Road Bike, Cycling Forums banner
1 - 11 of 11 Posts

·
Registered
Joined
·
793 Posts
Discussion Starter · #1 · (Edited)
I had a guy fit me with a fit kit. He says that I have long legs/short torso/long arms. I guess I need a taller seat tube but shorter top tube length than is conventionally setup on a stock frame. I assume that's where the stem length seat adjustment come into play to get the right "compartment".

Any way here's my stats:

Inseam: 88.2
Thigh: 42.3
Foot Length: 26.8 cm "Q" .480
Torso Length: 60.0
Arm Length: 62.5
U.B.M.= 122.5
Shoulder: 44.0 CM
Hand Medium
Weight: 165
Height: 5'11

Recommended Sport Road specs:

Seat Tube Length: 58.0
Seat Tube Angle: 73
Crank Arm Length: 170-172.5
Saddle Pedal Start: 94.3-95.9
Handle Bar Width: 40-42
Medium Drop 14-15 cm
Top Tube: 54.3
Stem 95-105

The fit kit says I need a seat tube length of 58.0 but a top tube length of 54.3. Nothing I see out there has this relationship. Should I opt to the 56 seat tube to get more into the ballpark of the 54.3 top tube length? Should I even go smaller than 56 seat tube length?

Do I need a custom made frame or can I get an off the shelf bike that doesn't look like it belongs in a circus?

Thanks
 

·
Registered
Joined
·
2,674 Posts
saddle tramp said:
I had a guy fit me with a fit kit. He says that I have long legs/short torso/long arms. I guess I need a taller seat tube but shorter top tube length than is conventionally setup on a stock frame. I assume that's where the stem length seat adjustment come into play to get the right "compartment".

Any way here's my stats:

Inseam: 88.2
Thigh: 42.3
Torso: 60.0
Arm Length: 62.5
Height: 5'11

The fit kit says I need a seat tube length of 58.0 but a top tube length of 54.3. Nothing I see out there has this relationship. Should I opt to the 56 seat tube to get more into the ballpark of the 54.3 top tube length? Should I even go smaller than 56 seat tube length?

Thanks
It all depends on what you're looking to pay. If you can afford to go custom for the frame then you will be able to work with the builder to get the fit you need. If not, with your measurements, you're likely to have to compromise somewhere as I can't think of many 56cm frames with a top tube that short. A 54 may give you the reach you want, but avoiding a big drop to the bars will be difficult without resorting to a lot of spacers. Not only is this rather ugly, but also it's bad for a carbon steerer.

So see what you want to spend and work from there. If you have to economise on the groupset to get the fit right then so be it. You'll get more enjoyment out of a comfortable 105 equipped bike than a Dura Ace setup which is a compromised fit.
 

·
Registered
Joined
·
10,160 Posts
don't believe it...

I think you fitter is all wet. I'm also a short torosed, but smaller rider and I fit just fine almost all stock frames (except Trek).

As an example, you height is 11cm more than mine and your inseam is about 5cm more. Proportionately, you torso is no shorter than mine, If you have long arms, then a longer top tube should not be a problem.

You don't mention what stem length or handlebar reach that was suggested to go with this TT length. I also see no mention of a seat tube angle to go with the TT length. A TT length without a STA means NOTHING. If you fitter doesn't know this, then he knows very little. You should get a second opinion, based on sitting on a REAL bike.

Do you have any cycling experience, so you have a valid saddle height? The vertical size of the bike is just as important as the TT length. With so many of today's bikes having sloped TTs, you have to pay close attention to the head tube length, with the headset, to avoid a goofy stem and spacer setup. Based solely on your inseam being 5cm more than mine, an appropriate frame size for you would be 5cm more than mine or 56-57cm, measured center to center. Add another 1.5-2.0 cm for frames measured center to top. Another reference point would be a head tube length of at least 170mm. Coincidentally, this would be a 57cm LOOK, in any of the popular models, like the 555, 565 or 585. The 555 has a slightly shorter reach than the other two models in this size. The TTs are a lont longer than your fitter recommended, but I can't iamgine that any of them would be too long.
 

·
Registered
Joined
·
98 Posts
Seat tube length?

I'm not sure what the importance of the seat tube length is- maybe someone can enlighten me- because once you have your seat post on, you'll have about 20cm of adjustment to play with. With todays compact frames, I *really* don't see the meaning behind this measurement. So IMHO, I would just worry about the top tube (virtual) measurement and the seat tube angle. The seat tube angle along with your saddle adjustment will dictate where your torso will be in relation to your pedals. Then assuming you have the proper virtual TT length, you should be good to go. At worst, you might have to change your stem. BTW, I find it handy to keep a few cheap 'closeout' bin stems of various lengths so that you can try them out and when you find the right size, then buy the super-cool carbon this and that stem in that size.
 

