Is 28 spokes wheel harder to tension than 24 and 32 spokes wheel?
How-To: Wheel Truing with Art's Cyclery 16
The ability to maintain your wheels is a skill all mountain bikers should possess, especially considering the punishment modern bikes are expected to endure. Vital MTB and Art's Cyclery are here to provide a few wheel truing tips so you can keep your wheels rolling strong for years.
It's good to think of a wheel as a single organism, whose spokes, nipples, hub and rim all interact with each other to create a strong, healthy being. Thus, maintaining overall health, which for a wheel means even spoke tension, is your goal as wheel therapist. Unfortunately, once a rim is bent due to impacts, it has begun an irreversible journey towards retirement. This fate can be put off for a while through good wheel maintenance, but, as we will see, proper spoke tension is hard to achieve with a damaged wheel. Knowing this, the importance of a quality wheel build is easy to understand. When a wheel starts its life perfectly tensioned, it is stronger, more resilient, and easier to fix when something goes wrong.
Keep a few basic tenets in mind. First, when working side to side, tightening spokes will move the rim toward those tightened, so if your rim deviates to the left, tighten the spokes on the right. When fixing out-of-round problems, loosening spokes will let the rim out from the hub, while tightening spokes will pull the rim in to the hub. Avoid trying to completely straighten each deviation the first time you work on that section of the wheel. Instead, work on the problem for a bit and then move around the wheel, rechecking all the spokes to bring them into even tension. Repeat this process incrementally, without turning a spoke nipple more than a quarter-turn at once.
Taper the changes you make out towards the edges of the affected section. For example, if you are working on an out-of-round section of four spokes and turned the two in the center one-quarter turn each, you probably need to turn the two on either end only an eighth of a turn. This is because spoke tension near the edges of the problem area will be closer to the correct tension of the rest of the wheel. Tapering applies when fixing side-to-side deviations as well. Finally, it’s better to have a wheel with correct, even spoke tension that’s a little out of true than to get your wheel perfectly true with fluctuating tension across the spokes—the wheel with even tension will be much stronger. Now, with these points in mind, it’s time to grab a nipple. Wrench.
If your wheel is out of round, fix that problem first. When attacking high and low spots you will need to adjust all of the spokes in the affected span of the rim, beginning at the section of the rim with the biggest deviation. If the rim jumps away from the caliper gauge—a flat spot, spoke tension needs to be decreased, so the rim is let out away from the hub. If the rim scrapes against the caliper gauge—a high spot, spoke tension needs to be increased, pulling the rim in. Again, don’t try to fix the problem all at once. Work on the worst section of the wheel until it is just barely better than the next worse section, and then move on to that section. Repeat the process while looking for spokes that are grossly out of tension until the wheel is within a millimeter or two from being round.
Side-to-side deviations differ slightly. Since a rim will move toward the tightened spoke, if the wheel is deviated left, tighten the spokes on the right and vice versa. Avoid loosening the opposite spokes simultaneously, which will make them too loose, since they have already lost tension when the rim moved to their side. If the rim has been knocked out of true due to an impact, tightening spokes to bring the rim back over will result in uneven tension, which, unfortunately, is the only option in this case. Remember that even spoke tension is more important than a straight wheel and just do what you can. Work slowly and tackle the biggest problems first. Taper the changes you make out towards the edges of the affected section.
When it comes to truing wheels, frequent inspection and preventative maintenance can go a long way toward protecting your rims. Check spoke tension by squeezing pairs of spokes all the way around the rim, looking for uneven tension. If you discover that spoke tension fluctuates noticeably, use your skills to fix the problem, this will save you lots of time and money later on. Examining your wheel in this way every few rides will also help you to discover potential problems and fix them before they turn into something bigger. Finally, remember that wheels are asked to take more abuse than any other part of our bikes, and that proper care, along with realistic expectations of what they can endure, will keep you and your wheels happy for many rides to come.
Art's Cyclery 3/6/2014 4:59 PM
16 comments newest first
In general, the fewer the spokes, the harder it is to true. So, 28 spoke wheels are slightly more difficult to true than 32 spoke, and 24 is more difficult than 28. WIth respect to tensioning, the number of spokes doesn't really matter. You can tension a wheel with fewer spokes faster, but only because there are less nipples to turn.
Why does everyone pick on Edmonton? Im sick and tired of folks from Edmonton being made out to look like idiots. We aren't all that dumb. Maybe next time you can make the meat head guy's name Boulder Bill. Santa Cruz Sam or Moab Mike. Thanks. Eh.
meet Bodhil the Bike Whisperer from Boulder in our latest How-To video : )
I think they should have gone in depth about the Spoke tension meter and how that helps the process of building and repairing. Showing proper tools for the job and how they are used would educate riders on why the bike shop is worth paying for.
