- Tire & Wheel Details
- Remove Spokes
- Determine The Condition Of The Spokes And Rims
- Refinish Wheels
- Install Spokes
- Truing The Wheels
- Differences When Truing The Rear Wheel
- What Done Looks Like
The R80ST has spoked wheels front and rear. In order to refinish the wheels using vapor blasting, I remove the spokes. This let me assess the condition of the spokes and spoke nipples so I can decide if I can keep most of them, or they need to be replaced.
On the rear wheel only 17 out of 40 spokes weren’t bent or rusted and only 8 spoke nipples were not damaged. On the front wheel every spoke was bent. So I replace all the spokes with stainless steel spokes and install new plated brass nipples.
I am an amature and this is the first time I laced and trued wheels. I started over about half a dozen times before finally getting the wheels true. So, beware that my documentation may not show the best or easiest way to true the wheels. That said, I did succeed after about a month and a half of chipping away at it. This is an example of a saying I use a lot, “Endeavor To Persevere”. 🙂
I bought a spoke wrench from Boxer 2 Valve. It covers a range of spoke nipple sizes: 5.6, 5.7, 6.0, 6.3, 6.6, and 6.8 mm.
After getting the wheels trued, I decided to use a spoke torque wrench to ensure all the spokes were at a recommended minimum torque. I got one from Warp 9 racing that has sockets to fit various size spokes and a handle for tightening the spokes, similar to the one above that I already bought from Boxer 2 Valve.
I found I the spokes were much too loose when I used the Boxer 2 Valve wrench as I don’t know how tight they are supposed to be, so my sense of feel was not calibrated correctly. I trued the wheels again using the spoke torque wrench so the spokes are now at least the minimum torque value (40-45 inch-pounds) recommended by Buchanan Spokes and Rims.
I made a spoke nipple wrench out of a screwdriver that will allow the spoke to extend past the bottom of the nipple. I used my Dremel tool with a milling bit to grind the slot in the screwdriver blade. This makes it much easier to install the new spokes.
I use a wire wheel mounted in my drill to remove the caked on tire rubber from the wheel wells of the rims.
I borrowed a wheel truing stand from my friend Matt Iles, an independent BMW motorcycle mechanic, who owns Iles Motorsports. The stand has a spindle at the top the wheel mounts on and two dial indicators to measure the radial and lateral run-out of the wheel.
Since the rear wheel does not have wheel bearings, the truing stand spindle can’t be used to mount the rear wheel in the stand. At Matt’s suggestion, I used my Marc Parnes wheel balancing tool to mount the rear wheel and place it on the stand.
I got the parts, with the exception of the rim tape (part# 61 13 8 351 989) that I got from MAX BMW, from Euro MotoElectrics who graciously is providing all the parts I need for free for this charity rebuild project for the Motorcycle Relief Project. Each wheel has 40 spokes, but the lengths are different for the front and rear spokes. I also install new rubber blind plugs that fit into the rear wheel.
I managed to round off several of the spoke nipples so I would recommend purchasing 10-20 extra nipples so you can replace any you damage while truing the wheels.
|61 13 8 351 989
|FABRIC-TAPE – L=50M, B=30MM (meter), Rim Tape
|36 31 1 458 284
|36 31 1 234 591
|SPOKE REAR – 18″/ L=140MM, Stainless Steel
|36 31 1 234 593
|SPOKE FRONT – 19″/ L=176MM, Stainless Steel
|07 11 9 930 070
|NIPPLE – M4
Here is video summarizing how I lace the spokes and true the wheels.
VIDEO: 1983 BMW R80ST Lace The Spokes And True The Wheels
Tire & Wheel Details
The tires have good tread, but they are certainly very old.
Before I remove the tires, I looked at the DOT date code to see how old they are. Starting in 2000, the date code has four digits. Since mine have three digits, I know the tires are older than 2000.
