Two wheels, two issues.

[Mustangski]

Hello,
I am having issues with both my main wheel set and backup set at the moment, hopefully you can assist.

My everyday wheel set I purchased used, unsure of the mileage from the previous owner however I have put about 2500 miles on them. DT 240 hubs, 20/24 CX-ray spokes laced radial front and two cross rear, Stan's Alpha 340 rims. I broke a spoke on the rear NDS last week riding into work, luckily I was close and only had to walk the last mile carrying the bike. I measured the spoke and ordered one from BHS, I installed the broken spoke and am pretty close to true however the dish is way off towards the DS. To be honest I never checked the dish when I bought them initially but I can't imagine they were this far off since I put 2500 miles on with no issues. Am I missing something with a single broken spoke? Is this normal to have to re-dish the entire wheel after breaking?

Second question,
I have been a diesel mechanic for the past 18 years in the Marine Corps and love fixing things. That interest along with a couple of posts on here got me interested in building my first wheel set, which I did two years ago. I used Bitex hubs from BHS, 20/24 Wheelsmith DB spokes, and Velocity A23 rims. The front wheel was easy to true, came out nice with somewhat even spoke tension. The rear took me longer to complete however it turned very true as well with even tension. I didn't put more than 50 miles on them initially, but the front had to be trued after the first couple of short rides which I assumed was due to me being a new wheel builder. Since I broke the spoke on my main wheels I have been riding them and they are out of true after each ride, I assume I should just pull them apart and start over but it seems odd that they went together so easily and the rear is holding true just fine. The wheel was built radial and I only weigh 155 pounds. Any thoughts? Or just pull it apart and start over?

I appreciate your assistance with the two questions. Sorry for the long post but I am currently out of two wheel sets right now and off the bike until I figure out a solution.

[oldpotatoe]

Originally Posted by Mustangski

Hello,
I am having issues with both my main wheel set and backup set at the moment, hopefully you can assist.

My everyday wheel set I purchased used, unsure of the mileage from the previous owner however I have put about 2500 miles on them. DT 240 hubs, 20/24 CX-ray spokes laced radial front and two cross rear, Stan's Alpha 340 rims. I broke a spoke on the rear NDS last week riding into work, luckily I was close and only had to walk the last mile carrying the bike. I measured the spoke and ordered one from BHS, I installed the broken spoke and am pretty close to true however the dish is way off towards the DS. To be honest I never checked the dish when I bought them initially but I can't imagine they were this far off since I put 2500 miles on with no issues. Am I missing something with a single broken spoke? Is this normal to have to re-dish the entire wheel after breaking?

Second question,
I have been a diesel mechanic for the past 18 years in the Marine Corps and love fixing things. That interest along with a couple of posts on here got me interested in building my first wheel set, which I did two years ago. I used Bitex hubs from BHS, 20/24 Wheelsmith DB spokes, and Velocity A23 rims. The front wheel was easy to true, came out nice with somewhat even spoke tension. The rear took me longer to complete however it turned very true as well with even tension. I didn't put more than 50 miles on them initially, but the front had to be trued after the first couple of short rides which I assumed was due to me being a new wheel builder. Since I broke the spoke on my main wheels I have been riding them and they are out of true after each ride, I assume I should just pull them apart and start over but it seems odd that they went together so easily and the rear is holding true just fine. The wheel was built radial and I only weigh 155 pounds. Any thoughts? Or just pull it apart and start over?

I appreciate your assistance with the two questions. Sorry for the long post but I am currently out of two wheel sets right now and off the bike until I figure out a solution.

1)Sounds like the dish was off since new. Breaking one spoke won't make the whole wheel go out of dish.
Breaking spokes means tension is irregular, maybe from deformed(dented) rim. One spoke doesn't mean the wheel is dead but if you break a second after true/round/DISH/tension, you may need a new rim(NOT new spokes).

Thanks for your service.

2) if these wheels go out of true every ride, the tension is too low or erratic or both. Now that the wheel has been ridden with perhaps too low tension, good chance the rim is now deformed(bent)..I'd say take all the tension off, and 'rebuild', true/round/dish and tension..high enough(I'd say 120KGF DS rear and front).

