Dura Ace WH-7850 C24 wheel set losing true

Discuss light weight issues concerning road bikes & parts.
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PBJDTX
Posts: 3
Joined: Thu Mar 07, 2013 8:00 pm

by PBJDTX

I have a 2010 Dura Ace WH-7850 C24 wheel set that has less than 30 miles on them. After approximately 10 miles of riding the wheels lose their true (the front wheel isn't as bad as the rear). The route I've been riding is mostly smooth, but there are some areas of the 10 mile loop that are bumpy and in bad shape, and I do my best to avoid as much of the rough parts as I can. My thought is the low spoke count (Front: 16, Rear: 20) is the primary cause, but this is an amateur diagnosis. Due to a minor knee injury and the winter months, I've gained some weight, and I'm around 190 lbs and 5' 9". I don't want to give up on these wheels, but only getting 10 miles down the road before they lose true is frustrating. Any thoughts or suggestions? If you tell me to lose some weight it won't hurt my feelings, and it needs to happen anyway. Would 24 spoke rear wheels solve my problem?

Thank you in advance.

-p

thisisatest
Shop Owner
Posts: 1980
Joined: Sat Jun 13, 2009 4:02 am
Location: NoVA/DC

by thisisatest

Once it's true, tensioned, and even, apply spoke freeze or any other wicking Loctite to the area where the spoke meets the nipple. This will help prevent vibration induced unwinding.

by Weenie


juanacity
Posts: 38
Joined: Wed Jun 27, 2012 12:22 am

by juanacity

These wheels should eventually prove fine for someone of your weight and the riding you described.

It is not that unusual to have new wheels come out of true after a short time. I have the RS80-C24 wheels and they came out of true after just a few rides. However, I trued them up once and now they've been fine for well over a thousand miles. I wouldn't worry about applying loctite or getting too concerned unless you trued them multiple times and had them come out of true multiple times.

PBJDTX
Posts: 3
Joined: Thu Mar 07, 2013 8:00 pm

by PBJDTX

Thank you to both of you for your input.

I've ridden the bike twice with these wheels and have had to true both wheels after the first ride, and the rear wheel only after the second ride. I'm shooting for a quick ride this evening after work, so hopefully I will have more info tomorrow.

Really appreciate your feedback.

-p

shadwell
Posts: 575
Joined: Fri Oct 16, 2009 1:25 am
Location: Gold Coast Australia

by shadwell

One of my MTB ride buddies had the same wheels, and the same problems.
He was about 90kgs at the time. He's 85kg now.

He chased the true on these for about 6 monthd then gave up.
Corrected and bonded spoks did not sem to cure it.

Sadly the wheels were just too light for his mass...
He moved to more robust wheels.

I'd recommend trueing and seling the DA wheels as there i nothing inherently wrong with them.
Then getting some Pacenti SL23 on Alchemy ORC & ELF hubs 20 / 24 radial Front, 2 cross BOTH sides Rear with CX Rays, from Fairwheel bikes in the US. Approx $950US.. NOT A QUOTE.. estimate only!!!
Drop Jason a line there and explain your intended use and mass (fully kitted).

Or if you want off the shelf, sightly cheaper and similar function look to pick up some of the 2013 HED ardennes. Hubs not as good but very similar otherwise.

mrfish
Posts: 1618
Joined: Wed Mar 28, 2007 12:49 pm
Location: Near Horgen, Switzerland

by mrfish

Likely not enough tension - once tensioned sufficiently these wheels should not go out of true as the spokes will have tension even under pedaling loads. Then there is no need for spoke locking compounds. I would ask an experienced mechanic to take a look.

dvincere
Posts: 204
Joined: Fri Jun 01, 2012 6:40 pm

by dvincere

To echo mrfish, it's an issue of tension. Just because the wheels look to be trued doesn't mean the tension is evened out properly nor does it mean it is high enough. Either you or a good wheelbuilder should de-tension all the spokes and work them back up properly. Those wheels should be fine under you.

PBJDTX
Posts: 3
Joined: Thu Mar 07, 2013 8:00 pm

by PBJDTX

Thanks everyone for your feedback. Taking the wheels to an experienced mechanic next week.

Thanks again, and happy riding.

KvnP
Posts: 152
Joined: Mon Nov 29, 2010 7:12 pm
Location: Somewhere out there..

by KvnP

Using both 7900/9000 C24's for both road & cross (jumps), they became out of true at first although after a retension from a reputable mech, it has been holding up well.

If you run tubeless, you may have to retension as well.
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Valbrona
Posts: 1484
Joined: Fri Oct 28, 2011 3:25 am
Location: United Kingdom of Great Britain and Northern Ireland

by Valbrona

I would be inclined to contact Shimano - just for the hell of it - and say that these wheels have not been stressed correctly in the factory. Say that they should get a local Shimano dealer to do the job free of charge. Only give them to a place that has a top notch tension meter.

But really, 20/16 spokes for a lightweight rim really isn't many ... if you ride poor roads.

Svetty
Posts: 487
Joined: Thu Mar 26, 2009 11:06 pm
Location: Yorkshire - God's Own Country

by Svetty

Have ridden these wheels for 1000s of miles and raced on rough roads. Even crashed such that Look carbon frame destroyed. Wheels still true!

6ft, 170lbs

by Weenie


RJKflyer
Posts: 53
Joined: Wed Sep 26, 2012 7:53 pm

by RJKflyer

mrfish wrote:Likely not enough tension - once tensioned sufficiently these wheels should not go out of true as the spokes will have tension even under pedaling loads. Then there is no need for spoke locking compounds. I would ask an experienced mechanic to take a look.


+1

If they were insufficiently tensioned, but true, then they'd untrue quite easily - then the very process of truing them up will inject uneven spoke tensions which becomes a never-ending problem.

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