I recently bought the Camp Thunderbolt, which is a folding bike with 16 gears. Since I live in mountainous La Paz, Bolivia, I need a bike with more than the standard 6-8 gears that are found on most folding bikes. All the reviews that I read online recommended avoiding the cheaper brands of folding bikes, but higher quality manufacturers like Dahon, Brompton and Tern charge an arm and leg for their folding bikes that have over 8 gears. The cheapest one that I could find was the Dahon Visc D18 Tour which costs $879, plus another $35 to add fenders and $36 to add a cargo rack. I consider fenders and a rack to be absolutely essential features on a bike, and it annoys me to no end that most bikes are sold as entertainment and fair-weather exercise devices, rather than a practical means to get to work in the rain and carry groceries. At a weight of 27 lbs, plus another 4 lbs for the fenders and rack, the Dahon Visc D18 Tour weighs a total of 31 lbs.
In contrast, the Camp Thunderbolt costs $425 if ordered from the manufacturer’s web site and includes fenders and a cargo rack. The Thunderbolt weighs 29 lbs, so it is a tad lighter and considerably cheaper than the Visc D18 Tour. In addition, the Thunderbolt includes disc brakes, whereas getting that feature on a Dahon bike would mean upgrading to the Visc D18 Disc, which costs $999.
I question whether it is worth paying the extra cost for a larger number of gears. The Ford by Dahon Convertible 7 Speed only costs $269 at ThorUSA (which is reportedly the best place to buy Dahon and Tern online in the US) and its user reviews on Amazon are about as good as the reviews for the Thunderbolt. In the end, however, I decided that it was worth paying the extra $155 for the Thunderbolt if it meant not having to get off the bike and walk it up hills. (Actually the Convertible 7 Speed is not as cheap as it appears, because it only includes a warranty on the bike if it is tuned by a bike shop, which adds $40-$70 to its price.)
The Thunderbolt took 9 days to ship from K7Sport in California to my parents’ house in Indiana, which was longer than the 2 to 7 days for free shipping listed on the Camp web site. It arrived preassembled in the box and it was very well packed to avoid damage in shipping.
The Camp Thunderbolt (with my added red chain on the cargo rack and extra lights on the front and back).
Problems I found with the Thunderbolt
Once I took the Thunderbolt out of the box, however, I discovered a number of problems. The front fender was scraping against the front tire, so I had to unloosen the bolt holding the fender to the front stem, then adjust the fender and retighten the bolt. The end of the front derailleur cable was sticking out, so it hit my foot with every rotation of the pedals. I had to loosen the cable’s nut and move the end of the cable so it would point it in toward the frame.
The screw in the quick release on the front stem was not tightened correctly, so the handle bars wobbled the first time I tried riding the bike. My father who is 75 years old fell off the bike, because he tried pulling up on the handlebars and they pulled all the way out of the front stem. Seeing my elderly father take a tumble on the bike gave me quite a fright, but he only suffered some minor scraps on his hands. Tightening the quick release’s screw eliminated the wobble in the handle bars.
There was only 1.5 cm of space between the Thunderbolt’s kickstand when raised and the back brake’s disc. When I kicked up the Thunderbolt’s kickstand, it moved far enough to bang against the brake’s disc on the back wheel, making it ring like a gong. After kicking up the kickstand a few times, I found grooves in the kickstand’s rubber bumper where it had banged into the brake’s disc.
Grooves in the side of the kickstand’s rubber bumper from banging against the back brake’s disc. Notice how I filed down the side of the bumper so it wouldn’t come so close to the disc.
I found that I could avoid the banging by raising the kickstand slowly with my hand, rather than using my foot, but that isn’t very convenient. I was concerned that this banging would warp the disc over time, so I tried to adjust the kickstand so it wouldn’t lie so close to the brake’s disc when folded up. Unfortunately, the kickstand is attached inside a slot, so it can’t be turned outward. I found that I was able to move the position of the raised kickstand so it was farther from the back brake’s disc by putting a metal wedge inside the slot where the kickstand is attached. Unfortunately, moving the kickstand outward with a metal wedge made it impossible to completely fold the bike, so I had 2 cm of extra space between the wheels when I folded up the bike.
