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Competitive Cyclist Calculator Question

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Competitive Cyclist Calculator Question

Old 08-14-18, 11:17 AM
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Competitive Cyclist Calculator Question

Hi guys! I just did the measurements calculator from Competitive Cyclist to determine my ideal geometry and it's telling me that my ideal top tube size is 57-58 cm. However, my first road bike was a 58 and it felt huge for me; I then went down to a 54, which is my current bike size, and it feels pretty good but I think I may need a longer stem. I test rode a 56 cm bike a while back and it also felt very strange to me, but could that be down to me being used to riding a bike that's one size too small for me? Should I trust Competitive Cyclist's calculator and get a bike that's a 58 or try out a 56? Can I stick with a 54 and put a longer stem on there? What are your thoughts?
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Old 08-14-18, 12:14 PM
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Originally Posted by Psychocycles
Hi guys! I just did the measurements calculator from Competitive Cyclist to determine my ideal geometry and it's telling me that my ideal top tube size is 57-58 cm. However, my first road bike was a 58 and it felt huge for me; I then went down to a 54, which is my current bike size, and it feels pretty good but I think I may need a longer stem. I test rode a 56 cm bike a while back and it also felt very strange to me, but could that be down to me being used to riding a bike that's one size too small for me? Should I trust Competitive Cyclist's calculator and get a bike that's a 58 or try out a 56? Can I stick with a 54 and put a longer stem on there? What are your thoughts?
Their calculator is purely programmed to accommodate your fit based on the geometry of your body and the geometry of a road bike.

The calculator assumes you will ride comfortably in the position you chose. The Competitive Fit even says in the description that many riders cannot be in that position comfortably and prefer a more relaxed fit.

The key to choosing a proper frame size is getting your saddle position correct, period.

The reach and stack are purely up to the rider and depend on arm length, core strength, flexibility, preferred hip angle and in some cases, abdomen size.

If you're able to ride a century on a bike and nothing hurts after and your stem is the proper length for you to be in full control, you're on the right sized frame.
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Old 08-14-18, 12:43 PM
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Originally Posted by 69chevy
The key to choosing a proper frame size is getting your saddle position correct, period. The reach and stack are purely up to the rider and depend on arm length, core strength, flexibility, preferred hip angle and in some cases, abdomen size.
That calculator can get you a ballpark answer .... it may be a little league softball park, very small ... or it maybe a park in another country, designed for another sport. it is just an algorithm. it is sometimes an aid.

I think [MENTION=409489]69chevy[/MENTION] nailed it. Even people with the precise identical dimensions have different bodies. That calculator might not understand yours at all.

I agree even more with his idea about the seat.

Find where the saddle works best for you. Find the right distance from pedal to seat, figure out how far back you feel comfortable. I usually prop the bike up against the washer/dryer on one side and use a plastic tool box as a step on the other, so I can sit in the saddle and and still be stable. Once the saddle is right (and this should be pretty much the same for all your road bikes) then i lean forward to whatever degree I know I can maintain comfortably. I take my bars, hold them as I would riding ... and there is where they need to go. i measure where that is and get stem length and angle.

I could not care less what "experienced fitters" tell me unless they are serious fitters ... the kind with video recorders and lasers and such. Everyone puts me on too big a frame, always. Everyone tells me my frames are too small. Nobody asks me how I can ride 40-50 miles and not be in pain after riding that "wrong" sized frame.

You can use the bike you ride now and make small changes. You can get stems from China for $7...... get three or for different lengths and angles and see what works.

As for as the numbers ... they mean nothing. Every bike is a little different---different angles, different tube lengths ... all that number means is ... well, whatever it means. Could be the "virtual" top tube, the actual top tube, could be the seat tube The question is how the frame and your body work together.

if you slap a 130-mm stem or even a 150-mm stem on your bike and it feels right ... ti's right. if you buy a "too-big" frame and use a 80-mm stem, it's fine. if the control surfaces are convenient and comfortable after a long ride, if your contact points provide enough supoprt without pain after a long ride, your bike fits ... regardless of what anyone else tells you.

What matters most ifs getting a feel of what your body prefers. A lot of frames can be made to fit with a longer or shorter stem and seat post, long- or short-reach bars, seat-post setback .... find out what feels best to you, and you should be able to set it up on a lot of different frames.
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Old 08-14-18, 12:48 PM
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IMO, calculators are a so-so thing.
Sure, they’re better than guessing blindly, but they don’t know you.
I have reduced mobility in my lower back and simply can’t do longer rides in manageable pain on a traditionally fitted bike. I need shorter stems or smaller frames.
Took me some time, and considerable discomfort before I decided to trust my body instead of the numbers.
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Old 08-19-18, 08:14 PM
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Thanks for the responses! I took your advice and bought a sized 54 aero bike and it seems to fit like a glove. Hopefully I'll be able to do a 60-80 mile ride soon and really see if there are any fit issues
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Old 08-20-18, 09:12 AM
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I don't like their calculator. It consistently comes up with too long top tube.

My custom frame from R+E Cyclies in Seattle is shorter than the Competitive recommendations.
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