Hi all,

Looking into building up a TT bike on a bit of a budget, certainly < £2000/$3000, so I am first trying to figure out which frame to base the build on. After a couple of basic fits in local shops and using some online calculators(Competitive Cyclist & Slowtwitch) I think in the ideal world my Reach should be around 430-435mm and Stack something like 650mm. Also think I will need a pretty tall head tube because my inseam is around 95cm, and have been told effective top tube lengths of anywhere between 57-60cm. These don't seem to tie in very well with any manufacturer geometries that I have seen so far!

Can anyone recommend a frame that would be closer to my size? Have never owned a TT bike before, so I'm struggling a bit with this one. None of the shops near me have anything in stock except the usual medium or if I am lucky, large, and they are pretty useless when you are 195cm! So can't really try anything before ordering unfortunately.

Thanks,

Campbell.

Ribble Ultra TT XL has a nominal top tube of 574 (78deg STA) & 164.8 HT. I'd primarily focus on headtubes to give you idea if you could get your TT bars at the correct height.

Thanks for the reply. According to Slowtwitch I should be on something like a 25cm headtube, which I don't think is going to happen!

For what it's worth, I run quite a big saddle-bar drop on my road bike(about 15cm), and in the 'phantom aerobar' position my back is pretty much flat. So I think this could be increased when I run a steeper seat angle/shorter saddle-bar 'reach' on a TT bike without any major problems, correct me if I am wrong please!

So I think I should be alright to go with quite a large drop, back of a beet mat calc says about 17-18cm depending on the seat tube angle, but will still need a head tube quite a bit over 20cm...

Remember the extensions with risers can be a lot higher than the base bar & stem.

Wiggo example

Have you looked at the slowtwitch fit charts? Sounds like you need a Short n' tall (Specialized) bike instead of long n' low (Cervélo). There are stack and reach plotted for a lot of bikes in various sizes on slowtwitch.

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Your numbers sound wrong. You are 12 cm taller than I and your inseam is 7 cm. Forget head tube. Mine is 165mm plus a King headset on my road bike, 32mm and 120mm on my tt bike. On my size medium Scott Plasma 2 my saddle from the center of bottom bracket to the top of the saddle is 80 cm. The top tube is only 53.5 cm and my stem length is only 10 cm. My tt bike is my best fitted bike since I'm most comfortable on it. The only numbers you should be concerned about is the correct saddle height and reach.

Looking at the Scott Plasma 2 I would think you would fit on a large or a XL. With mine if I did not cut the ISP post by 18mm I could be almost 50mm higher adjusting the topper which has 30mm of adjustment up from the lowest point.

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Do you want a UCI legal position? That would mean needing reach 430 or less.
If you're only worried about tri you could go quite a bit longer.

The calculators are not doing well for you. I'm 193 with 94 inseam and ride a 56 P5. Drop to pads 195mm (135mm on road bike for comparison).

If you're not constrained by UCI then it's hard to go past the trusty Cervelo P2 in 56/58 cm and choose some bars that have a good stack range (Zipp Vuka Alumina would be a good choice) so you can easily tweak your position.

I think you may be missing the effect of pad stack in your beer mat calcs - ~55mm min stack for a lot of recent bar designs.

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Thanks for the replies.

I was wondering about the 'accuracy' of the calculators as the numbers seemed pretty odd. UCI Legal position is preferable though, I want to be doing the British Champs in a couple of years and don't particularly want to have to buy another bike if/when the time comes.

I can get a really good deal(30% off RRP at least) on anything from Scott, Trek or Forme, so I'm hoping one of those will fit me well enough. Trek's 7 Series TT bikes are being switched over to Project One for 2014 so I was looking at one of those with the Zipp bars(had them in mind for a while because of the ability to have a high stack with the extensions staying the same height from the pads). Or is the geometry of those frames wrong for my size/build? I know it's nigh on impossible to tell from the internet but thought I would ask the question anyway...

Thanks,

Campbell.

More importantly - Trek 7 series is on the UCI approved list for MY2014 (sans BB fin) where MY13 is not (seatpost).
Trek and Scott both tall frames, which is likely going to be useful as you will probably need highish stack to compensate for needing to shift the saddle back to stay within reach constraints.
Trek certainly the fastest of your options, I think the fact that Formes site lists style first in the attributes is quite instructive...
I would need very low stack bars on an L SC7, or would have a bit more choice on an M

Based on saddle at 835mm height & 50mm setback


This would not be your starting TT position unless you already have a bit of experience, rather what you would be working to as you aim at nationals.

It seems strange for tall people to be looking at mediums but that is the reality of UCI rules and frames getting taller. Handling not really compromised on a smaller frame as your weight is necessarily pushed back.

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May I ask which charts you are referring to?

You may know more than I do, but there some changes for 2014 on Extensions morphological exemption...

http://www.bicycleretailer.com/sites/de ... C2%B04.pdf