I shoved a coin between the frame and the kickstand mounting to move the kickstand slightly outward.
I finally solved the problem by replacing the metal wedge with a thinner coin, shortening the kickstand to its minimum length and filing down one side of the kickstand’s rubber end bumper. With these 3 changes, I am now able to kick up the kickstand with my foot without banging the brake’s disc and I am able to completely fold the bike. Unfortunately, the shortened kickstand means that the bike is more liable to fall over, especially when parked on surfaces which aren’t flat or when carrying something heavy on the cargo rack.
Kickstand modified to not bang against back brake’s disc
Nobody else complained about this problem in the reviews of the Thunderbolt on Amazon, so maybe the kickstand on my bike requires more force than normal to raise it and that extra force causes it to strike the brake’s disc. However, it seems to me that the Thunderbolt’s kickstand is a fundamental design flaw. There isn’t much room to play with, since the kickstand can’t interfere with the folding of the bike. Maybe this problem could be solved by using a smaller disc in the brakes. In my opinion, the disc is too close to the road anyway and is likely to get scraped against curbs and accidentally kicked when trying to fold and unfold the bike and push it through crowded bus stations.
Shortening the kickstand makes the Thunderbolt lean over when parked, so I turn the front wheel away from the lean to give it more stability.
The second problem I found was that the front disc brakes constantly scraped. It is normal for disc brakes to scrape a little when a bike is new, but the scraping noise annoyed me, so I adjusted the brake pads so they wouldn’t lie so close to the disc, but that made the brakes mushy and it still didn’t solve the scraping. I was also annoyed to discover that the Yining brakes on the Thunderbolt only allow the position of one brake pad to adjusted. Better quality disc brakes allow the brake pads to be adjusted on both sides of the disc.
Black marks on the washers show where they were scraping against the front brake’s disc.
After taking off the front brake’s disc, I discovered that the washers on the brake were scraping against the disc. I tried to adjust the brake so it wouldn’t lie so close to the disc. The holes to attach the brakes are slots, so in theory the bolts holding the brake mounting can be moved away from the disc, but when I tried to move the bolts, the washers still scraped against the brake’s disc. In the end, I took a metal file and filed down the washers so they no longer scrape against the disc.
Filing down the washers that rub against the front brake’s disc.
The washers on the brake mounting after being filed down.
I also had to loosen the 2 bolts holding on the front disc brake mounting and readjust them so the brakes would evenly apply to the disc, rather than lopsidedly scape on one end of the disc. I also had to loosen the screw on the front wheel’s quick release, so the wheel would spin freely without scraping against the brakes. Clearly, the bike was sloppily assembled if it required this much adjustment.
Disc brakes don’t make a lot of sense on a folding bike in my opinion. People usually don’t ride folding bikes through snow and mud like mountain bikes, so debris usually doesn’t get on the wheels’ rims to hinder braking. Folding bikes also don’t need the added stopping power of disc brakes, since they generally aren’t ridden as fast or on as rough terrain as mountain bikes. The discs also add extra weight compared to normal rim brakes, and folding bikes should be as light as possible to be easy to carry.
None of the Amazon reviewers complained about the washers scraping the Thunderbolt’s front brake’s disc, so that was probably just caused by sloppy assembly of my bike, but several reviewers have complained that the Thunderbolt’s brakes squeal loudly when stopping. I also am annoyed by the squealing brakes. The squeal on the front brake was reduced once I adjusted the wheel in its forks and the placement of the brake pad unit, so there was no wobble to the brake’s disc, but I still hear the squealing. I have read online that squealing brakes can usually be fixed by replacing the brake pads and discs, but one Amazon reviewer tried that and reported that the squealing persisted after replacing the brakes. Camp could have avoided these problems altogether by using normal rim brakes. Disc brakes won’t have problems if the wheels warp over time and they are better at stopping when the roads are wet, but I think that the Thunderbolt would be better without disc brakes.
