Well my wife has finally acquiesced to my begging and pleading for a new tri bike. Before I can decide what to buy I need to resolve a fit and/or sizing question I have. I have been riding a Kestrel 200EMS in a size 54 set up for tri. This bike has a top tube measurement of 54.6. I am running a Thomson set back post "flipped" 180 degrees with full aerobars and pursuit bars (I know...Mr. E does not like this set-up but it works for me). Saddle is in the middle of the rails, Based on calculation formulae from Engineer Franke, et al, I believe I am riding at about 76 - 76.5 degrees. Therefore I assume my "virtual" TT length is shorter than the bike's stated 54.6.

How can I extrapolate from this to determine what size tri-bike I should be on? Should I just ignore the above and go off my "crotch to notch" measurement in fit charts since I am not sure the above is really proper fit or not? Seems to me I read somewhere that when determining desired TT length, (which I assume is most important dimension in fit) that you take the crotch to notch and then subtract 10-11cm for a stem and that will give you an approximate desired TT length. Does that sound about right?

As for what bikes I am looking at now...Felt S22, QR Caliente, P2K (although seem to be in between the 52 and 55 so it may not work) and am interested to hear about the new Kestrel tri bike coming out. If you have any other suggestions I would love to hear them. I need to keep it at about \$2K or less. Additionally, since I will be keeping my Kestrel as a road bike, would it be a mistake to buy a somewhat shallower tri bike (ie, S22 and Caliente are about 76 degree ST angle) vs going all out steep at 78 degrees. What is downside of these "multisport" geometries assuming you can slide the saddle up the rails to achieve 78? I live in a hilly area so thought a 76 degree tri bike may be more flexible for me.

Many Thanks!
Mike
Had a Caliente for two months now, and I also test rode an S32 extensively - very similar to the S22, just slightly lower-grade alloy and detail around seat stays, for what that's worth!

In comparison, the S32 rode like it was alive, like there was a direct connection between me and the road, whereas the Caliente felt smooth, relaxed, almost unexciting, but veeeery comfortable.

The decision came down to things like: I wanted to train long miles on the bike, so comfort was paramount; the S32/22 only has one set of bottle bosses; the dealer who sold me the QR measured me up professionally; I trusted the QR importer more than the Felt one (for UK); on the different websites I visited, and literature that I got from the importer, the geometry changed about three times in six months, and I felt uneasy about this, though I would trust Jim Felt as a brilliant builder, I'm not sure if it was his 'hand' on the torch, or whether the frames come from the Far East (and this is no bad thing normally)

As for angles, see many posts this site about how angles matter for nothing, it's where you put your saddle on the post that counts, and thus the length of top tube is crucial.

In conclusion, the QR is the 'head' choice, but the Felt is the 'heart' choice. Go ride.