What Is the Difference Between a BTR and BT8 Spindle

Question

Question:

Hi. Im wanting to buy new wheel hubs for my utility trailer. Seems I will need a BTR or a BT16 wheel hub but I dont understand the difference in these two hubs. Can you please explain?

asked by: William C

0

Expert Reply:

The BTR and BT8 denotations refer to the spindle, not the trailer hub. The difference between a BTR and BT8 spindle is that the BTR spindle uses a 1.063" diameter L44649 bearing and the BT8 spindle uses a 0.99" diameter L44643 bearing. In order to find out which you have you will need to pull the hub and either measure the spindle or look for the bearing numbers on the bearing.

If you have BTR spindles then you can use part # AKIHUB-440-2-2K.

expert reply by: Conner L

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Rich

8/5/2020

What wheel bearing size do I need for a 2000 trail star trailer?

Reply

Chris R.

8/14/2020

In order to determine the right replacement bearings you will need to actually pull one of the hubs and see if you can read the numbers stamped inside the bearings themselves. If not, you can measure the spindle where they sit to get their inner diameter. If you can let me know either piece of info I will be happy to recommend the correct replacements.

Reply

Brad

10/20/2024

@ChrisR I measure my spindle and it is 1.01" in on digital zeroed caliper. Which should I use, BTR or BT8?

Reply

John R.

7/29/2025

My trailer axel spindle is tapered. It has a Knott 6B2933 trailer hub which seems to be no longer available. What do I replace this hub with? John

Reply

Robin H.

7/29/2025

@JohnR you will have to measure the spindle where the bearings ride so we can identify the bearings and see if a hub is available. The other option is to give us the axle manufacturer along with the serial number off the axle tag which may be able to be used to identify it.

Reply

John R.

7/30/2025

@RobinH Thanks for getting back to me. The tapered spindle measures 1 3/8" at the back then tapers to 1 1/4" at the front. Knott 6B2933 trailer hub for tapered spindle. I appreciate your help, thank you. John

Reply

Robin H.

8/3/2025

@JohnR the only bearing that matches that 1-3/8" measurement is for agricultural hubs. More than likely it is an obsolete bearing combination. It looks like some places still carry the 6B2933 so I would get the exact replacement.

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See All (4) Replies to John R. ∨

Answer 1

Hi Jeff, welcome back! Is that the 126003? I don't see a 1260031 but the Lippert 126003 is a 3,500 lb hub with a 5 on 4-1/2 bolt pattern. Assuming that is correct, the Terran Axle Trailer Hub and Drum Assembly #TX68VJ will work as a replacement.…

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Answer 2

A BT8 spindle would have a diameter of .99 of an inch where the bearings would both install and would have a diameter of 1.24 where the great seal would ride. That would require a hub part #AKIHUB-440-2-1K for an idler hub. A BTR spindle would have…

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Answer 3

BTR and BT8 are the reference numbers for a standard trailer spindle size. When picking out a hub for a trailer you have to make sure that the hub is designed to fit the spindle. What you will need to do is measure spindles on your trailer where the…

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Answer 4

I have a few options for you to help with identifying the hub on your trailer. The first and easiest method would be to crawl under the trailer and look for the axle tag on the beam. This should give an axle capacity which we can then use to find the…

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Answer 5

You will need to measure the diameter of the spindles where the seal and bearings ride. Check out the picture I attached that shows where this is. You will need an exact measurement so either a digital or dial caliper will be needed. To pick out the…

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Answer 6

Verify your bearing numbers and bolt pattern to be sure but I believe either #8-258-5UC1-EZ for E-Z Lube axles or #8-258-5UC1 for standard axles is what you need. Both of these hubs include bearing #L44649 for the inner and outer. They have a 5 on…

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Answer 7

Hey John, thanks for reaching out. It sounds like you need the Timken Grease Seal #TMK36ZR which is I.D. 1.250" / O.D. 1.983". As far as the bearings it sounds like your hub uses the L44649 bearing which is the 1.063" ID. This goes…

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Answer 8

Hey Ray, for that we have the Dexter part #8-259-5UC1-EZ which has the EZ lube grease cap as well as comes pre-greased so it's ready to go. This has the bearing numbers you mentioned needing too.

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Answer 9

It is possible you can just swap out a 4-lug hub with a 5-lug hub so long as you know the hub you need. And in order to determine this (if you aren't sure already), there's a number of things you'll need to know. First, you need to know…

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Answer 10

Yes, I am and thanks for the information. It looks like your Reliable 2700lb Torsion Axle 08351 has a 1-1/16" x 1-1/16" spindle. I have two options for replacements and which one you need is going to be determined by how big your PWC…

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Answer 11

Hey Dan, thanks for reaching out. We do have the 7" electric brakes and drums. Electric brakes are typically less expensive and easier to service than disc brakes. Both could work but for a pop-up camper electric drum brakes would do fine and be…

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Answer 12

Hey Bruce, it sounds like you might have some older seals, perhaps Transcom seals with the 1.983" OD. We do have one seal, the #10-9 seal, which has proven to be a suitable replacement for these seals. This is a double lip seal with a 1.5"…

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What Is the Difference Between a BTR and BT8 Spindle

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