The front tire has date code “472” and rear has date code “511”. The three digit code’s first two digits are the number of the week in the year the tire was manufactured and the third digit indicates what year in the decade the tire was manufactured. Therefore, the front tire was made in the 47th week of 1992 and the rear tire was made in the 51st week of 1991. I think it’s time to replace them. 🙂
The front rim has markings showing the rim size, an arrow showing the direction of rotation and the date it was made, “82 11”, that interpret to mean November 1982.
The rear rim shows information indicating the size and direction of wheel rotation. This is on the side of the wheel that does not have the brake hub.
On the side of the hub opposite of the brake side on the rear hub are three rubber plugs and a center rubber disk. The rubber plugs are blind plugs that cover the casting holes for the rim. I replace them as they are very brittle. The center disk covers is okay and I will reuse it.
The rear hub on the brake side has a number of markings that are visible after I had the hub vapor blasted.
Rear Rim Offset From Hub
On many wheels, the rim is offset from the hub. On the 1983 R80ST, the front rim is not offset, but the rear rim is offset from the hub. The amount of the offset, according to Bob Fleisher, is 3 mm. So before I remove the spokes I put the rear wheel on my workbench, brake side of the hub down. The rim offset raises the edge of the rim above the hub. I measured some nut thicknesses and found that a 3 mm nut is close to 3 mm thick and a 4 mm nut is a bit less than 4 mm thick. So I used these to estimate how much the rear rim is offset from the hub. I found it was 3 mm.
Before removing the spokes, I took pictures of the wheels so I can install the new spokes in the same pattern. There are 40 spokes in each wheel, 20 on one side of the hub and 20 on the other side. All the front wheel spokes are the same length. All the rear wheel spokes are the same length, but the rear spokes are shorter than the front spokes.
The hub has 10 triangular blocks on each side and the faces of the blocks are at 90 degrees to each other. The apex of one of the triangular blocks is directly across from the valve stem hole on the rim. The lower hole in the block is oriented for an inside spoke and the upper hole in the block is oriented for an outside spoke. I put some tape next to the triangular block pointing at the valve stem hole with an “I” for Inner and “O” for Outer to remind me of the order of the spokes in the triangular block.
The spokes in the rim come in repeating groups of four spokes. The pattern of the group of four spokes is an outside spoke, two inside spokes and an outside spoke.
Since there are 40 spokes in the wheel, there are 10 groups of four spokes. Each side of the front and rear hub has 10 holes oriented for spokes on the outside of the rim and 10 holes oriented for spokes in the middle of the rim, which I refer to as “inside” spokes.
To figure out the spoke pattern, I start at the valve stem hole . The first inside spoke on the triangular block directly opposite of the valve stem hole is three nipple holes clockwise from the valve stem hole. The next inside spoke is four holes clockwise from it and so on.
The first outside spoke in the triangular block opposite the valve stem hole is four nipple holes counter-clockwise from the valve stem hole. The next is four holes clockwise from the first one, and so on.
This pattern is the same on the left and right sides of the hubs.
I used the spoke wrench to remove the spokes because I want to save them and the spokes if possible.
If you plan to replace the spokes, you can use a bolt cutter to cut the spokes and remove them.
But, many of them were rusted to the nipples, so I put some Kroil on the spoke nipples and also heated the nibbles inside the rim with a small butane torch. That got many of them loose. Unfortunately I had to use vice grips on some of the nipples on the front wheel to get them to turn damaging the nipples.
Determine The Condition Of The Spokes And Rims
I used a glass plate to check how straight the spokes were. I found all the spokes on the front wheel were bent and only 17 of the rear were straight enough for reuse and only 8 nipples were reusable. So, I made the decision to replace all the spokes with stainless steel spokes and all the nipples, which are chrome plated brass.
I put the rims down on my work bench and used a 0.508 mm feeler gauge to check if they are bent. I was not able to get the gauge between the work bench and the rim so both are in good condition.
I have not found a specification in the Haynes or Clymer manuals to confirm how warped a wheel rim can be and still be usable. The maximum lateral deviation along the rim when the spokes are tight is 0.2 mm. The feeler gauge I used is more than twice that amount as I figured the spokes could bend the rim to be within the 0.2 mm maximum deviation if there was less than 0.5 mm of warping in the rim. This is pure conjecture on my part.
