Technical Articles

Lacing Triumph 500 (to 1974) and 650 (to 1970) Rear Wheel (Rim 37-1007)

Lacing Triumph 500 (to 1974) and 650 (to 1970) Rear Wheel (Rim 37-1007)

You will need:

  1. A Triumph rim 37-1007, or equivalent, rim pierced to accept .300″ diameter nipples.
  2. A set of 40 spokes:
    • a. Buchanan spoke kit part #Tri511 (specify Chrome or Stainless spokes and nipples)
    • 10 spokes 7 9/16″ long with 90 degree head – left (drive) outside
    • 10 spokes 7 9/16″ long with 80 degree head – left (drive) inside
    • 20 spokes 7 7/8″ long with 80 degree head – right side inside and outside.
    • 40 .300″ diameter nipples. Buchanan part number N10307. (be sure to specify .300″ nipples as stock Buchanan kits come with .281″ nipples for Japanese rims.
    • (Note: Triumph used a couple of different head angles over the years – 95° on early years ans 95° and 110° in later years.)
  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.”Using a .250″ nipple in a .300″ hole can lead to wheel failure!
  2. Lubricate the spoke threads using Buchanan’s lubricant. Lubricate the head of the nipple on the edge that bears on the wheel rim.
  3. Place four nipples in rim as illustrated to identify how the rim is handed. This (37-1007) rim is handed and must be installed correctly.

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

Modified “Speed Driver” and 8″ Spoke wrench. Both save time and make the job easier, especially if your job is building wheels.THIS RIM (37-1007) is handed and must be installed the right way around! The rim is handed because the wheel hub has different diameter spoke flange holes on one side from the other.With practice you should be able to see the difference in dimpling and piercing that makes a rim handed. If you need some help try the method below:

  • In the picture I have placed nipples in the rim and I am measuring the distance between two adjacent nipples which are angled, front to back, away from each other.
  • Using the outside edge of the end of the nipple I get a measurement of 3″ (see picture below).
  • I then move to the other side of the rim and take a measurement on the a pair (it will be in the range of 3 1/4″).
  • By measuring the distance between the nipples you can determine which has a larger included angles.
  • From the angle you can determine which way the rims should be installed. The widest distance between the tops of the nipples (3 1/4″ in my case) goes to the drive side.

1
Time to offer the first, or “key””, spoke. It will be the drive-side outside and it is located like above: (On some early hubs there is a little half moon cut next to the “key” spoke hole.) When you offer the nipple run it on until the top of the nipple is even with the end of the spoke threads.

2
You take the first key spoke(7 9/16″ – 95 degree head) offer it to the hub and rotate it anti-clockwise like this (then follow with other 9 spokes). Your wheel will look like above.

3
Next you take the last 10 drive side spokes (7 9/16″ – 90 degree head) and offer them like above.

Because the timing side spokes sit in a “key” hole and will flop out as you offer them I take about 5 turns on each nipple as I offer the 20 spokes. I want to run on the nipples on the same amount. When I am done I want all of the nipples screwed on the same and just enough to keep them from hopping out of the key hole.

4
Time to move across the hub to the right side. You offer the third set of 10 spokes, (7 7/8″ – 90 degree head angle) like above:

5
The last set of 10 spokes, with the (7 7/8″ – 90 degree head), are offered like above.

6
Here is a map of where the spokes go. If you look you can see that the wheel hub flange closest (TS) is smaller diameter than the far side (DS) flange.You should also be able to see the the two spokes on the small flange TS – nearest the camera) are nearly parallel while a similar pair on the other side are not.If the rim was mounted wrong way around the spokes would have to bend for the nipple to be able to seat in the rim. If your spokes bend as they enter the nipple, the rim is on backwards.

Truing the rim:
What I am proposing is that you learn to establish the rim offset and run-out while the nipples are finger tight. To do this, start by offering the nipples and run them onto the spoke until the tip of the nipple is even with the end of the threads. With your fingers tighten each nipple a couple turns until they start to come-up to the point where the nipples are hard to turn with your fingers.

You will notice that not all nipples are equally tensioned at this point. Some nipples will still turn with your fingers while others will be quite tight. It is important at this time to balance the tension between the nipples. A lot of the difficulty people have truing rims comes when a small number of spokes remain loose while the rest are nearly fully tightened. Before you start truing go around the rim and snug-up any loose spokes and yes, loosen any spoke that feels tight.

Its time to take your first look at the rim’s off-set and run-out. With the run-out look first for a set of spokes that are too tight. With your fingers loosen the nipples adjacent to the low point in the rim. Then diametrically opposite look for a set of loose spokes. Remember loosen first to allow the rim to move by itself before you tighten to pull the rim in line. Remember you are doing all this with your fingers and remember to keep all of the nipples evenly finger tight.

Once you get the rim where you want it with your fingers pick-up your spoke wrench going and around the rim take a turn, or so, on each nipple until the rim starts to come up tight. Remember you are trying to keep the nipple tension equal throughout the process. What you will find is when you true the rim while the nipples can be turned by hand there will be little work needed to finish your perfect wheel.

Offset: Based upon the standard WM3  37-1007 Triumph rim the offset from face of hub where the sprocket is bolted to the edge of the rim the offset is: 1/4″.
(This is based upon the standard width of a Dunlop WM3 rim of 3″).


Problems to look out for:

  1. Many modern replacement rims are a lighter guage than the original Jones and Dunlop. One should be sure to lubricate the underside of the head of the spoke nipple where it bears on the rim. This is especially important when using stainless nipples as they are prone to galling against the rims steel. 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.
  2. 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.” 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.
  3. Applying too much torque to a spoke can lead to failure. While the nipple can 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 Buchanans instructions! The final torque using an aftermarket Triumph # 37-1007 rim would be more like 30 to 35 inch pounds (using thread lubricant. This can be a little bit tighter if using original Dunlop or Jones rim.
Definitions:

Key Spoke
The first of the ten spokes offered to the hub. In this case it does not refer to the spokes next to the tube hole in the rim.
Keyhole
The unique keyhole shaped spoke piercing on the TS hubs flange.
Cross Pattern
This wheel uses a cross three on both sides.
Dimple
The bulge pressed into the rim to accept the nipple. This rim is what is called 1×1 where the dimples alternate from one side to the other every other dimple. The front wheel for this bike uses a 2×2 pattern. This is where two dimples are on one side followed by two on the other side.
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. You should never use a nipple smaller than the piercing!!!
Drive Side and Timing Side
Refers to the side of the motorcycle. On this motorcycle the drive side is the left and timing side is the right side.

Text and Pictures Copyright John Healy 1998-2017