why are my rear spokes pinging on 12%+ climbs?

Everything about building wheels, glueing tubs, etc.
emotive
Posts: 151
Joined: Tue Nov 01, 2016 10:40 am
Location: Melbourne, Australia

by emotive

Geoff wrote:Check the hub flanges, too. I have broken a number of DT240 flanges and I am much lighter than you...
What should I be looking for, visible cracks?


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alcatraz
Posts: 2052
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Maybe it's my eyes but it looks like you are running 3x on a hub designed for 2x.

If this is the case, it would stress the spoke heads and flanges because they don't line up with the drill angles in the hub.

by Weenie


emotive
Posts: 151
Joined: Tue Nov 01, 2016 10:40 am
Location: Melbourne, Australia

by emotive

alcatraz wrote:Maybe it's my eyes but it looks like you are running 3x on a hub designed for 2x.

If this is the case, it would stress the spoke heads and flanges because they don't line up with the drill angles in the hub.
Does this help?
Image

alcatraz
Posts: 2052
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

My bad, seems that the 28h hub is 3x and 24h is 2x.

How's your spoke tension? Maybe it's a bit low.

You could feel the (drive side) spoke tension difference with the tire inflated and deflated. Tell us if you notice something weird like a large variation.

120kgf should feel quite stiff, like if you squeeze hard they could start hurting your hand a bit. Deflection could be 2-3mm at most at the crosses.

(Edit: valve is in the right position)

emotive
Posts: 151
Joined: Tue Nov 01, 2016 10:40 am
Location: Melbourne, Australia

by emotive

alcatraz wrote:
Thu Feb 07, 2019 5:38 am
How's your spoke tension? Maybe it's a bit low.

You could feel the (drive side) spoke tension difference with the tire inflated and deflated. Tell us if you notice something weird like a large variation.

120kgf should feel quite stiff, like if you squeeze hard they could start hurting your hand a bit. Deflection could be 2-3mm at most at the crosses.

(Edit: valve is in the right position)
I can make them move when squeezing a pair of drive-side spokes. they move 2 or 3mm at the cross, as you suggest. My LBS builds wheels, maybe I'll get him to measure the tension on them all.

alcatraz
Posts: 2052
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Sounds normal then. Maybe check the spokes for scratches? Is something touching them?

I have to say I'm very surprised. At 28 spokes too, and 85kg ride weight.

You must have legs the size of tree logs. :)

To be continued...

bm0p700f
in the industry
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Location: Glermsford, Suffolk U.K
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by bm0p700f

Is the RD catching the spokes?

Cascadian
Posts: 3
Joined: Tue Jan 29, 2019 6:39 am

by Cascadian

I had the same problem with my Mavic R-SYS SLR. It sounded like I was playing a piano very badly. The cure for me was a drop of teflon oil at the interface between the hub and spokes.

Geoff
Posts: 5255
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

@emotive, I can see from your pics that those are straight-pull 240s, which are apparently ok, so it is not that.

shimmeD
Posts: 487
Joined: Thu Jun 28, 2012 10:52 pm
Location: eNZed

by shimmeD

Hi Geoff, an earlier picture (on Pg 1 of this thread) shows DS spokes touching where they cross.
Less is more.

andreas
Posts: 129
Joined: Thu Jun 12, 2014 10:21 pm

by andreas

Cascadian wrote:
Thu Feb 07, 2019 11:43 pm
I had the same problem with my Mavic R-SYS SLR. It sounded like I was playing a piano very badly. The cure for me was a drop of teflon oil at the interface between the hub and spokes.
Every time pinging has happened for me (on a cross spoke pattern), the cure has been a drop of oil on the crossing points and then wiggle them a bit to distribute. Sometimes happens after extensive cleaning.

alcatraz
Posts: 2052
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Good point made by Andreas.

Lubing the heads and crosses is not a permanent solution but I would do it for failsearching purposes.

Maybe your spokes or hubs arent cut to proper tolerances so that you get a bad interface between them. Then when you apply heavy torque they start producing noises.

Even though it's not recommended maybe try some spoke head washers on your pulling spokes. You have 7 on each side but ds side is probably the highest tensioned ones where the noise is more likely to come from if the theory is correct. Problem with using washers is corrosion so brass or titanium would be more long term.

emotive
Posts: 151
Joined: Tue Nov 01, 2016 10:40 am
Location: Melbourne, Australia

by emotive

andreas wrote:
Fri Feb 08, 2019 6:14 am
Cascadian wrote:
Thu Feb 07, 2019 11:43 pm
I had the same problem with my Mavic R-SYS SLR. It sounded like I was playing a piano very badly. The cure for me was a drop of teflon oil at the interface between the hub and spokes.
Every time pinging has happened for me (on a cross spoke pattern), the cure has been a drop of oil on the crossing points and then wiggle them a bit to distribute. Sometimes happens after extensive cleaning.
took the wheels into my local bike shop, and he said the same. Also checked spoke tension, they are low, but within range. Have them booked in to tighen them up late this week, and lube the cross points.

alcatraz
Posts: 2052
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Don't forget the heads.

If the pinging comes back it wasn't because of tension.

Tension is set without a tire. It's normal for tension to drop a bit after mounting a tire.

by Weenie


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