I had the hubs vapor blasted at the Colorado Vapor Blasting division of Vintage Twins in Arvada, CO.
I used a drill and wire wheel to remove the caked on rubber on the inside of the hub. There was a lot of it to remove.
I planned to refinish the rims with “0000” steel wool and aluminum cleaner. I started work on the front rim, but there was a fair amount of pitting with tenacious crud and it was laborious to get them clean . So I decided to have them vapor blasted.
Refinishing Vapor Blasted Rims
When I got the rims back from vapor blasting, I used the “0000” steel wool to polish them up and then used a metal polish I had not used before, Luster Pad, that gave very good results.
After I refinished the hubs, I installed new wheel bearings and set the wheel bearing pre-load. You can read how I do that here.
I started with the front wheel. The first thing is to find the arrow on the rim that shows the direction of wheel rotation. When rolling forward the wheel turns counter-clockwise from the left side and clockwise from the right. The arrow is pointing in the clockwise direction, so the side of the rim with arrow goes on the right side.
Then I orient the rim so one of the triangular blocks the spokes go through is directly across from the valve stem hole in the rim.
The lower hole in the triangular block, next to my finger, is for the inner spokes and the upper hole on the other face of the triangle is for the outer spokes. I put a piece of masking tape next to the triangular block across from the valve stem hole with an “I” next to the lower hole and an “O” next to the upper hole to remind me of the pattern.
I start with the inside spokes on the left side of the rim. The first inside spoke on the triangular block directly across from the valve stem hole goes into the third nipple hole counting clockwise from the valve stem hole. I insert the spoke through the hole in the triangular block in the hub, put a small dab of anti-seize on the threads, poke the nipple though the hole in the rim and spin it onto the threads about a turn.
The next inner spoke is four holes clockwise from the first spoke, and so on.
I continue doing this for all 10 inner spokes on the left side of the wheel. This shows all the inner spokes installed on the left side of the hub.
I start the outer spokes at the fourth hole counter-clockwise from the valve stem hole.
The next outer spoke goes in the fourth hole clockwise from the first out spoke.
Here is the left side of the wheel with all the inner and outer spokes installed.
I flip the wheel over to install the spokes on the right side of the wheel. The spoke locations in the rim and hub are the same on the right side. I follow the same procedure to install all 20 spokes on the right side.
These are stainless steel spokes, but the nipples are brass. Since I usually use anti-seize on stainless fasteners I used it on the spoke threads. Later I found out that I should use anti-seize on the spoke threads to prevent galling only if I use stainless steel nipples. The brass nipples don’t gall with stainless steel spokes, so I shouldn’t have used anti-seize.
Truing The Wheels
The wheels need to be aligned, aka “trued”, in the radial and lateral directions; radial is along the spokes and lateral is across the rim. I decided to center the hub (radial alignment) first. The published specifications for maximum out of round for the wheel is 0.5 mm radial and 0.2 mm lateral. I start with the radial truing which gets the hub centered inside of the rim.
I spend a long time learning how the rims react to spoke tension. The material below is my attempt to simplify the process of truing the wheel. If this is your first time working on truing a wheel, you will find it an example of the meaning of, “Endeavor To Persevere“. 🙂
The video link above shows the techniques I used to true the wheels and is likely the best way to see how I did this work rather than relying on the following text and pictures.
Lessons I Learned Along The Way
I started reading materials and watching YouTube videos. Unfortunately almost all of this focused on dirt bike wheels which have much looser tolerances for truing the wheels than the R80ST.
I started with a spoke wrench and trued the wheels using it. Then I found out about spoke torque wrenches. So I got one and contacted Buchanan Spokes & Rims for their recommendation on minimum torque for the R80ST wheels, which they told me was 40 to 45 inch-lbs. I got a torque wrench after truing the wheels and checked the spokes. They were way too loose. That’s to be expected as this is my first time truing wheels and I don’t know what “tight” feels like. That said, I recommend using a torque wrench to do this work.
