Campag Shamal/LBS issue

lioneld

Any input from those experienced with wheel building trying welcome!

I have a 2015 pair of Campag Shamals that needed a slight true this year, nothing bad, maybe a mm, mm1/2 max out laterally, no issue spherically. LBS snapped a spoke as they said it had seized. Fair enough. Got them back today and laterally they’re better but still 1/2mm out but spherically they’re egged. LBS say that’s the best our wheel builder with 30yrs experience can do with a G3 wheel that’s this old! My view is that’s a load of bollocks and they can’t be arsed with it in case they have to rebuild it, but I’ll stand corrected if any of you folks have greater knowledge on this than I.

ugo.santalucia

I can't say that the G3 construction makes these wheels easy to true. If you then have a problem with seized nipples, as you seem to do, then you are left with a number of spokes that won't budge, trying to true the wheel working on the others, which is the least desirable scenario and probable the cause of what you call "egging". Best thing would probably be to return it to the customer as "untruable".

lioneld

Thanks for the quick reply. Is the long term solution to replace all the nipples and spokes and reconstruct the wheel? They’ve charged me £35 to date on this,

pilot_pete

I’d just buy some handbuilt wheels with a conventional spoken pattern, advised by a competent wheelbuilder considering your weight and their intended use. Sounds like rebuilding with new spokes and nipples just means you will presumably have similar problems next time they need truing....

PP

ugo.santalucia

Factory assembled wheels tend to be "single use". A rebuild would be un-economical and if the wheel is old is unlikely all the spares required will be available.

If you want something mendable, then either handbuilds or something alond those lines, like a pair of Hunt

gfk_velo

lioneld said:

Any input from those experienced with wheel building trying welcome!

I have a 2015 pair of Campag Shamals that needed a slight true this year, nothing bad, maybe a mm, mm1/2 max out laterally, no issue spherically. LBS snapped a spoke as they said it had seized. Fair enough. Got them back today and laterally they’re better but still 1/2mm out but spherically they’re egged. LBS say that’s the best our wheel builder with 30yrs experience can do with a G3 wheel that’s this old! My view is that’s a load of bollocks and they can’t be arsed with it in case they have to rebuild it, but I’ll stand corrected if any of you folks have greater knowledge on this than I.

It sounds like the LBS don't have any previous experience or training on G3 wheels - the wheel builder should perhaps have picked up the phone and talked to the local Campagnolo Service Centre. In the UK that would have been ourselves as the longest-standing one, or Chicken Cycle Kit

The problem now is that you've got possibly irrepairable damage to the rim.

G3 wheels require a specific technique to true - they certainly aren't "one trip" as Ugo says - but you do have to properly understand the wheel.

Most of the G3 wheels use Loctite on the nipples post build, certainly G3s of that age - and that Loctite needs to be released before any truing is done, Using the correct spoke holder, that can sometimes be done with torque and the right spoke key, but boiling water is a safer bet or, in extreme circumstances, a small butane torch with a needle flame, such as a lot of builders use for tying and soldering a wheel.

A small amount of penetrating oil between spoke nipple and rim is helpful because at the very high spoke tensions employed (about the same as you'd have in a conventional 24H wheel), the nipples drag against the rim. This is the same as any wheel built with alloy nipples where the spoke bears directly on the face of the rim.

The trick with truing an already-correctly-built G3 is not to change the tension in the wheel overall. Tension must be released, then added in, in equal measure, to move the rim where you want it to go - so to move the rim to the gear side, tension is taken out of the non gear side and then added in equally, on the gear side. The tension on the "pairs" of drive side spokes need to be kept as close to the same in both spokes of the pair, as is consistent with getting the truing result that is looked for.

The reason is that the G3 rim is not round to start with - it's slightly heptagonal, with the points of the heptagon at the spoke groups. When it is trued, correct tension is indicated when it is round. The "points" of the heptagon are pulled "in" and the flatter curves between are pushed "out" - essentially like popping the dents out of a ping-pong ball. Tension is built very evenly and progressively when building, to achieve this.

If too much tension is applied in an area, a bulge can appear between spoke groups - these bulges can at best only be corrected a little - usually, once they happen, they're permanent because there is no way to "pull" them back in and simply reducing spoke tension either side doesn't always allow the rim to regain it's former shape, if the elastic limit of the rim in that area has been exceeded.

So working on G3s is a skill that needs training - but it is a skill that can be acquired with training and knowledge of how the wheel "works" - we have guys on the UK full ProShop course who strip and rebuild even the very lowest-cost G3 wheels like Calima and Khamsin to factory standards after couple of hours instruction.

In this case, it may be that the wheel needs a rebuild on a new rim by the one of the SCs or it may be possible to "rescue" it - impossible to say without seeing it. If you are in the UK, send it to us at Velotech Cycling Ltd and we can advise.

gfk_velo

lioneld said:

Thanks for the quick reply. Is the long term solution to replace all the nipples and spokes and reconstruct the wheel? They’ve charged me £35 to date on this,

Not necessarily - please see my longer, more detailed post.
It depends if the LBS have permanently damaged the wheel.

ugo.santalucia

I am sure they can be rebuilt and have a second life, but it's always a case of whether it's worth it.
I can't find the price of a new rim, I suspect it won't be cheap... spokes are not cheap, labour is not cheap, couriers cost money too...

And then there is always the hub lottery... if the wheels are old, at some point something will break...

Worth repairing, not worth rebuilding

david37

so new spokes new rim and possibly a new hub. Sounds like single use to me

lioneld

.

lioneld

Thanks all for some genuinely useful feedback and insight. Mr Velotech, I will give you a call and see if we can rescue this before I pull the trigger on some new hoops.