I disagree with this perspective. Fit is an ecclectic amalgamation of factors affecting overall bike performance: Comfort, biomechanical efficiency, aerodynamics, ability to digest food on the bike, bike handling and several other factors. It is also the ability of the bike to interface correctly with the road, providing a wheelbase, turning radius, weight distribution and center of gravity that is appropriate for a given rider. Can the contact points of a 61cm bike be oriented in the same configuration and proximtiy to one another as a 48? Certainly- given the right stem and seatpost- they could. Would the handling characteristics be the same: No. Would the bike handle as well for a rider climbing out of the saddle: No, it would not- although the contact points are in identical proximity to one another the other relationships are different and that exerts an effect. To me, this is a somewhat myopic view. Colnago has a similarly myopic view of bike fit, but from the exact opposite perspective. My understanding of the philosophy behind Colnago geometry design is: Here is our bike in a series of given sizes seperated by 1 cm. increments: One of these fits you. It is designed for the best interaction between bike and road- position yourself as you see fit but never mess with the frame's relationship with the wheelss and wheel's interaction with the road: that the the primary determining factor in bicycle performance and fit. Other manufacturers take an opposite view saying "we fit the rider's body" or "We build our bike around the rider's body measurement". This doesn't always work since it can subordinate (sometimes seriously) the effect frame design has on handling. Does a 52cm Felt DA650, 52cm. Cannondale IM2000 and a 51cm. Cervelo P3 with 650c wheels each "fit" me in the sense that I can get the same proximity of body contact points on each bike? Yes. Do all three handle and perform the same? No, absolutely not. That is why I own all three. My sense is that if this prespective (Gerard's) were entirely correct I would only sell one triathlon bike in one frame size. If this is true, why bother with different sizes at all- just adopte a sizing system that enables an enormous variability in arranging the proximity of the contact points and say "Here, this is our adjustable bike- infinately adjustable to fit all persons- one size fits all". I know it doesn't work like that.

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Tom Demerly
The Tri Shop.com

Maybe this thread should read:

Fit/Gerard vs. Feel/Tom!!

Gerard is going to be mean to me, I just know it....

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Tom Demerly
The Tri Shop.com

[reply]I disagree with this perspective. Fit is an ecclectic amalgamation of factors affecting overall bike performance: Comfort, biomechanical efficiency, aerodynamics, ability to digest food on the bike, bike handling and several other factors. It is also the ability of the bike to interface correctly with the road, providing a wheelbase, turning radius, weight distribution and center of gravity that is appropriate for a given rider. Can the contact points of a 61cm bike be oriented in the same configuration and proximtiy to one another as a 48? Certainly- given the right stem and seatpost- they could. Would the handling characteristics be the same: No.
[/reply]

Tom, we don't disagree, that is exactly what I said. I said that both can fit me perfectly, but neither will handle very well.

And I am saying that if you have a certain position that you need, you can find a certain size of Felt and a certain size of QR that each will handle fine under that position. Given how little the experts know about what affects handling, and how little both brands differ in geometry (you can toss the 78 degree position on a Cervelo in there as well) it would be strange to assume that one of these bikes would handle well and the other doesn't. Especially considering a month later this customer comes back into the shop to finetune his/her position and the saddle and bars may be moved several cm.

Maybe I should make my posts shorter so they are read more closely, but here it goes in abbreviated style:

1) Concern yourself with position, not with fit.
2) This renders you the points in space, you can connect these a gazillion different ways (from a 48cm P3 to a 61cm P3) but there are several options that are acceptable, most likely at least one from each of the major players since they vary so little in geometry.
3) If your bike shop says the 54cm Felt fits you like a glove but none of the QRs does, be wary. You can look at the charts yourself and find a QR almost identical to the Felt, so it would render you the same position, weight distribution, etc. It is more likely the shop doesn't sell, or doesn't want to sell the QR for some reason nothing to do with the customer's needs.

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Gerard Vroomen
3T.bike
OPEN cycle

i am not tom or gerard, but a s long time bike rider and fan of bikes here is a view. both are right to an extent ( not surprising) but i lean more heavily towards gerard's view in light of current fashion. here is why:

as gerard says, once you know where you need to be in space you can fit on nearly any bike that is, or close to the right size. and, as tom says when you do this different bikes will work differently based on where you are sitting on the thing. the part i disagree with with regards to tom here is that he seems to be saying there is some . . . . dare i say. . . . "optimum" relationship that a rider needs to be at once in his or her position relative to the bike. this is not true, IMHO. infact, i like to use a different place on different bikes for different or even no reason at all. lok at the fisher genesis geometry, for example - the rider is moved back on the bike fully for a specific reason.

