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Here's a whopper for C-40 (and other size-minded types)(14 posts)

Here's a whopper for C-40 (and other size-minded types)serbski
Dec 9, 2002 4:26 PM
I'm new to this board and pretty new to cycling so bear with yet *another* sizing question. Here's the deal: I'm an ultramarathoner (50-100mi races) who's rehabing an injury with cycling and, after a number of borrowed bikes in various sizes (53c-c to 55c-c), I purchased one to call my own back in june. A little background: My LBS, where I was fitted and bought my bike is very low key (i.e. no pressure sales) and came highly recommended. I've been logging some fairly high miles (in my mind at least) and only now am coming to understand even the faintest notion of the concept of bike fit. In other words, I only wish I knew the little that I know now when I bought my bike (which *was* done with the help of my cat.2 racer friend at least). Here's my set-up: I'm 175cm tall w/cycling inseam 85.5-86cm. I ended up with a Look KG361 56c-c, tt=55.9, standover=81cm, HTA=73, STA=72.5. I'm running a Zepp 115mm stem (80dg. rise)w/2cm of spacers with the top of the saddle 20.6cm from the tt and about 10.6cm from the top of the bars. Does this sound about right fit wise et al. I only ask because it seems that everyone else rides tiny frames with 14cm stems (and I won't even get into what the pro bike sizing looks like to my uneducated mind). Generally, the bike is comfortable, yet I must qualify that statement by stating that I'm not sure if I know what biking comfort is! I've done 60-70mi rides with lots of climbing and all with no back complaints or anything of that nature other than a slightly sore neck. I come from a sport where suffering and disregard for creature comforts go hand in hand so if I *am* suffering needlessly, I don't think I'd know it! Mind you, after 12 years of running I won't accept anything less than a perfect shoe fit and that took eons to figure. Any opinions regarding my rookie/long-winded query would be most helpful...
Don't change a thing...Spunout
Dec 9, 2002 4:39 PM
Your back will stretch out, hopefully your neck pains will ease. Twist, turn, and stretch your neck when sore.
re: Here's a whopper for C-40 (and other size-minded types)Roger H
Dec 9, 2002 9:31 PM
I'm no expert, but I have spent a lot of time investigating various sizing resources. From what I've read and experimented with, your bike sounds pretty close to right on. Plus the fact that you are new to cycling and after a 60-70 mile ride only have a bit of a sore neck, speaks volumes. I agree with the previous poster, stick with what you got, at least for the time being.
re: Here's a whopper for C-40 (and other size-minded types)Tunji
Dec 9, 2002 11:47 PM
Serbski. it looks like you have the right fit. I may be in the same boat this spring when I order my bike. I'd like to go to my LBS (R&A Cycles) test a bike or two out on a couple of long rides, but in NYC, that could never happen without leaving your 1st born...& she'd better look like Jen Lopez! Coming from our sport (distance running) it's difficult to to understand what discomfort is on a bike. (other than getting used to sit bones) In training, when we go out on our weekly 20 mile run, you'd have to do a century or longer on a bike to come close to that level of discomfort. And your a ultra-marathoner?! Runners are natural climbers, so you probably amaze your cycling friends with your ability to get up mountains. On paper that bike is the right size, just find the right work out for your neck. (I don't know what it is) Remember, we're bent over but our head is up. Good luck rehabing you injury, & do some duathlons next summer. The longer the distance the better for you! (us)
re: Here's a whopper for C-40 (and other size-minded types)serbski
Dec 10, 2002 10:33 AM
Tunji. Nice to know I'm not the only injured runner trying to make his or her way in the world of cycling. Gotta say that I really dig it and it has kept my fitness up very well, dare I say, it may have improved it to boot. Yeah, climbing is fun as it provides the same misery/pleasure as does running. Later...
re: Here's a whopper for C-40 (and other size-minded types)koala
Dec 10, 2002 4:08 AM
You certainly shouldnt be on a smaller frame and with that much standover you could go one centimeter larger. If the top tube/stem seems right I would just ride that thing, and welcome to the board with a warning, cycling will become addicting.
things to consider....C-40
Dec 10, 2002 6:14 AM
LOOK frames have short head tubes and relatively short top tubes (due partially to the slack STA). If your posted 86cm inseam is correct, a 56cm c-c frame would be the recommended size. You also have legs that are about as long as they come for you height. The saddle height of 20.6cm above the top tube suggests that your inseam may be longer than you think, or you place your saddle higher than would be common. A saddle height of 17-18cm above the top tube would be more desirable.

The most effective saddle height can vary considerably among riders with the same inseam. Years ago I followed the traditional (but bad) advice of raising your saddle until your hips rock at a high cadence. If you're relatively flexible, this will produce a saddle height that is entirely too high. I always make sure that I can drop my heel about 2cm below horizontal, with my leg locked out at the bottom of the stroke. This insures that there will be some bend in the knee and the foot will not be pointing with the toes down. Some folks can pedal effectively with the saddle higher, but I've recently discovered that placing the saddle higher than necessary seems to reduce my comfortable cadence, which increases the torque required for a given power output. I'm pedaling much smoother with my saddle a little lower. To minimize stress on the knees, it's better to use a high cadence with less torque.