·
Registered
Joined
·
793 Posts
Discussion Starter · #5 ·
I added all the specs from the printout. And thanks a ton for your help. I'm certainly getting very good info and help here...
 

·
Windrider (Stubborn)
Joined
·
22,021 Posts
You & I have almost the same measurements......

saddle tramp said:
I had a guy fit me with a fit kit. He says that I have long legs/short torso/long arms. I guess I need a taller seat tube but shorter top tube length than is conventionally setup on a stock frame. I assume that's where the stem length seat adjustment come into play to get the right "compartment".

Any way here's my stats:

Inseam: 88.2
Thigh: 42.3
Foot Length: 26.8 cm "Q" .480
Torso Length: 60.0
Arm Length: 62.5
U.B.M.= 122.5
Shoulder: 44.0 CM
Hand Medium
Weight: 165
Height: 5'11

Recommended Sport Road specs:

Seat Tube Length: 58.0
Seat Tube Angle: 73
Crank Arm Length: 170-172.5
Saddle Pedal Start: 94.3-95.9
Handle Bar Width: 40-42
Medium Drop 14-15 cm
Top Tube: 54.3
Stem 95-105

The fit kit says I need a seat tube length of 58.0 but a top tube length of 54.3. Nothing I see out there has this relationship. Should I opt to the 56 seat tube to get more into the ballpark of the 54.3 top tube length? Should I even go smaller than 56 seat tube length?

Do I need a custom made frame or can I get an off the shelf bike that doesn't look like it belongs in a circus?

Thanks
although I am about 1 cm taller.

A couple of observations.

I would go for at least a 57 TT C to C if I were you.....54 will be way too short. 56 at the shortest if you want a longer stem. I use a 57.5 TT with an 11 cm 84 degree stem and 10 cm reach bars. If you are going to use normal 8.5 to 9 cm reach bars, you will have to adjust accordingly.

I'm assuming that the drop they are talking about is the Seat to bar drop...if so, 10 to 14 cm seems excessive....try that before you cut the steerer. This will also affect the TT length, Head tube Length Stem & Bar Reach you need. I would double check this.

As someone else said....don't ignore HT length and spacers/riser stem requireemtns.

Len
 

·
Registered
Joined
·
10,160 Posts
missing the point...

Seat tube length is sometimes the term used instead of c-c frame size. I know Serotta does this. You need some way of identifying one frame from another. What IS critical is the head tube length, unless you don't mind a wierd stem/spacer setup. Head tube length and frame size go hand in hand on stock frames.
 

·
Registered
Joined
·
10,160 Posts
won't fit....

I'm 4.5 inches shorter with about the same proportions as you have. I ride a frame with as much or more reach than the one that was has been suggested for you. It's just riduculous.

You need to get on some real bikes and try them, someting in the sizes I mentioned earlier. At the very worst, you might select a frame that was one size smaller and be forced to use a 96 degree stem, until you get some experience and can tolerate more saddle to bar height difference.

This brings up another point. I see a saddle height, but no handlebar height. Handlebar height is critical, IMO. Suggesting a stem length without a height is another huge mistake. Its easy to prove by graphical analysis that stem height and length have a nearly identical effect on torso angle, particularly if the arms and torso are both close to 45 degrees angles relative to horizontal. It's common for beginners to use less height difference, maybe 5-6cm and more experienced riders to graduate to 8-10cm.

LenJ made a comment about saddle to bar drop. He apparently confused your suggested handlebar drop (14-15cm) with saddle to bar drop. Very different items. The 14-15cm is a normal drop handlebar.
 

·
Registered
Joined
·
793 Posts
Discussion Starter · #9 ·
Might sound like a dumb question but isn't the steerer cut on a stock bike? It would be cool if it did come longer and you culd cut it down as you go...
 

·
Registered
Joined
·
10,160 Posts
Yes, but...

There is a limit to how long a steering tube can be to function properly and look reasonable. Stock bikes would typically be set up to have 3-4cm of spacer under the stem, or the maximum recommended by the manufacturer. IMO, if more than 2cm is needed, the frame is the wrong size or a higher rise stem should be used, rather than spacers, to increase handlebar height.
 

·
Registered
Joined
·
484 Posts
Some carbon steerer tubes have a maximum spacer height specified. I know I saw a limit on the Alpha Q site. I don't know if anyone else has these limits or not.
 
1 - 11 of 11 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top