[Tony T]

Make sure you're not getting spoke-windup. This could be the cause of the wheel going out of true as the spoke unwinds as you ride.

[Mustangski]

Originally Posted by oldpotatoe

1)Sounds like the dish was off since new. Breaking one spoke won't make the whole wheel go out of dish.
Breaking spokes means tension is irregular, maybe from deformed(dented) rim. One spoke doesn't mean the wheel is dead but if you break a second after true/round/DISH/tension, you may need a new rim(NOT new spokes).

Thank you for the sanity check, I will go over the entire wheel and see if it holds true.

Thanks for your service.

If I recall correctly from previous posts, you served in the Navy. Correct? So same to you, and for the continued service in helping people through this site.

2) if these wheels go out of true every ride, the tension is too low or erratic or both. Now that the wheel has been ridden with perhaps too low tension, good chance the rim is now deformed(bent)..I'd say take all the tension off, and 'rebuild', true/round/dish and tension..high enough(I'd say 120KGF DS rear and front).

I hope the rim isn't deformed, it went together so easily initially. Back to the drawing board to start fresh on the wheel I guess. Luckily one wheel set has a damaged front and one has a damaged rear, so I will have to assemble a Frankenbike for a while while I figure this out.

[Mustangski]

Originally Posted by Tony T

Make sure you're not getting spoke-windup. This could be the cause of the wheel going out of true as the spoke unwinds as you ride.

I did check for spoke windup when tensioning the wheel, I marked the spokes with a dry erase marker to ensure they didn't wind up so that shouldn't have been an issue. However it was my first wheel set build so that doesn't say much...

[AngryScientist]

how much do you weigh and what kind of roads are you riding?

low spoke count wheels arent built for everyone, even if they are built perfectly.

[Peter P.]

Breaking one spoke will not cause the wheel to go out of dish. Sounds like the wheel wasn't correctly dished from the get-go.

As for the new wheels going out of true. Spoke wind up isn't the only thing to cause grief when wheel building. You must pre-stress the spokes many times during the build process so the elbows seat well into the hub flange holes. Otherwise, that will occur while riding and consequently your wheels will go out of true.

Low tension is another possible cause but I think that's less likely than lack of pre-stressing.

[Mustangski]

Originally Posted by AngryScientist

how much do you weigh and what kind of roads are you riding?

low spoke count wheels arent built for everyone, even if they are built perfectly.

I weigh 155-160, so fairly light. I live in Okinawa, Japan right now. Riding is great and the roads are fairly smooth. I tend to ride hard every time though, averaging about 18 mph and never just simply cruise. I believe that stresses the wheel more, but not sure by how much or if that even matters. I imagine the front wheel was messed up during the original build and was not built perfectly so I will un-tension and start again.

[Mustangski]

Originally Posted by Peter P.

Spoke wind up isn't the only thing to cause grief when wheel building. You must pre-stress the spokes many times during the build process so the elbows seat well into the hub flange holes. Otherwise, that will occur while riding and consequently your wheels will go out of true.

Definitely noted, I pre-stressed the wheels during the build but maybe not enough.

[dcgriz]

Originally Posted by Mustangski

Hello,
I am having issues with both my main wheel set and backup set at the moment, hopefully you can assist.

My everyday wheel set I purchased used, unsure of the mileage from the previous owner however I have put about 2500 miles on them. DT 240 hubs, 20/24 CX-ray spokes laced radial front and two cross rear, Stan's Alpha 340 rims. I broke a spoke on the rear NDS last week riding into work, luckily I was close and only had to walk the last mile carrying the bike. I measured the spoke and ordered one from BHS, I installed the broken spoke and am pretty close to true however the dish is way off towards the DS. To be honest I never checked the dish when I bought them initially but I can't imagine they were this far off since I put 2500 miles on with no issues. Am I missing something with a single broken spoke? Is this normal to have to re-dish the entire wheel after breaking?