Try blocking up the wheels of your bike to recheck your inseam and verify standover clearance. The idea is to produce saddle-like crotch pressure when standing over the top tube in bare feet. The height of the top tube will be an accurate inseam measurement. Ideally, 3-5cm of blocking will be required. If the blocking under the wheels is more than 4cm, the frame could certainly be larger. Subtract 30-31cm from your inseam to get the proper c-c frame size.

One best methods of selecting stem length is to check knee to elbow clearance when riding in the drops, with the fingers in reach of the brake levers. If your knees and elbows don't hit with your upper back in a horizontal position, then the stem is long enough. With the bars as low as you have them, you should not need any significant bend at the elbow to achieve a horizontal back position. Additional stem length beyond the point of minimum clearance is entirely optional. If this stem length feels too long, you may have to tolerate some knee-to-elbow overlap until you become more experienced. I increased my stem length from 90 to 110mm over the course of several years.
things to consider....serbski
Dec 10, 2002 10:29 AM
I measured my inseam per your "blocking" instructions using books which may or may not be accurate enough and, allowing for some compression of said books, came up with 6.5cm. I remeasured a few times and that is what I still came up with. This doesn't jibe with the inseam produced via the "book against the wall" method as described in the Lemond chapter on bike fit but that's the number I ended up with. I guess my worry that the frame is too big, at least in ST length, seems to be unfounded based upon both measurements. All of my reading about pro bikes etc and the seemingly miniscule frames they appear to use put me in an unnecessary panic. I'll repeat this mantra: I'm a runner and a novice cyclist and *not* a rider in the peloton! It's a bit of a hard thing to enter into a sport about which one knows nothing after spending years within a sport about which I've become fairly knowledgable...
the fit is not that bad...C-40
Dec 10, 2002 12:38 PM
If you are comfortable with a 115mm stem and you have knee to elbow clearance in the drops, the top tube length of the frame must be pretty close to ideal.

If you've got 6cm or more of standover clearance, you are riding a frame that's as small as most of the pros.

As I noted, you've got unusually long legs for your height. If you increase the frame size by too much, you will end up with top tube that's too long and a stem that's on the short side. As long as the saddle to bar height difference doesn't bother you, the bike will be fine. You might consider a 120mm Ritchey WCS stem, flipped over to 96 degrees to get the bars up with fewer spacers under the stem.

Next time you buy a frame, try a 57cm or 58cm c-c. If you get a brand other than LOOK, the head tube length will be longer and you can reduce the steering tube spacers.
What did the shop do to fit you to the bike? nmO
Dec 10, 2002 7:42 AM
What did the shop do to fit you to the bike? nmserbski
Dec 10, 2002 10:18 AM
Actually, it was a process of elimination of sorts because at first I came in with a borrowed Lemond/55c-c which they set up for me, telling me that this bike would work quite well for me if the owner wanted to sell it. When it came time to buy a bike (the Lemond owner wasn't parting with his bike) I went in with my uber-serious racer buddy and he and the shop owner all looked at me on various frame sizes (54 thru 57) which all happened to be Look as they fell in my price range and (I'll admit) they looked good. Basically, as a runner and not a cyclist, I just had to trust their judgement though I'd done enough research to know that bike sizing can be a major source of opinion, discussion and frustration. Only now, with 3,500 miles on the bike do I even begin to have the *slightest* clue as to what I've read about this subject.
What did the shop do to fit you to the bike? nmO
Dec 10, 2002 1:34 PM
Did they do any measurements on you while you were riding the bike? Seat angle and seat post set-back can affect your position on the bike? Do you hunch over while you are riding or are your shoulders pretty square? I would say from my experiences visiting many bike shops that many shops do not not what they are doing when they are fitting bikes. And, racers can have some of the worst cycling positions.
What did the shop do to fit you to the bike? nmserbski
Dec 10, 2002 7:28 PM
I'll hazard a guess that I hunch over while riding as that is probably what one wants to do naturally though I make an effort to flatten my back out. Just like running, when you're pushing it, form is the first thing that goes out the window... No, the shop didn't do any measuring that I can recall other than checking the top tube length against that of another frame.
Get a fitting done at a shop that cares about doing fittings....O
Dec 10, 2002 8:53 PM
Make an appointment at a shop that does fittings, preferably a Serotta size cycle dealer (look on the Serotta website). Bring in your current bike with you. But, if you have a choice among dealers for a fitting, make sure you can get scientific answers for the changes which will inevitably be made to your fit; not because it "looks good to me." I have learned so much about bike fit over the last two years. I recently finished a professional program on fitting. Most cyclists are heavy opinionated ignoramuses when it comes to bike fit. If you have further questions for me, please post a new thread. Oh hunching your shoulders forward will inhibit the flow of air going into your lungs, plus this will possibly cause neck and upper back strain.