Friday, July 30, 2021

Brompton Dynamo Package

I've been riding my Brompton at night to avoid the extreme heat we've been experiencing here in Southern California this summer. I decided to invest in a dynamo system but I don't ride enough to justify the price of a Schmidt SON. So I decided to buy a system based around a Shutter Precision dynamo.

 https://www.perennialcycle.com/shutter-precision-upgrade-dynamo-package-for-brompton.html

For almost $400 (after tax and shipping) I got...

  • New front wheel built around a Shutter Precision SV-8 dynamo hub, with rim tape
  • Busch & Muller IX-SX front light and mount
  • Busch & Muller Toplight Line Plus tail light
  • Wiring and zip ties.
Although the photo on their website shows all the pieces separate, some assembly had already been done for me. I got the black one to match my bike.


The rim tape was already on the wheel and the through-axle was installed. The front light was wired. The rear light cable is cut for a light mounted on a rack. I don't have a rack so I chose to shorten my cable.

These were my installation steps, which took about an hour.
  • Turn the bike upside down, deflate the front tire and remove the wheel.
  • Pull the tire and tube off the wheel and put them on the new wheel.
  • Install the new wheel with the connector on the right when the bike is the right way up
  • Remove the front brake from the frame and discard the front reflector and mount
  • Put the front light and mount in the same place the reflector was
  • Reinstall the front brake and make sure it still works correctly
  • Inflate the front tire
  • Plug the front light into the dynamo and use a zip tie to hold the wire in place
  • Spin the wheel to make sure the light is working
  • Remove the rear reflector
  • Plug the rear-light wire into the spade terminals on the front light
  • Route the wire along the rear brake and gear cables using zip ties as needed
  • Shorten the wire if needed and expose 1cm of bare wire each
  • Push the exposed wires into the two holes at the back of the tail light and slide the black lever over to lock them in. Polarity is not important.
  • Install the tail light where the reflector was
  • Spin the wheel again to make sure the tail light works too
You have the following parts left over. If you have more or less, check the installation steps again.
  • Original front wheel with rim tape and locking nuts
  • Front reflector and mount
  • Rear reflector
Note: The new front light mount is wider than the old reflector mount and doesn't quite fit the frame properly. I used a vice to slightly narrow the new mount so it fitted better.

The dynamo feels very notchy (I assume it has 8 magnets from the name) but it's not fair to compare a dynamo on the 16" wheel and a 27" wheel because the larger wheel has a much greater moment of inertia. The truth is in the ride. More on that later...

So I went for a 14 mile ride up in the mountains and I have to say the SP dynamo seems to have more drag than the SON. I'm not sure how much of this is the smaller wheel and how much is the cheaper dynamo, but it's noticeable. It's also possible that I was dragging because I was at 7000' where there's way less oxygen. Let's assume there was some drag and we don't know how much. Maybe I'll try it again at sea-level.

The front light has a beam pattern that is optimized for mounting 30" above the ground. Because the Brompton mounts the light 18" above the ground, the near-field is brighter than it would ideally be although it's not a show-stopper. Other than that, the beam pattern is lovely and I could see road hazards up to 100' ahead if there weren't too many other lights around. That gives me five seconds notice at 15 mph. The light also lets photons escape to the side, which is a nice safety feature, although reflective tires work better.

The light rubs on the bottom of the front bag that my friend, Greg, made for me which is a bummer. However, my Suntique bag works fine so that will be my new go-to front bag. The photo's below show the bags with the reflector, but you can see why Greg's bag rubs the light. If your bag partially obscures your reflector, it will probably rub on a front light.

Suntique does not rub :-)

Greg's bag rubs :-(

The tail light is a Toplight Line Plus. I have the Brake version on my road bike with a custom seat-stay mount so I already like this light. It's actually one of the things that attracted me to this package. It's big and bright and has a wide viewing angle. I pair it with a Cygolite spot tail light which is very bright but has a narrow viewing angle.

Overall I would say this is a good dynamo/light package at a reasonable price. I have a far more expensive dynamo/light set on my road bike because I frequently ride all night on it, but that will never happen on my Brompton. Installation was easy and all the parts worked properly.

