Ampandy Posted December 30, 2014 Posted December 30, 2014 Aluminium and vibration are not good friends at all. The slightest crank or flaw will become way worse when exposed to vibration.
V12man Posted December 30, 2014 Posted December 30, 2014 Apparenty it clicks/pings a little as the tension settles? Just what the guy who built up my crests onto new hubs told me. Told me it's normal. Perhaps I have been mislead...It is normal if you dont stress relieve the wheel during building. And I think all good builders do that. .. the poor ones dont. see this for more info - may not be the best reference, but better than nothing. http://www.wheelfanatyk.com/blog/wheel-building-tip-no-4-how-to-pre-stress-your-wheel/
David Marshall Posted December 31, 2014 Posted December 31, 2014 The "ping" is usually from spokes that have become "wound up" during tensioning. Some twist has been introduced when the nipple is turned and then the spoke springs back when the tension is reduced. This can happen when you inflate the tire or load the wheel. As V12man says stress relieving will sort this out and what I do is kneel on the floor with a new wheel, axle end on a wooden block, and my hands in the 9 and 3 o'clock positions on the rim. I then ease my knees off the ground so that my weight is on the rim. The spokes on the underside become relatively looser and "ping". Rotate the rim in small increments and repeat on both sides. You then need to re true because the wheel will be out wherever a spoke has straightened. This also gives you a good idea of the overall spoke tension. You ideally want as much tension as you can get without the wheel folding when you lean on it. I also reduce wind up by marking the spokes with chalk when I build and by keeping the marks in the same relative position while building. Being able to do this is one of the big advantages of hand built wheels. Machines cannot easily deal with wind up, so manufacturers build with straight gauge spokes and low tensions. Even then some straightening occurs and you find brand new wheels going out of true after the first ride. The more expensive wheels are "hand finished" or built with bladed spokes that can be held while tensioned. The marketing gurus will then find some way to convince you that straight gauge spokes are stronger or that bladed spokes will improve your mtb ride!
Breezer Posted April 14, 2015 Author Posted April 14, 2015 Yesterday my bike went in for a service and the front wheel was trued. When I got on the bike I heard a clunk and the front wheel started to buckle. The front wheel also cracked at a nipple. Definitely to much tension like my rear wheel in December.
V12man Posted April 14, 2015 Posted April 14, 2015 Yesterday my bike went in for a service and the front wheel was trued. When I got on the bike I heard a clunk and the front wheel started to buckle. The front wheel also cracked at a nipple. Definitely to much tension like my rear wheel in December.Change your LBS.....
Andrew Steer Posted April 14, 2015 Posted April 14, 2015 Yesterday my bike went in for a service and the front wheel was trued. When I got on the bike I heard a clunk and the front wheel started to buckle. The front wheel also cracked at a nipple. Definitely to much tension like my rear wheel in December. Fool me once, shame on you...Fool me twice
PeterF Posted April 14, 2015 Posted April 14, 2015 Is it the nipple cracking or the rim around the nipple? If it is the rim then it is certainly due to over tensioning the spokes. If it is the nipple it is probably aluminium nipples which do corrode over time and crack.
David Marshall Posted April 15, 2015 Posted April 15, 2015 Over tensioned. Going above the optimum tension leaves the wheel weaker laterally and susceptible to warping from any side force.
Bobbo_SA Posted April 15, 2015 Posted April 15, 2015 For me its become an easy decision, I lusted after a set of crests for a long time but they were always just outside the acceptable price point for me, then I managed to get hold of a set of Novatec hubs and was in a position to choose a rim. I went for a set of Rapides, although the 650b version, but the 29er version has an identical profile: http://rapide.co.za/product/rapide-tr21-tubeless-ready-29er-rim/ And at 420g per rim they were plenty light enough for me, crests are advertised at 365g so it would be 110g "heavier" for the set. I asked Kiwi if he would build them up for me and he did an amazing job, very highly recommend.
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