Frame Size - planet x stealth

[grellboy]

Did ask a similar question yesterday but a moderator helpfully moved it to an obscure area of the website that nobody ever visits! Maybe if I rephrase it I might have more luck.
Got two bikes. Road Bike: effective top tube 57cm.
Caadx (cx) effective 56cm.
Got a chance to but a planet x stealth time trial bike. It is a medium and I am at the max recommended height for this size (6ft). However the effective top tube seems pretty short compared to my other two bikes - 53cm.
I really want to buy it but do you think it is too small for me? I sat on it and it felt ok but it didn't have any pedals so couldn't ride it!

 

[Tommy2]

You can potentially make a smaller frame fit with a longer stem up to a point as opposed to trying to make a too big frame fit.

If it's going to be tt with aero bars the top tube will be shorter than a road bike setup anyway won't it?

I would take some pedals and get it on a turbo trainer or something before you commit.

 

[grellboy]

You can potentially make a smaller frame fit with a longer stem up to a point as opposed to trying to make a too big frame fit.

If it's going to be tt with aero bars the top tube will be shorter than a road bike setup anyway won't it?

I would take some pedals and get it on a turbo trainer or something before you commit.

Excuse my ignorance, but why will it be shorter than a road bike set up? Is that just the way TT frames are?

 

[Ajax Bay]

At 6 foot, a 53 (virtual top tube c-c) frame will be too small, I'm afraid. You can try and make a frame fit, but much better to start with a frame as close to the 'right' size as possible. And your two other bikes seem just the right size (or maybe very slightly small) for a six footer. Clearly riders have different proportions (torso/legs) but whatever, 53 is too small.
@Tommy2 what TT bike have you got? I thought you just had the pro carbon and the London Road.

 

[Tommy2]

Sorry Ajax, I do also have a Ribble Reactt which I mainly use on the turbo trainer at the moment, it's a 54 frame I think but I'm 5'10'' so was border line when I bought the planet x bike, went for a smaller frame in the road bike to get a bit more of an aggressive position but could have gone for the larger 56cm frame for all day comfort.
The tt frame would have been too stretched out if I'd gone for a 56cm considering your elbows/shoulders are over the stem rather than extended arms/hands.
I may have that totally wrong and you have to take into account the geometry I.e seat post angle I guess BUT I'm happy to be corrected.

On a side note I would love to change my Ribble for a Planet X tt frame so all my bikes are matching, just can't find one at a reasonable price at the moment and it's not up there on my list of priorities just yet.