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Fitting Your Bike Are you confused about how you should fit a bike to your particular body dimensions? Have you been reading, found the terms Merxx or French Fit, and don’t know what you need? Every style of riding is different- in how you fit the bike to you, and the sizing of the bike itself. It’s more than just measuring your height, reach and inseam. With the help of Bike Fitting, you’ll be able to find the right fit for your frame size, style of riding, and your particular dimensions. Here ya’ go…..the location for everything fit related.

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Old 11-03-13, 05:28 PM   #1
Xsive
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Fitting a new bike- Euro style!

I have a racing partner who is trying to get me to buy my new bike two sizes smaller than what I'd normally ride (XS rather than M).

He says that b/c the head tube is shorter that I can get a more aggressive aero position and that I can run the saddle higher to compensate for the tighter geometry. Thus, theoretically I can fit the XS (I'm 5'10'') that has a 52.5 virtual top tube.

Apparently the European racers have a habit of choosing their bikes as small as possible, but I'm concerned about the geometry and also about the fact that I'd be on a bike with 170mm crank arms rather than my usual 172.5mm.

Should I expect differences in handling (faster b/c the shorter wheelbase, but anything else?)?

What about the crank length? Will that affect my knees or feet and cause discomfort?

Thank you for your input.

Last edited by Xsive; 11-03-13 at 05:39 PM.
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Old 11-03-13, 05:37 PM   #2
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It's a fad. Buy the correct size.
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Old 11-04-13, 05:14 AM   #3
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Quote:
Originally Posted by Xsive View Post
I have a racing partner who is trying to get me to buy my new bike two sizes smaller than what I'd normally ride (XS rather than M).

He says that b/c the head tube is shorter that I can get a more aggressive aero position and that I can run the saddle higher to compensate for the tighter geometry. Thus, theoretically I can fit the XS (I'm 5'10'') that has a 52.5 virtual top tube.

Apparently the European racers have a habit of choosing their bikes as small as possible, but I'm concerned about the geometry and also about the fact that I'd be on a bike with 170mm crank arms rather than my usual 172.5mm.

Should I expect differences in handling (faster b/c the shorter wheelbase, but anything else?)?

What about the crank length? Will that affect my knees or feet and cause discomfort?

Thank you for your input.
You are going about this totally the wrong way.
The euro racers use smaller frames because they can. For them the bike is a tool and they have very specific information about what works with them. They have had years and dozens of frames to get to know their own preferences.
You one the other hand don't seem to even know what kind of frame is going to fit you. That is not a good thing when trying out silly extreme stuff.

A few questions.
Do you ride 100% in the drops? if yes, then you might need a lower frame.
Do you have your current stem slammed and flipped? do that first.
Can you get your palms to the ground when stretching froward? If not then just forget about it.

Many racers go for a fitting and actually end up with a higher handlebar and more aero riding position because aero is not just having massive drop.
Your arms are more aerodynamic when they are signifigantly bent at the elbows than when you had your arms straight.

My sincere advice is that go to the extremes when you know, I mean KNOW EXACTLY what works for you. Otherwise you might very possibly end up with an unusable frame.

It's not necessarily a fad but many people go for it for exactly the wrong reasons
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Old 11-04-13, 07:22 AM   #4
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Elcruxio is onto it pretty much, though I will add a couple of thoughts...

A lot of it depends on the frame design, and it's unwise to go just by a sizing number, e.g. Small or 55cm or whatever. For example, I'm just a tick over 6' and I ride a 54cm rather effectively, so you see the problem with just throwing around a number. Now, in your case, you've got a critical number, ETT, of 52.5, which, prima facie, seems quite a bit short for a 5'10"er. Which brings me to the next point...

A lot more of it depends on your design, i.e. your body type. Proportions, fitness, and flexibility all work into the mix, and really determine what is possible. That 52.5 ETT might be the ticket if you've got a short torso, or maybe short arms, but it's going to depend on the frame shape.

So, like Elcruxio said, one really has to know what works for them to fit at the extremes. Anyone can ride just about any size frame in reality, but making the power and having the comfort to race it effectively is something else altogether.

I do agree with your racing partner on the principles that for racing, lower and tighter is better. The rub is that any ol' small frame won't get you there, it's gotta be one whose design meets your demands.

Just to elaborate on my 54cm a bit, it has a 570 ETT and a short 140mm HT, so it's both long and low. I did fit 175mm cranks, which are a little longer than typically equipped on a 54cm frame, but they keep me a little lower and allow me more leverage. Downside is that on the short 984.4mm wheelbase, I do get a touch of toe overlap now, but for a bike intended for fast road riding as opposed to more low speed endeavors, it's not an issue. Ideally, I'd have spec'd an ETT around 573mm and gotten a slightly longer wheelbase to accommodate the longer cranks, but alas, a custom frame was not in the cards (or should I say wallet?!) for me.

If you can go throw your leg over one of these XS bikes your bud is advocating, that's the best thing.
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Old 11-04-13, 10:37 AM   #5
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Quote:
Originally Posted by elcruxio View Post
You are going about this totally the wrong way.
The euro racers use smaller frames because they can. For them the bike is a tool and they have very specific information about what works with them. They have had years and dozens of frames to get to know their own preferences.
You one the other hand don't seem to even know what kind of frame is going to fit you. That is not a good thing when trying out silly extreme stuff.

