First Dynamo wheel build help!

[atk]

A spoke tensiometer is a nice toy, but you don't actually need one. I built several sets of wheels before getting one and it didn't make enough of a difference to justify the £60-odd I paid.

...and if you do get one, make sure it's calibrated correctly! :)

[gairym]

Hope it's ok that I piggy back this thread, just tell me to bugger off and start my own if you like

So.....

I've got my rim, got my eye on a Son28 from Rose bikes (where I'll buy my spokes once I figure out what length they need to be).

I've also got a PDF of that wheel building book from a few years ago and enough wood knocking around to fashion myself a jig.

The aim for this setup would be to trickle charge gadgets (usb) and/or a power bank thingy during the day and run lights at night.

What else do I need to buy?

All help appreciated.....

Cheers, Gairy.

[Moder-dye]

No worries Gairy.

I've got the PDF book too. Can't order bits until payday

One thing that hasn't been answered yet is if will the wheel need dish in it with it being a disc or is it a case of seeing when you put it in the frame? I guess I could measure off the current non-dyno wheel in there but not being g a dyno hub I assume it will be different?

It may be a false economy, but I'm planning on a budget build so won't be going top end dyno and accessories. I already have a power bank that work as a bypass feed so is it worth getting one of those USB stem cap jobbies to take the cable up through the stem ?

[Moder-dye]

Wasn't planning on making a hobby of it and buying a tension meter, was planning on just using a tuner to make sure they are the same tensions. Got a jig in the form of an old set of forks with bits taped on to gauge.

[Jurassic pusher]

No worries Gairy.

I've got the PDF book too. Can't order bits until payday

One thing that hasn't been answered yet is if will the wheel need dish in it with it being a disc or is it a case of seeing when you put it in the frame? I guess I could measure off the current non-dyno wheel in there but not being g a dyno hub I assume it will be different?

It may be a false economy, but I'm planning on a budget build so won't be going top end dyno and accessories. I already have a power bank that work as a bypass feed so is it worth getting one of those USB stem cap jobbies to take the cable up through the stem ?

AFAIK, the hub will dictate the amount (if any) of dish by the distance between spoke holes on the hub flange and the drops or through axle ends. If the distance on each side is different then the side with the shortest distance from the hub centre will be dished.
Clear as mud??

[whitestone]

Gairy, you'll probably need a converter/charger to convert and smooth the AC output to DC. This page is a reasonable start - https://www.cyclingabout.com/best-hub-dynamo-system/

[gairym]

Thanks for the info.

Even this simple graphic from that article has more than doubled my previous knowledge:

[rufus748]

[quote="gairym"]

What else do I need to buy?

All help appreciated.....

Cheers, Gairy.[/quote

Gairy, you need a power converter, I currently use a an Igaro, much bettter than the Cycle2Charge. A cache battery (bit of a mine field) and a light (again i now use K-lite it's a plug and play system that's really bright (I think the new one pumps out 1500 lumen?).

K-lite (Travers is now the UK dealer) is worth a look at just for tips on Dynamo set ups. Kerry, the guy who designed and makes them (also designed the Revo) is a wealth of knowledge. His info is scattered around the web, Facebook and his own site, there's not a single place to obtain it all though.

He was recently recommending the Cinq passthrough battery, apparently it charges at a much lower input than most although not cheap!

And then passthrough charging or just charge batteries and and connect cut them to the GPS etc to recharge in the evening.....

[sean_iow]

One thing that hasn't been answered yet is if will the wheel need dish in it with it being a disc or is it a case of seeing when you put it in the frame? I guess I could measure off the current non-dyno wheel in there but not being g a dyno hub I assume it will be different?

/pedant mode/ Bicycle wheels do not have any dish to them/pedant mode/ (apart maybe from fat bike wheels)

The centre of the rim will be over the centre of the hub, however, the centre of the hub will probably not be mid way between the flanges If you take a wheel out of a bike and put it in backwards (i.e. disc on the drive side) the rim will still be in the centre of the frame. If you make a gauge to check the dish it only has to check one side in comparison with the other, not measure an absolute value, which is why a gauge is easy to make - details in the Musson book.