Thursday, July 15, 2021

Review of Touhuhot 5000 lumens front bike light with free tail light

 To be honest I bought this thinking it would be crap and I would return it. It's not crap, although it certainly isn't as good as the manufacturer claims. You can see it on Amazon here.



It costs $40 so I'm going to compare it to a 1200 lumen Cygolite front light costing $80. The Touhuhot compares well.

We will look at the front light first.

Let's start with the mount which is commonly the weak point of otherwise excellent lights. It's not bad, a bit clunky, but it is certainly strong enough to hold the light in place and firmly attach to a wide variety of bar diameters. This light is probably too heavy to attach with one of those glorified rubber bands. The weakness is the release button which I circled in red above. It's too flimsy and I think it will be the first thing that fails. You have to hold it in as you slide the light into place or it won't lock and the light will slide right back off again. This is not mentioned in the instructions. Quite a few people on Amazon are complaining they are having problems with how the light locks onto the mount.

While the mount will rotate vertically, it cannot be rotated horizontally which is a problem because I like to point my light slightly towards the center of the road so I can control how much light oncoming traffic sees.

The light is quite heavy - 225gm verses 185gm for the Cygolite. It has a solid feel to it with an aluminum body, which could use some cooling fins. The usb cover is poorly designed as it butts up against the mount stop which makes it a total pain to open. I'm thinking of just ripping it off. It has a USB C port for charging and also a USB A port so you can use the battery to charge other stuff. It's also quite large and takes up more handlebar space than the Cygolite.

The light is not 5000 lumens and I did not expect it to be. A true 5000 lumen light will cost over $500. However, using a lux meter and a 1200 lumen calibrated source, I calculated this light emits around 2100 lumens. This technique is notoriously inaccurate but I am confident this light is less that 2500 lumens at its brightest setting. A 2000 lumen led requires about 20 Watts (best case). This means it's pulling about 4Amps from the battery which explains the heat issues.

When operating at maximum brightness this light gets uncomfortably hot to hold - I would say over 100F. That's why it needs cooling fins or some other heat management system. I fully charged it and then set it on the high setting. After a while it automatically dropped to a lower setting and eventually died after 7 hours. Note, this was not 7 hours at the high setting but 7 hours is very impressive for a battery light. If the lights stayed on full brightness pulling 4 Amps from a 5200mAh battery it would only run for 75 minutes. Note the marketing hype on Amazon claims 15 hours. It seems they are doubling both the brightness and duration numbers.

When operating at the lowest brightness there is no heat problem. This would be perfect as a flashlight or for riding at less than 15mph (say, up hills). The lowest setting produces about 200 lumens and runs for about 20 hours.

There is a light on the power switch that gives you a rough idea of the battery condition and it works slightly better than the same feature on the Cygolite. The power switch lets you cycle through three solid modes by single-clicking and three flashing modes by double-clicking. One of the flashing modes spells S-O-S. The marketing claims 9 modes - I only found 6.

The Cygolite gives you the option to hot-swap batteries. I've never used this feature. The Touhuhot does not offer it.

The marketing says you can fully charge it in 2 hours. It took me nearly 4 hours on a charging block which is more than I expected, but not a big deal.

Like most battery lights it has a circular beam with a bright spot in the middle. This is not a good beam pattern because the bright center washes out the road close to the cyclist and the road beyond that is invisible. If you mount the light to push the bright spot further up the road you will blind oncoming traffic so they will use their hi-beams. A better beam pattern is to become progressively brighter further "up" the beam with a sudden cut-off at the very top. This illuminates the road evenly and doesn't blind oncoming traffic. However the mirror and lenses required to do this are expensive and not found on low end lights like this.

So how do the Touhuhot and Cygolite stack up?

