Kabuto

I'm looking to buy my first road bike, and have tried several online calculators that give me sizes anywhere from 55cm to 61cm (see below). I'm 183cm tall with 92cm cyclist inseam and 190cm arm span. Long legs, long arms and short torso. I'm looking for a bike with a more relaxed endurance type position with the bars fairly close to seat height (which is about 82cm from the BB) rather than a slammed race type position. Could I really make any of these sizes work for me?

I assume that with my body proportions and requirement to have the seat quite high, smaller sized frames (endurance or otherwise) will have a larger bar drop. So I'm thinking 61cm... If I could swing 61cm, I'd love to grab this 61cm size Roubaix Sport 2020 at the excellent clearance sale price. But every calculator other than the two shown below tell me that 61cm is a bit too large for me. So which is it??? Could I make 61cm fit if it were to be a bit too large? Or should I just wait for a smaller bike to come along? Any advice appreciated. Like elsewhere outside Japan, bikes for sale are thin on the ground here so options are very limited, especially in the sizes I'm looking at.

Ideally, I would test ride before buying, but in Japan 56cm bikes are uncommon, and 58cm bikes and larger are almost non-existent. I could also just go and get a proper bike fitting... but corona.

Iride01 

Long legs and long arms do favor you being able to handle a larger frame. I've rode way too large frames for my size 5'-11" (180 cm) and 34.5" (87ish cm) legs. I just went from a 60 cm frame from 1991 to a 56 cm frame on a 2020 bike. And I have ridden for many years a 63.5 cm bike. All comfortable.

Smaller frames do have more potential to drop the bars low, but they come with a heck of a lot of spacers that have to be removed first to get low. So don't just look at stack, because it doesn't tell you where the bar/stem height is. Add another 30 mm or so if you can't find out that from the specs.

Also pay attention to what else changes from one size to the next. Crank length changes a lot on Specialized and I'm not a believer in the proportional crank sizing thing. I like short cranks. 165 mm. I don't feel like I'm thrashing when I ride at fast cadences.

Be sure you can shorten your reach enough on a larger frame. If it already comes with a short stem, then you might regret the bigger frame.

But as long as the cost of your new bike isn't a blow to your pocket book and you can easily afford another if this isn't the one, then get some first hand experience so you'll know what works for you.

Clem von Jones

A typical newbie mistake is to buy a frame slightly too large. 56~58cm is right for you. On the 56 you'd run a 120 or 130mm stem at +6 degrees. On the 58 you'd be running a 100-110 stem at -6 degrees. On the 56 frame you might desire a seatpost with additional offset in the 25-35mm range instead of the typical 20mm but this depends on your saddle choice too. The problem with excessively long (big) frames is with your saddle too far forward it's difficult to engage the glutes and you'll overwork your quads, calves. With saddle all the way back your front wheel won't have enough weight to handle properly. The pros chose smaller frames with large-offset setposts and long stems so they can distribute their weight for epic long rides. With that setup you can flip your stem positive or negative for either epic hill or epic flat rides respectively.

On an endurance style frame with its taller headtube I'd be inclined toward the 55-56cm ETT size.

Kabuto

Thanks for the reply. Very interesting to read that you have comfortably ridden a range of bike size, including bikes that are supposedly too large for you.

The Roubaix Sport 2020 size 61 I'm eyeing off comes with a 110mm stem and an offset seatpost, so I guess that leaves some room for reach adjustment. The differences between the 56, 58, and 61 don't seem that much...

Kabuto

I certainly qualify as a typical newbie. As an older newbie, my rides don't necessarily have to be epic though. I'll settle for just going the distance comfortably

Very interesting comments about body weight distribution over the bike and saddle position (especially about having the saddle too far forward making it difficult to engage the glutes - that's something I hadn't read before). I guess its all about balance. Excellent food for thought. Thanks!

mack_turtle

Online bike fitting tools are nothing better than a vague point of reference. There is no substitute for getting on the pedals of the actual bike in question. The way to find the right length stem is to get on the bike and ride it, and try a free different stems u til you find the best fit.

Iride01 

Just to be clear, I started riding that 63.5 cm frame back in the late 70's when I was a late teen. And I rode it till about 2011. Though a lot of the in between years were just occasional rides around the neighborhood. So I might have gotten used to that large frame while young and more adaptable. Since getting rid of that bike, the smaller I've gone, the less issues I've had finding just the right positions for everything.

I'd always favor trying a bike out before buying. Even if the shop doesn't have the exact bike you are going to buy, maybe they have that same frame with a different tier groupset on it and you can get an idea from it. I rode two different size Tarmac frames with a lower tier groupset for 10 miles each before making my last purchase. While a parking lot ride on both made me think the 58 was the size, the 10 mile ride on both convinced me the 56 was the size to pick.

Still, with covid, inventory shortages because of covid and all sort of other stuff, you sort of have to be flexible. Don't buy your bike to your one and only bike. Buy it to get some experience and then once you've learned where it excels and where it leaves something to be desired, then get another.

c_m_shooter

The most important part of fit will be the cockpit length and headtube height. These can be adjusted to a degree with different stems and spacers, but you kind of need to know where you need to be. The short answer is 58cm for a sportier fit and 61 for touring fit.

Kabuto

Thanks for the comment. A local store with a used 58 size 2018 Roubaix Sport let me sit on the bike (no test rides allowed unfortunately) and with the seat set at the correct height for me (about 81 cm from BB to saddle top), the seat towered over the handlebars. The drop to the bars must have been at least 10-12 cm, probably more. As a newbie, I think I would struggle with that amount of drop, and I expect the drop with a 56 size bike would be even more extreme. Thinking of looking at a 61 size now...

c_m_shooter

The handle bars will be 20mm higher from the factory with the 61, but the top tube is longer, so you would need to get a stem about 10mm shorter to offset that. You may be better off looking for a model with a taller headtube like a touring or "comfort road" bike. I switched from a Surly Cross check with a 91mm headtube to a Soma Pescadero (all parts except brakes switched over) with a 140mm headtube to get the bars up to saddle height without a goofy stack of spacers on the steerer. Going up a size kept the cockpit length the same in my case because as the bars are raised they come back also.

63rickert

Of course you are confused. It has never been so confusing to size a bike. Look at those little thumbnail drawings. Seat tube length is what? And what if the mfr decides not to put the seatpost clamp roughly where it might be if this were a (non-existent) level top tube bike. Going to the chart for the Roubaix we see that seat tube length on the 58 is 50.5. No, you cannot make sense out of that. Standover height is where on that sloping top tube? And what if on a quick dismount you land a bit further forward?

Seatpost flex is now a big part of ride comfort and bike handling. Who has the formula for how to size the frame for optimum seatpost flex?

Best is to have the bike in front of you. Or underneath you.

Going way backwards to classic sizing you would be anywhere from 57 to 60cm on frame size. You could ride any of those, they would not feel the same. Kind of useless because current era designers do not even remember classic frames. Although they make nods on that direction when telling you the 50.5 is a 58. For new stuff S, M, L, XL makes more sense. The Eddy fit and French fit charts are purely a joke. Eddy did not ride bikes like that. Old Frenchmen did not ride bikes like that. Who gets what information from any of this?

Try hard to get some test rides. Don’t spend real money on a retail bike if the fit process is less than clear.