Wheel building

[hedgehog]

does the right side have some sort of device,that takes space,so it is even left and right?

[Duck!]

No. In order to be equal the right flange would have to be a lot further inboard than the diagram suggests.

[hedgehog]

i perfectly understand,but its some sort of fancy dyno hub with some sort of gadget on the right side.
i think?

[ianganderton]

No. In order to be equal the right flange would have to be a lot further inboard than the diagram suggests.

the diagram is taken from the Sapim spoke calculator that uses different methodology

And yes there is 'stuff' on both sides of the hub in this case. On the left (or non drive side) there is the disc mount and on the right (drive side) there is the Dynamo wiring

[ianganderton]

If anyone wants 32 x DT Swiss Revolution 2mm/1.5mm/2mm 286mm spokes with brass nipples at Bike24 prices PM me [emoji30]

[Duck!]

OK, gotcha - somewhat generic diagram on the calculator.

Your later version is pretty well on with the method for getting flange distance, which is especially useful for asymmetric (i.e rear and regular disc front) hubs; divide the axle length from the locknuts by two to determine your mid-point. Then measure, as you're pretty well done, from the face of the locknut to the centre of the flange - I find butting the axle up against a bench edge or similar to give a solid reference point works best, and subtract that measurement from the half-length of the hub. What's left is the centre-to-flange distance.

I'm stumped how you got flange distances of 60 & 66mm on a hub that's only 48mm between flanges!

[hedgehog]

symmetric?

[ianganderton]

I'm stumped how you got flange distances of 60 & 66mm on a hub that's only 48mm between flanges!

I thought id found the information I needed on the net plus miss read the diagram SP put out too. Don't have the experience to see the problem in just numbers

This is only my 4th and 5th wheel builds. First was an alfine, 2nd and 3rd normal ish Mtb wheels with hope hubs then these 2 dynamo hubs so nothing is normal yet to give me comparisons. I was expecting the dynamo hubs to be quite big. Turns out they are just normal sized hubs

Then

I was ordering the hubs and spokes all at the same time online. No chance to measure anything.

Need to order more spokes now [emoji30]

[hedgehog]

yes 660mm 600mm i understand from the start.
just thought to point out other things,on the right side of the hub.

[find_bruce]

Your calculations look close enough to me Ian. The diagram I have shows a flange thickness of 3.5mm which would make the flange distance closer to 23 mm, but that is not going to make a difference to spoke length

I made a similar mistake to you & used much to big a flange distance. What I learnt from the exercise was how the flange distance is not critical. In your case you were ~40mm out on flange distance but it only made a difference of 5mm to spoke length, so within 2 mm is fine.

The two critical measurements are pitch circle & erd.

What length nipples are you using ?

[ianganderton]

What length nipples are you using ?

I'm not quite sure to be honest. The nipples has been an interesting one.

For my previous wheels I ordered from either wiggle or c r c and they all specify brass 14mm nipples. Bike 24 specify aluminium with the black spokes and brass with the silver (DT revolutions) which I thought strange.

My previous nipples are all in the wheels so difficult to measure

The ones bike24 sent me measure about 10mm which is also weird because the dt Swiss calculator doesn't have that length, I think from memory 12/14/16

Interestingly the Sapim calculator doesn't require nipple specs

Agree on the flange distances. I guess they are very much the short side of the triangle.

It's a good lesson learnt any way and won't have cost me a huge amount of money. Just the time to lace and unlace a wheel (which is unite a while as I'm S. L. O. W.

[Lukeyboy]

Nipple length makes no difference to the spoke length as its all about the rim thickness.

[QuangVuong]

But if you have slightly short spokes, then you could use long nipples which have extra thread. It isn't ideal as the nipple heads could break as the spoke isn't threaded through there, but you can get away with it.

[jimh]

Hi Folks,

I've got a pair of shimano 7850 hubs straight pull 16F / 20R - which was gifted to me (I showed interest in the skewers and got the hubs as well)

Wondering what I could get done with them as far as building them up into a set of wheels ?

Anybody out there done this or would like to suggest a rim / spoke combo that would work for a ~73Kg person ?

cheers
Jim

[hedgehog]

bare rim i find easy to check for straightness.

but checking for roundness?

i find it hard to check for roundness.

how do i check for that slight out of roundness?

before building and fine truing a wheel?

and correct the roundness?

[Duck!]

About the only way you can check roundness is the same principle as measuring the effective rim diameter for spoke calculation:

Use two spokes long enough to overlap in the centre of the wheel when threaded through opposing spoke holes, with a nipple threaded onto each one so the tip of the spoke is flush either with the base of the slot or the top of the nipple head - doesn't matter which, just as long as you pick one and use consistently as a reference point for spoke threading & effective length. Mark across the two spokes in the section where they overlap, preferably with a thin line for finer accuracy. Start with one spoke in a hole next to the valve and the other next to the join (the join is always opposite the valve); eg if you have the valve hole at 12-o'clock and the join at 6-o'clock and start from the spoke hole to the right of the valve, the second spoke is to the left of the join (clockwise rotation). Then repeat the process for each opposing pair of spokes around, checking the alignment of your marks on the spokes where they overlap; if they deviate at all anywhere you'll see where there's a high or low spot.

