1. Trailer Spindles
  2. Redline
  3. For 2000 lb Axle
  4. Standard Spindle
  5. 1.38 Inch Diameter
  6. Round
Spindle 1.38" RD x 4" STUB

Spindle 1.38" RD x 4" STUB

Item # R104BT8-38
lowest price pledge
Our Price: $25.92
You Save: 33%
Trailer Spindles
Orders above $99 qualify for Free Shipping
Shipping Weight: 3 lbs
In Stock, Ships Today
Spindle 1.38 Inch RD X 4 Inch STUB
zoom in icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images


Lowest Prices for the best trailer spindles from Redline. Spindle 1.38" RD x 4" STUB part number R104BT8-38 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
  • All Info
  • Reviews (9)
  • Q & A (19)
  • Videos (1)
  • Photos
  • Why etrailer?

Redline Trailer Spindles - R104BT8-38

  • For 2000 lb Axle
  • Standard Spindle
  • 1.38 Inch Diameter
  • Round
  • Redline
  • 4 Inch Long

  • Includes washer, castle nut and pin

Part No. Capacity A B C D E F Round/Square
R104BT8-38 1000 lb 1.38 1.24 0.99 0.99 1.00 4.00 Round

Video of Spindle 1.38" RD x 4" STUB

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Redline Trailer Spindles - Standard Spindle - R104BT8-38 Review

Today were going to review part number R104BT8-38. This is the Redline Trailer Spindle. This trailer spindle has a weight capacity of 1,000 lbs. It is a round design spindle. It does include the spindle washer, the castle nut and the cotter pin. Those pieces are used to install the hub onto your spindle.

The spindle also requires a bearing kit which would be sold separately. The bearing kit for this part number would be BK1-100 and the bearing kit will actually include the inner and outer bearings with their races, a grease seal and a cotter pin.Now, Ill give you a few dimensions on the spindle. The spindle you do have to match the dimensions of the spindle on your trailer to the replace spindle you get to replace it and the measurements are in 1/100s of an inch so on a lot of these measurements I will be using a digital caliper to get correct measurements. The first measurement I want to give you is the length of the stub on this spindle. This would be 4 inches.

Now, the overall length of the whole spindle will be 8 inches. Now I do want to give you a few dimensions. There are some different dimensions that are needed. The first one would be the diameter of the stub which is this part back here. If measure the diameter it will be 1.380.

Next diameter will be the grease seal dimension which is this part of the spindle right here. On this one well measure 1.24. The next dimension will be the inner bearing surface diameter which is that part right here and that would be 0.99 inches. The next dimension will be the outer bearing surface diameter and that one will also be 0.99. The last one will be the diameter of the threaded portion of the spindle.

On that will be right on 1 inch even.That should do it for part number R104BT8-38.

Customer Reviews

Spindle 1.38" RD x 4" STUB - R104BT8-38

Average Customer Rating:  4.9 out of 5 stars   (9 Customer Reviews)

- R104BT8-38

great product it's a spare in case i bend one on my trailer 444411

i keep it as a spare axle for my atv trailer i built nothing worse than getting stuck 15 miles off the end of the road when your out moose hunting
dan - 10/20/2018


- R104BT8-38

Excellent Service 703763

- R104BT8-38

Good product, received on time. 566444

- R104BT8-38

Product was received in perfect condition. Shipment was fast. Product is exactly as depicted on website and worked perfect for my fishing boat axle repair. Thanks again! 433244

- R104BT8-38

I'm very pleased with the quality of the stub axle and all the dimension were as advertised . The parts is being used on a motorcycle trailer to replace a bent stub axle after a car tried to jump over the trailer while park in my driveway. This part will save me from having to buy a whole new axle. 426737

- R104BT8-38

Got it, was as advertised, great transaction, thanks. 303345

- R104BT8-38

Very satisfied with the axle. It fit perfect and works great. 293662

Working well so far. Trailered from Denver to SF and back with no issues.
Todd W - 09/18/2017