moreover, this whole " get the one that fits" mantra is getting out of hand. ususally the bikes in question are with a cm or two of each other, and the same position can be found with minmal fuss. the bikes will work well as the rider is within reasonable parameters of what the frame can accomdate. so then, far more bikes can "fit" than one would be led to believe by current mantra proponants.

finally, the ENTIRE issue of ride quality and subjective appreciation of the finer points of ride seems to have been eclipsed by this over-thought and myopic mantra, IMHO. H-O-W the bikes rides is still a parameter of how much enjoyment the bike delivers. the distingiushing rider would, again IMHO, do better to pay more hed to this in their new expensive purcahase, get the right size, and then be sure to dial in fit on that correctly sized, and "right" for him.her feeling steed. to just blow off ride quality entirely is to shortchange your riding experience, ...........IMHO.

All points from both Gerard and Tom taken into consideration, would it not be true then that a bicycle shop which stocks (or has access to multiple sizes) at least one model of each of the major players bicycles, both road and tri, would be a better bet at fitting a customer than a shop which focuses on one brand? Also considering that the "big" shop has kept up to date on "fit" and positioning. Bicycle purchasing is an important decision which should not be done half-heartedly over some mail/internet site. Taking the time to shop a shop when possible is very important. This is evident by the post about the guy driving 10 hours to tap the expertiese of Tom.
Shawn

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"Nothing in life ever just happens. Calculated progression insures your strength."
Shawn Spencer
Bike Cycles
Wilmington, NC
http://www.bikecycleshop.com

I agree with this. That is why we try to stock and carry all the major triathlon bike brands. The ones we do not commonly sell we like to have say we at least looked at carefully, or tried. I do see big differences between brands: Ratios of true seat tube length to top tube length, and I think therein lies an opportunity. There have been MANY, MANY times when I have had 20 Cannondale tri bikes in stock, on the floor, invoices coming due and I have said "I recommend a Cervelo P3 for you since I believe it fits you better- the head tube is lower and you can acheive a lower, more aerodynamic posture". I didn't have the P3 in stock at the time. Logistically it would have been easier to just say "Ahhh, yeah, here, look at these dimensions, gee, what a coincidence, this Cannondale fits you perfectly- and guess what!?! I've got it in stock! Your lucky day!" My customers know, I don't do it like that. I believe the different brands are like different fit tools. Some are better suited for a particular body type than others. Some are better suited for a particular terrain than others. That is why we sell them all (or try to). There have been MANY times I have walked past a row of one brand of bikes sitting on my sales floor to recommend a brand a customer has to wait 8 weeks for because I firmly KNOW, from my experience selling, riding, racing on and building triathlon bikes- thousands of them- not just a couple hundred like all the "johnny come latelys" that the bike they have to wait for will be a better option. In the past 12-16 weeks every time I have sold a P3 over a Cannondale Ironman 2000 I have had to say "There may be a wait involved." All the P3s we sold arrived in a pretty timely manner, and for the customer, it was worth the wait. The bike fit them better.

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Tom Demerly
The Tri Shop.com

I DO NOT SAY: Buy a 48 or a 61, it does not matter.

I DO SAY: Your position is independent of the frame size. You figure out your points in space, then determine which bike gives you basically the best handling with that position. And with the differences in geometry between a lot of brands being as small as they are, it is not credible to say a QR will work and a Felt won't.

Tom should be happy with this, he sells both (and then some) and so he can explain to the customer that he/she has a choice, and what the pros and cons are. The guy down the street can only tell the customer that the QR "fits better" because he doesn't sell Felt, or vv. And when you hear that sort of statement, bolt for the door and go to Tom, or Dan, or Cid, or any other shop with choice.

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Gerard Vroomen
3T.bike
OPEN cycle

OK, let me try this:

Your position is independent of your frame size.
Your frame size and geometry influences your bike handling.

Together these factors determine the quality of your ownership experience. Optimizing both will optimize performance contribute to the best buying decision.

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Tom Demerly
The Tri Shop.com

[reply]There have been MANY, MANY times when I have had 20 Cannondale tri bikes in stock, on the floor, invoices coming due and I have said "I recommend a Cervelo P3 for you since I believe it fits you better- the head tube is lower and you can acheive a lower, more aerodynamic posture".[/reply]

This is definitely valid, but those are two extremes. The difference in headtube is more than a few cm. But if the difference in headtube length is a few cm or less, this delta is smaller than a difference between a stem flipped up or down, or a Syntace or Head stack height, or a spacer here or there. Therefore, either bike would fit in most cases.