However, this method will not show if there is variation in the sidewall height, nor will it show if the rim joint is smooth; it's not that uncommon for the join to have a slight bump.

Out-of-roundness from manufacture isn't hard to correct when building, as the variation is likely to be over a wide sector of the rim, and fairly shallow; simply pull the high spot/s in and slacken the spokes to let the low spot/s out. Bumps in used rims from impact dents are usually concentrated in a short sector and often have a pronounced flat spot and sometimes flaring of the sidewalls. You will not get these out, but if they're not too bad the tyre will largely compensate and disguise the flat spot when riding.

[hedgehog]

rim joint slight bump,
i measured a rim joint bumb by memory (AT) 0.175 mm with vernier caliber.

out-of-roundness from manufacture,i call it( egg shape) wheel.
i try to correct with adequate spoke tension where needed and let it settle.

rim width and run out:
i only check with dial gauge on one side.
do it on both sides and it will drive me crazy.

side wall height?
trickiest of them all .

even spoke tension?

should i go for even spoke tension?
perfect roundness?
perfect straightness?

with disc brakes is ok for me to compromise on all three.

but rim brakes?

thanks duck! for your input,i completely understand and grateful

[Duck!]

A 0.175mm bump at the join is nothing to be worried by; it's very common for there to be a slight bump on the join, and the tyre will hide it once fitted. For the same reason you can be a little less picky about the roundness of the wheel, but it's good to get it as close to round as possible.

I would place the greatest importance on getting the tensions even - remembering of course that virtually all rear wheels and disc brake fronts are asymmetric to allow the fitting of cassettes or brake rotors, so the tensions will be different on each side of the wheel. Getting the tension sufficiently high and even will build a more durable wheel.

Lateral trueness is also fairly critical, as kinks can affect the bike's handling, and with rim brakes can generate brake pulse when feathering the brake.

i only check with dial gauge on one side.
do it on both sides and it will drive me crazy.

Good setup; my truing stands, both at home and at work are set up very slightly off-centre for exactly this reason; it's easier to see when the wheel is straight when you only use one side to gauge it. The carefully-calibrated gap to the other arm of the stand is used for centring the wheel.

[hedgehog]

so at this point is it, first spoke tension.?
second run out .?
and last roundness.?

of course all three under 0.5 mm, mind me my
spoke tension meter reads in millimeter too.

i would like to say before i got my tension meter,
my wheals i trued by feel and sound got a long way.

but i think the less spokes the more necessary is
the spoke tension meter.

i think?

[Duck!]

Yep, even tension becomes even more crucial with fewer spokes; as each spoke is supporting a greater sector of the rim, imbalances in tension increase the stress on the more highly-tensioned spoke/s. So yes, order of importance is tension (both outright and balance) -> lateral straightness -> roundness.

Tuning by ear is OK for getting the tensions even, but doesn't really tell you if you have enough or too much tension. Due to the nature of the materials, carbon or steel rims need higher tension than aluminium.

I somewhat doubt your tension gauge measures in millimetres; tension meters work by measuring the deflection in a relatively short section of the spoke, and millimetres is too coarse a unit for that kind of measurement with different profiles & gauges of spokes. The standard unit of measurement for tension is kilograms force (kgf), essentially the tension equivalent to a given weight being suspended from the end of the spoke. The scale used on any given tension meter doesn't in itself use any precise unit of tension force, but rather measures the deflection in the spoke and correlates that against the spoke profile to relate to the actual tension. Different tension meters use different scales, so you'll get a different deflection number for a given tension depending on what tool you're using. Always refer to the chart supplied with the tension meter to determine the actual tension relative to the scale used!

[hedgehog]

its a dt tensio swiss made serial no.4091.
its red and its got a dial gauge incorporated in it.

yes its better than sound or trying to feel the spoke tension.

carbon or steel rims need higher tension than aluminium.
thanks duck i did not know that.
carbon or modern things i know nothing at all.
@duck! thank you.

[Lurkin]

Duck is there any dial gauges that are recommended that are preferably cheap? I realise its a trade off with price/quality/accuracy, but the Park Tool ones are pretty expensive... I imagine theres a version out there without the fancy bike part tax?

[QuangVuong]

I have plans on making a 3D printed tension meter similar to the DT gauge. The main body of the tool will be printed, and the only other parts needed to be bought would be a dial indicator, which is sub $10 off eBay, a small compression spring, and a couple screws and nuts, and probably a couple bearings. Ill be starting to draw it up at the end of the month when I've got some time off from uni. Then I'll get a few out to wheel builders I know and let them test it out and help create a calibration chart too.

And hopefully it'll be a reliable(should do a decent job as a comparative gauge) and definitely a budget alternative to what's available on the market now. Park's tool is quite basic, but the it is ~$90 which is a decent amount of money.

[find_bruce]

If you are making your own tensiometer why wouldn't you copy the jobst brandt design?

[Duck!]

Duck is there any dial gauges that are recommended that are preferably cheap? I realise its a trade off with price/quality/accuracy, but the Park Tool ones are pretty expensive... I imagine theres a version out there without the fancy bike part tax?

I haven't come across any dial-type tension meters, so can't help you on that one.