How the Thunderbolt rides
Once I fixed the scraping of the brakes and adjusted the kickstand so it doesn’t hit the back brake’s disc, I took the Thunderbolt on a 1.5 hour bike ride in La Paz. Even with 16 gears, I still had to get off the Thunderbolt and push it up the steep hills in La Paz. With a normal bike, I can stand up to pedal up steep hills, but the frame of Thunderbolt is not that long, so standing puts my body over the seat, rather over the center crossbar of the frame like on a normal bike. Because it is uncomfortable to pedal while standing on the Thunderbolt, it is harder to pedal up hills and harder to ride over rough terrain. Because the frame is not very long and the seat post and front stem are adjustable, the Thunderbolt allows me to ride in a more upright position, so I don’t have to hunch my body to reach the handlebars, like I do on a normal road bike.
It takes some adjustment to get used to riding a bike where the wheels are so much lower than your center of balance and the turning is very fast due to the smaller wheel size. On a normal bike, I only loosely grip the handlebars, but the Thunderbolt feels a little unsteady underneath me, so that I grip the handlebars more tightly to control it. I’m sure I will get used to it over time, and it is a lot of fun to ride because it turns so fast. At the higher gears it can really move. I used to ride unicycles and the first time I got on the Thunderbolt it reminded me of riding a unicycle. You have to be a little more aware when riding the Thunderbolt and constantly adjusting to keep everything steady.
It is difficult to jump curbs with the 20 inch wheels on the Thunderbolt and I often have to stop the bike to haul it over curbs. The wheels are only 1.5 inches thick and they have very little tread on them, which makes them glide smoothly over flat asphalt, but they are not designed to handle rough terrain. Many of the side streets in La Paz are paved with stone and riding over them in the Thunderbolt rattles every bone in my body. The seat adds a little cushion, but otherwise there is no suspension.
How well the Thunderbolt folds
The hinges on the Thunderbolt feel very stable and rigid when latched closed. I don’t feel any wobble from the hinges in the center frame or front stem when I ride the Thunderbolt. The Thunderbolt frame only comes with a 1 year warranty, whereas Dahon’s new frames have a 10 year warranty, but the Thunderbolt’s aluminum frame and its hinges look very sturdy and I doubt that they will fail me. People who are close to the 250 lb limit for the bike, however, might need to avoid jumping and other types of riding that put a lot of stress on the frame.
The hinge on the center frame has a safety latch that is manually pushed down to prevent the center hinge from coming undone while riding. One thing that I don’t like about the hinges is the fact that their latches flap around freely when the bike is folded. Other folding bikes have springs to prevent flapping latches. I worry about the long-term durability of the plastic folding pedals; I suspect that they will have to be replaced after a couple years of hard use.
It takes a little practice to fold the Thunderbolt correctly. The quick release on the handle bars has to be undone and then the handlebars turned upwards so that the break calipers and gear shifters aren’t in the way of the wheels. If the handlebars aren’t turned upwards, then the two wheels won’t touch when the bike is folded. The front stem is folded down so it will hang between the two wheels when the center frame is folded. The front light with 3 AA batteries that I added to the handlebars is thin enough that I don’t have to take it off when folding the bike, but it rubs against the front tire when the bike is folded and I have to take it off if I plan to push the bike on its two wheels.
The seat post is pushed down to provide a leg for the Thunderbolt to rest upon when folded.
In order for the bike to be stable when folded, the seat post needs to pushed all the way down and the seat turned to the side so that the bike can rest on the bottom of the seat post. The bottom of the seat post has a plastic bumper on the bottom to prevent it from damaging delicate flooring. If the seat post is not pushed down, then the ground will scrape against the brake handle and the chain and teeth of the front sprocket.