Getting the dial indicators on the truing stand to measure the radial and lateral deviation of the rim was tricky as there are almost no flat areas on the rim. I tried the outside edge of the rim for the radial measurement and found it was dinged up too much. So I put the radial dial indicator on the inside of the wheel well where there is a strip that is flat. That made the radial measurements more reliable.
There are pits from corrosion on the rim and I learned that if I saw a sudden change in the dial indicator that I should ignore it as it was due to a surface defect, not the rim being out of true. If there was a sudden jump in the indicator that lasted a bit, I would inspect the rim to see if there was a gouge or ding, and if so, I ignored the indicator and did not adjust the spokes to try and remove the deviation.
I found a section of the front rim (about an inch or so long) that had a very large lateral deviation and also a radial deviation. I chalked that up to the wheel having hit a curb or big pot hole sometime in it’s 64,000 mile life and ignored that deviation. If I tried to true that area, the rest of the wheel went out of true.
I had to have patience to do this work. If I felt tired, annoyed or focused on “just be done”, I stepped away from the workshop. I can’t do this work if I am irritated, annoyed, frustrated or feeling in a hurry. I ended up starting over about a half-dozen times before getting the wheels trued. As I mentioned above, the spoke torque wrench was essential for getting the spokes tight.
Initial Radial Truing Of The Wheel
In this section, I show truing the front wheel. The rear wheel is trued in the same manner as the front, but with some minor changes due to having the rim offset from the brake side of the rear hub.
The spokes come in groups of four spokes. There are two outside spokes, one on the right and one on the left side of the rim, and two inside spokes toward the center of the rim, one on the left side and one on the right side of the rim.
The outside spokes will move the rim more laterally (left to right) while the inside spokes will move the rim more radially. That said, all four spokes in the group cause lateral and radial movement of the rim.
To start centering the hub inside the rim, I work with the two inside spokes in each set of four spokes and finger tighten them to move the hub until get it centered inside the rim.
To help me keep track of the differences in redial alignment, I numbered each section of the hub between the triangular blocks the spokes go into starting with the first full section near the valve stem hole which is just a bit counter-clockwise from the hole.
I use my 8″ Vernier caliper from the outside edge of the rim to the inside edge of the hub. I make measurements in the center of each of the 10 hub sections. I start with the spokes loose and move the hub to get it reasonably centered inside the rim. Then I finger tighten the two center spokes in each section of four spokes to adjust the hub until I get it close to being centered, say within 0.3-0.2 mm maximum deviation.
Later on, I decided to use two strips of scrap 3/4″ plywood so the rim would be level with the hub to minimize the work when truing the wheel laterally. I place the strips so they are under the edge of the hub and the rim. The picture below was taken earlier so it doesn’t show this “trick”.
I draw a diagram in my rebuild journal and record the measurements. Then I look at them and see where the hub is bulging out and compute the maximum deviation from being true.
For sections that seem to be bulging outward, I tighten the group of four spokes attached to the rim across from that hub section and loosen the group of four spokes on the opposite side of the hub. For example, in the diagram above, section “5” is 180.8 mm while the section opposite it, section “10”, is 180.0 mm. So I loosen the group of four spokes across from section “10” then finger tighten the group of four spokes across from section “5”. As I loosen and tighten the spokes I measure sections “5” and “10” and adjust how tight or loose the spokes are until the radial distance for both sections is very close. If necessary, I use the screw driver with the slot in it to tighten the center spokes to help get the hub centered inside the rim.
After trying to remove as much difference in the radial distance for all 10 sections, I measure around the wheel again in all 10 sections to see what the result is and compute the maximum difference in the radius of the 10 sections. After about 5 times doing this procedure, I got the maximum radial difference to 0.3 mm which is within the maximum allowed difference of 0.5 mm.
This gets the wheel close to true radially, but I have to use the truing stand to get the wheel trued both radially and axially. I believe this preliminary radial truing reduces the amount of radial adjustment I have to do on the truing stand.
Lateral Truing Of The Wheel
I mount the wheel in truing stand on the spindle and adjust the two dial indicators so one measures the radial distance and the other the lateral distance.