- R104BT8-38


- R104BT8-38

Excellent product and outstanding delivery. Thanks 157382


Ask the Experts about this Redline Trailer Spindles

  • How to Find a Replacement Spindle and Hub for a 5x10 SnowBear Utility Trailer with 2000 lb Axle
    We do have spindles and hubs for 2,000 lb axles, but we first want to determine which spindle and hub will work best for you. To do this we will need additional information about your current spindles and hubs to ensure the new spindle and hub match what you currently have. Unfortunately SnowBear does not provide general spindle and hub information for their trailers. The best way to ensure you get the correct spindle and hub is by using the part numbers of your bearings and grease...
    view full answer...
  • Which Trailer Hub and Bearings Fit Spindle # R104BT8-38
    For spindle # R104BT8-38, you can use hub # AKIHUB-440-2-1K. This hub comes with the proper bearings # L44643 inner and outer. The Cap has an outer diameter of 1.986 outer diameter and Seal # 34823. The hub assembly is a 4 on 4 bolt pattern for 2,000 pound axles. You will want to make sure that the old bearings are stamped with L44643. If they have different numbers, let me know what they are and I can determine what the correct replacement hub is.
    view full answer...
  • How Far Apart Do the Races Need To Be On a BT8 Spindle
    There is not really an exact required distance between the inner and outer race on a spindle as the trailer hub will dictate this distance and there can very well be some variances between different trailer hubs. However, I went out to our warehouse and pulled a trailer hub that is fit for the BT8 Spindle part # R104BT8-38 and measured the distance between the inner and outer races (inside to inside). I found this to be right at 2-1/16" so your trailer hub will need to be very close to...
    view full answer...
  • Axle Recommendation for a Converted Off-Road Trailer
    If you are planning on purchasing a new trailer axle it will have a spindle already attached to it. Installing spindles is a very precise job that should only be done by a qualified fabricator with trailer fab experience. Since your planning on using the trailer for off-road purposes a better option might be the Timbren Axle-Less systems like the # ASR2KHDS03. This will give the trailer a 4 inch lift, is setup for wide off-road tires, will give better ground clearance than a standard...
    view full answer...
  • Recommended Replacement Spindles for up to 2,000 lb Axles
    For your replacement spindles, you will want the Spindle 1.38" RD x 4" STUB # R104BT8-38 for a round axle or # SP204BT8 for a square axle. This will give you the dimensions you referenced. You will want to have a professional shop do the welding to ensure they are safely attached and won't have any angle that could cause problems with your bearings, hubs, or wheels.
    view full answer...
  • What are the Dimensions of Redline Trailer Spindle R104BT8-38
    I checked with my contact at Redneck, and spindle # R104BT8-38 has an overall length of 8-3/4 inches.
    view full answer...
  • Are the Redline Spindle # R104BT8 and etrailer Idler Hub Assembly # AKIHUB-545-2-2K Compatible
    The Redline Spindle # R104BT8 and our Trailer Idler Hub Assembly # AKIHUB-545-2-2K are not compatible, but you could use the Redline EZ Lube Spindle # R104BTREZ instead as it has the correct spindle measurements. For a hub that will work with the Redline Spindle # R104BT8 you can use part # AKIHUB-545-2-1K. To determine if a hub is compatible with a specific spindle you will need to make sure that the inner diameters of the Inner Bearing, Outer Bearing, and Grease Seal of the hub...
    view full answer...
  • How to Determine the Correct Grease Seals to Order for a 2002 EZ Loader 21 Foot Boat Trailer
    To determine the correct grease seal for your trailer spindle and hub, we need to know the inner bearing number installed on the trailer or the dimensions of the seal surface on the spindle and the seal surface in the back of the hub. This will require removing one of the hubs and the grease seal in that hub. If you cannot find the inner bearing part number, you will need a precise measuring tool like a dial caliper to get measurements accurate enough to select the correct grease seals. Boat...
    view full answer...
  • How to Determine The Correct Replacement Trailer Hubs by Bearing Numbers or Spindle Size
    The best way to determine which replacement hubs you need for your trailer would be to remove one of the hubs and retrieve the bearings. Find the numbers stamped into the bearings and with those we will be able to get you the correct hubs. If you are unable to retrieve the bearing numbers, you can take measurements of the spindle. I have included a link to our spindle main page. At the top of the page is a diagram showing all of the measurements we would need to find the correct hubs...
    view full answer...
  • Dimensions Of Dexter Hub Assembly For 8 to 12 Inch Wheels
    The Dexter Hub Assembly, part # 34822545BX is designed to be used with 2,000 lb axles and for 8 inch to 12 inch wheels. This assembly includes bearings, races, seal, grease cap, wheel bolts and lug nuts. I have attached a photo of the hub and have the hub length noted on the photo. The length of the hub is 4-1/4 inches and the inner diameter of the inner and outer bearings, part # L44643, that are included with the hub measure 1 inch. A spindle that is designed to work with the...
    view full answer...
  • Does Trailer Hub Assembly for 2,000 Pound Axles Include Bearings and What Spindle Will Fit