A few questions.
Do you ride 100% in the drops? if yes, then you might need a lower frame.
Do you have your current stem slammed and flipped? do that first.
Can you get your palms to the ground when stretching froward? If not then just forget about it.

Many racers go for a fitting and actually end up with a higher handlebar and more aero riding position because aero is not just having massive drop.
Your arms are more aerodynamic when they are signifigantly bent at the elbows than when you had your arms straight.

My sincere advice is that go to the extremes when you know, I mean KNOW EXACTLY what works for you. Otherwise you might very possibly end up with an unusable frame.

It's not necessarily a fad but many people go for it for exactly the wrong reasons
Stem is flipped and slammed. I can palm the ground. I ride the drops about 35% and I'm on the hoods with bent elbows 60%. I ride with no hands 5%.

I have owned over 12 road bikes and sold all but two of them b/c I've been fit incorrectly so many times. I have a long torso and shortish legs with a 32'' inseam.
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Old 11-04-13, 10:42 PM   #6
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There are a few pro racers who run negative angle stems. There are even a few who run adjustable stems set to -90deg (straight down).

You could try an adjustable stem just to see how you like the fit position.
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Old 11-05-13, 10:19 PM   #7
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I think that there are three primary issues with such a small bike (although the top tube is 52.5 and that's long enough, thus it's not an issue):
1) Saddle to bar drop (and potential discomfort on rides/races >75 miles)
2) Crank arm length
3) Toe overlap (and maybe a fourth being fore/aft).
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Old 11-06-13, 06:18 AM   #8
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..the top tube is 52.5 and that's long enough...
Long enough for what?
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Old 11-06-13, 01:01 PM   #9
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Long enough for what?
Long enough for my reach with a 100mm stem.
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Old 11-06-13, 03:00 PM   #10
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Long enough for my reach with a 100mm stem.
Oh, right, you're the OP!

I don't think you'll have any issues with toe overlap or the short wheelbase. Toe overlap only crops up when going slow, but this is a race bike, right, so no issue there; the short wheelbase, I believe, will make the bike feel more responsive, even if you lose a little stability when out of the saddle (geometry is bigger factor in that, though).

I say fit it-n-rip it!
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Old 11-06-13, 03:25 PM   #11
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Oh, right, you're the OP!

I don't think you'll have any issues with toe overlap or the short wheelbase. Toe overlap only crops up when going slow, but this is a race bike, right, so no issue there; the short wheelbase, I believe, will make the bike feel more responsive, even if you lose a little stability when out of the saddle (geometry is bigger factor in that, though).

I say fit it-n-rip it!
Chaadster, your words exude confidence; thank you!
Toe overlap is only a concern while doing track stands at red lights.

Any thoughts about crank arm length and how a 170mm crank arm relates to power and/or fit?
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Old 11-06-13, 04:10 PM   #12
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Chaadster, your words exude confidence; thank you!Toe overlap is only a concern while doing track stands at red lights.Any thoughts about crank arm length and how a 170mm crank arm relates to power and/or fit?
Oh, I may sound confident, but don't forget this is all speculative, as I don't know any more about you and the bike than what you've told me, so there's still plenty of room for me to be wrong!

That said, I really think there's a lot of dogma tied up around the issue of bike fit, yet it seems quite obvious to me that the range of successful fitments is much wider and diverse than many would have believe.

To your question about crank length, in general, shorter cranks are better for spinning, as the trade off some mechanical advantage, or leverage, to longer cranks. I would not expect any real issues, and of course if you do find you want longer cranks, while pricey, swapping to 172.5mm is not hard. If you were going from 175s to 170s, I'd be more concerned. Is there any way you might get the shop to do an exchange for you at a reasonable cost?

As far as fit goes, the shorter cranks will place you a little higher on the bike, and will necessitate a taller seatpost, but we're talking a couple mm here, nothing crazy. For crit racing the shorter cranks might buy you a fractionally earlier pedal stroke out of turns, but again, I'd think pretty minimal impact for all but the most seasoned racers.

Again, these are just my opinions, and reality may be different. Others will have other opinions that may be worth considering and just as valid. Keep us informed of what you decide on!

Last edited by chaadster; 11-13-13 at 08:04 AM. Reason: edited for paragraph spacing
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Old 11-06-13, 06:48 PM   #13
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They are young and flexible , are You?

the Pro Bike has changed a lot since the 1st TdF, 100 years ago..


Quote:
Any thoughts about crank arm length and how a 170mm crank arm relates to power and/or fit?
ou need a Sports Physiology Department to show the slightest difference through testing , Got one?

No? dont sweat it ,,

If you place well in a bunch of races a coach may take an intrest in helping you do better
for a Fee.

Last edited by fietsbob; 11-06-13 at 06:52 PM.
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Old 11-12-13, 09:58 PM   #14
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They are young and flexible , are You?

the Pro Bike has changed a lot since the 1st TdF, 100 years ago..




ou need a Sports Physiology Department to show the slightest difference through testing , Got one?

No? dont sweat it ,,

If you place well in a bunch of races a coach may take an intrest in helping you do better
for a Fee.
When I played college golf my coach told me, "never take lessons from someone that you can beat."

I think that the benefit from a cycling coach would be merely monitoring the mundane; barring time restrains, I think that it would be more time effective to monitor and track my progress with spreadsheets and charts. On the other hand, as I enter my late 20's it is unlikely that I will earn a living cycling, but I love to compete and winning NEVER gets old.
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Old 11-13-13, 01:33 PM   #15
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Stick to golf then, Kid.
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