several years ago I saw pictures of a soft tail MTB modified to do that and converted to a Hard tail when assembled again.
The Shock under the top tube was replaced . Cyclists day job was in a Machine Shop .
Thanks to gizmag for the excellent article, and thanks to the readers for your comments!
I wanted to respond to a few of the points that were brought up:
"So where does a 24" tire fit inside a 23" space?"
Good question. Bicycle industry wheel sizes are mostly inaccurate. This is because many different tires sizes can fit on the same rim. In our case we are using a 1.5" wide tire on a 20" dia rim (bead seat diameter), which brings the overall diameter to about 23". If we used a bigger tire, such as a 2.25", the diameter would increase. To try and keep it simple, the bike industry calls it a 24" wheel. Regardless, you may notice that the seat is still slightly higher than the wheels, this will be the same height for production making the height 23" as claimed. Source: Tire Sizing Systems
About the slot on the fork and steerer tube:
The fork and steerer are of adequate thickness and the slots are not at high stress points. We've done extensive simulation and real world testing and have confirmed it is strong and safe.
About the weight:
Our claim of 21lbs is total bicycle weight including pedals. It is common for bicycle companies to post weights without pedals, which may or may not be the case here. Without an actual hands-on review of either bike, the numbers are just manufacturers claims. Even so, the author brings up a valid point and we hope to make good on our claim for production!
About the price:
Folding bikes are generally more expensive because of the hinges and locks. Helix will be made out of titanium, which is significantly more expensive than steel, aluminum and carbon. With that said, it is still very competitively priced in comparison to other titanium bikes, folding or not.
About world's smallest claim:
Based on the numbers provided for the Brompton (585mm x 545mm x 270mm or 23" x 21.5" x 10.6"), the total volume would be 5241.7”. Helix is 5175”. The main differentiator being the width measurement, helix is slightly thinner, this makes it easy to get through doors and other tight paces where height is less of an issue.
Rigidity will be one of our biggest selling points. Helix uses a patent pending tube-in-tube locking device that is very rigid.
Helix will have mounts for mud guards, racks, lights and more. There will be a unique carrying option as well, but it will be available after our first production run. Stay tuned! "
The Helix looks very interesting. No rear brake on the prototype. Website indicates disc brakes. Pictures show what appears to be two cables coming off the right brake lever/shift lever with housing going into the frame.