The dial gauges have roller ball tips screwed into the stems. But these are too small a contact patch for good readings. I unscrewed the roller ball tips so I have a bigger diameter tip on the end of the stems so readings aren’t as easily disrupted by minor dings and scratches in the rims.
I mount the dial indicators on the rim. I mount the radial indicator so it touches the left outside of the rim.
Later I found there were a number of dings and flat spots on the outside edge of the rim. So I installed the ball tip and positioned the radial dial indicator inside the rim near the well where it is pretty flat. There are some pits on the inside of the rim that I have to ignore, but generally the inside surface is smoother than the outside edge of the rim.
I mount lateral dial gauge on the right side of the rim. So a (+) deviation means the wheel is off center to the right and a (-) deviation means it is off center to the left.
I put a piece of tape on my work bench showing the direction of the lateral dial gauge (+) and (-) readings, the direction of lateral movement it indicates and the direction I need to adjust the rim to reduce a too large (+) or (-) lateral deviation. This helps me make the correct adjustments.
When I spun the wheel to see how out of true it was, the lateral deviation was so large that the radial dial indicator would rub against the lip of the rim. So I need to start correcting the lateral runout before I can work on the radial truing.
The maximum lateral deviation is 0.20 mm (0.008 inches). That means I want to hold the lateral deviation of the rim within +0.10 to -0.10 mm.
The above link to the video I made shows the techniques I learned to true the wheel. It is easier to understand how I do this by watching the video than explaining it in words and pictures. So the following is just a brief summary.
To adjust the wheel laterally, for a too big (+) deviation, I loosen the right outside spoke in the the group of four spokes in a hub section and tighten the outside spoke on the left side. Frequently I have to adjust multiple groups of four spokes to get the lateral difference within the maximum of 0.2 mm. And, I often have to adjust the radial difference as well. I try to adjust the outside spokes to keep the lateral difference in range and tighten or loosen the inner spokes to adjust the radial difference.
Final Radial Truing Of The Wheel
After I get the lateral adjustments close to +/- 0.10 mm, I true the wheel radially. The wheel has gotten egg shaped as there are alternation sections of too large (+) deviations and (-) deviations. That suggests that the spokes in the sections with too much (-) deviation are too tight and have pushed out the spokes in the sections of too much (+) deviation. So, I loosen all the spokes in the too large (-) sections and small equal amount and tighten the spokes in the too large (+) sections. I measure the rim again and repeat this adjustment until I get the radial deviation with in the specification of a maximum of 0.5 mm (0.020 inches).
Now both the radial and lateral deviations are pretty good with some sections that need some final adjustment. But, before I work on that, I set the spokes.
Setting The Spokes In The Hub
When you set the spoke heads in the hub, the wheel will get go out of true a bit. So it’s easier if you set the spoke heads when you get the wheel close to true since you are going to have to adjust the spokes after you set the spoke heads in the rim.
The side of the spoke head has two ridges. These are designed to prevent the spoke from turning in the hub. I use a punch and hammer to sent the spoke heads in the hub using a firm whack of the hammer.
I show the adjustment techniques I use in the video link, above, which is a good way to see how I make the lateral and radial truing adjustments in more detail.
After setting the spokes, I check the wheel for being true. It changed a bit after setting the spokes, so I adjust the wheel as appropriate to get the radial and lateral deviations back within specifications.
Torquing The Spokes
I recommend using the spoke torque wrench instead of the spoke wrench to true the wheels. I set the torque to 1/2 the recommended value and trued the wheel radially and laterally. Then I set the spoke heads in the rim. Then I set the torque to the minimum value and trued the wheel again. When you set the spoke heads, the wheel will go out of true a bit, so that’s why I set the spoke heads when I got the wheel true at 1/2 the minimum torque.
The final step is to use a spoke torque wrench and verify that all the spokes are at least as tight as the minimum torque specification. There is no specification published in the Haynes or Clymer’s manuals. So, I checked with Buchanan Spokes and Rims to get the minimum torque specification for the front and rear wheels. They recommended between 40-45 inch-pounds. When I tested the spokes I had tightened using the spoke wrench I found they were way too loose. So I had to start over using the torque wrench to true the wheels while getting the spoke nipple torque at least 40 inch-pounds.
