ClintP

Two days ago, I started noticing some odd noises from the hub power generator on my 2007 Specialized Globe City 7.1. This morning heard them again and turned off the generator to see if it was that or my wheel rubbing the fender or something. It was the generator.

About halfway through my commute, the lights started pulsing and then about 5 minutes later, went out all together.

I bought the bike this June and I was wondering if you guys think there is a warranty for it. I just sent an email to Specialized, but have not heard back yet. Will I just have to buy a replacement?

I didn't like going all ninja this morning in the dark. I am glad I bought that reflective vest last weekend. Also, someone turned their brights on me this morning.

mechBgon

For warranty, take the bike to your Specialized dealer. In the meanwhile, if you have a flashlight, figure out a way to attach it to your handlebar (some strong rubber bands, duct tape, whatever).

CliftonGK1

In looking at the Specialized site, the 7.1 doesn't list a hub dynamo; but the 6.1 and 3.1 both do, so I'll guess it's the same one. That's a Shimano dynohub, so probably a 3N71, and if you just bought the bike in June there's no way it shouldn't be a warranty repair.

Odd that the hub would have issues so soon if it's the 3N71. I have a friend who uses one on his randonneurring bike and probably has over 5000 miles on it this year so far. Check back with the dealer and get it repaired/replaced.

ClintP

I guess it isn't a hub one. I think I got my terminology wrong. It is a basta side mount one. I had seen some people call them hub ones so I was just going with that until I googled the brand Specialized put on there.

ClintP

I just called the bike shop and they said it probably is under warranty. I am going to go to lunch with a coworker who has a pickup, so I guess I will just drop it off then.

2manybikes

If the tire gets wet or it deflates as it normally would in a couple of days, the generator wheel can slip. Check the tire pressure before each ride. It's not likely the generator, it's probably slipping.

Do what Mech says anyway, carry a spare light, generators blow bulbs if it's a halogen light.

CliftonGK1

The style of dyno you've got is called a sidewall or bottle generator. As 2manybikes mentioned, they can slip if the tire is low on pressure or wet from rain or snow. There's a couple different solutions for that, along with checking the tire pressure every couple of days...

Get a tire with a generator strip on the sidewall. It's a raised, ridged line on the sidewall which is designed to give better grip to the generator wheel.
Get a wire brush replacement wheel for the generator. Instead of a rubber wheel, it's got straight stiff wire like a polishing brush. It gives better contact in wet and snowy weather. Peter White Cycles has them for the Dymotec series of bottle generators, and if the spindle is the same you might be able to use it on the Basta you've got.

ClintP

Good advice with the extra light source and different tires. I'll have to look into those.

I think there is something wrong with it though since I check my air pressure every 2-3 days and it was dry the past 2 days when it start acting up. The noise it was making was god awful, so that leads me to think the generator is the source of my troubles this time.

CliftonGK1

If that Basta/Union generator becomes a consistant problem even after repair/replacement with a new one, consider the Dymotec S6 as a replacement for it.

ClintP

Cool, thanks. Yeah, if the replacement kills over again later, I will probably put a better one on there or something since I like having the ability to have lights without batteries. How hard is it to install a hub one on a bike? Anyone have experience with that? Is it beneficial to do that?

ok_commuter

Switching to a dynamo hub requires a front wheel build. (Mine new dynamo front wheel should arrive from Peter White any day.) Once you have a wheel with dynamo hub, the rest of the installation is dead simple and works much like your sidewall dynamo.

rbrian

Cheap battery LED lights are good at getting you seen, if not allowing you to see, they last for at least 50 hours with two AAA batteries, and they're cheap. Get plenty! I have 2 at the back of my bike, 2 more on my panniers, and 2 at the front. I'm looking for places to squeeze a few more in, since they're selling them for £3 at Tesco.

CliftonGK1

Like ok_commuter said, you've got to build a new front wheel to get a hub dynamo. The generator is built into the front hub, and the wiring attaches right to the immovable part of the hub shell. If you use the spreadsheet "SPOCALC.XLS" you can easily figure out what length spokes to buy based on the hub and rim dimensions. Lacing a wheel is far easier than calculus, and with Sheldon Brown's guide to wheelbuilding, anyone smarter than their spokes can at least lace the wheel up. If you're not up to the task of tensioning and truing a wheel from scratch, then bring the whole deal to your LBS after it's laced up, and have them tension/true it for you. It may cost more than a routine wheel truing, but certainly less than what shops charge to build the wheel from scratch.

I built my SON28/RR1.1 front wheel and tensioned/trued it myself. It took about 3 hours, but I've built a few other wheels before.

The benefit of a hub vs. bottle dyno is that there's no slippage, no matter what the weather. There's also nothing external to damage if your bike tends to get banged around on a public rack.
The drawbacks are that a hub dyno always has a little bit of resistance, and cheaper ones have much higher resistance than expensive ones. You can't keep a second set of wheels unless they have a hub dyno also, or you have a backup lighting system. Finally, hub dynos are heavier than bottle dynos; but it's centralized spinning mass so you don't really notice it.

The Shimano 3N71 and new 3N80 are both pretty light, offer great performance and low drag (both when turned on and when off), and won't cost you an arm and a leg. The 3N71 hub is under $100, and with a mid-grade rim like the Alex DA16 and some DT spokes, you could build your wheel up for $150.

rhm

Can you describe the sound? I had a generator fail on me once; it was a very nice Sanyo one that mounts under the BB, but I hadn't used it in a few years. I mounted it on my new bike, and it worked great. But after less than a mile it started making these high-pitched squeals intermittently; and every time the dynamo screamed, the light would go out for a second. It kept that up for a few miles; getting better for a while, getting worse for a while; but before I got to destination it became all squeal and no light. Is that what yours did?

ClintP

Basically the same effect, but the noise was a crunching/grinding sound. Before it killed over, it was making a droning sound that I thought might be my tire rubbing my fender, but I was pretty certain it was the generator. It just got worse and worse until it died. Now, just pushing the bike walking causes it to make the grinding crunch noise.

I took it to the bike shop at lunch today, and they said they would call Specialized to see if it has a warranty or whatever. If it doesn't, I will probably mount a flashlight or get some other cheap alternative until I replace it with that other brand generator mentioned above.

huhenio

i don't bother with generators

minewt x2

n4zou

It may have come loose from the bracket and gone out of alignment with the tire. Here is a photo of a bottle type dynamo with a straight rod used to ensure the dynamo is properly aligned with the tire.

One end of the rod is centered on the wheel axle allowing the dynamo to be properly aligned with the rod parallel with the dynamo shaft.

Szczuldo

this is exactly why I plan to use battery powered lights. If I really wanted to I could still charge them with my trainer...but you know it seems it's just as easy to go overboard saving money as it is spending money.

n4zou

It's not really about saving money. The only limit for a dynamo light is the rider. Batteries run down and need to be replaced or recharged. A dynamo will run as long as you can. It's nice not being worried about your batteries running out. Of course you should always have a backup light of some kind if nothing more than a "be seen" light. A nice battery powered flashlight is a must have addition to your patches, tube, and tools if you ride at night. It's also very difficult to fix a flat or thrown chain in the dark having only a dynamo light.
Just a couple of years ago you had to carry spare bulbs for your dynamo lights but LED's have eliminated that problem. They typically operate for 50,000 or more hours and the new LED's are much brighter than halogen bulbs.