I think my bike (54 cm) is a tad bit small for me. I am about 6 feet fall. When my hands are on the hoods my back is slightly curved. After a while I get lower back pain.

Should my back be curved or should it be straight when I"m leaning in and holding onto the hoods? Is the problem my back muscles rather than the bike? The pain actually disappeared toward the end of the ride ... and I'm not feeling any residual pain.

On the other hand it does seem that my bike is the smallest of the peloton's ... and my seatpost is very, very low comparatively speaking. On the other hand if my seatpost is any higher I wouldn't be able to touch the ground without leaning the bike to one side significantly.

You should be able to keep your back muscle taught and not in a forward bend. This eliminates the strain. It is the ideal position for carrying the load of your torso. The pressure in your hands should be minimal. Yes 54 is small for you. You should be on a 56. I ride a 56 and I am 6' .5". My next bike is going to be a 58. I have had a Schwinn XL which run big. The top tube height was just a tad high for me. The simplest method to sizing is stand over the bike. If you are not in danger of a falsetto but can't go any higher you are good. This gives you high speed stabilization. Also the bars on a 54 are narrower. Having your hands point in gives you less stability at high speeds.

At 5'11", I always thought my 56cm upright was too small. Although 58 was definitely too big. You're supposed to get off the saddle to put a foot down.

Keeping the back straight is easier on your back. if you're too cramped on the bike (I'm assuming road bike), and 54 is generally small for a six footer, you can extend the reach a little with a longer stem, perhaps raising it a little. And as a last resort moving the seat back extends reach - although traditional bike fitters cringe at the idea of adjusting reach with the saddle.

Touching the ground while seated is the least important part of sizing or position on a bike, in fact I'd go so far as "irrelevant."

Maybe you need to work on the Muscles , though By the time people who do Physical jobs get up to retirement age a Bad Back from On the Job injury is Normal ..


Yes, If You feel a Need to have a foot on the Ground at stops, maybe a Crank Forward Bike, is what is right for you.

saddle to pedals distance is about pedaling not stopping. laying the saddle angle way back moves the seat down but distance to the pedals remains ..

You should observe the other riders in the peleton and see whether they can plant a foot on the ground while still in the saddle. My guess is that (to steal from Sesame Street) "one of these things is not like the others."

I think you have your answer. Too small frame for your height and/or saddle much too low. I am 5'8" and ride a 55 cm frame. That is the size that gives me the correct reach and comfortable position for my back when riding. I cannot touch the ground with my feet at all when seated on my bike.

I'm 5'10", and I ride a 56cm, and yes your saddle is too low if you can touch your feet to the ground while seated.

When my saddle is at the correct height I can just barely touch the ground with my toes. If you can get your feet on the ground when seated on a traditional double-diamond bike, your saddle is too low.

Also, what model of bike do you have? For a traditional level top tube bike (generally found on older bikes), a 54 would definitely be too small - a person at 6' tallshould probably be on a 58 or 60 cm bike. But with modern sloping top tube bikes, depending on how they are measured, a 54 might be ok or it might not. I am 6'5" an I ride a 64 cm traditional road bike, but the last time I had a sloping top tube road bike I had what the manufacturer called a '58cm' and it fit well.
The problem is that different companies measure and label their bike sizes differently. I find the s/m/l/xl size system more helpful than numeric values that are inconsistently applied. I cannot believe that everyone above who said "I ride an Xcm frame and I am Y'Z"" doesn't know this.
One person's experience on a 56 cm giant does not necessarily have any relevance to a question about the fit of a 54 cm Trek.

It would help to have pictures, but even without I would say pretty confidently that: 1) your frame is too small; 2) your saddle is too low; and 3) you need to bend your elbows more.

Just my 2 cents but at 6'5" and riding 80's vintage road bikes I find 64cm to 66 cm to be the right height for me. I am fairly regularly proportioned and have a 64 cm Nishiki international, a 64 cm Raleigh Record Ace(80) a 66 cm Miyata 610 and ride all of them on rotation almost daily. I have fitted them all with 2" rise mtb style bars with thumbies.

inability to do a 1 foot tip toe stop in the saddle is a result of BB height , more than frame size ,

since the pedal to saddle top height is to be the same by seat post extension , for the same rider ..

Big difference: My High BB Pocket Llama & low BB Brompton.

