How to Measure a Trailer Spindle

Question

Question:

I need to find out how to measure a trailer spindle.

asked by: Derek T

0

Expert Reply:

I have included a picture that shows the measurements needed for a spindle, bearings, seals, faces, and hubs. The spindle measurements are labeled A through F.

A is the spindle shaft diameter
B is where the grease seal sits
C is where the inner bearing sits
D is where the outer bearing sits
E is the thread diameter at the end of the spindle for the nut
F is the spindle shaft length

I have also included a link to our spindle main page for you. The measurements need to be as accurate as possible so you will need to use dial or digital calipers.

expert reply by: Michael H

0

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Michael M.

9/7/2024

I bought a digital caliper from Harbor Frt. so i can you spindle measurements requested as follows A = 1.739 inches B = 138.2 inches C = 1.356 inches D = 1.074 inches E = 0.746 inches F = 1.085 inches I still think that inner bearing hub measurement is about a half inch shorter than my old drum bearing height that i provided in an earlier email. Please call 440 221-9610 if you have questions. Thanks. Joe Veri

Anthony

9/23/2025

F but overall length is 106mm C is 34.7 A is 43.6 No B dimension D is 1 inch E 7/8 15/16 The last two don’t have a digital caliper - tape measure The length in 4areas are starting at mount flange 1” 1 7/8 1” 1 of threaded

Jon G.

9/23/2025

@Anthony Thanks for all of the numbers! Let me reformat this info real quick: A = 1.717" B = N/A C = 1.366" D = 1" E = 7/8" or 15/16" F = 4.173" Ideally we'd have caliper dimensions for all sections, but from the info you gave me, it sounds like you have a #84 spindle so a replacement bearing kit would be # BK2-100. Were you just looking for a bearing kit?

Anthony B.

9/23/2025

@JonG looking for everything - hub and bearing and seals Also considering changing to a electric brake kit to upgrade the trailer My current wheels are 5 ok 5.5 and the center hole of wheel is roughly 3 1/2 inches if that matters

Jon G.

9/23/2025

@AnthonyB In that case you'll need the Easy Grease Trailer Hub and Drum Assembly # AKHD-555-35-EZ-K (2 per axle) and the etrailer Electric Trailer Brakes # AKEBRK-35-SA (1 per axle). You're also going to need a Trailer Breakaway Kit # 3802308, 10 Gauge Wire # 10-1-1, and Butt Connectors # DW05745-10 in order to power up and use the electric brakes properly. Do you already have a 7-Way plug on your trailer?

Answer 1

Hey, Brandon! Good news, we have exactly what you want. The Dexter Trailer Idler Hub #8-258-50BTUC1 is a great match. It’s galvanized for corrosion resistance and comes as a complete kit with bearings, races, seals, lug nuts, and a center cap, so…

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Answer 2

Hi William! If you're looking for a drum brake version that's similar to the Demco part #DM8104311, the closest Demco option is the Demco Hydraulic Brake Actuator with Drop, Part #DM8204011. It has the same basic design and is built for drum…

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Answer 3

There is not a Cad drawing of the #42 E-Z Lube Spindle w/ Flange for 5.2K to 7K Trailer Axles - 2-1/4" Diameter #TRU37FR available, but I did include a diagram showing all of the dimensions. It is recommended to have a an axle shop weld the…

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Answer 4

The Demco #DM72VR Hydraulic Trailer Brake Actuating Coupler would require four 1/2 x 4-1/2 inch grade 5 bolts to install it on a trailer tongue. I've linked to a product description video as well as a photo with the bolt spacing that you might…

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Answer 5

Hey Greg, There unfortunately there isn't a guide to tell us the bearing and grease seal combination for your hub so you'll have to remove it and check the bearings/seal for their part numbers or use a digital caliper #PTW80157 to measure the…

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Answer 6

Hi again William! The Demco part #DM8104311 measures approximately 31-5/8 inches in overall length, including the electric lockout solenoid that extends from the rear of the actuator. The main actuator body itself measures about 16-1/4 inches long,…

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Answer 7

There really should be a flat washer between the outer bearing of your hub and the nut that holds it on. The washer protects the back side of the bearing from the edges and points on the back side of the spindle nut. The Washer For 1 inch Spindle,…

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Answer 8

Hi Tony; the #BK2-100 and #TMK52VR come with the same size bearings and grease seal. The main difference is the Timken name. This is usually associated with a higher quality bearings that are made in the USA which also accounts for the higher cost.

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Answer 9

The #99 trailer spindle is typically found on 9,000 lb and 10,000 lb axles. This is not a spindle that we carry at this time, but I did find some of the measurements. I have attached a diagram showing the dimensions of a #99 spindle for you to check…

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Answer 10

Thanks for providing all of the information for your axle. This axle is going to use the standard 3,500 lb axle bearing sizing. You can use the Bearing Kit #BK2-100, which will come with bearings, races, seals, cotter pin and tang washer - everything…

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Answer 11

The Demco Hydraulic Brake Actuator part #DM8104311 is a fit for trailer tongues 3" wide. If this is what you have then it will work well. If you are however looking for the bolt hole spacing then you can reference the attached photo.

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Answer 12

Hi Rusty; the Dexter #84546UC3-EZ and etrailer #AKHD-5475-35-K will both fit a 3,500 lb axle but they have different bolt patterns. You already ordered the Dexter in the past so I'm assuming your wheels are 5 on 4-1/2. For the same bolt pattern…

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How to Measure a Trailer Spindle

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