I came into possession of a folding bike frame (by way of throw-in sweetener in a swap deal for "real" bike parts). Always wanted to build up a folding bike for travel in Europe (rock up at the train station, fold it, ride the train, hop off, unfold it, ride off). Now that I had a first proper look at the frame I realize that there are a lot of things that are vastly different from 700c road bikes which I ride normally. The purpose of the post is to run a few things by the experts here who hopefully will/can help my clueless self to find the way to a rideable bike. So here's the plan: Single speed, reasonably priced, and sturdy are the main objectives; low weight is not a consideration. Making use of my parts bin and avoid buying too many parts is another goal.
- The head tube has an inner diameter of 44mm. My understanding is that this a specific folding bike standard. It seems for this type of head tubes there are only headsets available for forks with 1 1/8 diameter. What I have found so far is a head set from a company called litepro. Unfortunately they don't give information on their website regarding the inner diameter. Anybody knows if that is for 1' or 1 1/8' forks? I suspect that it is for forks with 1 1/8 diameter. If so, can I use both, forks explicitly for folding bikes and bmx forks as well? Also, when looking at steerer column: are there two different standards; one similar to quill stems and one similar to ahead-set type stems? The former for 1' forks and the latter for 1 1/8' forks? Are there any alternatives for this litepro head set which you could recommend?
- Are folding bike forks for 100mm hubs like road bikes or do they have a different standard? If I run disc brakes, are the calipers the same standard as road bikes? Or do I need some kind of adapter?
- The bb shell width measures 68mm. I presume, therefore, it is BSA. The spindle of the bb which is currently still stuck in there has an insane length of approx. 145mm with some threads at the end. (the thread is part of the spindle - never seen anything like that) Are there specific folding bike cranks that require these ultra long, threaded spindles? I was planning to use an old (2001) Campagnolo square taper crank with a 1x chainring. They would normally be combined with a 102mm bb. What would be the chainline implications when using a road crank on a folding bike? What is a normal/ideal chainline for folding bike 1x drive trains measured from the center of the seat tube? 48.5mm? or something else entirely? Can I use a road bike crank at all?
- The rear dropouts are 135mm. No rd hanger. I suspect folding bikes are run with internal gearing hubs - at least this one sure is. Has anybody heard of 135mm single speed hubs? Or are there specific rear hubs for folding bikes that meet some chainline requirements which I am not aware of? Has anybody tried to cold set these "monocoque" chainstays? (it's a steel frame)
- The required seatpost diameter is 28.6mm. I am tall, so I need a 600mm seat post. So far I only found one post 28.6/600mm from a company called Woodman. Are there any alternatives out there?
- I remember having seen some foldable pedals. Couldn't find them anymore on the internet. Anybody has a link and/or an opinion regarding those pedals?
- Anybody running drop bars on a folding bike? Experience? Does it fold reasonably well?
- Any recommendations for sturdy 20inch rims with 28h or 32h?
I know, a lot of question, a lot of them probably stupid, but I'd appreciate any input as I am a thoroughly confused currently with the uncommon (for me) standards on this bike. Thanks a lot!
My Dahon frame is set up for 1-1/8" fork and the head tube has integrated(?) bearings, the cup does not stick out of the head tube. You'll need to look at your frame or bring to a bike shop to determine what kind/size you'll need.
My rim-brake Dahon has a 74mm OLD front hub, this is quite common on folders now. Dahon's and others' disc bikes usually have 100mm front hubs to be able to use available hubs with discs. I think Bike Friday always used 100mm front hubs for rim and disc brakes, in order to use standard off-the-shelf parts. My rear hub is 130mm, they vary between that and 135mm, or narrower like 120 or 110mm I think for some models with internal gear hubs, like Bromptons. Cold-setting the rear stays on that design frame... I can't say. The front hub width can complicate finding matching rims. Dahons on 74mm come with 28 and 20 hole front rims with rim brakes, and on 100mm with discs I think 28 hole.
Lack of rear derailleur hanger is easily solved; You can use a rear derailleur with a built-in claw-mount that goes under the axle nut (see pics below), or buy a claw-mount that will do same and accept any standard mount RD. My frame also had no standard RD mount, just the hole forward of the axle for Dahon's compact RD, which worked terrible, too far forward of the cogs so increased lateral flexibility of the chain meant it shifted awful into lowest cog. Now it shifts great.
Bottom bracket shells are typically 68mm wide and BSA threading. You can of course use square taper and cartridge, however when I upgraded my gearing to a double crank, I went with the newer design 2-piece hollow-spindle design (similar to Shimano Hollowtech 2), and LOVE it, and amazed that it's backwardly compatible into old bikes. I went with 24mm hollow spindle and ISO External standard bearings, the most common wrench standard. My chainline is 43.5mm (center of frame to middle of 2X crankset) which is perfect on my 7 speed cassette 130mm hub.
That seat post diameter: Will be easier to find accessories, like a clamp-style rear derailleur to fit the seat tube if no front derailleur braze-on, and more clearance to have a proper chainline. EDIT: No, I now see your seatpost is swaged down at top, below is larger, so worst of both worlds. My 33.9mm seatpost and 40mm seat tube, stronger, but no clamp FD fits, and adapter to use road FD was a really tight fit to still have good chainline, I had to grind away a small portion of the inboard lip on the FD for things to work.
You can use ANY handlebars on a folder, it just may be a less compact fold. I use 58cm flat bars, with bar ends (more comfy than my old 40cm bullhorn bars), plus bolt-on aero bars which complicate folding (need to remove forearm rests), but I don't fold it often.
Folding pedals: If plastic body like my stock pedals, they typically contain thin stamped steel races (cups) and with a lot of miles, mine cracked the cup after a year. There are better folding pedals, especially pedals that don't fold but disconnect quick and easy.
Pics: This was originally a Dahon Speed D7:
The folding bike market has become more competitive. Before building up the bike, you may want to check on the price of a Zizzo Forte, good reviews on multiple threads on here, may be a better deal with cost of all components AND fork AND wheels.
Also, that folding hinge design tells me that is a low-quality folding frame. And I now see a lot of rust. I recommend against investing in that frame. Start with a new frame or get a complete bike, it'll be both better and cheaper.
EDIT: Country code MY, Malaysia? Oh I think parts and frames are dirt cheap there. There's a member on here from Indonesia, he builds up bikes at incredibly low cost with top quality. Here in the USA, we can't get FnHon frames and good Shimano components near as cheaply. Look for complete folding bike buildup threads by Ron Damon, as well as threads from others reviewing the Zizzo Forte (I don't know if that bike is available there).