Second question,
I have been a diesel mechanic for the past 18 years in the Marine Corps and love fixing things. That interest along with a couple of posts on here got me interested in building my first wheel set, which I did two years ago. I used Bitex hubs from BHS, 20/24 Wheelsmith DB spokes, and Velocity A23 rims. The front wheel was easy to true, came out nice with somewhat even spoke tension. The rear took me longer to complete however it turned very true as well with even tension. I didn't put more than 50 miles on them initially, but the front had to be trued after the first couple of short rides which I assumed was due to me being a new wheel builder. Since I broke the spoke on my main wheels I have been riding them and they are out of true after each ride, I assume I should just pull them apart and start over but it seems odd that they went together so easily and the rear is holding true just fine. The wheel was built radial and I only weigh 155 pounds. Any thoughts? Or just pull it apart and start over?

I appreciate your assistance with the two questions. Sorry for the long post but I am currently out of two wheel sets right now and off the bike until I figure out a solution.

1) not as much info as I would like to have but I'll go out on a limb and offer a couple of other possibilities why the wheel dish may be so far off but fine when mounted:
Dish changes when the tire is fitted and inflated. This change is biased towards the DS and may be more dramatic on some lightweight rims than others.
Another possibility may be assymetrical stays, by design or accident.

2) spokes primarily break because of inadequate tension to keep the spoke within its elastic range as the wheel rotation cycle fatigues the metal from loading and unloading. Inadequate tension may be ultimately caused by one or more of the following, applied singularly or in combination with others: uneven tension, windup, lack of stress relief and spoke angle alignment.

You are not indicating how you conclude there is 'somewhat even tension", by tone or measurement? Even tension is paramount but absolute tension is also important to know.
On your radial arrangement are you heads-in or heads-out? Are the elbows supported?
The lesser the amount of spokes, the more load each spoke must see. This is the case with your 20h front. If it does not, the wheel may be knocked-off from the first major bump it sees, amongst other things.

[Tony T]

Originally Posted by dcgriz

You are not indicating how you conclude there is 'somewhat even tension", by tone or measurement?

I'm also curious about this, and if by measurement, which tool and what was the avg kgf?

[Mustangski]

You are not indicating how you conclude there is 'somewhat even tension", by tone or measurement?

I'm also curious about this, and if by measurement, which tool and what was the avg kgf?

I used a Park tension meter, I pushed for 120 kgf which was right in the middle of what Velocity recommended for their wheels. The tension wasn't perfect, but close. I wish I had kept the tension sheet, I don't recall exactly the measurements though. At this point I will scratch it up as beginner's error and start again.

Thanks again for the assistance.

[Tony T]

For the front wheel (your 2nd ques), you don't need to de-tension and start over based on what you posted.
If you pull the tire, Re-true and re-check the tension.
120kfg is a good target tension (btw, the Park tensinometer is usually about 10%-15% on the high side).
For the front wheel you could also just re-true with the tire on (but don't change the absolute tension as it will be lower with an inflated tire — you could check the relative tension though).
For the rear (your 1st ques), as already suggested, I would re-dish and check the tension (but not detension), and if another spoke breaks, then get a new rim.

[belopsky]

Originally Posted by Tony T

Make sure you're not getting spoke-windup. This could be the cause of the wheel going out of true as the spoke unwinds as you ride.

This. I am pretty sure this is what caused my front wheel to go out of true during my short 11mile ride.

The rear did as well, but less so - also I was better about watching the spoke windup/taking care of it when building.

I'd pull both wheels off (in terms of the second set you built) and check all the tension, then stress the wheel, and true as best you can, and see how it goes.

[oldpotatoe]

Originally Posted by belopsky

This. I am pretty sure this is what caused my front wheel to go out of true during my short 11mile ride.

The rear did as well, but less so - also I was better about watching the spoke windup/taking care of it when building.

I'd pull both wheels off (in terms of the second set you built) and check all the tension, then stress the wheel, and true as best you can, and see how it goes.

Lots of 'pinging' first ride? Yup, spokes unwinding. Couple of wAys to prevent but new wheels should be silent first ride.