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The front 26" wheel on my commuter rubs on the mud guard under load. If I honk out of the saddle or even, sometimes, heavy breaking. It's just a factory bonty wheel that's only seen action once I moved it onto my commuter.
On quick inspection, the wheel doesn't feel like the spokes are particularly loose, but I anticiapte that when I get it on a jig and pay attention it will need tightening up. If this is the case,. tightening the spokes evenly and truing the wheel should fix it I guess?
Yes, to some degree. But in practice you will find some spokes are stretched, some nipples will have sized up and what seemed like a small fixable problem turns into an expensive mess.
So, if its just for commuting, Id put up with it. Or be brave and tighten them all to see what happens 🙂
I think I read that if the spokes are reasonably tight to begin with, then additional spoke tension has little effect on wheel stiffness?
Wheel rub under braking sounds like a crappy/loose quick release though, tried lubing and tightening the QR? Better yet, swap for a Shimano?
Only up to a point.
I thought about the hub / fork interface. It's a bolt thru. I'll deffo double check it again tho.
Yup, clothesline effect.
some spokes are stretched
Another myth.
It depends,
The first road wheel I built (Stans Alpha 340 and 20/24 DT Rev's) was horrible to ride on, it flexed all over the place despite being true and with even tension. Stripped it and rebuilt it 3 times, and by the 3rd attempt ended up with an acceptably stiff wheel (I'm 90kg, have been 105kg!) with much closer tension. So yes, it's entirely possible to have a straight wheel where the spoke tension is all wrong even if it is within the supposedly acceptable range.
By contrast, everyone's favourite training wheel (Mavic open pro on 105 hubs with 32 DT Comps), you can get away with murder whilst building them, the rims stiffer so it feels stiffer when pedaling and more spoke means the brakes don't rub.
The caveat to that is, I occasionally lose a spoke in the front wheel of the Stans rim'd wheelset, yet it still feels fine to ride until I get around to replacing it.
Yup, clothesline effect.
I've never entirely bought into that for spoked wheels, the principal is that a force cannot have an effect perpendicular to it's direction. But the spokes are by design not perpendicular, either radially, torsional or laterally to the forces applied (the only ones that are would be a radial laced rear wheel or disk braked radial wheel).
The "debunking" above assumes that lateral stiffness (in the lower half at least) is a function of the rim's ability to resist lateral loads. But if you plotted the spoke elongation ona graph the loaded side stretches faster than the unloaded side relaxes, which means the overall tension must be increasing, which means the radial (arch) stiffness of the rim is coming into play at the very least.
Couple that with the fact that wheels tend to buckle fairly catastrophically, and I think a much better analogy is prestressed reinforced concrete. Where the tension applied to the reinforcement is proportional to the stiffness of the overall structure (or at least you're able to move the knee point on the stress strain curve far enough one way that the structure is essentially operating on one side of it right up until failure).
Sure it isn't your fork flexing?