x120. It is 5x114.

Here is my machining caliper (I am actually a machinist, you can see some of my projects at www.atdms.com), set to 4.72" (about 120mm). As you can see, this fits perfectly the replacement rear rotor that does "not" fit in the rear hub in my 2010 TL:






If I leave the caliper at 4.72" and try to line it up with the wheel nuts in car (tips of caliper touching the nuts, with the one on the right being right in the middle of that nut), you can see what it is physically impossible for the car to have a bolt pattern of 120mm:



If I adjust the caliper to 4.50", and again, line up the inside edge of each tip with the middle of each nut, you can see that in fact, my car "does" have a bolt pattern of 4.5", or 114.3mm:







I can't explain this, but:
- I have rotated front <-> back tires several times in the 2+ years I have owned this car, so I know the bolt pattern on the OEM wheels is exactly the same.

- I bought this car used, as a CPO. I have no idea if at some point the car had (somehow) the hubs changed.

- the bolt pattern in my car is in fact 5x114mm, not the expected 5x120mm

- the kit that I got came with front rotors with a 5x114mm pattern and rear rotors with a 5x120mm pattern

- I did try to install/use the 5x120mm replacement rotors, and there is no physical way they can fit in the rear hubs (which based on measurements makes sense).



I am currently in dialog with RockAuto so that I can get the correct rotors for the rear.

Will

 

Here is the used, front rotor I took out for the new one in the kit. Here I set the caliper to 4.5", and line up the first inside edge with the center of one of the holes:





Then line up the other inside edge of the caliper with an opposite hole - perfect alignment at 4.5":



I then set the caliper to 4.72" (about 120mm), and repeat the alignment:





and the other hole - obviously impossible for the bolt pattern to be 120mm:




Will

 

Will,

I took digital calipers to my 2012 TL, and the distance between the center of one lug and the center of a lug 2 lugs away is also 4.5":





But, that does not mean I have a 5x114 lug pattern. Take a look at this explanation on the Discount Tire website on how determining the size for a 5-lug pattern is not as simple as a lug pattern with an even number of lugs:


http://www.discounttire.com/dtcs/infoBoltPatterns.dos


So when you measure the distance between the center of one of the lugs on the TL with the center of a lug 2 lugs away, you get very close to determining the lug bolt pattern, but it will be a little shorter than the actual lug pattern size. One way to calculate the bolt pattern on a 5-lug setup without using a bolt pattern gauge is to multiply what you and I measured by 1.05:




http://www.mrt-wheels.com/boltpattern.html
http://www.myboltpattern.com/measure-rims-bolt-pattern


So, 4.5" x 1.05 = 4.725", which converts into 120mm.

Also, the wheels you have are 4G specific. So, if you somehow got a 5x114 lug pattern installed onto your car, someone would have had to go through the trouble of converting the lug holes in these 4G wheels from 5x120 to 5x114 to fit (highly unlikely).

As for the rear rotors delivered to you with a distance of 4.75" between the center of one hole and the center of a hole 2 holes away, multiplying 4.75" with 1.05 equals 4.9875", and that converts to 120.65mm which is the next size up lug pattern size for a 5-lug setup. If you show photos of your measurements to RockAuto as well as the photo of their rear rotor not quite clearing your rear lugs, I think they'll agree they sent you 5x120.65 rear rotors by accident.

 

Thanks so much - the final piece of the puzzle now falls in place. I was wrong for thinking that center-to-center gave the pattern - I just did not know about the 1.05 factor. Now things make sense as to my car being 5x120 pattern, which is what my initial research said it should be.

I did send the photos and measurements to RockAuto - my guess they will in turn check with Power Stop to figure out the exchange for the correct rear rotors. The minimum thickness is 9mm, and I measured 10.2mm on the existing rear rotors, so I am still OK in the short term.

Will

 

I used RockAuto three times, I will never use them again. I, just like you got the wrong set of rotors delivered for my Lincoln LS a few years ago. They sent a new set and it was the same problem. It was resolved and I decided to use them again. I bought new A arms for the LS and they are Aluminum from the factory. I had the A arms on for one week and one snapped. So obviously the aftermarket product was inferior to the OEM product. The reason for replacing the A arm was due to replacing the ball joints and Ford made the A arm and ball joint one unit. I sent pictures to them and had the shop that installed them contact them as well. I was told it was not installed correctly. So move onto the third item, which was a radiator and for the LS and using a partial credit from the A arm, I received a radiator that already had a hole in it and was the wrong one as well. That was my last attempt to use their sorry excuse of a company. But I guess that's what you get when you try to save a few bucks.

 

You're welcome, and I'm glad I was able to help clear the muddy waters.

 

see told you lol.. your measurements were wrong.

tks si1point6 for clarifying it..

fact is.. all 4g comes in 5x120 no matter what..

 

Nice center caps (si1point6). I noticed my 2009 are painted too. I like them in 3D.

 

echodigital,

I just realized the difference between the 2009 with the 2D black acura logo and the 2012 with the raised logo. I agree: I like the 3D one better. I just looked them up on acuraeomparts.com: they run $38.66 each. If you are quick, you can swoop up used ones for $10 each on this ebay auction I found:

http://www.ebay.com/itm/Acura-TL-RL-X-Series-Center-Hub-Cap-Caps-Hubcap-2010-2013-/161284161263?pt=Motors_Car_Truck_Parts_Accessories&hash=item258d48feef&vxp=mtr
I measured my center caps, and they are approximately 2-3/4" in diameter.

 

Glad we figured it out haha. I wish they did build this car with 5x114 lug pattern though. Make wheel shopping a whole lot easier with more options.

By the way, your brakes look very nice!

 

Yup, you guys were right - my apologies for the extra drama while trying to figure this out.

I will update the thread again once I get the replacement rear rotors.

Thanks much,
Will

 

i believe they needed to go 5x120 due to the extra weight and awd system it had.. 5x120 also mean that it needed bigger studs which is why acura went with m14x1.5 pitch threads... thats atleast from what i know.

 

RockAuto sent me a pre-paid FedEx shipper to send the rear rotors back. These go out back to them tomorrow.

 

RockAuto came through with flying colors. The replacement rotors are the correct size (center hole to center hole of 4.5", or 5x120mm bolt pattern):



I did a quick dry fit, and yes, perfect fit:



I then of course replaced both rear rotors:






Will