How far "off" can a bike be from perfect fit and still be adjusted?

[scottcw]

My "normal" fit is a 58 cm c-c ST with a 57.5 cm c-c TT, 11 cm stem, 73.5 ST angle. How far can I stray from these numbers and still get a bike to fit by adjusting the seat post, stem length, saddle setback?

I ask because I am looking at a bike with a 56 ST, 55 TT, and 10 cm stem. Can I bring the seat post 2 cm higher, get a 12 cm stem and be close enough to not matter?

[Kurt]

does your current frame feel good and work for you? Using a longer stem is good for sure, but the rest of the frame seems small really. If it does not fit you will hate and never ride it, trust me.

[weisan]

I have been riding my Legend Ti 54 cm standard geometry for a while before I got a steel Altanta at 53 cm a few months ago. I thought the 1 cm difference is minor and can be compensated with a longer stem and seat adjustments etc. After I did that, I rode the Atlanta for a couple of times but just couldn't get comfortable on it or felt like my riding was not optimal. All this time, I have using the Legend as the benchmark. My adjustments are not entirely scientific or exacting but I can usually get a really good feel for a bike when I seat on it and start moving things around.

Recently, I got an italian frame to replace the Atlanta. It runs 54 cm. I transferred all the components over from the Atlanta, and guess what, the ride is close to perfect and compare very favorably against the Legend.

So, from then on, I learn my lesson. No more 52, 53, 55, 56....it got to be 54 EXACT. If not, I am not even going to touch the bike, even if it's an OTTROTT!!! :D

weisan

[Kurt]

If really focusing on a published frame size is the way to go about it. The sta and tt are the main factors that come into play with size. About one degree of steeper sta = 1cm shorter tt – mucho important. There are only three contact points on a frame, getting fit is not that big a science. Seat height and setback are the first thing to get dialed in – seat high enough not to rock back and forth and it one just hits the lower knee bone with the ball of the foot and the axle it not a bad place to be. From there its just a comfort issue and getting a stem long enough to promote stability with the given frame size. What a standard fit will not tell you is what kind of power you are getting to the cranks – if folks spent a few hours moving their seats fore and alt or time on trainer that measures power they would be amazed of the differences. Having max crank power and having the frame disappear are the only important things to me, but everyone has different objective I guess. Anyhow, this is ot I guess.

[scottcw]

does your current frame feel good and work for you? Using a longer stem is good for sure, but the rest of the frame seems small really. If it does not fit you will hate and never ride it, trust me.

My current frame fits perfect and feels great. This would be a second bike.

[Kurt]

My current frame fits perfect and feels great. This would be a second bike.

if you have something you like, stick with it. a second bike should fit just as well as the 1st.

58 cm c-c ST with a 57.5 cm c-c TT, 11 cm stem, 73.5 ST angle. is very close to my second bike - optimo cdale, great second bike if you ask me. my legend is 58/58.5/72/120/25mm post - cdale is 58/57.5/73/120/35mm post. save your money, buy what works I say

[Ken Robb]

I ride a 62cm Rambouillet and 63cm Rivendell Allrounder, both measured c-t with 59 and 60cm toptubes. 10cm stem on Rambo, 9cm stem on AR. I have odl bike 62cmx59 c-t with 10cm stem. All have their bars and saddles about even at 79cm saddle height. All have B-17 saddles and measure about 55cm from nose to the backside of handlebar. I "ift" them all quite well and switch off riding them as the spirit moves me. Once in a while I sneak out on Leslie's 58cm c-c CSi. It has a 10cm 0 degree stem. I swap her saddle/Thompson zero set-back post for a Nitto with set-back and get my usual 55cm nose-to-bar distance and it's pretty good too, thought the bars are not quite as high as I would prefer.
Different bikes are designed for different distribution of rider weight. I have found that when I ride some bikes that "bike fitters" say are perfect for me (LeMond Zurich 57cm c-c,and others) I sem to have too much weight on the front and get high speed wobbles. Sliding way back on the saddle and barely touching the bars sometimes helps. I've heard other people state that their bikes would not turn well due to too little weight on the front wheel though I have never experienced THAT problem myself.
So my unscientific opinion is that you can get comfy on a reasonable range of sizes but hanging too far over the front may look better on paper than the results on the road.
Several of our experienced and speedy riders have expresed their preference for smaller bikes with longer stems and feel that short stems make their bikes "nervous" or "twitchy". The shorter the stem the more movement of the fork for a given distance the hands/bars are moved so a shorter stem would make for quicker steering, at least at low speeds. At higher speeds we are not moving the bars much for corners anyway. Note that except for the CSi all my bikes have relaxed angles and are toward the relaxed end of the handling spectrum so the short stems are fine for me. I do remember that the steering on the CSi got a bit "livlier" when I swapped the 12cm. -17 degree stem it came with for the zero degree 10cm to get the bars up and back. It is a magnificent handling bike with either of them--quick and lively but still very stable at 47 mph.

