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Another sizing question.......(23 posts)

Another sizing question.......sierranevada
Nov 14, 2002 7:46 AM
I don't have a LBS that specializes in upper level road bikes, so it looks like I'm on my own trying to get the right size frame.
Stats: Height 5'-10.5" (barefoot), Inseam 31 3/4" (barefoot), Wingspan 73". The top of my saddle is 29.3" from center of bottom bracket.

I currently own a '92 Bridgestone RB-1 that just has never been ridden because it seems a bit small - 54.5 center to top of top tube (maybe 53 ctoc)....and 54.5 top tube.

Question #1: Am I on the right track looking for a frame that is roughly 55cm center to center, and 56 cm top tube?

Question #2: I would like the saddle and bars to be approx. level without using 3+ inches of spacers. What length headtube would accomplish this for me, given the 29.3" saddle height (from bb) and using a more acceptable 3/4" or so of spacers.

I am going to stay with steel, preferrably from Colnago, Torelli, Serotta. Any suggestions would be great, as I simply don't have the option of test riding in my area.
Thank you.
Not a complete answer to your questions, but ...Allez Rouge
Nov 14, 2002 8:12 AM
... if your inseam measurement of 31.75" is correct, your RB-1 should not feel all THAT small to you. Per the fitting "rules" in LeMond's book (with which not everyone agrees: see Heron, Rivendell, etc), frame size measured c-c should be roughly 0.667 x inseam length, and for you that would work out to 53.8cm measured c-c. If the RB-1 is 53cm c-c that's less than 1cm difference and that's not enough to be HUGELY noticable. Further, saddle height should be roughly 0.883 x inseam length. This works out to a tick over 28" and that's substantially less than your 29.3" measurement.

So, there are two possibilities. One is that your saddle is too high, the other is that your true inseam measurement is longer than you think it is. Since you say the RB-1 feels noticably small, I'd bet on the latter. So before going any further, you might want to double-check your measurements.
You are inseam is closer to 32.5" not 31.75"sierranevada
Nov 14, 2002 8:19 AM
not sure where the 31.75 came from, but I re-measured and ended up just less than 32.5.

Hard to say.............Len J
Nov 14, 2002 8:13 AM
but I can give you a little direction.

On first pass, I would say that you are undersizing the frame (At least the seat tube length) for what you want to do. Top tube seems about right though. The problem with threadless headtubes is that standard frame sizing is always going to leave you either with a large drop from the saddle to the bars (2 inches +) or with tons of spacers.

Couple of suggestions:

1.) Make sure you have measured your Bike inseam correctly. You should be measuring it to your pubic bones (stocking feet spread about shoulder width, Use a level pressed up till it hits the bones, make sure it's level & have someone measure to the floor). This minus 4 to 5 cm will give you approximate max standover.
(Inches X 2.54 = CM).

2.) Check out some web sites on fitting. I don't have them with me but a search of this site should find them. Colorado Cyclist, Sheldon Brown, and a few others are pretty good & give you a good starting point.

3.) Especially if you are looking for bars around seat height check out the Rivendell web site.

Grant Peterson has very different fitting biases from anyone else.

4.) I also live in an area with no local LBS that carries high end roadbikes. I felt that it was worth it to travel 2+ hours to get a professional fitting. I felt that, spending as much money as I think I am going to, it was worth the drive.

Good Luck
re: Another sizing question.......Fez
Nov 14, 2002 8:14 AM
What seems small about your current frame? Is saddle overly high? Problems getting the bars high enough? Stem too long?

You should determine if the bike is too small before you think about going bigger.
Sizing is not his main reason for getting a new frameelviento
Nov 14, 2002 9:13 AM
If he has a '92 RB-1 and looking at a new Colnago/Serotta, he is shopping for a new frame and while he is at it, get a better fit.
re: Another sizing question.......sierranevada
Nov 14, 2002 9:19 AM
yes to all three of your questions. With nearly 3" of stem showing (and a 0 degree stem), the bars are still 2.5 to 3 inches below the saddle. The stem is a 120mm in length I believe, and the cokpit still seems somewhat cramped.
sizing answer....C-40
Nov 14, 2002 10:08 AM
I've got the same inseam and saddle height as you've posted, but I'm a lot shorter at 5'-7". You've got a fairly long torso which isn't ideally suited to the Colnago geometry.

In a Colnago frame you will need a 55cm (c-t) for the best vertical fit. You could ride a 56, but the saddle height would be low and standover clearance at the bare minimum, although it would raise the bars 1cm.

If you install a Ritchey WCS stem with an 84 degree angle and no spacers, you would get a saddle to bar height difference of about 8cm or a little over 3" on the 55cm frame, with it's 134mm head tube length. This difference could be reduced to 6cm with spacers, but that about the best that you're going to do without using more stem rise. The Ritchey stem could be flipped to produce a 96 degree angle and reduce the height difference to about 3.5cm.

You could also use an 80 degree stem flipped to produce a 100 degree angle for another .5cm reduction, compared to the 96 degree.

If you use the 96 or 100 degree angles, you will need to use a 10mm longer stem (130 instead of 120).

