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  1. #1
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    Bike fitting and buying online.

    Seems once you know your size buying online is the best option for good parts and cheap prices. What does a bike fitting tell you what you need? how the handlebars frame and seat should be?

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    Senior Member d2create's Avatar
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    The easiest thing to do is start with a bike that fits you well and go from there.

    Take measurements of the current bike and compare to the posted measurements of the bikes you are considering. The biggest thing to look at is the c-c top tube measurement with horizontal top tubes or the virtual top tube measurement with sloping top tubes. These are the main things that take into consideration your height (waist down) and reach (waist up). Then there's things like head tube angle, seat tube angle, bottom bracket height, etc that make smaller differences in fit. Lots of things to consider.

    Once the bike is chosen and in your possession you can make some small tweaks with stem length/angle, seat height, type of seat post, position of seat...
    2008 Rivendell A. Homer Hilsen
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  3. #3
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    So at my local LBS I can get fitted for $100 and they will tell me all my measurements. I look around and if I don't find a good deal then I go home and buy one online with the specifications they gave me?

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    Quote Originally Posted by d2create View Post
    The easiest thing to do is start with a bike that fits you well and go from there.
    +1. If you don't already have a bike that fits well, then buying on-line is very risky.

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    In beaurocratic limbo urbanknight's Avatar
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    As long as you understand the geometry. It's not rocket science, but if all the shop tells you is "you're a 56" that won't do diddly for you.

    I'll also point out that if you don't plan on maintaining your bike yourself, the first year of free tune-ups will come in handy if you buy locally. I try to buy thing locally because I want the shop to stay in business so they're there when I have an unexpected purchase needed to get me back on the road.
    "Well, I guess you can cut the arts as much as you want... Sooner or later, these kids aren't going to have anything to read or write about." (Richard Dreyfus as Glenn Holland)

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    I do all my bike cleaning and maintanence, I live in washington and close to oregon and we're one of the most dense biking states in the us. I figure since its a 2 hr session for 100 bucks they will tell me more than just the size of my frame.

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    In beaurocratic limbo urbanknight's Avatar
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    Yeah, just make sure to get as much info as possible. Recommended (in order of importance imo) top tube length, seat tube angle, seat tube length, stem length, saddle fore/aft, saddle height, and crank arm length.
    "Well, I guess you can cut the arts as much as you want... Sooner or later, these kids aren't going to have anything to read or write about." (Richard Dreyfus as Glenn Holland)

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    Senior Member texascyclist's Avatar
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    Quote Originally Posted by kmac27 View Post
    So at my local LBS I can get fitted for $100 and they will tell me all my measurements. I look around and if I don't find a good deal then I go home and buy one online with the specifications they gave me?

    Do the competitive cyclist fit and save your $100. I did it and got a fit afterward. No changes.
    "Progress means not just changing, but changing for the better" -C.S. Lewis

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    I found a bike shop that carries one of my most looked at bikes, fuji and they offer a 10% off if your a student.

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    Senior Member thefatguy's Avatar
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    Buy locally. Help the shops to help you. You buying online won't do anything to keep their doors open, and if you ride for any amount of time you will need them someday.

  11. #11
    Blissketeer HokuLoa's Avatar
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    Sounds like you have not been fitted before and perhaps have never ridden a bike that REALLY does fit you. Save the online adventure for future bikes once you have a dialed in sense of what does "fit" you. It is far better to get a quality fit and buy locally for the first real bike. Most good shops will help you refine your fit over the course of your first rides. That ability to "try and buy" is worth much more than the savings of an online purchase. Plus, the advantage of having your LBS for free adjustments and warranty work cannot be overstated. No offense, but I find it hard to believe that you are a quality wrench and yet you do not know about fitting. I may be wrong but either way, it is worthwhile to have your LBS for quality (and free) assembly and adjustments. In a pinch they can also be awesome as quick tutors for "how do I do this." A six pack of beer or a pound of good coffee goes a long way but it is far better to have a good preexisting relationship with your LBS staff.

    Good luck either way!

  12. #12
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    I would definitely get your first "serious" bike fit at a shop that knows what it's doing. I don't have any recommendations on how to tell if they're good or not but I'd use the "gut instinct" method. Are they fit? Nice? Do they ride? Do they have a team? A local shop here is owned by a former pro and his (ex-)World Champion wife. They'll have experienced a lot and will know how to fit you, even if you have a bum knee or some other issue.

    As someone who's fit hundreds of cyclists, am very particular about my fit, and whose frames tend to be ordered sight unseen, I look for the following when checking frame fit:

    1. Seat tube height - leg length related, simple. This can vary by a lot due to different types of frames. I have frames that measure 44 cm center to center and 52 center to top. They all fit me correctly due to the next two measurements.
    2. Top tube length, horizontal/virtual - this relates to your torso and arm length. It's affected by your cycling fluency - a more experienced or performance oriented rider will want a longer setup. A newer or less experienced rider will want a shorter one. This is due to lower back strength, glute strength, and comfort sitting on a saddle.
    3. Head tube length (height) - this is CRITICAL for proper bar height. I cannot say how important this is. It used to be a given with level top tube frames. You can get a bike that has the right seat tube and top tube and the bars might be 2 or 3 cm too high or low, and without a radical stem it won't fit you. A shorter headtube is good for those more experienced/performance-oriented riders. A longer headtube is geared for less experienced or more comfort oriented riders. A good example is the difference between Giant's TCR (performance) line and their OCR (recreational) line. The OCR frames have longer headtubes for a given size.