The correct frame size is the one that allows you to obtain a proper fit (numbers be damned!) For most people, there is more than one frame size that can provide this. Frame sizes are very subjective and vary widely between brands and models. Basically, a 54 in one frame can be very different from a 54 in another.

Chances are, at your height most any 54 frame will not allow you to get a good fit.

I am 6'-3" and I typically ride a 58 with a 575mm VTT dimension. That is about the smallest frame I can ride and still get a good fit. To make that work I use a 130mm stem, a seatpost with at least 20mm of setback that is nearly extended to it's maximum (semi-compact geometry), and a saddle with long rails extended back about as far as they'll go. I ride a fairly aggressive position, but that configuration works well for me and has done so for many miles at reasonably high intensity.

This.

Everybody is proportioned differently. Every frame is shaped differently. Saddle setback, head- and seat-bue angle, and stem length affect fit as well.

There is a lot more to it---if you don't have sufficient core strength or sufficient flexibility to maintain the proper alignments (comfortable while allowing power output) over the length of a ride, you will start to "cheat," rolling your hips back or putting more weight on your hands, which can overstress certain areas. Possibly you roll your back because you roll your hips back to open the hip-angle for more comfort and power---possibly your cockpit is too short (stem to saddle) so when your arms and hands are set right, you cannot extend your back enough. Can't tell from here.

Also, when you mention "if my seatpost is any higher I wouldn't be able to touch the ground without leaning the bike to one side significantly" we cannot tell if you mean standing flat-footed while in the saddle or touching a toe-tip, or out of the saddle straddling the frame. Most riders can get the toes to couch while in the saddle while staying upright---but that isn't really an important measurement. if your leg is properly extended (but not over-extended) while pedaling, the saddle height is right, and the rest is what it is. We don't set up our bikes to work well standing.

For-and-aft saddle position should be determined by the crank location---most people recommend starting with KOPS (Knee over pedal spindle) and making minor adjustments from there. Because you are putting so much force through your knees, you don't want to mess with this set-up once you get it right. Change everything else, but don't risk your knees.

I am about the same height you are and I ride (comfortably) a very small frame and a very large frame. I have been shopping for a new frame and trying to weigh which would work better between 54 and 56--54 is what I want, but the short head tube on that specific frame would drop the bars too far for my fat belly and aging back. The 56 might be a little too long, so I would compensate by using a very short stem. I am not built for biking, I guess. very long limbs, very short torso, fat belly, stiff joints.)

There are other people exactly the same height who ride 58 with a long stem and find it tremendously comfortable--or a 58 with a 70-mm stem and that works. No single right answer for all.

I would assume, coming from a state of ignorance, that if your back is forced into a curve, your cockpit is too short. Possible a longer stem could fix that---but possibly flipping your stem would drop the bars, creating a bit more length ... but possibly that would put the bars too low.

Possibly after a while you will have to blow $100 for a serious fitting. But I think you might be better off playing with what you've got a little, and reading up on bike fit. Maybe try some core-strengthening exercise. Possibly pay attention to keeping your back straighter and see if this puts your weight too far forward.

Whatever yuo do, let your body tell you what works, not the numbers, or comparison with others. By the way ... there are some interesting resources online: Bike Fit Calculator | Find Your Bike Size | Competitive Cyclist)

In bold because it is the only part of the post worth reading.

I'm 6' and ride a 61cm with a 59cm top tube. I buy my bikes according to the top tube length, not the seat tube length or the nominal size of the frame.

In Yoga they teach you to keep the stomach held in, lower back filled out, don't let it sag. It totally works, you breathe better and your back won't tire as quickly.

I'm 5'8" and I currently ride a 54cm frame. Although, to be fair, it is simultaneously too big and too small for me, in different areas. But that has to do with my leg, arm, and torso lengths which are "non-standard". I've made it work, but I think I'll eventually spring for a custom frame.

Anyway - probably a tad small, but I bet you can make it work while you find something that fits better. I'd recommend going to see a bike fitter. I put it off for 4 years, and finally went to get a bike fit. Very educational. A professional bike fit is a very good thing.

And your feet don't need to touch when you are in the saddle.

Depends on which brand. I'm 5'-11" and my sLitespeed is a 57cm and fits great. I was 6'-0" when I bought it almost 15 years ago. Age has taken its toll. My 54cm Cannondale fit good too. I tried a 56 and it was way too big.

Keep your back straight and bend at the waist. Don't lock your arms. Keep your elbows bent.