If the seat post isn’t pushed down, then it can be used to push the folded Thunderbolt on its two wheels. The Thunderbolt can being pushed forward in front of your body, but not pulled behind like Brompton which is more convenient. There is a noticeable wobble back and forth between the two wheels when pushing the folded Thunderbolt forward. When pushing around the folded Thunderbolt, I often forget that it can only go forward. If I step backwards, the pedals will start moving and jam into the wheels, which jerks me to a halt. I also tend to forget to always hold up the Thunderbolt, and I try to set it down on its front procket and handlebars, which isn’t good for the bike. It takes a bit of practice to remember to always go forward and never set it down when wheeling around the folded Thunderbolt.
The metal plate from the front wheel only partially touches the magnet from the back wheel when the bike is folded.
There is a magnet on the back wheel to hold together the folded bike, but the metal plate on the front wheel doesn’t line up well and only touches part of the magnet, so the bond between the two wheels isn’t as strong as it could be. Camp also provides a velcro strap to hold together the two wheels and it probably should be used when transporting the Thunderbolt for long distances to ensure that the bike doesn’t unfold.
Using the Thunderbolt on public transport
I plan to carry the Thunderbolt in a bag on public transport, but I found that it feels very heavy and bulky when carried. I bought a Camp bag to carry the Thunderbolt for $25, but it takes quite a bit of wrangling to get it into the bag. The Thunderbolt does fit into the Camp bag with the seat post all the way down and the seat turned at an angle, but it is easier to zip up the bag if the seat post is pulled out of the frame and lain on top of the folded bike.
It takes me between 1.5 and 2 minutes to fold up the bike, put it inside the Camp bag and zip it up. Hopefully I will get faster with practice, but I don’t find it very convenient.
The shoulder strap on the Camp bag doesn’t have much padding, so it bothers me the way it digs into my shoulder if I have to carry it for more than a couple minutes. I will probably buy a replacement strap with better padding for the shoulder if I use the bag very often. I do worry that the shoulder straps are only attached to a little patch of the bag that could pull free over time. In contrast, the hand straps are much better attached to the bag. If I use the bag which weighs a tad over 2 lbs, I also need to carry it in my backpack when riding, which weighs another 2 lbs. When folded up, the Camp bag takes up all the room in my backpack, so it is not a small bag.
Strap on Camp bag.
I bought the Thunderbolt to avoid spending 30 minutes walking every day to get to work, but I’m not sure that I will go through the hassle of folding it, wrangling it into the bag, then unfolding it every day since it only will end up saving me roughly 15 minutes. On the other hand, I enjoy riding a bike, and I love the freedom of being able to avoid public transport altogether when the weather is nice.
The deciding factor in my buying a folding bike is the new public transport being implemented in La Paz, Bolivia where I live. Most public transport in La Paz consists of converted Toyota or Honda vans and half-sized Blue Bird school buses, where there is little room to carry a bike. La Paz has full-sized buses for a few routes through the city, but the folded Thunderbolt is too big to fit inside, and I am fearful of using the bike racks in the front of the bus, because the distinctive Thunderbolt would be a target for theft. I bought a thick motorcycle chain to lock up the Thunderbolt to deter potential thieves, but I can’t use that on the bus racks.
Nonetheless, La Paz recently added Mi Teleférico, which is a new network of aerial cable cars. The cable cars are designed to hold up to 10 passengers, but they are almost never full, so there is usually plenty of room for me set down a big bike bag. I have to carry the bike bag in front of my body when going through the Teleférico’s turnstiles and some of the stations require walking for several minutes to get to the next line, but I have now taken the Thunderbolt folded inside a bag through most of the stations in the Teleférico without mishap.
The Thunderbolt on my porch with cable cars from La Paz’s new Teleferico in the background.
