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

0

Rich

8/5/2020

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

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.

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?

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

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.

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

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.

See All (4) Replies to John R. ∨

Answer 1

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 2

Hi Andi, A 5.3R12 wheel would have an overall diameter of 21.9" and the Kenda 145/80R12 #AM35351DX would have a 21.13" overall diameter, giving you a .77" difference. This going smaller would slightly lower the trailer, but at…

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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

Unfortunately the negative offset is not something we carry in that wheel size. Depending on the offset needed, you may be able to use the zero offset Kenda K500 SuperTurf Tire with 8" White Wheel - 5 on 4-1/2 - Load Range B #AM89992. This wheel…

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Answer 5

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 6

Hey Tyler, yes the CE Smith trailer hub part #CE13315 that you referenced would work for you as this was designed to fit a straight spindle that is 1-1/16 inch in diameter. This has the very common 5 on 4-1/2 bolt pattern too. If you have a 5 lug…

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Answer 7

Hey Lee, so in general the radial tire construction is preferred over the bias ply. You'll get a more stable ride and generally a little less heat build up. If you will be under the weight and speed capacity of your current tires I think…

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Answer 8

For a 4.80-12 trailer tire, the overall diameter or height is 20.5 inches. For a 5.30-12 it is 21.9 inches. That is a difference of 1.4 inches but you will only see half of that, 0.7 inches, in added height. Please keep in mind that going to a taller…

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Answer 9

The best way to find the correct replacement hub is to obtain the reference numbers from the inner and outer wheel bearing. I've provided a photo showing where to find the reference number on the bearing. The inner bearing would most likely be a…

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Answer 10

The Demco #DM15851-76 Spare Tire Carrier you'd looked at wouldn't work for you, as the mounting plate for the tire wouldn't fit inside the wheel. I'd recommend using a simple U-bolt style locking spare tire carrier like #FETCLB0201.…

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Answer 11

With your rim having an inner diameter of 7-1/4 inches, the Demco Spare Tire Carrier for Bolt-On Swivel Jack - Black #DM15853-76 will end up being a little too large. The place where a wheel secures to it measures right at 8-3/4 inches and will be a…

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Answer 12

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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What Is the Difference Between a BTR and BT8 Spindle

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