2 X 2 Posted October 19, 2015 Posted October 19, 2015 Lost a lot of spokes and it was recommended that I replace all my spokes with double butted spokes. This was done but the spokes still break. It breaks on the part where the spoke changes from thin to thick just before it hooks on to the hub (rear wheel) BTW. it is on a Mtb Tandem. Does wheel pressure have a influence on spoke breakage? We run on about 1.5 to 1.7 bar.
the nerd Posted October 19, 2015 Posted October 19, 2015 Lost a lot of spokes and it was recommended that I replace all my spokes with double butted spokes. This was done but the spokes still break. It breaks on the part where the spoke changes from thin to thick just before it hooks on to the hub (rear wheel) BTW. it is on a Mtb Tandem. Does wheel pressure have a influence on spoke breakage? We run on about 1.5 to 1.7 bar. Get a wheelset built by a reputable wheel builder, especially on a tandem where the forces on spokes are huge! BTW who rebuilt the wheel?
Belgarath Posted October 19, 2015 Posted October 19, 2015 I'd increase the tyre pressure, but that is not the reason. I had an issue after I broke a spoke on a race. Finished the race (knackering my rim in the process), replaced the spoke, but I lost two more on two different occasions. In the end the LBS recommended I replace the rim, as it's too uneven, so they cannot get the spoke tension evened out.
2 X 2 Posted October 19, 2015 Author Posted October 19, 2015 I'd increase the tyre pressure, but that is not the reason. I had an issue after I broke a spoke on a race. Finished the race (knackering my rim in the process), replaced the spoke, but I lost two more on two different occasions. In the end the LBS recommended I replace the rim, as it's too uneven, so they cannot get the spoke tension evened out. I replaced the rims about four weeks ago on recommendation of various bike shops, so the rims are brand new. They even put copper washers on the spokes where it meets with the hubs to prevent breaking, but as I mentioned, the spokes break on the part where it changes from thick to thin on the double butte part
2 X 2 Posted October 19, 2015 Author Posted October 19, 2015 Get a wheelset built by a reputable wheel builder, especially on a tandem where the forces on spokes are huge! BTW who rebuilt the wheel? Front was done by Bruce Reynecke cycles and the back wheel by Cycle House
Skinnyone Posted October 19, 2015 Posted October 19, 2015 Spoke tension is the primary cause - too low or uneven. also how many spokes do have in your tandem wheels? too few and then you are putting enormous strain on the spokes, I would not build a tandem wheel with less than 32 spokes... Also tieing and soldering helps distribute the spoke tension more evenly (only if the tension is fairly close to start with.... Perhaps PM me as I do a lot of wheel building and we can discuss your options and remedy. I am based in JHB...
2 X 2 Posted October 19, 2015 Author Posted October 19, 2015 Spoke tension is the primary cause - too low or uneven. also how many spokes do have in your tandem wheels? too few and then you are putting enormous strain on the spokes, I would not build a tandem wheel with less than 32 spokes... Also tieing and soldering helps distribute the spoke tension more evenly (only if the tension is fairly close to start with.... Perhaps PM me as I do a lot of wheel building and we can discuss your options and remedy. I am based in JHB... We are on 36 hole rims. My road tandem is on 24 hole rims and I have not had a spoke broke in over 4 years. My thinking is also that the tension is too high. Will PM you
johannrissik Posted October 19, 2015 Posted October 19, 2015 Let us know when you sort it out please...I have a special interest
droo Posted October 19, 2015 Posted October 19, 2015 Get them built 4x by someone who knows about stress relieving. Double butted spokes from a decent manufacturer (DT Swiss, Wheelsmith and Sapim come to mind), brass nipples and even spoke tension within the spec of both the spoke and the rim.
RockCoach Posted October 19, 2015 Posted October 19, 2015 On a tandem you need a strong set of rims built by good wheelbuilder. My business partner, Jason at The Trailhead, has a rear toxic green Spank Subrosa & Hope wheel which has nearly completed 3 J2C's on the back of various tandems. He usually loans it out on Day 1 when a tandem wheel fails. The last time the wheel needed truing was in 2013.
2 X 2 Posted October 19, 2015 Author Posted October 19, 2015 Let us know when you sort it out please...I have a special interest I hope I can get it sorted. Already spent more on fixing wheels, than what the tandem cost me originally
johannrissik Posted October 19, 2015 Posted October 19, 2015 I hope I can get it sorted. Already spent more on fixing wheels, than what the tandem cost me originally I'd be interested to know what rims, hubs, spokes and what wheelsize ?
LeTurbo Posted October 19, 2015 Posted October 19, 2015 In that book "The Man who cycled around the world" (I think it's called), Mark Beaumont speaks of getting his wheels rebuilt in some little village after he'd broken spoke after spoke. As I recall, the mechanic rebuilt them quite loose, and the wheels lasted for the rest of the journey. Maybe they're too tight? Not that I can comment really, because I've never actually broken one. Chains breaking is also beyond my comprehension.
2 X 2 Posted October 20, 2015 Author Posted October 20, 2015 I'd be interested to know what rims, hubs, spokes and what wheelsize ? The front one is a Mavic 36 hole, the back is a Alex rim 36 hole. Don't know what hubs it is. It came with the tandem when i bought it. Cant think that the hubs can cause the spokes to break.
Belgarath Posted October 21, 2015 Posted October 21, 2015 The front one is a Mavic 36 hole, the back is a Alex rim 36 hole. Don't know what hubs it is. It came with the tandem when i bought it. Cant think that the hubs can cause the spokes to break.Well, you've replaced everything else...
David Marshall Posted October 24, 2015 Posted October 24, 2015 This is interesting in that it is an unusual place for a good spoke to break unless the chain has damaged the spokes when coming off between the cassette and spokes. I can't believe two different builders both have a bad batch of spokes. The usual place for the spoke to fatigue is in the J bend or at the end of the thread. There are a number of things to consider such as number of spokes, number of crosses, wheel size, weight of riders etc. Tire pressure on a MTB will not significantly reduce spoke tension and tension is unlikely to be too high as the rim would fail before the spokes break. If the hubs are the correct width for the frame they are also not likely to cause the problem. I would consider 36 holes on a MTB tandem too few but getting a rim and hubs with more will not be easy - assuming you have disc brakes. 24 holes on a road tandem wheel is just asking for it! Just a matter of time and mileage before the problems start. I won't even guarantee the spokes on a normal road rear that I build with 24 spokes.
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