Recognizing Wheel Offset

Recognizing Wheel Offset

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Offset on both front and rear motorcycle wheels is something that becomes unnoticed and pushed under the rug but plays a crucial role in how your motorcycle will perform and handle. Today's blog post I will show you how to check wheel offset using a Triumph dual leading shoe front wheel. You can also use all the information below to help you with any motorcycle wheel, not just British.


Those that fail to check wheel offset are putting themselves at risk. Whenever you have to replace a rim or relace your wheel I would recommend that you check the offset before you disassemble the wheel. If in doubt refer to your workshop manual or contact a specialist.


The chart below shows most Triumph and BSA models that where equipped with the correct wheel that we are specifically referring to in this blog. "Dual leading shoe" a.k.a. "single leading shoe" with the cast iron flanged hub.


 Brand Model Year Engine Size Hub Size
Triumph Bonneville / Tiger / Trophy (All) 1966-1970 650CC 8"
Triumph Daytona T100R 1968-1974 500CC 8"
Triumph Tiger T100C 1969-1972 500CC 7"
BSA Lightning / Thunderbolt / Firebird / Royal Star 1969-1970 500CC / 650CC 8"
Triumph TR25W Trophy 1969-1970 250CC 7"
BSA Star Fire / Barracuda 1969-1970 250CC 7"



What is a Dual leading shoe front wheel?

 Dual Leading Shoe Wheel


Before we get into detail let's discuss what a dual leading shoe wheel is. In 1967 the Triumph racing department designed and used a new prototype of brake which would later be referred to as the dual leading shoe or twin leading shoe brake.

This new brake features 2 brake shoes and 2 brake pivot cams which operate interdependently. Each cam has there own lever tied together. When the front brake is activated each shoe is evenly applied inside the hub - when properly adjusted.

As we now know the dual leading shoe was first seen in 1967 but in 1968 most Triumph and BSA models where equipped with this new brake set-up. This included both export and home market models.

The dual leading shoe brake uses the same hub as found on 1966-1967 Triumph 650 twins but at that time the brake was single leading shoe. This hub is also referred to as the cast iron flanged hub. In 1969 both Triumph and BSA had to widen there top and bottom fork yokes by 1/4" to accept the new wider brake plates.


What is wheel offset?

 There are many definitions of what wheel offset means. Here is a brief definition of what wheel offset means according to "TSW Alloy Wheels".


 "The offset of a wheel is the distance from the hub mounting surface to the center line of the wheel. The wheel offset is measured in millimeters and results in a positive, negative, or zero offset. Positive offset is when the hub mounting surface is toward the front or wheel side of the wheel. It is common to find a positive offset in newer and front wheel drive vehicles. Negative offset is when the hub mounting surface is toward the back or brake side of the wheels centerline. A negative offset wheel usually has a "deep lip" Zero offset. The hub mounting surface is even with the centerline of the wheel."



Obtain a straight edge 

Bar Strap


To measure the wheel offset you will need a straight edge long enough to cover opposite ends of the rim. You can measure the offset of the wheel with the tire on - just make sure your straight edge covers both sides of the rim without interfering with the tire wall giving you a false reading.

I used some steel bar that I had laying around the shop that I used to check the offset. I measured the distance of the rim (straight across) and cut my steel to the proper length required.

You can use any straight edge as you please - yard stick, meter stick, level gauge, etc. Get creative!

Here are the specs on my steel bar that I used on my 19" front rim.


 Material Thickness Width Length
Steel 1/4" 1 1/4" 19"


Put the wheel on a flat surface


Triumph Front Wheel On Vice



If the wheel that your measuring has the tires and axle still in place, I would recommend that you put the wheel in a vice and lay it flat (use a soft cloth towel to wrap the axle to prevent damage). You can also use the shoulder part on the hub cap to rest the wheel. If your tire and axle has been removed from the rim simply lay the wheel assembly on a flat surface.


Measuring the offset 

Measuring Stick On Wheel

Using the front wheel we must measure the offset on the brake drum side. This means you will have to remove the brake plate. Once the plate is removed you can lay your measuring stick over the shoulder of the rim and over the brake hub. The stick should run diagonal down from one side of the rim to the other.

Once your measuring stick is in the correct position check and see if your hub is sitting lower or higher than the shoulder of your rim. This would indicate the offset of the hub in relation to the rim shoulder. If your hub is sitting lower than the shoulder of the rim that would be a negative offset - if your hub is protruding over the rim shoulder that would be a positive offset.  


