Size Debate
 

I'm 6'4" with an inseam of 37". So, most of my height is from my legs and not my torso. My current bike is a Giant with an XL frame. Looking to buy a new road bike, and they have a 58 that feels pretty decent. I can obviously adjust the saddle to a proper height, and the reach is a bit shorter, not putting too much pressure on my hands, which is good. In another words, it works. But, I still believe a 61 would be a better fit. Not having it in stock, I can't compare, so they will have to order one.

Any thoughts on which size may or may not be better?

At your height, I'd highly recommend the 61 over the 58. If the 58 feels ok to you (but with plenty of extra standover), then the 61 should feel better. The 61 should have a taller stack; meaning the stem and bars are a bit higher (good for you).

The only drawback to the 61 would be the longer top tube, if that puts it out of the range of comfort. You could probably fine-tune it with a different-length stem.

Thanks. :thumb:
That's what I'm thinking too. I'd rather adjust the reach with a different stem, and have a bike that's the proper height.

I dunno. I'm also long of leg/shorter torso, (albeit a lot shorter) and my cycling life was changed by realizing I needed to size down to find the right fit. I'm 5'9" with a 33" inseam, and everything and everyone on the planet puts me on a 54, but the first time I got on a 52, it was obviously perfect. (I had a 54 that I put a short stem on and the handling got twitchy. The 52 was night and day compared to that. I got rid of it and got the 52.)

my my point is, don't be so sure the 61 is the right size. I think it might be better to get the 58 and then put a longer stem on it if you needed more reach. If an average person 6'4" is "supposed" to ride a 61, I'd pick the 58.

Yeah... not all 58's or 61's are created equal ether. Maybe most 60 or 61's would feel right... and a few 58's. Either way... if it feels right... it feels right.

I assume you are test-riding a new bike with an uncut ridiculously long steer tube.

So, if you think of the bike as having 3 points of contact, seat, pedals, and bars. Then you should be able to adjust both bikes to almost the same fit, to give a reasonable test ride. And, if you're ready to plunk down a few thousand on a new bike, the shop should be willing to help you with the fit on the demo (assuming you're not just yanking their chain).

Some of the angles will be slightly different so the seat forward/back position may appear different, but you should still be able to set them to almost the same position.

Assuming a casual rider, then I'd go with the 61, or even larger.

If you're doing competitive racing, then you might consider the smaller frame which would allow more lower handlebar adjustment.

61 over 58 for sure... squeeze into a 59 Lemond-type road bike with its exceptionally loooong top bar perhaps but as far as modern sizing goes, the 61 will never be too big.

There may also be some calculations of optimum crank length for those taller riders.

There is a bit of a trade-off of cadence vs torque with longer cranks, but the power remains about the same with long or short so it may be rider preference.

175mm is common.
177.5 and 180mm is available from most major manufactures.
Longer is probably a special order item.

I agree with the 61. I'm your height, but with a smaller inseam (more upper body). I've tried 58 - 60 and always feel cramped. a 61 -63cm frame lets me feel like I'm in the bike rather than on it. As well, you will have more wiggle room in the cockpit for adjustments with the taller headtube.

61cm, no doubt about it. I'm 6'3" with 36" inseam and comfortably ride a bike with a 62.5cm effective top tube. If you must, you can always adjust your reach with a stem swap. As others have already mentioned, the larger frame will have a higher stack height which is an important consideration with bike fit.

Depending on your riding background, a 58cm might feel comfortable on the sales floor but out on the road things are different. True, you can just as easily swap stems on a small frame as a large, but the steering feel and handling deteriorates considerably (IMO) with extra long stems. Slight discomforts which seem to be small and inconsequential in the showroom grow larger the longer you ride.

I've spent a lifetime trying to fit myself onto bikes that were too small. I've been hunched over too small frames with long stems, toes overlapping front ends and seats slid back on offset seatposts. Mostly because the correct size wasn't readily available. "We can make it fit," they'd say. And me, always impatient and unwilling to wait for an ordered bike, wanted to believe.

I strongly recommend you find and ride a 60-62cm bike -- even if it's nothing you'd want to buy. Try it out for size and feel. Obviously, it would be best if you could find something with similar geometry as the bike you really want but even if it's not exactly the same it'll give you a better idea about what a larger frame size feels like to ride. Take note of top tube lengths and stem lengths for an idea about what feels best for your reach. If you can't find bikes to ride in your size at your local shops, remember Craigslist. Then, go order the bike you want in the size you need. Good Luck!


-Kedosto

Thanks, guys! I do believe 61 is the way to go.

Surely you can go to various shops and actually try a few sizes?

I am a little shorter than you abut have similar proportions (maybe more extreme) with a lot of leg and a short torso, and I find that bikes which are "supposed" to fit me have too-long top tubes. It seems the smaller frames sometimes have slacker seat tube angles which means I can get the saddle back far enough by raising the seat tube, where on a slightly larger frame I need to push the saddle back further on the rails, while with the shorter top tube (and head tube and thus stack) I can run some extra spacers and a steeper stem angle (not length) to get what I need.

But ... it is rider-specific as well as bike specific. I strongly suggest trying several frames in several sizes. And as was mentioned above, if you really plan to buy a bike there, and they are not willing to bring in a 61 for you to test .... don't buy a bike there.

This is certainly a mileage varies thing, but I'm the same dimensions and ride a 66cm.

I found that the Bike Fit Calculator worked very well for me. As a result, I got a bike one size larger than popular wisdom and the salesman recommended and it fits great!

Bike Fit Calculator | Find Your Bike Size | Competitive Cyclist

It will take the guessing out of the equation.

Bike fit calculators put me on a 56cm, I ride a 58cm, and I find it maybe a little small. I wouldn't go to a 61, but it's close - but I'm only 6" (and almost 1/2"). I probably just need to get a longer seat post.

Heck, I'm only 5'8" with a 30" pants inseam, and I ride 23"/57-58cm bikes - Yes, 'the boys' would be in for a world of hurt if'n I was to come down flat-footed, but that has yet to be an issue in over 43 years of riding that size frame! I felt too cramped on 21"/53-54cm-frame bikes. Maybe I'd like a 22"/55-56cm, but that opportunity has never presented itself.

That said, all of my bikes are vintage diamond-frame steel frames. Maybe things have changed with new 'sizing'...