There really is no way to get the bars level with the saddle without resorting to a custom stem with a lot of rise, which would look pretty ugly.

Concentrate on improving abdominal and back strength in order to tolerate at least 5cm height difference. Saddle position should also be adjusted for proper weight balance.

See for interesting opinions on weight balance.
Ssome links you may find usefulAllez Rouge
Nov 14, 2002 9:29 AM
In no particular order:
Nov 14, 2002 9:45 AM
I went through this about 6 months ago with a new bike. I played around with a couple of sites for fitting (Wrench Science and Colorado Cyclist). First- it depends on who takes the measurements. My wife came up with 2 different inseam measurements. But the important one is the tt length.
I have always had a problem with tt and stems and after I nailed down which frame I wanted (Colnago Master X-Light) I requested that my LBS (a Colnago dealer) do a fitting (they usually don't). I had a fitting and the owner built my bike and everything came out perfect. Which ever bike you go with, just purchase from an authorized dealer and they will be familiar how the frame fits, but they need input from you as how you position yourself and how you ride as it's more than just fitting.

Why do you want your saddle and bars level? You would have to have an incredible amount of spacers and it might not be possible. Do you have a lower back problem? I'm an old guy (60) and have a 10cm saddle to bar drop. I find riding with a lower saddle/bar drop helps my lower back as you want to be low and spread out (I've found). I also had to play around with my KNOPS and saddle height and I found riding with a perfectly level saddle makes a difference (for me anyway).

I keep on seeing posts about raising the bars, but I don't think this is the answer. Work on flexibility and your abs. I find riding in an upright postion causes for more jarring as your spine is contracted and you want it relaxed.

I'd think you would not want a drop that is higher than 2 inches (5 cm).

But that just my $.02...
the problem with TT length fitting...C-40
Nov 14, 2002 2:44 PM
While it's certainly important to get a TT length that's reasonably close to "perfect", it can be the most difficult to obtain without screwing up the vertical fit.

With Colnago and most other brands, it takes a 2cm change in the frame size just to get a 1cm change in the TT length. A long-torso rider could end up with NO standover clearance and a saddle that is way too low in an effort to get a top tube length that's 2cm longer.

The long torsoed rider must be aware that the total deviation in TT length among all brands is rarely more than 1cm, for a frame of the same (vertical) size. The long torso rider will have to use a longer than average stem, unless a custom frame is ordered. Stock frames just aren't made for long torso proportions.
Short torso hereDINOSAUR
Nov 14, 2002 3:35 PM
In my case I ride a 59 c-t 56.9 tt stock Colnago Master X-Light. My other option was to go custom......I have a short torso...the Colnago was a perfect fit for me....but I think it pays to be correctly fitted with someone who is familiar with Colnago geometry.....
me too...C-40
Nov 14, 2002 5:34 PM
I ride a 54 or 55cm Colango. I'm not quite 5'-7" tall but I've got an 83cm inseam. Either size works well with a 110mm stem.

Guys that have my inseam with at 5'-10" won't fit so well. A 130mm stem is likely.
Hey C-40 - a few fit questions...Fez
Nov 14, 2002 7:26 PM
I've got a few questions about your fit posts. I'm sure your bike fits you fine, but I was wondering about your numbers and the relation to the bike fit formulas.

If you have an 83cm inseam, wouldn't the .67 multiple put you in the neighborhood of a 55 or a 56 c-t frame? You say you have long legs, shorter reach, so I guess that's why you ride a Colnago 54 c-t. Anything bigger and I guess you would use a shorter than ideal stem. But since you have long legs, wouldn't your saddle over top tube measurement be a tad over 19cm?

Do you just deal with a tad more standover in order to get the reach right? Or do I have the numbers wrong?

I was wondering because I have almost the same proportions as you and when I used to ride a 55, I pretty much had to use a 90mm stem. 53 and 54c-t frames give me the right reach, but more standover than I care for.
55 or 54cm...C-40
Nov 15, 2002 9:51 AM
I've ridden both sizes over the years, depending on the brand. With Colnago, there's not much difference in the top tube length between the two (only .3cm) not enough to notice. I sold a 55cm C-40 and got a 54cm this year. The only change I made was my brand of stem. A Ritchey WCS with it's 84 degree angle and taller steering tube clamp produced a slightly higher bar height on the 54cm frame, than the ITM with an 80 degree angle that I used on the 55cm (both with no spacers). I use a 110mm stem on both. I tried a 120mm stem on the 54cm, but it was too long and caused shoulder pain. As long as you have knee to elbow clerance when riding in the drops, the stem's long enough. A 90mm stem would cause knee to elbow overlap for me.

