It’s too wet to ride today, so I decided to lace up a wheel. My project started a Hope Pro 4 from the parts box. This hub needed new bearings and a new freehub. Replacing the bearings in a Pro 4 is relatively simple, although the freehub seal is usually a PITA.
Once the hub was serviced it was time to calculate spoke length. Spoke length is determined by three factors: 1) Effective Rim Diameter (ERD), this distance from one point on the spoke bed to a point directly opposite, 2) Hub Dimensions including flange diameter and hub center to flange distance, and 3) Spoke Lacing Pattern.
I use rim rods to measure ERD, and a digital hub measuring tool to measure hub dimensions. Spoke lacing pattern is determined by the number of spoke holes, anticipated system weight (rider and bike combined), and anticipated use. Once I have this data I enter it into an online spoke calculator to determine the required spoke lengths.
Once the spoke length has been calculated I start prepping to lace the spokes. This includes soaking the nipples in assembly oil, applying a tough of light grease on each spoke hole (spoke bed side), and cleaning the spokes. Once the spokes are clean I dump the nipples into the shuffler.
Once the nipples are in the shuffler and the excess oil is dripping off I load the spokes in the hub. I build wheels using the Brandt method. This is how I was trained and I feel that there is much less room for error or rim damage compared to the Shraner method.
When I lace the wheel I place the drive side down on the bench, with the hub label and rim valve hole facing me. The first spoke laced is the first heads up spoke clockwise from the 3 o’clock position. I’m using a 3 cross lacing pattern here on a 32 spoke rim.
If the first pair of spokes has been laced correctly you should be able to see the hub label through the valve hole. We call this the “style check” in wheel building.
Once the spokes are laced on each side it’s important to double check to ensure that it’s laced corrctly. An extra minute now can save a lot of work later.
Once the spokes are laced and checked I like to add my spoke locking solution before tensioning. In the past I’ve used boiled linseed oil and wheel fanatyk fix. Lately I’ve settled on Loctite 222. Its the same formula as DT Swiss Spoke Freeze, but way cheaper.
After the 222 is applied I bring the spokes up to work tension. This is the point where the wheel is no longer flopping around on the spokes, but only about 10% of final tension. I use a nipple driving bit in a cordless screwdriver set at low torque. This saves a lot of time.
After the wheel is dished it’s time for the initial radial (round), and then initial lateral (side to side) truing. After the initial dish and true its time to start layering on tension. I like to take it slow by working in 1/4 turn increments.
At this point the spokes are approaching final tension. Its now time to stress the wheel to ensure the nipples and spoke heads have settled into place. I do this by firmly squeezing parallel pairs of spokes on each side of the wheel.
Since I’m building a disc brake mountain bike wheel balanced spoke tensions are more important than radial and lateral true. My goal is to have the wheel radially true within 0.5mm, and laterally true within 0.2mm. I use an online application to enter and map the spoke tensions. My goal is to balance my high (drive) side spoke tensions with 5% while maintain dish and true. The low side (non-drive side on a rear wheel) tensions aren’t as important as the high side tensions, and the rule of thumb is to let them fall where they may. Mapping the low side tensions allows me to track and correct any outliers that are unusually high or low. As I layer on tension in 1/4 turn increments I’m watching the radial and lateral dials to ensure that the wheel remains true. After each layer of tension I stress relive the spokes to remove wind up, which can give false tension readings. Rims are never perfect out of the box, so there’s always compromises to be made with spoke tension and wheel true.
I’m glad to hear that Steve. I squeeze parallel pairs of spokes together, really hard. It’s interesting to see the changes that happen during stress reliving, and I can usually feel any wound up spokes untwist. I find spoke twist is an issue with lighter spokes like the Sapim Laser. But all round spokes tend to wind up a bit during building.
It was raining this evening so I decided to take another poke at tension balance truing this wheel. It wasn’t quite where I wanted it to be, and I knew I could do a little better. So I backed the spoke tension off in 1/4 turn increments, stress relieved the spokes, trued the wheel, measured the tensions, then I started layering on tension in 1/4 turn increments while maintain dish, radial and lateral true. When adding tension it’s important to lightly stress relieve the spokes after each adjustment.
As the spokes near the goal tension even minor adjustments of 1/8th of a turn of the spoke nipple can impact spoke tension, dish, and true. At this point the tension of each spoke impacts it’s neighbouring spokes. If a spoke has low tension it’s neighbour is likely carrying the load with higher tension. Adding or removing tension to a spoke on one side of the wheel will impact the tension of the spokes on the opposite side of the wheel as well. With a bit of patience it’s possible to chase out minor imperfections in radial and lateral true by distributing the correcting force required amongst neighbouring spokes. Rim quality also plays a factor here, I’ve never pulled a perfectly round and true rim out of the box, some higher quality carbon and welded alloy rims are close, and some lower quality pinned rims are just awful.
It’s also important to take your time during this phase. We’re moving metal here, it sometimes takes a minute or two for everything to settle into place.
Here’s the spoke tension map after the initital truing, but before tension balanced truing:
At this point the wheel was true radially and laterally, but the spoke tensions were a little wacky. My high (drive) side tension average was at my goal tension of 110kgf, but the variance was 25%. I was shooting for a low (non-drive) side tension of 60-70% of high side tension (66-77kgf). The low side came in a little lower than I like, and the variance was 40%.
After a few laps with the spoke wrench, digital tensiometer, and truing dials I was able to balance the high side spokes at 109 kgf and no variance. The low side tensions settled in at 72 kgf with a +/- of 5%. I’ll take it!
