benajah

Ok I know this could invite a bunch of smart a$$ answers but its a serious question. We always talk about how important bike fit is, but if a bike is a size too big or a size too small, what are the real implications...loss of effeciency? discomfort?
Now, the reason I am asking is that my wife gave me a bike several years ago that I love, is very comfortable, but is a little too big. I have several other bikes that fit me perfectly, road bikes, but the bike in question is a touring bike that I am planning a 2 weeks long, 100 mile a day tour on.
I am just asking because I got to thinking about how the bike is a bit big but I still like it, and how much we emphasise how important fit is...so it got me to wondering what the actual ill effects of fit are if they are not too far off.

10 Wheels

Did you ever go for a long walk in shoes that were too small or too large?

MegaTom

Maybe one or both. But not necessarily. Poor handling & control is also a possibility. But if the frame is at least close to a good fit and feels comfortable enough to you (perhaps with a shorter or longer stem or other adjustments), then there's no reason why it wouldn't work just fine for your trip.

benajah

See thats the funny thing. This bike is a Surly Long Haul Trucker, which typically run big, so she got me my normal size and it is at least 2 cm TT-HT big. I can see the front hub in the hoods, knee is at an obtuse angle with the crank at 90 degrees to the ground, and I feel a little stretched out, but I enjoy riding it, can ride it all day without feeling like anything is out of whack.
that is exactly the thing that got me thinking, do we take bike fit too seriously?
However, if on a higher performance road bike, where you are trying to get every bit of effeciency out of your body you can, fit might be extremely important. My question is, what is that importance, as in, engineers answer

awesomejack

I'd imagine just some discomfort over time. A majorly incorrect fit is obviously going to be painful immediately. But when its just a little bit off, its probably just some soreness in the elbows, knees, hips after rides. So my answer would just be that a bike to big or small is just going to cause some discomfort.

Machka 

You've heard people comment, "Oh, I couldn't possibly ride [25 km/50 km/100 km/whatever], I'd be in too much pain. My [knees/butt/shoulders/whatever] would be way too sore. How do you do it???"

Chances are, their bicycles don't fit them, and if they got a bicycle that fit, or adjusted their current bicycles to fit, the pain of cycling would be greatly reduced.

rollin

Discomfort. It can be done, it's just better not to.

roadiejorge 

I had a bike whose top tube was 2.5cm bigger than I need for a comfortable fit but I tried to make it work, and while I could ride it (and did so regularly since I couldn't get another bike) I never enjoyed the riding as much as I did once I got one that fit properly.

WHOOOSSHHH...

This probably sounds stupid. But if it's comfotable, it fits and if it's not, it doesn't.

LarDasse74

THis is not stupid. It should be the mandatory training mantra for all bike shop employees. OF course, everyone has a different version of comfort...

datlas 

^^ This.

If you have been riding road bikes for awhile, you can probably figure it out for yourself.

However, if you have not been riding, or your version of "comfort" is an upright beach cruiser on the boardwalk, it may take some time to get comfortable on a properly fitted road bike.

To the OP, I don't see why you couldn't take the bike in question on your trip.

Oh yeah, you can say ass.

cyclezealot

May I add a question to the question above , in regards to fit...
How do you align your saddle to position your upper torso with the handlebars.. Say, your back is at a 30 degree slopped position. Where does your hands fall in relation to the handlebars, without stretching... The result would be your hands naturally fall adjacent to the drops . In order to hold onto the grips surrounding the brake lever it feels like an abnormally long stretch.. Your saddle 's position would greatly influence what part of the handlebar your hold onto .. Where does your hands normally fall relative to your handlebar.. ?.

DaveSSS 

I would anticipate no problem unless the fit of your other bikes cannot be duplicated on the too-large frame. Most often, one size larger frame means a 10-20mm shorter stem and maybe you can't get the bars quite as low. Other than than, that it shouldn't be a big deal.

If the frame has a 10-15mm longer front-center, you'll probably have a little less weight on the front.