    The inner and outer bearings, races, seals and cap are all included. We carry three spindles that will fit this hub. The differences is the shanks that are to be welded to the axle, but the machined portions will fit the hub assembly you were looking at. The spindles are part # R104BT8, part # R104BT8-38, and part # SP204BT8.
    view full answer...
  • Trailer Spindle that Works with BT100 Hubs
    For your hub that uses L44643 bearings you can use one of 3 spindles: # R104BT8 # R104BT8-38 # SP204BT8 I have included links to video reviews of each of these spindles for you. If your bearings do not have L44643 stamped into them let me know what they are and I can see if there is a spindle that will work with them.
    view full answer...
  • Which Spindles Will Work with the Trailer Hub Assembly for 2,000 lbs Axles
    You can use any of three spindles with the Trailer Hub Assembly - 2,000 lbs Axles - 5 on 4-1/2, item # 34822545BX. I have listed these spindles below. The main difference in these spindles is the mounting dimensions on the inboard end of the spindles. the bearing seal and threaded portions of the spindles are all the same. Spindle 1.25 inch RD x 4 inch STUB Item, # R104BT8 Spindle 1-1/2 inch Square x 4 inch Long Stub, for 2,000 lb. Trailer Axles, Item # SP204BT8 Spindle 1.38 inch RD...
    view full answer...
  • What Is The Correct Bearing For A 1.38" Spindle
    I do have the correct bearing for a 1.38" spindle like part # R104BT8-38 however, the L68149 bearing is not the correct bearing for this spindle. The correct bearing for the 1.38" spindle is the L44643 bearing like that in the Bearing Kit for 1" BT8 Spindle part # BK1-100 which is designed for 2,000 lb. axles. The Replacement Trailer Hub Bearing part # L68149 is compatible with an #84 spindle such as the Spindle 2" x 4" part # R40484 which is designed for use on a 3,500 lb axle. I...
    view full answer...
  • Should a Spindle That is Chipping be Replaced
    Anytime that a spindle is starting to take damage you will want to replace it as that will affect the performance of your bearings and seal. In this case since that chipping is right where the seal sits (as you mentioned) that will eat at the rubber seal which will likely cause it to fail. A failed seal will leak grease and cause further damage to your spindle/hub area. From the picture you sent in it looks like you have a round BT8 spindle. For replacements we have parts # R104BT8,...
    view full answer...
  • How to Determine the Correct Replacement Spindle With Bearing 07100
    Bearing 07100 are older bearings with the same dimensions as bearing # L44643. The spindles that uses those inner and outer bearings are # R104BT8 and # R104BT8 - 38. The difference between these is one measurement, the furthest outer diameter, which is 1.25" on R104BT8 and 1.38" on R104BT8 - 38.
    view full answer...
  • Replacement Trailer Spindle that Takes L44643 Bearings
    If both the inner and outer bearings are L44643 then you have a BT8 spindle. You can use # R104BT8, # SP204BT8, or # R104BT8-38. All three of these spindles are rated for 1,000 pounds by themselves so they would be on a 2,000 pound axle. I have linked videos for all 3 spindles for you. Please note that installation of a spindle is a precision job that requires someone with experience in welding on spindles. If the spindle is welded on a little off then it can cause tire wear, suspension,...
    view full answer...
  • Which Spindles Work with Trailer Hub Assembly - 2,000-lb Axles - 4 on 4 with L44643 Bearings
    There are several different spindles that you could use with hub # AKIHUB-440-2-1K. You will need a BT8 spindle such as # R104BT8, # SP204BT8, or # R104BT8-38. Any of these spindles will work with the hub # AKIHUB-440-2-1K. I have linked videos of all 3 spindles for you.
    view full answer...
  • Spindle Options that are Compatible with the Trailer Idler Hub Assembly # AKIHUB-440-2-1K
    We do have spindles that you can install on your axle which are compatible with the Trailer Idler Hub Assembly # AKIHUB-440-2-1K that you referenced. Part # R104BT8 has a 1.225" Round x 4" Stub Part # R104BT8-38 has a 1.38" Round x 4" Stub Part # SP204BT8 has a 1-1/2" Square x 4" Stub All of these are rated for a 2,000-lb axle. You will just need to choose the one that best suits your application.
    view full answer...

Do you have a question about this Trailer Spindle?

  • Why etrailer.com?

    At etrailer.com we guarantee:
  • Highest quality trailer spindles for the best price.

    Our Lowest Price Pledge ensures you will never overpay for the parts you need.
  • Real product know-how.

    We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.
  • Most detailed, accurate trailer spindle information available.

    Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.
  • Installations, made easy.

    We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.
  • Fast shipping.

    Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.
  • Personalized service for life.

    We provide one-on-one, personalized service from the ordering process through the life of your product.
  • Trusted since 1946.

    We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.
  • Returns Policy

    Need to return an item? No problem. Please read our Returns Policy for more information.

Info for this part was:

Expert Research:
Sarah L
Expert Research:
Michael H
Expert Research:
John H
Installed by:
Jeff D

At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.

Product Experts Available Now!

Call 800-298-8924