horaceunit

I'll try to make this as short as I can. A little background: I have a Trek 7100 Hybrid that I have had for about 4 years. I am 6 foot and about 285- hence the reason for my starting to commute with the bike. Can't really jog any more- kills my knees, and dieting doesn't help much without the excercise. My problem is that I am blowing spokes out on the rear wheel. I had the original wheel replaced (32 hole) with a 36 spoke wheel, but I just found another broken spoke on that one today- about 10 rides on the new wheel. I have heard that a 42 or 48 spoke wheel from a tandem would be a good idea, but none of my LBS seem to be able to find one that will fit my bike. Besides any other advice anyone has- does anyone have any good online sources for wheels? My main problem is that to build one most places want a lot of money (I have been quoted as high as $600.00) so I am willing to try and do it myself if I can find the right parts. I'm sure I'll have more questions, and thanks in advance on any help anyone has!

CACycling

You should not have a problem with a decent 36 spoke wheel. Might want to ask in the Clyde's forum about specific wheel recommendations as well as other hints for heavier riders.

bubbagrannygear

Are the broken spoke on the right (non-drive) side of the bike ?

horaceunit

On both the new wheel, and the old the spokes that went were on the side opposite the gear cassette. The old wheel was replaced a year and a half or so ago with another 32H one that the LBS got and it was all black instead of the original all silver. A couple of months ago I had a spoke go and it was replaced with a silver one, and then another one went about 3 weeks ago and I had it fixed but then decided to try a 36H wheel. The new wheel had a new cassette installed and I still have the old black 32H and I just went and looked at it as well and both the newer silver spokes are on the side opposite the cassette too. Thanks!

horaceunit

Would that be as in Clydesdale? I resemble that statement! I will take a look, thanks!

Retro Grouch 

That's fairly common. It means that you need more spoke tension.

FWIW, I'll add my opinion to the folks who said that a well built 36 spoke wheel, with a reasonably stout rim should be adequate for you.

Grand Bois

I suggest that you never go back to the place that quoted you $600 to build a wheel.

gerv 

After about 50 miles on the wheel, you should have brought it back to the LBS for re-tensioning, particularly if it was a relatively cheap replacement wheel.

I had a similar experience with a replacement wheel for my hybrid bike a number of years ago. Got 100 miles on the new wheel and it started to taco about 30 miles from my house.

If you have any mechanical inclination, you could easily learn to true and tension a wheel yourself. They last a lot longer when carefully looked after.

wmodavis

Spokes mostly break due to metal fatigue. That largely occurs at either the threads or the bend near the head of the spoke. That fatigue is caused by the constant stress cycles the spokes go through as you ride the bike. The spokes undergo low tension (sometimes zero tension - read as 'BAD') at and near where the wheel contacts the ground, and higher tension the remainder of the rotation. To reduce the effect of the stress cycles you must have the spoke tension as high as practical. The high limit is determined by the rim. Rim manufacturers frequently provide a range for spoke tension for the specific rim. Strong, durable, well built wheels will have the tensions set to near the high end or even a bit above the manuf recommended max tension for that rim. If you get a a decent rim (and one with more spokes helps but is not the only factor), and be sure it is properly tensioned you should not be braking spokes even at your weight.

Gonzo Bob

Could just be poor builds that led to the broken spokes but because you've had issues with more than one wheel (is it three total?) I half suspect something else. Maybe the brakes are contacting the drive side first and pushing the rim over thus loosening tension on the non-drive side during braking?

Perhaps look into getting an offset rim for the rear wheel so that spoke tension is more even on the left/right sides. I think they make offset 700C rims for touring bikes, 29ers, and tandems.

Al1943

The brake pads should contact the rim at the same time. An offset rim like any other rim should be centered between the frame's dropouts, chainstays, and seatstays. An offset rim has an asymmetrical shape that should partially reduce the tension differential between the left side and right side of a rear wheel. But the braking surfaces should be equal distant from the dropouts and stays.

dabac

It looks like the OP's bike has V-brakes, and v-brake arms brace against each other. Short of having a completely botched assembly job (or having one brake arme seize solid) there is no way to get enough force into the system to actually cause a significant amount of sideways push on the rim.

It's perfectly possible to have v-brakes set up in a way that will have one pad contact the rim before the other, but this is more on a nuisance/aestethics level than actually influencing the bike or the ride in any significant way.

vredstein

https://www.peterwhitecycles.com/wheels.asp
He's a very respected builder who takes responsibility for his work. Talk to him on the phone. He'll suggest a wheel build, and it will probably cost you under $200 for the rear wheel.

AndrewP

Spend $60 on a Park spoke tensiometer. This will allow you to put the spokes at max tension, and also ensure that the tension is even all around. When a single broken spoke is replaced, the tension wont match the other spokes after it has been ridden a few miles.

noglider 

I think you got a bum wheel. Now that spokes are breaking, you know that they are all fatigued, and more will break, and it's too late to save the wheel. Was it warrantied?

Time to rebuild. I recommend reusing the hub. Reuse the rim if it's not damaged. Get some high quality spokes. Do it yourself this time. It will take time, but you'll know it's done right.

horaceunit

I just ordered a Spin Doctor truing stand and some spoke wrenches. I think that you are correct, I am going to have to seriously look at building my own wheels. First step is to learn to true the two I have now, and be able to replace the spokes myself. Next will be to order all the components and put one together. From what I am learning here it really isn't all that hard and just takes practice. Thanks!

noglider 

Many years ago, I was head mechanic at a couple of bike shops. I've built many wheels. Others here are full of knowledge, patience, and eagerness to help.