Bikes can be transported on the Teleférico, but they require buying a second ticket for the bike. Since almost nobody in La Paz has ever seen a foldable bike, the Teleférico employees don’t suspect that I am carrying a bike in my bag. So far, I haven’t been asked to buy a second ticket when carrying the Thunderbolt on the Teleférico. I make sure to stick my bike helmet in my backback and I’m wearing normal clothes for work, so it isn’t obvious that I’m a biker. I wonder if other commuters in La Paz will start using folding bikes and the Teleférico employees will eventually start looking for passengers carrying bike bags to charge them extra, but I doubt it will happen any time soon. Almost all the bikers in La Paz are either kids or tourists who get a thrill from riding beefy mountain bikes down dangerous Andean slopes.
Final thoughts on buying the Thunderbolt
I still can’t decide whether I made the right decision in buying the Camp Thunderbolt. The problems I have encountered so far convince me that it is best to buy a quality brand like Dahon, Tern or Brompton. Several of the Amazon reviewers compared the Thunderbolt favorably to Dahon models, but I doubt that I would have encountered the sloppy assembly and the design flaw in the kickstand if I had bought a Dahon. On the other hand, I wanted a higher number of gears to be able to ride up hills and I wasn’t willing to pay the prices charged by Dahon. If I had been 100% sure that I would use the folding bike every day to commute to work, I might have bought the Dahon Visc D18 Tour, but I bought the bike as an experiment so I wasn’t willing to invest that much.
The real choice for me was between paying $250-$300 for mountain bike and paying $450 for a folding bike with a bag. I needed a bike and I figured that I was going to spent at least $250 on a decent bike, so I decided that I might as well spent an additional $200 for a folding one with a bag that I can carry on public transport. Even if I end up not using the Thunderbolt during my daily commute, I will use it at other times to get around the city and on long distance buses when I travel in the Andes.
If the Thunderbolt holds up over time, then I will feel that I made a good purchase despite the initial problems that I have encountered with the bike. I don’t mind tinkering with a bike to fix minor problems and I’m too impecunious to invest in a more expensive bike. If living in a flatter place that doesn’t require as many gears, the Ford by Dahon Convertible 7 Speed or Muon are probably a safer bet than the Thunderbolt for people on a tight budget.
As a commuter bike, the Thunderbolt is simply too big and bulky in my opinion to be used on most public transport and it isn’t easy to carry in a bag. It takes me at least a minute and a half to fold it up and wrestle it into the Camp bag. Only in places where you can push it around on its own wheels would I recommend it for commuters using public transport. A smaller folding bike like the Brompton or Dahon Curl with 16 inch wheels is much more practical for public transport, but those types of commuter bikes simply aren’t designed for the rough roads of La Paz.
Trying to ride up the steep hills of La Paz has convinced me of the utility of electric bikes, but an electric motor and a large battery would add another 10 to 15 pounds, which will make the bike too heavy to carry in a bag on my shoulder, so I would have to pay extra to transport an ebike on La Paz’s Teleférico. Also, motorized bikes technically aren’t allowed on Teleférico, but that rule was probably written for scooters and mopeds. Most Teleférico employees have never seen an ebike before, so they will probably think that an ebike is a normal bike and let it pass.
Another option is to use a folding electric scooter, rather than a folding bike. They aren’t any lighter, but they fold more quickly than a bike and are easier to carry on public transport. On the other hand, I wouldn’t like to constantly worry about charging the lithium-ion battery and it can’t be transported on an airplane. Since I have studied the environmental impact of fabricating lithium-ion batteries, I am reluctant to needlessly increase my carbon footprint when I can use a non-motorized bike. Also electric scooters can’t be carried on airplanes (see below) due to their large lithium batteries, and shipping one to Bolivia via sea and land would be costly and dealing with Bolivian customs often involves weeks of bureaucratic hassle.