I suppose technically all wheels have dish, but on a normal bike this is zero. I think the confusion is the multiple uses of the word dish.

Dishing a wheel - the act of adjusting the rim to hub position (even if you're trying to get it over the centre of the hub)
Dished wheel - wheel that has had dishing carried out? See above
Dished wheel - (correct use) - wheel where the rim is offset from the centre of the hub

I think fat bikes have dished wheels - the rim is off-set towards the disc side to give more clearance for the chain to pass the tyre? But this I'm not sure off as I've never built one.

[chris n]

What else do I need to buy?

Spoke key.

[pistonbroke]

That graphic is clever, the only change I would advise is to get a Kemo charger/switch due to cost, the stem cap ones are about £150 whereas the Kemo is £30 from Maplin and has a switch so the blue dot route can be followed. It can be mounted on the headtube and allows you to switch from charging a cache battery to direct power to a light on the go.

[ScotRoutes]

I think fat bikes have dished wheels - the rim is off-set towards the disc side to give more clearance for the chain to pass the tyre? But this I'm not sure off as I've never built one.

Early fatbikes used standard 135mm hubs. The seatstays/chainstays had a 35mm offset, so the rim needed a similar offset. Forks were similarly offset.

With the advent of 170 and 190mm hubs, this is no longer required, though one can still buy offset frames and forks.

To confuse things even further, fat rims come with two rows of spoke holes...

[whitestone]

There's one big problem with most of the converters and batteries - USB connectors. USB was never intended for outdoor use, it's in no way waterproof and the contacts inside the connectors will eventually corrode. Partly this has come about because of the EU ruling that all mobile phones must use USB charging connections. But that ruling only applies to mobile phones and by implication their dedicated plug-top chargers. I've a "water resistant" powerbank but it still uses USB so won't have any water resistance whilst in use.

Igaro do mention this and supply/fit spare USB connectors for when the fitted ones fail. I'm not sure what other manufacturers' policy is.

The other problem with the USB connectors is stress at the point the cable enters the connector, if it's not sturdy enough the constant flexing will lead to the wires inside breaking. You've a long connector sticking out of the USB socket with an even longer cable hanging off that. Even with a stronger cable you are only delaying when this happens. You can get angled connectors that reduce the turning moment - they are referred to as "angle up/down/left/right".

There's only power being supplied through the cables not data so something like the waterproof connectors used on Igaro's power leads would be enough.

Sorry, rant over

Edit: If you are charging a battery then charging devices from that then allow for up to 20% loss of generated power in the various conversion processes.

[sean_iow]

Early fatbikes used standard 135mm hubs. The seatstays/chainstays had a 35mm offset, so the rim needed a similar offset. Forks were similarly offset.

With the advent of 170 and 190mm hubs, this is no longer required, though one can still buy offset frames and forks.

To confuse things even further, fat rims come with two rows of spoke holes...

Thanks for that, I did wonder about the ever increasing hub widths makes sense now. The two rows of spoke holes and calculating the spoke lengths does up the difficulty but I think the latest Musson book might cover that as well, wheels with large spoke hole stagger.

I should of mentioned for the OP that once you've bought the book you can then download future editions for free as it's revised to cover such developments

[Moder-dye]

OK, then...

I've have a 'normal' wtb 32 hole 29er rim, i19.

I guess the question (ignoring the term dish) is will the rim likely to be off set from the flanges enough to need different spoke lengths to have it centred on the hub?

It may be answered in the spoke calculator site, but thought someone might just know.

Didn't realise the stem cap converters were so pricey. I could well end up just getting an additional battery pack if I felt it was worth it, and just build a non-dyno wheel for the experience and fun.

[Moder-dye]

The kemo switch would seem like a better option

[whitestone]

Didn't realise the stem cap converters were so pricey. I could well end up just getting an additional battery pack if I felt it was worth it, and just build a non-dyno wheel for the experience and fun.