And I'll make one more reservation, I'm talking about 650c QRs of their normal models, not their 700c bikes (which for some reason have slacker seattubes), or their Zero Gravity (which for some reason....(never mind, just read what Dan wrote).

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Gerard Vroomen
3T.bike
OPEN cycle

...kind of supports my point :) And most importantly, Good Morning Gerard, nice to hear from you again.

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Tom Demerly
The Tri Shop.com

"I DO SAY: Your position is independent of the frame size. You figure out your points in space, then determine which bike gives you basically the best handling with that position. "

It's like determining your optimum position first and then trying to build the bike underneath you?

Your point in the earlier post about being able to fit a wide variety of frames. I have a TCR road bike size medium that seems very comfortable. My friend is two inches taller and rides the same frame albiet with a different stem and seat post. The TCR comes in only three sizes whereas your Soloist is in more. If on a Soloist I would ride a 54 cm rather than a medium TCR. Do you feel most riders could be dialed in a bit better on a Soloist than with the Giant approach of three frames and different stems/seat posts. I would tend to think so, but the TCR does seem like a good fit for me.

I think more fit options do offer more precise fit. I like the Soloist MUCH better than the Giant as a retailer since I have more opportunity to get a more precise fit. I have owned a Giant TCr, both Medium and Small. I didn't care much for either: The Medium felt too large, I had to run a hortish stem; the the top tube was too long. The small was absurdly small for me: Felt like there was nothing under me. The two bikes handled and rode very differently, neither one good for me. I needed a "Small and a half" which of course, does not exist. The Soloist is available in more sizes and has, IMHO, an overall better design, nicer tubing and more size options. That's my choice. I have one on order for myself right now.

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Tom Demerly
The Tri Shop.com

[reply] Your point in the earlier post about being able to fit a wide variety of frames. I have a TCR road bike size medium that seems very comfortable. My friend is two inches taller and rides the same frame albiet with a different stem and seat post. The TCR comes in only three sizes whereas your Soloist is in more. If on a Soloist I would ride a 54 cm rather than a medium TCR. Do you feel most riders could be dialed in a bit better on a Soloist than with the Giant approach of three frames and different stems/seat posts. I would tend to think so, but the TCR does seem like a good fit for me.[/reply]

If a 54cm Soloist and a medium TCR have the same geometry (not saying that's exactly the case, just as an example), then obviously you will fit both, they will handle the same, etc. Now if you're a bit taller, you can still fit both of those bikes to your position (longer stem), but at some point the handling will be compromised because you will have too much weight on the front wheel. At that point you can switch to a 56cm Soloist, but you can't switch to a Large TCR yet, as it is still too big (it would be more like a 58cm Soloist).

So bottomline, if you need a 48, 54, or 58, a S, M or L will also work for you. If your handling would be better served with a 51, 56 or 61, you should really get a SM, ML or XL, but those aren't being made. The sizes above are just an example, I'm not saying they fit exactly like that, but you can get the point.

The real question is, how many sizes do you then need. Why 3 or 6 size, why not 1, 12, or 24, or 48? That's obviously open to debate, but it comes down to "resolution". By moving around on your bike, you will be able to shift your center of gravity a cm or two. On a road bike, it's a bit more (sitting up vs. in the drops).

So if you shift around that much, there is no point having frames in sizes that only differ 5mm from size to size. Your weight distribution then shifts more by moving around, then by changing frames. Since obviously moving around on the bike is perfectly acceptable, it is not necessary to have frame sizes that differ less than that. That said, having them differ by 5cm is too much. So somewhere in-between is what you want to achieve. Say the shortest toptube you need on a tri bike is 49cm and the longest is 57cm for 98% of the population, those 8cm can be covered by 5 sizes if you change the toptubes by 2cm each time.

I hope this makes sense, it's hard to describe it clearly without drawings.

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Gerard Vroomen
3T.bike
OPEN cycle

"Your position is independent of your frame size.
Your frame size and geometry influences your bike handling."

and OTHER factors, often overlooked these days, affect how much you like to ride the bike. a bike with 1 1/2 inch thick aero seatstays is going to ride differently than one with double tapered pencil thin ox platinum steel ones. a bike with a bb drop a cm larger than the next will steer differently. etc. these things matter in an owners enjoyment of the bike, and belong forefront with fit in a high end bike purchase, unless you are simply buying a raceday weapon - even then there are ride qualities best suited to that task. how a bike rides is independant of handling AND fit - and is worth pursuing. all roadies know this, i am puzzled as to why tri-heads blow it off.

