I've been mulling over this whole situation and apparent discrepancies too, thank you for bringing up this point. Agreed vs. the Ballista, and that point had confused me a bit when compared to the Wavecell whitepaper that claimed a 48x reduction in concussion risk. Upon further reading of the study methods, the discrepancy does not seem quite as big, although some info is still lacking.AJS914 wrote: ↑Wed Mar 20, 2019 5:25 pmMany of their helmets have been on sale for the last month. Maybe they are keeping the Ballista MIPs in their lineup at the $200 price point. I imagine the market for the $300 aero helmet is small.
Interestingly, in the Virginia Tech study, my Ballista MIPS rates a 10.9. The XXX WaveCell rates a 10.8 - only a .1 improvement. It's not quite a 30 year advance over yesterdays top of the line helmet tech.
The claim of a 48x reduction in concussion risk was based on the methods used in the Wavecell whitepaper, where they tested a Scott Arx Plus helmet, a Scott Arx Plus (MIPS) helmet, and a Scott Arx Plus which was carved out internally to allow replacement of 15mm of EPS foam with 15mm of Wavecell material. When comparing the Cadence Arx (non-MIPS) to the modified helmet with Wavecell, they get a 48x based on their calculations, with the MIPS model being somewhere in between. Here is that article, just to make it easy for anyone who wants to see what I'm talking about: https://www.sciencedirect.com/science/a ... via%3Dihub
If you look at the Virginia Tech ratings, the Scott Arx Plus (MIPS) is a 4* helmet with a rating of 14.3, vs. the Ballista a 5* model at a rating of 10.9, so the Ballista does seem to be a superior traditional EPS foam/MIPS helmet to the Arx Plus MIPS. Virginia Tech did not test a non-MIPS Arx Plus, but they do seem to have a trend of MIPS helmets performing better in general (the top 15+ helmets are all either MIPS or Wavecell). While it would be nice if they would do more "apples to apples" testing of models available with or without MIPS, to see what the effect of the MIPS is in isolation, I think it would be a pretty safe bet that the non-MIPS Arx Plus that Trek compared in their whitepaper would end up with a lower rating than the MIPS one. Here are the Virginia Tech ratings: https://www.helmet.beam.vt.edu/bicycle- ... tings.html
Thus, we look at the Specter Wavecell model vs. the Ballista (which seems to be a best of breed traditional model) and go "That's it? Only a .1 improvement?" whereas the whitepaper is comparing a much lower ranked traditional model, with no MIPS. That might seem shady and manipulative, but in Trek's defense, the research detailed in that whitepaper was done many months ago, before Trek had developed their own Wavecell models and, quite possibly, even before they had licensed the tech. In other words, it was the Wavecell guys that did that research, and it could very well be the case that they used that research to sell the idea to Trek in the first place, with Trek being just as WOWed as us with the 48x claim.
As to why the Wavecell guys choose that Scott model vs. say, a Ballista, it may look like they were gaming the system, but there are several legitimate reasons they could have had. They wanted to compare standard vs. MIPS vs. Wavecell. To do that, they needed a model available with/without MIPS, whereas many top helmets now, like the Ballista, are only MIPS equipped. Secondly, given that they were going to mill out the interior foam for the Wavecell test, they probably wanted a single density foam model, rather than a dual density model, to eliminate that variable, which rules out more helmets from Kali, Fox, Bell, Leatt, Fly, and others. And lastly, the Scott Arx Plus (MIPS) was the top rated model in Consumer Reports 2016, which included impact testing, so it is no slouch.
The 48x reduction in concussion risk still seems like a real stretch though, as it is compared to what is probably a reasonably average EPS helmet (Arx Plus), whereas the Virginia Tech 5* rating, which begins at scores under 15, denotes a 70+% reduction in concussion vs. a bare head! Even though the Ballista and top Wavecell models have scores under 11, which should mean they are well above a 70% reduction in concussion vs. a bare head, that is still a far cry from a 48x reduction vs. a decent quality EPS helmet. Here is the Virginia Tech testing methodology, if anyone cares to read further and compare to the above whitepaper: https://vtechworks.lib.vt.edu/bitstream ... sAllowed=y
What I haven't had the time to do is look at exactly how each of these studies are calculating risk of concussion, which might account for more of the discrepancy, especially if they use differing thresholds or risk progressions for different g-forces. As a random hypothetical example, do they both consider subjecting your brain to 50g to be half as risky as 100g, or does one consider a halving the force to more than halve the risk.
Anyway, I think we can all agree that the "30-year" claim is BS when compared to the Ballista in the VT data. Ok, everyone discuss further...
Oh, P.S. on a somewhat unrelated note, I was pumped to see the bit in the Wavecell whitepaper about them putting 2 nylon stockings over the headform, in an attempt to simulate the movement of the scalp and hair. That has been one of the major criticisms of the MIPS research from Sweden, which, as far as I know, always uses a rubberized headform with the helmet very firmly strapped down. Many people have pointed out that skin and hair function as their own slip planes, so MIPS research doesn't accurately simulate the real world/real head conditions of a crash. This Wavecell study with the nylon stockings seems like a big step in the right direction and, interestingly, it somewhat validates the value of MIPS vs plain EPS foam.