Overall "toptube" fit question

Discuss light weight issues concerning road bikes & parts.
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go4custom
Posts: 152
Joined: Sat May 21, 2011 3:30 am

by go4custom

I'm getting a new frame (Swift Ultravox Ti ) and don't know how I should make up for the shorter toptube, 130mm stem or 120mm stem with bars that have longer reach?

My custom Sycip has a 55cm TT with a 110mm stem. The swift has a 53.7 TT. Trying to figure out if I should get a longer stem (130) making the overall TT length 667mm vs. the Sycip's 660mm. OR run a 120, 657mm overall with bars that have slighter longer reach. Now, I'm aware that overall length is generally measured to the center of the bars, but since 90% of my riding is on the hoods, this is the length I'm looking at.

Thanks.
Last edited by go4custom on Wed Aug 28, 2013 5:39 am, edited 1 time in total.

wasfast
Posts: 346
Joined: Tue Sep 26, 2006 1:03 am
Location: San Diego California

by wasfast

Simple answer: I'd get the shorter TT frame. That said, it comes with a couple caveats. The longer stem will slightly reduce the steering response. That's not necessarily bad, just different.

The potentially bigger issue is the head tube length. The smaller frame is nearly guaranteed to have a shorter head tube. You will either have more spacers or more saddle to bar drop.

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WMW
in the industry
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Joined: Sun Jul 29, 2012 2:59 pm
Location: Ruidoso, NM

by WMW

You *must* know the respective seat angles or the reach measurement, and the headtube length or stack. You will put the saddle in the same place you do now, which will be a different place on the rails if the seat angles are different. The TT length alone doesn't tell you anything.
formerly rruff...

go4custom
Posts: 152
Joined: Sat May 21, 2011 3:30 am

by go4custom

The seat angle on the Sycip is 73.5, the Swift 73.7, nearly identical when looking at the position of the saddle. Secondly, HT length is only 2mm difference, so this doesn't mess too much with my drop.

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martinSL
Shop Owner
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Location: North Bend, WA

by martinSL

In the TT\TRI world it's all about reach and stack. and these measurements are great to compare road and CX bikes too. The thing in TT is that some superbikes do not allow you for a lot of adjustments with the stem as they have the integrated cockpit system. The frames in TT tend to be low and long or high and short or in-between. Unless you are now on a hugely extended cockpit you should not go bigger in either direction. Smaller is most likely OK as you can always get a longer stem and/or add spacers under the pads/aerobars; be careful not to have the pursuit bars way too low. Great adjustability in the cockpit is the key - canyon speedmax CF has one of the best - some 600+ different combinations
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wasfast
Posts: 346
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Location: San Diego California

by wasfast

Martin, I think you made the same assumption I did initially, that he was looking at Time Trial frames. TT=top tube in this case for a road bike.

go4custom
Posts: 152
Joined: Sat May 21, 2011 3:30 am

by go4custom

Edited the topic. That might help people.

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martinSL
Shop Owner
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Location: North Bend, WA

by martinSL

wasfast wrote:Martin, I think you made the same assumption I did initially, that he was looking at Time Trial frames. TT=top tube in this case for a road bike.

Totally - how funny!!! But interestingly the concept of reach and stack still applies. For me this is the ticket plus I like to know the wheelbase and chainstay length - these two factors can really make the ride different; rake\trail and BB height are good ones to take into consideration too.
Cheers guys
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