My saddle is 17cm above the top tube on a 54cm, which is pretty conservative. Saddle height can vary 1cm just from different shoes and pedals. I use Sidi shoes and speedplay pedals which keeps the saddle as low as possible. Saddle height can also vary at least 2cm for riders of identical inseam, depending on preferred pedaling style.
re: Another sizing question.......tarwheel
Nov 14, 2002 10:07 AM
I am just about your size, 5'11" with 33" inseam in cycling shoes. If you want your bars about level with the saddle, which is the way I ride, then you should be looking for a 56-57 cm frame. A 55 frame would be too small -- unless you don't mind using a riser stem with lots of spacers. In my case, a 56 frame seems to fit best across the top, but a 57 is better for achieving the right handlebar height. A couple of other points to consider:
-- If you can find a frame with a threaded (quill) stem, it is easier raising your bars to the height you want. However, new frames with threaded forks/stems are getting hard to find unless you buy a custom.
-- If you buy a frame with a threadless stem/fork, which is the way most new frames are being built nowadays, you probably will have to use a riser stem and a few spacers to raise the handlebar to near saddle height. Once you get used to the riser stems, they aren't so bad and there are lots of models and sizes to choose from.
-- Read the frame sizing discussion at Rivendell bikes if you want your handlebar height to be about level with the saddle. It makes a lot of sense. The gist of the discussion is that you'll need a frame larger than what is commonly recommended because as you raise the handlebar higher it shortens the reach (or effective top tube length).
-- Be cautious about following the frame sizing formulas at and if you prefer to ride with higher handlebars. These formulas will recommend a frame that is much too small because they assume you want to ride in an aggressive position with a large drop from the saddle to handlebar.
-- When you start picking components for your bike, buy a stem (threaded or threadless) with a removeable facecap so you can easily change if you need to try some different sized stems (which is probable). Once you get the frame size dialed in, the stem is the most important component for proper fitting and a removeable facecap makes it much easier to try different sizes. Buy your stem from a dealer (such as Excelsports) that will let you exchange or return stems that don't fit.
-- Since your height and inseam is about the same as mine, you might want to consider a frame with a more "square" geometry -- that is, with top tubes about the same length as seat tubes. Most US frames (Serotta being the exception) have top tubes longer than seat tubes. A number of European brands have shorter top tubes -- including Colnago, Merckx, Viner, Gios, Cinelli. has a good selection of frame with a square geometry.

Good luck.
Thanks All !!sierranevada
Nov 14, 2002 11:21 AM
This is a great website. Determined the B-stone is a bit small (basically confirmed what I already felt while riding), so it will most likely go up for sale (or morph into an 'around-town' bike).
Now shopping for a 56 Master X-Light - and thinking that I should be just fine with a 2" or so drop to the bars.
Hummmmmm, Chicagoland Bicycle is only a 2 1/2 hour drive.
colnago sizingtarwheel
Nov 14, 2002 12:32 PM
Make sure you study a Colnago sizing chart real well. They size their frames center-top, so a size 56 Colnago is really more like a size 54 center-center. A size 58 Colnago actually measures 56 center-center.
You're welcome, and ...Allez Rouge
Nov 14, 2002 12:39 PM
... a 2.5 hour drive is NOTHING when the goal is a high-end bike. Even five round trips would be just a little more than a day, total, out of your life. That much windshield time is a small price to pay for the many many years of pleasurable and pain-free riding that will come from having a properly-fitted bike under you.
Thanks All !!DINOSAUR
Nov 14, 2002 1:41 PM
You will love the Master X-Light, go with the carbon Flash fork. Chicagoland I'm sure is familiar with the fitting of Nago's. The main measurement for me was my torso and my LBS put me on the correct TT and I had the option to swap out stems if mine didn't work out. For info, sizing charts put me on a smaller frame and it wouldn't have worked, bar drop would have been way too low as the saddle would have been jacked way up.

A 2 1/2 hour drive will be worth it. I had to wait 11 weeks for my MXL, almost drove me up the wall but it was worth it.

What paint scheme/groupo are you going with?

Keep us posted...

Nov 14, 2002 1:09 PM
download the pdf's .. do the measurements.. and you are set....
Get a reputable LBS to fit you to a bikeAvidrider
Nov 14, 2002 4:42 PM
The best thing that I ever did when purchasing a road bike last year was have a local bike shop fit me to the bike. They took into account the usual measurements like inseam length, arm length, torso height, shoulder width, etc. to make some suggestions as to frames that I might be interested in. I have short torso and long inseam so a frame recommended was built up. My second visit was spent fine tuning the fit on a trainer with a variety of seatposts and stem lenghts. I tried using alot of the recommended websites previously mentioned to get an approximate frame size, stem length, etc. I found that there are so many variables to take into account(Top tube length, seat angle, stem length, stem height)that getting professionally fit to the bike takes the guesswork out of making a wrong purchase.
Me too....DINOSAUR
Nov 14, 2002 8:03 PM
That's what I did also. Actually I was all set to go custom and I called up the owner of my LBS to see if he would give me a deal and we set up a before hours appointment and he did a fitting and we talked about how I liked my bike set up etc. It was one of the best phone calls I ever made. Best of all, he cut me a deal that I could not match anywhere else. I guess it pays to do business with your LBS, I order over the internet also, but 1/2 of my orders are from my LBS....I guess the point I'm trying to make with all these posts is to make sure you get fitted's more important than the frame material..I could order the same bike now over the internet, but before I would have been in the dark....and would have ended up with the wrong size (been there done that)...