Cost - Touhuhot wins at less than half the price of the Cygolite
Mount - Cygolite wins with a sturdy and flexible mount
Brightness - Touhuhot wins for maximum brightness even though it can only produce it for 30 minutes before dropping to a dimmer mode
Run time - Touhuhot wins even though it doesn't come close to the the marketing hype
Convenience - Cygolite wins for the battery hot-swap and usb port design
Size - Cygolite wins because it uses 33% less handlebar space
Beam pattern - a tie 
Free tail light - Touhuhot wins because it has one

Summary - once you know what this light is really capable of it's clearly a good deal. It really doesn't need the marketing lies.

Interesting note - if this really was a 5000 lumen light that ran for 15 hours on a single charge it would need a 150000mAh battery but this light only has a 5200mAh battery)

Now let's look at the 'free' tail light

The free "$21" tail light is very similar to the CANWAY which sells for $16 on Amazon. This is not a review of the Canway - just an attempt to put a reasonable value on this tail light.

It is not very bright compared to a Cygolite 200 lumen spot tail light that costs $40. It's not visible in daylight or under city lights at night. It would be fine on a bike path or quiet road.

The mount is quite good, being a big rubber band that allows you to mount it to almost anything. You can also rotate the light from vertical to horizontal. The light attaches to the mount at a slight angle so if you mount to a seat post or seat stay you can keep the light pointing horizontally.

It has blue and red leds which can be alternated. Note it's illegal to have blue flashing light in some states - that's reserved for emergency services. Probably not going to get you a ticket, though.

Overall I would say the tail light is not up to the same standard as the front light. I've ridden Cygolite spots since they hit the market and this light isn't going to make me change my mind. The wide angle of the light and the blue options might make this a secondary light on one of my bikes.

Wednesday, July 14, 2021

Aerobar bag

Extending my discussion of bicycle bags, I asked my friend Richard Stum, owner and chief bottle washer at EOGear about the lack of bags that attach to aerobars. He suggested that he try altering his handlebar bag to hang vertically from aerobars. Both Amber and I have Profile T3+ aerobars which are ideal for this configuration. After a couple of tries I think Richard has the perfect aerobar bag.

It has a large main compartment with a moveable divider with full access via a double zipper. There is a zippered pocket on one side and strong velcro straps on the other for attaching a bulky item such as a wet rain jacket. It attaches to the aerobars with four short velcro fasteners.

Here's a picture from the external pocket side. You can see how the bag hangs down out of the way but doesn't obscure the front light. You can see it is more aero in this configuration compared to attaching to the handlebars.

External pocket suitable for maps, cue sheets, etc.

The double zipper makes the inside of the bag very accessible while riding. I use the movable separator to create a battery compartment at the front so I can power my GoPro. It would be easy to run a second cable back to my Wahoo for rides lasting more than 15 hours.

Here's a rider's eye view.

Easy access to snacks, glasses, and everything

 I bought one for Amber too. We far prefer these over the top tube bags that keep slipping off to one side or the other. This bag is at least twice the capacity of the largest top tube bag we could find.

For riders whose aerobars are too close to each other to use this configuration, you can also mount them sideways so that the main zipper is on the side and the external pocket is underneath.

Monday, July 5, 2021

A bag for all occasions

I rode with Greg and Stacy last week for the first time in over a year. We were all supposed to ride our Bromptons but they cheated and brought regular bikes. They hadn't seen my Brompton before so I showed it off with some pride. I hope one day we will all ride our Bromptons together.

Greg had made me a Brompton bag he made from a modified handlebar bag and a generic Brompton mount he bought on Alibaba. I now have four different bags for my Brompton.

My smallest is my 3D printed waterbottle mount with a single bottle and a bottle shaped accessory bag made by Epessa. It's perfect for shorter rides or when I know where all the water fountains are.

3D printed water bottle mount


The next largest is a small hard-shell box I bought on Amazon made by Suntique. I holds quite a bit more than the Epessa but I need to carry a strap on water bottle mount for the stem. It has a cute Union Jack on it too.

Suntique hard shell

Greg's gift is about twice as capacious as the Suntique. Here's a photo. It's a waterproof roll-top handlebar bag, repurposed for the Brompton. I think this is the bag link 

Greg's bag

Lastly, I have a proper Brompton bag for when I need more air resistance. I doubt I will never use it which is a shame because it costs a lot.

Great for shopping at Costco