Right Size
 

Hello. I don't know if my questions can be answered or not. I'm nube. I want to know about my size. I will post my measurements below. I am looking for a road bike which I will also use for triathlon. I will hopefully get some arobar attachments and try to set up the bike for triathlon position, however I will also use it to commute through mountain highway to work which is about 30-40km. I am in Taiwan, and although a large size bike has been recommended here, I was hoping to find out that I am close to the gap, and could adjust a medium size frame to fit me. Is that possible? It's just that there are so many great used bikes here... most are size S or M. Thanks in Advance.

height = 181cm
inseam =86cm
arm length = 65cm
ground to torso = 150cm

Depending on the bicycle you will be buying and bicycle type your size will either be a Medium or a Large. When you go the shop ask this question exactly.

More than likely you will be a large frame adjusted small. However, as I said depending on the bike, you very well could be a medium adjusted tall.

Good luck.

I think your best choice for an online fit calculator is here. It's no substitute for a trained fit specialist, but it's a whole lot cheaper.

You should arm yourself with as much knowledge as you can. There are a thousand theories but only you can decide what's right for you, especially when it comes to final adjustments.

Here's a primer on sizing and fitting.

Look for shop staff that will spend time with you and beware a shop with limited stock that steers you toward a particular size because they don't have other sizes for you to try.

One thing I noticed when I bought my new bike this summer. The bike store owner made sure I bought the right size frame and had it initially adjusted so it felt comfortable. The trouble is, most people stop there. After I had it a couple of months, put 500 miles on it, THEN I went back for the big fit-up on the trainer. Turns out I could handle a longer stem for better position, needed the seat adjusted. When I left the shop, it was perfect.

In short, I recommend an initial fit to make sure you have the right bike, then dial it in exactly when you're more used to it.

thanks and more details
 

Hi, thanks for all your posts. To sum up your advice, I need to be certain to get the right frame size. I might be a L frame fitted small, or a M frame fitted big, or maybe I could be borderline and possibly use either? I think I might be within this borderline range, because one bike shop told me I could only use a large, and the other bike shop told me I was probably a large or M depending on the frame. To be fair to the bike shop owners, the one who said I could be both had many different types of bikes in his shop, while the one who said I was certainly a large was only selling Merida bikes, so he probably knows his stock better, and there would be more consistency of the bike sizes.

Here are the details for my situation if anyone can comment that would be greatly appreciated. Take into consideration I would be trying to fit aerotards to my bike and using it a few times a week for a 30-40km commute, and also on weekends for long highway rides, as well as triathlon competitions.

Any help is appreciated.

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I am considering the M frame from the 2010 Kuota Kharma
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Forget seat tube based sizing - effective top tube, ie B in the above geometry, is a more useful number. As per CC, you are looking at a 560mm effective top tube and a 110mm stem.

Even allowing for a slightly smaller reach for a more aggressive triathlon-oriented fit (eg, my own reach is a good 25mm lower than what is recommended by the CC calculator, with a 5.5" saddle to handlebar drop), a size M with a 535mm ETT might be a bit too small for you possibly?

V.

The listed inseam and saddle height do not match-up. A common saddle height for someone with an 86cm inseam would be around 76cm, not 79-81cm. Makes no sense at all.

The M or L sizes could both be made to fit the same. The 145mm head tube length is on the short side for a 76cm saddle height, unless you know that you can tolerate a saddle to bar drop in the 7-9cm range, or you're willing to use a flipped-up stem. That might make the size L a better choice, since the head tube is only 9mm taller. It will require one size shorter stem. To deteremince the stem length difference, you have to compare both the TT lengths and the seat tube angles. The steeper angle on the size M increases the reach by about 5mm, so the difference between them becomes 10mm, not 15mm.

EDIT: OK I missed the part where you mentioned a 110cm stem :D

Thanks for all the help. What is a "flipped up stem"? Do you mean flipped up handle-bar? Thanks so much for the advice and fit info.

Just to make sure I understand your meanings: Both bikes could be made to fit the same, but the L frame will allow me to have further and higher handle bars, and wider range of riding positions.

Should the fact that I may be riding lots of hills, and mountains and would like to have a little more control over my bike make me lean towards a L or M frame?