I thinking to upgrade my touring bike with a hub dynamo. I currently use a tire side dynamo. It is nice but I think the hub dynamos have less rolling resistance and are a bit more powerful (more watts). In addition it is constant on and I could use it for daytime running lights instead of the battery lights I use for flashing lights right now.
I just wonder if it is worth it and if yes if I should just get the existing wheel re-spoked or just buy a new wheel. The bike is over 20 years old and so are the wheels...
Any thoughts?

Thanks and happy riding

I think it's well worth it, and I wouldn't bother re-building with an old rim. You can even buy pre-built wheels that are a good value. I have one I bought a couple years back in the USA with a Sanyo hub and a no-name double-walled rim in a touring width, shipped, for $100 from an e-bay seller who is probably still active.

I wouldn't go back to other light sources for bikes ridden often in the dark.

If you already have a bottle dynamo, you know the advantages of always being ready for riding in low visibility conditions. You need to ask yourself why you're thinking about going to a hub dynamo?

If you're riding brevets or other long rides at night, the lower drag will probably be worth it. Go all in, with a Son hub for the lowest riding resistance. Prepare to spend big bucks. It'll be worth it.

For commuting, you need to ask yourself how long your commute is and whether it's worth the cost to change over. I'd guess you'd be looking at a Sanyo or Shimano hub, since drag isn't that important compared to 3-10X cost differential.

Either way, I'd suggest getting a new wheel. There's a good chance you'll need new spokes, since Murphy's Law won't let you find a dyno hub with the same ERD as your current wheel. Rim cost will be lost in parts and labor cost to swap the existing rim over to a new hub and spokes. After 20 years, there's a good chance your rims have been worn by braking and will need to be replaced.

You might just want to get a new light. The newer lights are SO much brighter than the older generations, it's amazing! And if most of your riding is in the day, your current wheel exhibits lower drag without the bottle dyno on than even the best SON hub.

Thanks guys. After checking the prices I am not sure yet. Looks like it would be expensive. I just recently got me a new B&M Cyo light which works great on the bottle dynamo. During the winter times my evening commute is always in the dark but from spring through summer I hardly ever commute in the dark. I will be thinking a bit more about it and do some research how much a wheel for my bike would really cost.

Shimano Dyno-hubs in factory machine assembled wheels are cheap , less than the total cost of the parts at retail .

check the suppliers to your local bike shop. the shop will hand check the wheel before handing it to you ,in Person,

maybe even swap the tire and offer trade in for your old wheel to go in their future repairs..

Im happy having the light right there .. on, as soon I ride.. No matter what the weather ..

wet tires and sidewall dynamos slip .. as the magnetic resistance is greater than the grip of the roller on the wet tire.

but maybe it rains there even more rarely Than Riyadh .