Nice video. I appreciated the overall guidelines, and that it was techy enough without being overwhelmingly nerdy.
I don't quite agree with the part about loosening the spokes at a flat spot. When that flat spot was created by your awesome huck to flat, It's already loosened those spokes by taking some of the load off of them. If you loosen them even more, you're just getting further away from even spoke tension. If anything, I'll tighten them slightly, enough to somewhat even the tension, but not enough to pull the rim even more out of round. Like he said, it's all about even spoke tension. If you really want to geek out on wheel building and have at least some math knowledge beyond calculus, there's a book by Jobst Brandt, I think just called "The Bicycle Wheel" that goes into incredible detail, including all of the equations, of the dynamic system that is the spoked wheel.
You are right Big Bird. If you have a flat spot "created by your awesome huck" then your rim is bent and you will need to actually tighten the spokes in the affected area in order to restore even tension in the wheel. The advice on loosening spokes to improve flat spots is intended for undamaged rims. As explained, once a rim is bent, it begins an irreversible journey towards retirement. At that point it is all about mitigating the damage through a restoration of spoke tension.
On another note, we'd like to second your endorsement of "The Bicycle Wheel" as an outstanding book on wheel building. Anyone who is serious about wheel building should read it.
Good point. I should have been more specific. I guess we have different definitions of "Flat spot." To me it's where the rim has been bent vertically toward the hub. What you're describing I'd call a high spot which Is generally dealt with when first building a wheel, not repairing one.
Is the best (cheapest) way to check spoke tension to just grab the spokes with your fingers? Ive always had a hard time with that. It just doesnt seem very accurate. But can you get it "close enough" using your fingers?
Contrary to what he said, the sound of the spoke when you flick it with a finger is a very good indication of it's tension. Just don't try to hear them all at once while spinning the wheel and yes, a child's toy is not required. Just use your ears. The higher the pitch, the tighter the spoke. This is most effective on motorcycle wheels (Of which I've built about five hundred.) which ring a bit better. Personally, I do mostly use the fingers on bike wheels. A spoke tension gauge like he uses in the video is probably the most accurate way, but I could never really be bothered to mess with one.
Great Info. Thanks! Although I was really looking forward to pulling out my kids toy synthesizer. And one other question. Do you think a truing stand is a must or just a convenience?
Whether or not you need a truing stand just comes down to the need for precision and convenience. With a professional truing stand it is possible to true a high end rim to within 20/100ths of a millimeter. With a dial indicator that number drops to 5/100ths of a millimeter! Even if you don't require that kind of precision, it can be difficult to achieve trueness better than 2-3mm without a truing stand. Moreover, it is much easier to identify deviations in a wheel with a truing stand as it greatly speeds up the process, especially for someone that is new to wheel truing.
This has been one of the best tech videos. I built wheels for years and the truth is a slow spoke wrench wins the day. Take your time, be patient. I have seen some OEM rebuilds that looked hopeless last for years once they were properly tensioned and trued.
@Big Bird I built a new rear wheel once when I was in a pinch with Popcicle sticks and black tape on the rear triangle when I had to have my bike the next morning for a moab trip. Two years later still going strong.
I've trued many a wheel with the old zip tie (Or zap strap if you're Canadian.) around the fork or frame, but it's really not as easy as having a stand because with the zip tie you're relying on sight to know when the rim is touching. Whereas with a truing stand with metal feelers you can hear the slightest touch. Also, with a stand it's much easier to measure and control the dish, or centering of the rim over the hub, which the video doesn't really get into.
Right again Big Bird on the fact that you can use tone to measure spoke tension. However, when spokes intersect with each other and actually touch, like on a standard 3 cross j-bend spoked wheel, this alters the length of the "string" being plucked. Not only that, depending on if the spoke is going over or under its neighbor, this will also affect the tone. For this reason, if you were to match the tone of all the spokes on the drive side of this type of wheel, you would not end up with a true wheel, even if the tension was even on the non-drive side. The exception are wheels with straight pull spokes, which generally do not touch one another where they intersect. If the wheel was built using this style of hub and spoke, then tone truing is ideal (of course you would need a perfectly round and true rim (read: un-bent) in order for it be completely effective). That is why Easton uses this technique to build its wheels. So, bottom line, if you have a traditional wheel and don't have a spoke tensiometer, we feel that your best indicator of tension is to squeeze the spokes by hand.