Since I mistakenly put anti-seize on the spoke threads, I have to reduce the torque to avoid over tightening the spokes and rounding the brass nipples. I reduce the torque by about 25 percent so the torque range is 30-34 inch-pounds.
I torqued the spokes and true the wheels in two stages starting at 1/2 the minimum torque. Then I set the spoke heads in the hub using my punch as I explained above. Then I increased the torque to the minimum amount and trued the wheels again. Some spokes are tighter than the minimum which is okay.
Checking For Spokes Poking Through The Nipples
If the spokes are extending past the head of the spoke nipple, the spoke needs to be ground off or it will puncture the inner tube. All the spokes on the front wheel do not extend past the face of the spoke nipple so I don’t have to grind them. If I did have to grind them, I would use my Dremel tool with a burr on it to remove the excess spoke and insure the end of the spoke is recessed a bit beneath the top of the head of the spoke nipple.
Differences When Truing The Rear Wheel
Due to the rim offset from the hub on the rear wheel and the fact there are no wheel bearings in the R80ST rear wheel, there are some differences when truing it.
Setting The Rim Offset
I start by using three nuts taped to the outer edge of the rear rim. I choose the M4 nuts so I start with more offset than the 3 mm recommendation. If the rim has a bit more offset it’s okay. And, as I learned, when truing the wheel, the rim has a tendency to move and it can end up even with the hub if you aren’t careful.
I centered the hub inside the rim as I did for the front wheel. But, to keep the hub from being pulled up as I tightened the spokes, I put a battery on top of the hub to ensure it stayed flush on my workbench. I learned this the hard way as the first time I used my 8 inch Vernier caliper to center the hub inside the rim, I found the hub had been pulled up off the workbench.
Mounting Rear Wheel In Truing Stand
After I got the hub close to centered in the rim, I can not use the truing stand spindle to mount the rear wheel as the rear wheel does not have wheel bearings. I learned from Matt Iles that the Marc Parnes wheel balancing tool can be used to mount the wheel. I have that tool and it worked, after a fashion.
I used the shallow nose cone on the inside of the hub and the long nose cone on the outside. I used the two sleeves to position the bearings at the end of the shaft.
The pictures above show the left side of the hub on the right side of the truing stand. I turned the wheel around so the left side of the hub was on the left side of the truing stand. That made it easier to check the rim offset while I trued the wheel.
The Marc Parnes bearings sat on top of the legs of the truing stand, so the assemble shifted easily which made it much harder to true the rear wheel. I used two straps to clamp the bearings to the top of the legs. That kept the assembly from moving as easily, but after I adjusted spokes, I spun the wheel so the valve stem was opposite of the lateral dial gauge and zeroed both gauges and then slowly spun the wheel back to where I made my adjustment to verify if I got that section true or not. It took more time, but it is doable.
Verifying Rear Wheel Rim Offset As I True The Wheel
As I worked on truing the rear wheel, I periodically checked the rim offset. I used a long piece of all thread I had, but you could use a steel ruler, and my Vernier caliper. I measured the thickness of the all thread rod and then measured from the distance from highest point on the edge of the rim and subtracted the thickness of the all thread rod.
Several times the rim offset got too small. So I went all around the wheel and in each group of four spokes, I loosened the two right side spokes a little and tightened the two left side spokes about the same amount.
Then I checked the offset and continued until the offset was at least 3 mm but not more than 4 mm. Each time I did that, I had to adjust the lateral truing of the rim to get it back in tolerance.
After exercising a lot of patience, I finally got the rear rim true within the radial tolerance (0.5 mm) and lateral tolerance (0.2 mm), the rim offset between 3 and 4 mm and the minimum torque on the spokes at 30 inch-pounds.
What Done Looks Like
Here is what I started with.
And here is what the wheels look like after refinishing them and lacing and truing the wheels with new stainless steel spokes.