CPFITNESS

As someone who knows a lot more about golf than biking I would say that in golf club fitting is very important to maximize potential. If a big hitter is trying to play with ladies flex shafts or vice versa you are going to have a hard time hitting the ball well consistently. With that said, I can give any PGA Tour pro any set of golf clubs and they will still probably shoot even par. So the better you are the more you are going to be able to adapt and make necessary adjustments.
As a personal trainer I would think the effects of an ill fitting bike would be the same as any typical overuse injury. Generally overuse injuries don't happen in one or 2 weeks, they happen over a period of months sometimes years of doing the same motions incorrectly. Seems to me that if you feel comfortable on this bike and know that it's not gonna be your daily bike, you'll probably be okay.

AngryScientist 

you can compensate for TT length directly with stem length. if your saddle position, relative to the BB is not correct, try moving to a zero-setback post, and finally, shorter crank arms.

i'll echo what the others said too, if you can ride it for miles pain/discomfort free, it probably fits you fine.

DaveSSS 

A larger frame does not place the saddle further back, unless the STA is more slack. In that case a different seatpost setback might be appropriate, but switching to a nonsetback post is equivalent to a 1.5-2 degree steeper STA. It's a big jump.

AngryScientist 

i agree, depending on the setback of the original post, of course.

DaveSSS 

I assume a setback post to have 20-25mm or setback. A very traditional post would have the front of the clamp very close to the centerline of the seat tube. With a 40mm clamp length, that's a 20mm setback.

Measuring setback from the center of the seat tube to the center or the seat rail clamp is not the best method, IMO. If you really want to know the maximum setback, measure from the seat tube centerline to the front of the clamp.

George

Handlebars with a shorter reach should help. If that doesn't fix it get a shorter stem. If your set up with the saddle is in the right place, you don't want to mess with it. You have to make your adjustment to fit, with the front.

nitropowered

You can usually set up a size too big or size too small bike up correctly with stem and seatpost adjustments. If handlebar and seat positions are the same on two different sized bikes, there is little ill effect.

now if you can't get your bars close enough, or seat low enough, then you have a problem.

ridethecliche

Truth.

There is more than one correct fit. If the bike you have allows you to attain something that's comfortable, without loss of functionality, then it fits.

LarDasse74

Your saddle should not be adjusted to change your positionn relative to the handlebar - it should only be adjuster to adjust your position relative to the bottom bracket. To adjust the position relative to your bars, adjust the position of your bars.

You question is one I have heard many times over the years - "what is the correct angle you back should be at? And how far should you have to reach?"
For body angle, there is no right or wrong, and trying to angle your back at a perfect 30 deg. slope then reaching for the bars is awkward, unnatural, and pointless. I guarantee that if a person has an ideal back angle, it is not going to be a round number like 30 degrees.

There is no right answer, although some profess to know what is best. The problem is - everyone has differend bodily proportions, different flexibility, and different expectaton when it comes to comfort. I could answer you assuming you are racing in the European pro peleton, or assuming you like to ride with your grandmother along the multi-use path in your town. These are two completely different answers, and in a sense both are correct.

You said it feels too long - then it is possibly too long. If you are talknig about a bike you already have then get a stem that is 10 or 20 mm shorter - it will make a world of difference. If it is a bike at a LBS or a friend's house that you have sat on once or twice, you really need to take the bike for a few rides to see what it feels like to actually do a few miles. If you are considering buying a bike, see if the shop where you are buying will swap out the stem for a different one after a few rides when you have a better idea what you need.

And if you have absolutely no idea what a proper fit should feel like, find a shop that does professional fittings and work with them to figure out your ideal measurements.

Kimmo 

I'd say if your frame isn't quite the right size but you've got the right position on it, handling will be slightly compromised.

It's prolly no big deal as far as many folks are concerned, cause they're not going 10/10ths down mountainsides and it's something you tend to adapt to without really noticing after a while (might feel a bit funny at first).

Better to have a frame that's a bit too small rather than a bit too large though, for the sake of standover clearance and getting your bars as low as you might want.

cyclezealot

Thanks Lars.. What is everyone's sense of where your hands should fall relative to your handlebar.. I sense I rarely curl my hands about the brake lever grips because the distance is too far.. Seems that would be a comfortable position..

guadzilla

You can also put an extra spacer or two below the stem to raise the bars and reduce reach a little.