Two wheelbuilding questions

cookiemonster

Im just working my way through "my first wheelbuild"; simple stuff - formula track hubs, 36 aci double butted spokes on open sports laced 3 cross, and have a couple of questions for all you experienced wheelbuilders...

First off, how "perfect" can you get a build? From just looking at the rim spinning in my hands, or looking at it on the bike relative the brake pads, it looks perfect. However on the jig I see some play - lets say half a millimetre in both lateral and vertical movement. Am I getting too picky trying to get this out? Or is it feasible to get something thats truly perfect. Should I care?

Second and more importantly, the truing is as above, however having got hold of the park spoke tension tool (after I'd built them) I've found a fair bit of variability in the tension - say ranging from 100 to 120 kgf. So all within the correct range and tolerances for an open sport rim, but like i say, variable. Within what kind of range do I need the tensions to be? and any tips for aligning tensions while keeping the rim in true?

Cheers

jon

2Phat4Rapha

pt1: You should try to achieve 0.2mm laterally, 0.5mm radially and 0.5mm either side for dishing (1mm total).

pt2: Even tension per side is more important than equalising tensions on both sides- something you can't achieve on a sprocketed rear wheel anyway due to dishing. All tensions within 20% of the average tension per side is a pretty good target.

I've been working on just this topic as an update to my spoke length calculator/database that's a free download at http://www.wheelingwrinklies.co.uk/WBPE/WBPE.html

It's functionally identical on Mac and Win although I've yet to finish some of the Windows cosmetics (I develop on Mac) but you're welcome to it.

daLynchi

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Monty Dog

The British Standard for new bikes is something like 2mm lateral truth and 5mm radial so your first attempt is well inside that.
Achieving greater levels of truth and even tension is initially just a case of how much time and tweaking you're prepared to invest - the more accurate the build then the less likely you'll have problems in the future IME.

cookiemonster

Thanks - very helpful

Jon

ugo.santalucia

I would say that anything under 0.5 mm is good... you can get a bit lower than that laterally. The 0.2 Target is a bit difficult to achieve (measure) with budget truing stands.

I normally check and recheck the tension 3-4 times before the truing process. Remember that every time you change the tension in one spoke, you will slightly affect the others... that's why checking the tension is a long and tedious process if you want to achieve perfection. 10% variation between spokes is perfectly acceptable, 20% is not so bad... just make sure you don't have any particularly loose spoke.

I really suggest you don't rush to the truing step, but spend a lot of time trying to get the tension and dishing right... once that is done, the truing will be a lot easier.

After every step, destress the wheel... I destress it 10-12 times during the building process

jermas

Your wheels should be fine. Fronts wheels are normally problem free. Importantly you have nice high spoke tension, combined with 36 quality spokes and a strong rim- should give you a good reliable set of wheels.
You might need to tweek them after the first few rides (depending on how well you removed spoke twist).
Anyway well done! On to your second build now (much easier).