[scottcw]

My thought is this... raising the seat post 2 cm to get the same saddle to crank center distance will put the saddle back about 1 cm, making the TT effectively 56 cm. Putting on a 12 cm (compared to the 11 on my Ottrott) stem gets me an extra 1 cm. Now I have an effective 57 cm TT. My weight distribution will be different, probably a little further back.

Please correct any wrong assuptions that I am making.

[jeffg]

My thought is this... raising the seat post 2 cm to get the same saddle to crank center distance will put the saddle back about 1 cm, making the TT effectively 56 cm. Putting on a 12 cm (compared to the 11 on my Ottrott) stem gets me an extra 1 cm. Now I have an effective 57 cm TT. My weight distribution will be different, probably a little further back.

Please correct any wrong assuptions that I am making.

Did I miss the STA for the other bike?

[Kurt]

My thought is this... raising the seat post 2 cm to get the same saddle to crank center distance will put the saddle back about 1 cm, making the TT effectively 56 cm. Putting on a 12 cm (compared to the 11 on my Ottrott) stem gets me an extra 1 cm. Now I have an effective 57 cm TT. My weight distribution will be different, probably a little further back.

Please correct any wrong assuptions that I am making.

you did not mention the sta or if your current or new frame has a slope, but in general, the ht on the smaller frame will have a shorter ht, so you will have to use more spacers (yuck) or a positive stem position (double-yuck) to get your bars high enough. The wheel-base might be shorter, which may or may not be what you want. Is this bike a really good deal or something? I just can't see the logic in getting a different size frame from what you are using. you want to shoot for getting your weight forward, not backward - that's what modern frame like.

[Peter]

Assuming the current bike is a good fit, with a reasonable amount of seatpost visible and the bars are able to be raised high enough, then I'd venture to say the bike you're considering is too small, and WAY too short in the TT/stem.

There is a sense of proportion I look for in a bike and at some point I say "that bike is too small/big for that rider". I think the bike in question is too small.

I'd say if your current bike is fit as I mention above, then going a centimeter, maybe two larger is the more correct dimension for where you should be if you are considering another bike.

[scottcw]

you did not mention the sta or if your current or new frame has a slope, but in general, the ht on the smaller frame will have a shorter ht, so you will have to use more spacers (yuck) or a positive stem position (double-yuck) to get your bars high enough. The wheel-base might be shorter, which may or may not be what you want. Is this bike a really good deal or something? I just can't see the logic in getting a different size frame from what you are using. you want to shoot for getting your weight forward, not backward - that's what modern frame like.

No slope on my current frame. Specs:

TT: 57.5 cm; ST: 58 cm; SA 73; HT angle: 73.5 deg.

I was told by Serotta this is "stock" geometry for their 58cm.

The second frame is a Weigle with Campy Record. Actually, I prefer my weight back so I am not putting my weight on my hands. The bike I rode prior to my Ottrott had a 74 ST angle and a 13cm stem. My hands were always going numb from having my weight too far forward. The more relaxed angles and 2 cm shorter stem of my Ottrott are perfect.

[Kurt]

I don’t know what else to add on this thread – I asked about the sta of the new frame, I already know what your current frame is. If you mean it’s a Peter Weigle frame then maybe the seat tube is more relaxed ala old-school and maybe it uses a quill, which can be raised high enough to get the bar where your serotta is. For me, I would pass on the bike, because for me it has to fit to generate power. Just compare the ht and stack on the current and the weigle, that will tell you if it plausible to get it to fit. If you think sitting back is the reason your hands feel better, think again – higher bars, sometimes closer, saddle tilt and a strong core is what makes the hands feel good. Bikes handle better with more weight over the front, period. You have an Ottrott so it would seem you could afford the mistake if it turns out to be a dud, so roll the dice.

[Serotta PETE]

Weigle is a beautiful frame but >>>>

If your 58cm fits great, I think you will be at the far side of what "can do" in down sizing by going to a 56. I personally would pass it up.

This is just an opinion but I have never been able to get a 2cm smaller frame to work for me.

Sorry.

PETE