Time Trial / Time Trialling / TT

Now the only question is how much of a tit will I look if I buy and race in a pointy helmet and come DFL...?

There will be people there with all the kit who are targeting sub-6h. Because it's an iconic distance, the 100 does attract enough people for whom just finishing is an acheivement that anybody getting even close to 20mph is unlikely to be responsible for the timekeeper being kept up late.