I highly recommend the book The Bicycle Wheel.

horaceunit

I have to say that I did indeed already contact Peter White, as well as a couple of other online places, and was quoted some very high numbers. About 3 times what you mentioned in your post. The LBS did it for $200, and of course I am already having problems. The rep that Mr. White has is impressive (researched it on the web), and I have in the back of my head that in 6 months to a year I may seriously consider having him build an entire bike for me, with a custom rear wheel. The Trek is a good bike, but not really, I have found, what I want. Something closer to a road bike, even if it has to have a beefy rear wheel is what I want. My wife and I have discussed it, and if I can loose 50 lbs or there abouts I can look at getting a new bike. The range we talked about was 1,000-2,000, and it seems to me that for a bit more (well, OK a 1,000 or so more) I am in the ballpark for a custom bike. Either way I have ordered a truing stand so I can start learning how to fix, true and possibly even build my own wheels! Thanks to all for the help on this!

horaceunit

I have seen that book mentioned now a coule of times but I also just purchased this book: The Art of Wheelbuilding: A Bench Reference for Neophytes, Pros & Wheelaholics by Gerd Schraner. I may have to get the other one as well, but thanks for the advice! I am finding that these forums do have a lot of knowledge to tap! Thanks!

Little Darwin

At your weight, a well built 36 spoke wheel should not be a problem. It should be strong enough to hold your weight... I know.

I have a 2003 Giant Sedona DX with 36 spoke wheels. I have put about 3,000 miles on it, and I have broken only 1 spoke.

I also ride a Schwinn Voyageur touring bike with custom built 36 spoke 27" wheels with modern 10 speed cassette hubs that have been no problem. (lower mileage than the Giant so far).

For all of these miles, I have weighed between 300 and 365 pounds. I am 6 ft tall as well.

There is no reason to look at a higher spoke count in my opinion, unless perhaps you are riding on some seriously bad surfaces.

Do you ride on to or off of curbs? If so, stop it, or at least minimize it.

Do you stand on the pedals for pot holes and other rough stuff if you see it in advance? If not, do it to use your legs to absorb some of the shock. This is good riding technique for protecting the equipment, and rider. It also leads to better bike control.

There are threads in the Clydesdale forum concerning wheels for us large riders that will give you sources and specific recommendations for good wheels for clydesdales. Look through one of the stickied threads for links to a few good threads on the subject.

noglider 

Do yourself a favor and toss that book in the garbage.

Panthers007

What thread on wheelbuilding would be complete without Sheldon Brown surfacing?

https://sheldonbrown.com/wheelbuild.html

bubbagrannygear

You are on the right path. In for a dime, in for a dollar. Since you now have a fine book, a truing stand and a spoke wrench, all you are missing is a tensionmeter. Take advice listed previously and get the Park.

I was in the same place about 2 years and 7000 miles ago. Could not keep my factory built rear wheel true. (capmagnolo 8 speed - significant dish). Got the Schraner book, a truing stand and the tensionmeter and haven't looked back. Here's what I've learned:

1) This forum is a fantastic resouce. Use the search function - there are alot of passionate wheelaholics who have alot to offer. I have benefitted by advice from Al943 and DannoXYZ (and may others). You should read, experiment, and decide who makes sense to you.

2) Most of the problems associated with the rear wheel are the result of the different spoke tensions associated with the drive and non-drive sides of the wheel. The bottom-most, non-drive spokes, which are under low tension in the static unloaded state, are under almost no tension when under high torque pedaling (or breaking forces). In my case, since I am not a clyde, the leading spokes of the NDS loosened and the wheel would not keep true.

In your case, my guess is ,that the subsequent loading as those same spokes rotated to the loaded portion of the wheel was significantly higher than in my case. What this likely caused was fatigue failure as previous posters have suggested. (if you are not familiar with the term - fatigue is the case where a material is subjected to repeated stresses such that the magnitude of that stess is within the yield strengh of the material; but a repeated application of that same stress will ultimatly cause failure) Bottom line is you likely need 36 spokes laced in a 3X, more initail tension (will reduce the change in stress for each spoke as it rotates), and double butted spokes (at least on the NDS).

noglider 

I agree with bubbagrannygear on all but three points.

I recommend against the Schraner book, though if it taught him to build good wheels, I'm glad.

I also feel that 4x is just as good as 3x. Use either one.

And use double butted spokes throughout the wheel.

And yes, read everything Sheldon Brown wrote. He was a wealth, and it's a terrible pity that he died so young.

horaceunit

Wow! Really a lot of info here! I wish I'd heard about the Jobst Brandt book before I ordered the other one! Oh well I guess it can't hurt to have 2 books on bicycle wheels! I found out that the LBS I got the wheel from actually did not do it in house, but ordered it and the spokes were not put together with locktight. I had one broken and 3 or 4 loose. The LBS has the bike and is going to "fix" it. It probably needs to be completly redone, but the boss wasn't there when I dropped it off so we shall see.

On the bright side I found a local bike club, and everyone who answered a question I posted on their yahoo group gave me the same name for a local bike shop/mechanic. This was not the shop I got the wheel from. I stopped at the reccomended shop and the mechanic (and owner) threw the bike on a stand and found the broken spoke and showed me the loose ones. He took one out and showed me that there was no locktight on it. I bought a tire and tube from him, but he didn't charge me anything to look at the wheel. He seemed very knowledgeable and a nice guy too. At least I know where to go from now on! I kep saying it- but thanks everybody!