I’ve decided to give TTing a go next season (swore id never do it but dipped my toe in this season on my road bike and sort of enjoyed it).

However im a bit confused about where to start. For a TT bike would i go for the same sort of size as mny road bike (medium / 54cm) or do i size down? I’ll likely be buying second hand so wont have the chance to try before i buy.

I can find geometry charts for bikes like the Cervelo p2 or p3 but i cant find an up to date size guide for these bikes, only the old models from about 10 years ago (and the geometry has changed since then). At about 5ft8 am i better going for something like a 51cm frame? Unless im reading things wrong the reach on the 51cm frame is more than that of my 54cm road frames.

Cheers

I always found them like for like. Eg I rode a 54cm road bike and 54cm TT bike albeit from the same manufacturer.

If you can try before you buy I would really encourage it.

I’m in a similar boat (albeit I’m still not sure if I want a TT bike) so not an expert but…

I’d have thought the longer ‘reach’ is to accommodate being further forward over the BB?

Over the last couple of weeks ive look around the local shops but none have any tt bikes in stock so its proving a bit tricky to try. Wish i’d decided to give this a go a few weeks earlier when they were selling off the 2017 models for cheap!

Not sure if it’s any use to you but Merlin are selling off argon frameset very cheap, it’s aluminium but we’ll thought of and a good starter bike. Admittedly you’d have to build it up but 105 groupset and some wheels would get it mostly going.

Both the TT bikes I have bought have been the same size as my road bikes. I think a size smaller frame might have been better to get a shorter reach, but it felt that the bars were too low and closed my hip angle too much.

Again, i’m not an expert in TT but bought my first one without a test ride and then bought the second based on a quick sit on it in the shop and it being roughly the same size as the first one.