Triumph Wheel Offset Chart


According to a Triumph workshop manual the offset on a dual leading shoe wheel should be -1/64" (negative). That means the brake hub should sit -1/64" lower than the shoulder of the rim - you should be able to fit a .015" feeler gauge between your measuring stick and the brake drum surface.


Measuring BSA Wheel Offset


Another wise way to measure offset is to mount the rim on the front and or rear section of the motorcycle without the tire on. Get your ruler out and measure using the fork legs or the swing arm as a guide. For this dual leading shoe on a BSA the rim shoulder must be centered between the two fork legs.


If the rim is pulled more one side, your offset may be the culprit. With the wheels mounted (front and rear) without the tire on, now would be a good time to check and measure that the front and rear wheels are running true together in a straight line. 


Example #1 - the good


Negative Wheel Offset


Notice that the hub is sitting lower than the shoulder of the rim?


Here is an example of a wheel that we laced here at shop years ago. The offset is not exactly -1/64” as show in the book but it very close! This offset would not cause any troubles as it falls in the precviable margin.


Example #2 - the bad


Positive Wheel Offset


Here is an example of a wheel that has the incorrect offset. Notice that the brake hub sits higher then the shoulder of the rim? This type of offset would be considered a positive offset which is incorrect for our application.


Side note... The flange on the dual leading shoe hubs are very fragile. When lacing a wheel do not over torque the nipples as that can cause damaged. The cast iron flange hubs are known for cracking and breaking due to an excessive amount of torque.


Symptoms of incorrect wheel offset



 Recently, I was working on a customers 1970 BSA Lightning and noticed that the front wheel was not sitting in the center of the forks! After checking and double-checking I noticed that the offset on the rim was not correct. The person who laced the front wheel had a positive offset which was pushing the wheel too far to the left (as if you were sitting on the motorcycle). At that point the front and rear wheels were not aligned.


 The symptoms of a wheel that has the incorrect offset is subject to bad stability and handling. It is crucial that you check in observe your wheels to see if they have the proper offset.




There you have it lads - checking wheel offset is a task that shouldn't be over looked. Triumph and BSA wheels all have a certain type of offset whether it is a front or rear rim. A great source to have if you are experiencing difficulties is to try Buchanan's Spoke & Rim located in Azusa, California.

If you have any questions or if you would to drop us a comment please do so using the comment section below. Don't forget to read our other useful blog posts and tips.


  • SparkyJ

    I have a hard tailed 66 Tr6 with WM3 Dunlop 18" rear wheel. I just replaced the tire (an Avon 120/90 18, very wide) with a thin Coker Classic 4.00 18. I had the rim trued at Buchanans. I never notice the rear being offset from center with the wider tire. But the new thinner tire shows the rear being “off center” from centerline of frame. Is this acceptable? Are all vintage 60s Triumphs (drum type) over to the right? Or is the rim supposed to be set up so the wheel falls in the centerline of the bike through to the yoke and align “centered” with the front wheel?

  • Bruce Fowler

    Thanks for the excellent info!
    1970 T120R has a steel rear rim and an aluminum front rim. My issue is on the front. I came to find out that my brake anchor plate is the old style where the cable comes in near the bottom as opposed to at the top. I found out because I ordered a cable for a ‘70 and it was too short. I don’t know if the hub itself is also old style. Would a ‘68 anchor plate work with a ’70 hub?
    Also, after rebuilding the forks, i have found the wheel is waaaaay offset toward the left fork. The fork rebuild included new stanchions in effort to eliminating binding issues. Now the forks work great and move freely. I’m confident the spindle is correct because the grooves fit right to the holes without pinching.
    Will re-lacing the wheel get the wheel to center? Does the aluminum wheel affect that? Should i just buy a correct steel rim?

  • Steve Sargent

    Hello there
    I am building my rear wheel for my 1966 tr6 r l have a standard bolt on hub
    I have built the front wheel successfully but I am unsure were to measure for the offset
    On the rear hub is it the drive side or the speedo drive side
    Any help and info will be appreciated
    Many thanks

  • stephen Young

    I just laced a new WM3 X 18" rim on my back wheel. Bike is Triumph 1959 5TA.
    Your chart, does that say 1" 3/4. I used that measurement and the offset is way out.
    Its much to much. Am i reading that correctly. Just by eye i would of thought 3/4 of inch
    would be about correct.
    Would appreciate your assistance
    Thank you

  • Darcy Tredrea

    Thank-you for your efforts to blow away the mist of uncertainty about the offset on my triumph trophy . Lacing up wheels for the first time is to say the least stressful. With respect.Darcy👍

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