Originally Posted by
Jipe
If you consider any ETRTO size to be standard, then yes ETRTO 507 is a standard component..
ETRO is a standard like ISO. Thus per definition any tire of any ETRO size is a standard tire, though it may be more or less common... If Peter had defined a special, new tire size for the Helix than we would talk about a non standard tire. Luckily he did not do that.
Originally Posted by
Jipe
The only thing I am sure is that it drastically reduces the choice of tires (and tires a crucial for the bike performances, the same problem exists for the Brompton, no high end high performances folding tires unless the Schwalbe One presented on the 2019 CHPT3 become available as spare parts),
Over all the years that I've been riding a Brompton I never missed a bigger choice of tires. This may be because on any given bike I only use two tires at a time and those are usually the same model.
Therefor I personally cannot agree to the often heard lamenting about not enough tire choice for Bromptons. Most of the time it seems to origin from people that do not own a Brompton btw.... There are in fact roughly about 15-20 different tire models available for the Brompton. I consider this to be sufficient.
Originally Posted by
Jipe
it makes the bike bigger (an Helix with ETRTO 406 wheels would be smaller) and it increases the weight (an Helix with ETRTO 406 wheels would weight less).
Too bad that the whole idea of the Helix is about bigger wheels than the common 406 - that makes one of it' USPs and part of the attractiveness for a lot of people as far as I can judge. I own btw. a folder with 507 wheels and while there is not a immense choice of tires fitting my taste there clearly is a sufficient choice. How many tires would you need? Furthermore I would clearly say that there is a difference between 406 and 507 wheeled bikes, so if you prefer a more grown-up ride, closer to "usual" bikes, the 507 shows it's advantages.
Originally Posted by
Jipe
In your list of Brompton improvements, you forgot that the wheelbase of the Brompton was increased what changed the behavior of the bike.
The longer wheelbase was just a result of the new folding hinge with it's semiautomated welding process, not a feature on it's own. Therefor I left it out, even more as I do not consider the older, shorter wheelbase a bug that needed to be removed. I could not recognize a change in behavior between the two versions. Obviously YMMV.