I think the Cycle2Charge converter is about £50, there's a review by Stu on here.

[chris n]

OK, then...

I've have a 'normal' wtb 32 hole 29er rim, i19.

I guess the question (ignoring the term dish) is will the rim likely to be off set from the flanges enough to need different spoke lengths to have it centred on the hub?

It may be answered in the spoke calculator site, but thought someone might just know.

The calculator will give you different precise lengths for each side if the flanges/offsets are different. These may be close enough that you can use the same length spokes (which typically come in 2mm increments) for both sides, or they might not.

[Moder-dye]

[redefined_cycles]

No worries Gairy.

I've got the PDF book too. Can't order bits until payday

One thing that hasn't been answered yet is if will the wheel need dish in it with it being a disc or is it a case of seeing when you put it in the frame? I guess I could measure off the current non-dyno wheel in there but not being g a dyno hub I assume it will be different?

It may be a false economy, but I'm planning on a budget build so won't be going top end dyno and accessories. I already have a power bank that work as a bypass feed so is it worth getting one of those USB stem cap jobbies to take the cable up through the stem ?

Yes... the only hubs that are totally symmetrical are from rim/v brake hubs... everthing else has more 'real estate' on one side than the other...

So you would need to rim to be dished one way and thus need different spoke lengths. There are a current set of rims called 'assymetrical' which have the spoke holes off centre to make up fkr the dishing slightly and not have to use overly different tensions from one side to the other..

[pistonbroke]

So you would need to rim to be dished one way and thus need different spoke lengths.

Not necessarily, I mentioned a few posts ago that the reason for the Lovemud hub's different flange widths is to avoid the need for different length spokes. Of course if you buy a Shimano hub then you will need different length spokes.

[gairym]

After a morning of reading, researching and weighing up options I think I've reached the state of 'dynamo nonsensical information overload' in record time.

This happens every time I look into it.

I get reinvigorated by the idea of a dynamo setup, start asking around, feel like I'm making progress and then BOOM! conflicting information, confusing advice, escalating costs and before I know it I'm right back to thinking that simply buying a couple of AA batteries every couple of days from a corner shop is massively appealing.

I'm not ready to give up yet but it's quite a ball-ache!

[ScotRoutes]

My dynamo usage is primarily about lights. That makes things pretty straightforward

[whitestone]

Gairy, work back from your energy requirements. You need to know the capacity of the batteries in each device you wish to keep charged: GPS, phone, etc. You also need to know how long the batteries last, a phone in Airplane mode is going to last a lot longer than one that's constantly trying to stay in contact with the network when you are out in the wilds for example. And that's before you actually use it.

Once you've got a rough daily usage (in mAh) then you can work out how much pedalling you need to do to supply that charge. At a maximum you'll produce around 500mAh so if your requirements are 5000mAh per day then you have to be riding (at speed) for ten hours each day to keep everything topped up. In practice, unless you have occasional access to mains power, you'll slowly lose stored capacity over a period of time.

[pistonbroke]

FWIW my advice is before you start with the technicalities of dynamo, charger, usb outputs, lights etc, you need to take a step back and consider the type of riding you do. It boils down to how fast the front hub is spinning, not necessarily average speed.

If you are building a 29+ or fatbike wheel, you will need to be travelling about 15% faster than a 700c or 26" wheel with a slick road tyre to achieve the same power output. If your riding is up and down long steep hills or tight singletrack, the 15kph at which dynamos start to work may be difficult to achieve as well.
Newer tech (and higher price) dynamos such as the SON and chargers such as the Cinq5 may claim a more efficient output at lower speed but a top of the range setup could give you little change from £500 plus lights and gps. That buys a lot of AA batteries or power banks.
During last year's 8 day trip across Spain, the power bank that I charge from my dynamo was still at 100% at the finish as it was largely fast riding, however I'm not planning to use it on the Turin Nice as I don't think the route lends itself to maintaining a steady speed.
Horses for courses and all that.