I've been struggling with this same kind of issue. Gerard and I had e-mail several weeks ago about the bike measurements that are NOT adjustable, and the need for a common standard. Slowman helped me with a related issue on Softrides just yesterday

I would posit that the locations in space of the saddle, bb and arm rests are paramount. Choose your criteria - aerodynamics, most watts, best comfort, whatever - that is something we have to know about ourselves. From there: what is the frame that will best accomodate that triangle, and handle well. It matters where the wheels are with respect to that bb. It matters how long that stem is. Finally, it matters what that bike's personality is. I think a fitting sequence like that can work.

At any rate, that's what I'm going through. I can suddenly ride almost as low on the front as Dan's formula calls for. With limited conditioning, I'm hammering on the group rides with the fast guys without a lot of distress. Now I'm gonna get off that road frame and onto something that will feel like the wheels are under and in front, as opposed to under and behind.

Very well said ! I have tried to state this point myself BUT wasn't able to do it as well. If a shop does the things you mentioned-----then adjusts the small thing according to riders individual likes, needs, etc. AND provides continued adjustment through the year to provide for flexibilty, weight, strength changes it takes training but it ain't rocket science!

The new carbon seat post, is it lighter? How much? Stiffer? What are the advantages? I am sure I'll get one just for the looks-----Does the weave show?????

On target. Laser guided. Perfect.

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Tom Demerly
The Tri Shop.com

[snip]

who was it that said the quality of posts on this forum are suffering as of late?

i'm going to take a shot at restating gerard's position, not because gerard hasn't stated it well, because he has, but because i'll just throw light in another direction.

you can change the seat angle by means of a variety of seatposts, you can change the top tube length by means of a variety of stem lengths, you can change the head tube height by adding spacers. so you can make every bike fit, one way or another. but you can't make every bike handle, by virtue of the things you CAN'T change.

what CAN'T you change on a bike? you can't change where the wheels are in relation to the BB. so when it comes to HANDLING you'll want to look at chainstay, front/center, and perhaps BB height. when you figure out your points in space--where it is YOU sit in relation to the BB, and these are fixed points that do not relate to any particular frame, these are YOUR specific fit measures--then you place a frame underneath you that best optimizes that position.

you ought to take into consideration where the wheels are, because that's a handling issue. gerard's point is that for FIT ONLY, it matters not where the wheels are. ANY bike can be made to fit. but not any bike can be made to handle, and where the wheels are matter.

as previously stated, there are other things you CAN change, but not without some compromise. Felt bikes have fairly small head tubes, which i personally like. but if you're going to ride it like a road race bike, yes you can make it fit by adding spacers. but are a huge stack of spacers a good replacement for simply having the head tube be longer?

what bike shop owners OUGHT to mean when they say, "buy the one that fits," is that you ought to find your points in space and then choose the bike that has seat angle, head tube length, etc., that are easiest to accommodate, and which have the wheels in the right place in relation to the BB.

what bike shop owners, magazine bike reviewers, etc., USUALLY mean when they say, "buy the one that fits," is "we don't have the faintest clue which bike fits you best, because we don't really know what we're talking about. so go out and test ride a couple and YOU choose the bike you want, in which case we're sort of off the hook since the decision was yours not ours."

btw, i think you can also see that tom and gerard essentially agree, and only differ in semantics and emphasis. but i'm glad gerard brings this point up, because most dealers don't have the faintest clue how to fit you on your bike and "buy the one that fits" is a phrase that needs to be held up to scrutiny.

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Dan Empfield
aka Slowman

Tom I think you and Gerald almost agree. Most points seem to be the same. The big difference I see is he makes money selling bikes and you make money selling bikes and fit.
The point I think he is making is that some people may abuse (not you) the fit thing. They fit the person to the bike they want to sell or have on the floor.

"how a bike rides is independant of handling AND fit - and is worth pursuing. all roadies know this, i am puzzled as to why tri-heads blow it off."

I've wondered about this myself but tend to think that because tri bikes are single purpose bikes, expectations for them to do anything but race a tri aren't high. Very few are going to take one on a group ride, century, race a crit or even daily commuting. Roadies are generally more bike savy because their road bikes, being more versatile, are likely used for a wider range of activities. It seems that tri-geeks are more likely to tolerate shortcomings in a bike just as long as it's fast in a strait line.

But Tom, what size do I need if I am buying a Colnago and I live in Chile???

;-)

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"To give less than your best is to sacrifice the gift." - Pre

MattMizenko.com

"I hope this makes sense, it's hard to describe it clearly without drawings"

Mkes all the sense in the world. I'm just lucky that the TCR fits. Of course I haven't compared it directly to a 54 cm Soloist. Looking up the specs, they are similiar but different. I'll have to try out the Soloist for a comparision.

He's two guys that went to the same class at the same time and they can not agree on fit,if i were Dan i would feel a little sad.Randall