Technical Articles

Lacing Triumph 500 (1967 to 1974) and 650 (1967 to 1970) Front Wheel Rim (37-1230)

Lacing Triumph 500 (1967 to 1974) and 650 (1967 to 1970) Front Wheel (Rim 37-1230)

This also applies to the earlier 1963 to 1966 – all nail head hub.

You will need:

  1. A Triumph rim 37-1230, or equivalent, rim pierced to accept .300″ diameter nipples.
  2. A set of 40 spokes
    •   
    • a. Buchanan part #Tri712 (specify Chrome or Stainless spokes and nipples)
    • 10 spokes 4 3/4″ long with 95 degree head – Right outside  
    • 10 spokes 4 3/4″ long with 80 degree head – Right inside
    • 20 spokes 5 9/16″  long  with nail nead – Left side
    • 40 .300″” diameter nipples buchanan part number N10307
  3. Screw driver or modified offset-screw driver (picture below).
  4. Spoke wrench. 
  5. Nipple lubricant.

Where to Start:

  1. Verify that the holes pierced in the rims and the nipples measure .300.”
  2.    
  3. Using a .250″ nipple in a .300″ hole can lead to wheel failure!
  4. Lubricate the spoke threads using Buchanan’s lubricant.
  5.    
  6. Lubricate the head of the nipple on the edge that bears on the wheel rim.
  7. This rim is not handed.It can be fitted either way round.



This is a picture of a .250″ nipple in a .300″ hole. The nipple should fill the hole in the rim. Using a .250″, or .281″ nipple, in a .300″ hole can lead to wheel failure!

wheel-building-035

Modified “Speed Driver” and 8″ Spoke wrench. Both save time and make the job easier, especially if your job is building wheels.

Three Types of Spokes used on the 1966-1970 Front Drum Wheel

37-1230-4

Three different spokes are used to lace this wheel. (left) Drum side outside spoke with 85° head. (middle) Drum side inside spoke with 90° head. (right) non-drum side spokes – nail head.

Where Do I start?

37-1230first

  • Click picture to enlarge

 

  • This is a pretty straight forward rim to lace.
  • You start with the hub flange side (brake drum side) and offer 10 of the 4 3/4″ x 80° spokes.
  • Notice the placement of the first spoke (indicated by the arrow) relative to the non-drum side nail head spoke holes.
  • The arrow sits between the two adjacent non-drum side hub spoke holes.
  • You would call this the key spoke for this wheel and must be offered first.
  • Offer the spoke to the rim and run its nipple on until the end of the nipple is even with the last of the spoke thread.
  • Got That One. What do I do next?

37-1230-2

  • Now you can put spoke set 2 and 3 in the opposite side.
  • These are all 4 3/4″ nail head and you simply push them through the hub.
  • Again, offer them to the rim and run the nipples until they are at the end of the threads.

Offering the last 10 spokes – Brake Drum Outside

37-1230-3 copy

  • Yes, I flipped the wheel over for this shot.
  • Next take the last 10 spokes (7  9/16″ – 95 degree head) and offer them like this.
  • Again, offer them to the rim and run the nipples until they are at the end of the threads.

The 37-1230 rim has 2×2 dimpling

37-1230rim 

 The preferred 37-1230 rim is a 2×2 dimple-piercing pattern. Two dimples on one side then two dimples on the other repeating around the rim.

Rim Offset:

The offset for the earlier 1963-65 non-flanged hub using all nail head spokes, and the later 1966-1970 (500 to 1974) flanged hub, is the hub’s brake drum side minus 1/64″ from the nearest side of the rim. Lay a straight edge onto the brake drum side side of the rim. You should be able to slip a .015″ (1/64″) feeler gauge between the straight edge and the side of the brake hub.

Problems to look out for:

1. Many modern replacement rims are a lighter gauge than the original Jones and Dunlop.


Buchanan lists the spoke torque on the insert in their spoke packaging as such:
“For large displacement cycles, the torque should be in excess of 80 inch pounds. Hub and rim structure will determine the amount of torque that can be exerted.”

This hub and rim is not considered a “large displacement motorcycle!” Depending upon the rim you can only expect to use 30 to 35 inch pounds when you tension this rim. Because the original rims a a lot stiffer than aftermarket rims you can go to 40 to 45 inch pounds on original Dunlop or Jones rims.

2. One should be sure to lubricate the under side of the head of the spoke nipple where it bears on the rim. This is especially important when using stainless nipples and or stainless rims. Stainless is prone to galling and can actually bore a hole in the rim as you tighten the nipple. One must be extra careful when using stainless nipples in a stainless rim. Lubricate the parts well before assembly and stop if the spoke stops getting tighter as you turn it.

The key to reading this sentence is “Hub and rim structure will determine the amount of torque that can be exerted.” See the brake drum in picture below. The spoke tension broke the cast hub. While this happening is rare as the hubs age it is something you need to be aware of.

broken-drum-2
Applying too much torque to a spoke can lead to failure. While the nipple can pull through the rim the cast hubs can also fail. This is a 1967-70 Triumph front hub.


Triumph IS NOT A LARGE DISPLACEMENT MOTORCYCLE as described in Buchanan’s instructions! The final torque using an aftermarket Triumph # 37-1230 rim would be more like 30 to 35 inch pounds. This can be a little bit tighter if using an original Dunlop or Jones rim.

Definitions:
Key Spoke: The first of the ten spokes offered to this hub. They are key because they are the ones you must start with.
Cross Pattern: This wheel uses a cross one on both sides.
Dimple: The bulge pressed into the rim to accept the nipple. This rim is what is called 2×2 where two dimples alternate from one side
to the other.
Piercing: The hole in the dimple for the nipple. There are three common sizes: .250″ and .300 used on British wheels and .281″ used on Japanese wheels. This rim is pierced .300″ and you must use a .300 diameter nipple. side is the left and timing side is the right side.


Text and Pictures Copyright John Healy 1998-2015