Traveling on airplanes with folding bikes
I only had one day to play with the Thunderbolt, before I packed it up and shipped it on a plane to Bolivia. My father figured out that I would be able to avoid paying oversize shipping fees by cutting down Thunderbolt’s box it so it was 14 inches wide, 26 inches long and 21.5 inches tall. Most airlines don’t charge oversize fees for checked luggage which is 62 linear inches or less. My father also cut some plywood panels to fit at both ends of the box to avoid the bike being crushed in transit. Given that the walls of the Thunderbolt’s carton box are double thickness, the extra wooden panels probably weren’t necessary, but my father thought that it would be a good idea. I took off the wheels, cargo rack, fenders and tied down the dérailleur to save space and I took the brakes’ discs off the wheels to avoid them being bent during shipping. (The nuts holding down the brake’s discs had washers on one wheel but strangely didn’t have washers on the other wheel.) We were able to cram everything into our cut-down box except one wheel, which I stuck in another suitcase.
The Thunderbolt box reenforced with plywood panels at the ends and cut down to 26 x 21.5 x 14 inches to avoid paying oversize luggage fees on airlines.
With the derailleur tied down, the frame of the Thunderbolt only needs a box which is 24 inches in length. If we had cut two inches from the length and added two inches to the width, we probably could have gotten the second wheel in the box, but we left the box its original width of 14 inches.
When I got to the airport, the lady checking me in for United Airlines asked me what was in the box. I told her that it was a folding bike, and she informed me that I would have to pay $150 extra to ship a bike, even though it fit within 62 linear inches and was under the 50 lb weight limit. I told her that charging an extra fee for a bike was unfair, since it shouldn’t matter to United Airlines what is inside the box as long as it complies with the normal baggage requirements. Seeing no way to contest the extra fee, I paid it. As I waited to board the plane, I used the free Wifi at the airport to check the United baggage requirements for sports equipment, which state:
United accepts non-motorized bicycles with single or double seats (including tandem) or up to two non-motorized bicycles packed in one case as checked baggage. If the bicycle(s) are packed in a container that is over 50 pounds (23 kg) and/or 62 (158 cm) total linear inches (L + W + H), the item(s) will be subject to standard oversize and overweight service charges. First, second and excess checked bag fees may apply. If the bicycle(s) are packed in a container that is less than 50 pounds (23 kg) and 62 (158 cm) total linear inches (L + W + H), there is no bicycle service charge, but the first or second checked bag service charges may apply.
The following are bicycle restrictions:
- Handlebars must be fixed sideways and pedals removed, or
- All loose items must be enclosed in plastic foam or similar protective material, or
- Bicycle should be transported in a sealed box.
- If your itinerary includes a United Express flight, please contact United for information regarding aircraft cargo hold limits
- United is not liable for damage to bicycles that do not have the handlebars fixed sideways and pedals removed, handlebars and pedals encased in plastic foam or similar material, or bicycles not contained in a cardboard containers or hard-sided cases.
Note: Bicycles will not be accepted during an excess baggage embargo when no excess baggage is allowed.
With this information in hand, I complained about being charged the extra fee to ship the bike. It took the United agent almost an hour to figure out how to refund me the extra $150 that I had been charged, but we got it resolved before I boarded the plane. The moral of the story is that you need to know the baggage requirements for the airline beforehand and have a copy of the airline’s rules with you, because the airline agents probably don’t know their own rules and it is a hassle to contest the extra fees afterwards.
Given the amount of time that it takes to cut a box to the right proportions, disassemble the bike to fit in the box and then reassemble it upon arrival, it is worth buying a bag like the Downtube Folding Bike Soft Suitcase for $99. It doesn’t require any disassembly of the bike and it has rollers, making it easier to carry than a box. It looks like normal luggage, so you are unlikely to get questioned by airline agents about its contents. However, my custom box with wooden panels provides better protection against getting crushed, so I will keep using it. Tern reports that their 20 inch bikes can fit in a standard 30×21×13 inch hardbody suitcase if disassembled, so it might not be necessary to use a custom box.