G-Sport

@dissend: Anytime. I was supposed to come ride Bellingham with Taj this year after Sea Otter but pinched a nerve in my neck the week before. Hoping to get out there one day. The digressive nature of tyres is a big part of the reason for OPTIS so I think you would really appreciate being able to tune some progression in there.

Testify. Short chainstays aren't everyonels cup of tea but they ARE some people's cup of tea and they are MY cup of tea. Currently riding a specialized with stays cut down to 417 and considering going shorter with a 26" rear wheel.

@dissend: Run-flat is very limited with OPTIS. The main benefit is that you can keep the bike under control following a tyre failure rather than careering into a tree. You should get plenty of time to bring the bike to a safe halt. But, if your tyre is fully flat and you press on at full pace the OPTIS bladder is likely to pull off the valve and you will then be unsupported. With a slow puncture, where there is still a little air in the tyre, you should be able to ride out gently for a good distance though rather than having the tyre burp the last of it's air and leave you stranded. Hope this helps clarify, and thanks for the interest.

@dissend: The max inflation pressure for the MTB versions is 50psi. But that is so that it can cope with a complete depressurisation of the tyre around it. ie. a pressure differential of 50psi. What pressure did you have in mind? OPTIS works very differently to say Pro-Core, it fills a much larger proportion of the tyre volume and is intended to help add support from about mid-stroke of the tyre (which is where the tyre's natural digression starts to be kick in). So running it at a small pressure differential to the tyre actually yields the best results for a lot of people and riding conditions.

They don't look bad but that name is taken.

@thekaiser: No pictures of the cross section in the article no, you need to look at OneUp's site to see it (where they have one expertly cut by a beaver (I assume) using a blunt hacksaw)

No weights for the rims? I like the ribs each side of the spoke holes for extra strength, wish I'd thought of that... oh wait, I did...

Youpeng is your backward friend... props to anyone who gets that..

At what point do we declare Intradrive to be vapour-ware? They've had millions in grants (£2.5m I believe) over 10 years and still haven't released anything, even if it does come out this year (they've been promising it within a year since what 2023?) it's biggest selling features are now hopelessly outdated. Retro-fittable to Shimano mounts (that ship has sailed), 700W (hardly competetive now) 4.5kgs, even heavier than Pinion (which also doesn't seem to have managed wide release), and soon to have to compete with ecvt's at lower weights and higher outputs. I'd love to be proved wrong, but I'm going to stop holding my breath...

I'm all for innovation, I've actually sketched up some ideas similar to this in the past. This one raises a couple of questions straight away:- 1. How do you push the disc closer with the "chain" filling the gap? Belt CVT's like you find on a bandsaw have to move the belt out evenly rather than in steps, which requires some slip. If this is using a chain with distinct steps then I don't see how you would move a single disc inwards, instead you would need to segment the moving disc and move a segment at a time while it is in the chain-free part of the rotation. This is not insurmountable but it adds more complexity. 2. Another issue is chain strength, with a very small front sprocket the applied torque starts to generate a very high tension in the chain, a standard bike chain won't handle something as small as this looks.