    To a lessor extent, I check the following:
    1. Seat tube angle - based solely on quad length, but unless the angle is extreme (less than 72, more than 75), it's probably going to be fine due to various seatposts which have or don't have setback.
    2. Stand over height - make sure you can get off the bike without squealing.

    Once you get the bike, you'll install the following parts. Based on your previous fit knowledge, you'll probably have the proper lengths already:
    1. Stem - this adjusts the overall length of the bike for you. A newer rider should aim towards frames which use shorter stems - this way they can use longer stems as their body acclimates to cycling.
    2. Crank length - this is based on riding style/preferences but a longer/shorter crank will move your seat forward/backward and down/up respectively. 5mm is 5mm. It'll be unusual to need to change frames for this but realize it's a factor. Probably stem or bar changes will suffice.
    3. Bar width, drop, and reach - all affect the overall length of the bike. I rarely change bars (I have the same bar on my bikes) but if you're getting a snazzy carbon bar, make sure it doesn't throw off your length too much. More width increases length slightly. Drop can be corrected using a stem (unless the adjustment is out of range). Reach is critical since a 2 cm longer reach will mean you need a 2 cm shorter top-tube/stem combo, a significant difference when selecting a frame. However, if you end up with a frame that's not quite right, a radical bar change can make a big difference.

    The following have absolutely nothing to do with fit but everything to do with how the bike handles, a totally different topic:
    1. Head tube angle - a 73 or so will give you a responsive bike that is still stable.
    2. Chainstay length - shorter keeps more weight on the rear when standing. Longer is softer/comfy.
    3. Wheelbase - reflects the above two factors, but basically a shorter one is more agile.

    A good fit will recommend:
    1. An overall seat height (measured from the sole of the shoe to the top of the saddle). This means the following affect it: pedals, shoes, crank length, frame size, and saddle.
    2. An overall length - seat to bar, depends on how detailed they get. This is affected by saddle, top tube of frame, stem, bar, and height/angle of stem.
    3. Crank arm length - I've decided this really depends on riding style and has virtually nothing to do with leg length.
    4. Bar width - easy enough - about the width of your shoulders - but affected by riding style.
    Based on the numbers and questions about your riding, the fitter will probably make some recommendations on bike and equipment.

    Remember you only contact the bike in five spots - bars (twice), pedals (twice), and saddle. As long as those spots are in the right place, you can have anything between them, within reason. Once you know where those five points are, your job (and whoever else - LBS etc) is to figure out a way to connect the points in a logical and efficient way.

    hope this helps,
    cdr

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    I've ridden mountian bikes but just got one and started riding it and adjusted the seat. I didn't know until a few months ago that you should get fitted!

  14. #14
    Michigan Rider lesdunham's Avatar
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    kmac27
    If your bike fits now, you may have the right size frame and pretty much fitted. You can learn much from other riders as well. If your'e logging 50 miles a week or more with no pain why mess with success. If you are reaching for an extra mph or have some indication that something is not right then pay for a fitting.

    Are you a Vancouver rider? I grew up in Camas. Great part of the country and they have done super work for bikes in the metro area. Consider your self blessed .... Michigan roads suck. I still log 3k miles a year.

  15. #15
    Senior Member kk4df's Avatar
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    Quote Originally Posted by carpediemracing View Post
    I would definitely get your first "serious" bike fit at a shop that knows what it's doing.
    I got my first bike from a LBS, but got a poor fit. I think they sold me the size they had in stock rather than the size I really needed. I rode it for a year before ordering online the size I knew I needed, based on competitivefit.com. I could tell I was cramped on my bike, and knew about how much larger size I needed. I went from a 50 cm bike with 535 mm top tube to a 55 cm bike with 555 cm top tube. The bike is SO much more comfortable now. I wish the LBS had done a better job fitting me in the first place. Make sure they really take the time to measure and fit you. Don't be tempted with "this looks about right, try it and see" like I did.

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    Some bike shops are much better than others. Ask you cycling friends about what bike shops are the best in your area. Or ask in one of the local forums on this web site.

  17. #17
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    Thanks for the lesson carpedium. One question in regards to head tube length since I'm comparing my current OCR and the current BD group buy potential (Kestrel RT700). My large OCR has a 200mm head tube, the Kestrel 57cm has a 160mm head tube. Does this mean, with similar headset stack height, the handlebars on the Kestrel will be 40mm lower than on the OCR? Or is it not that cut and dry?

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    Based on the 40mm difference in head tube length, yes, you can figure on having approx 40mm diff in your base stem height. This is based on using standard forks (they'll be a certain height usually).

    The OCR was designed to be more upright. If you have a stem that points up and/or a lot of spacers, losing 40mm of height may not be desirable. However, if you are looking to drop your bars a bit or otherwise experiment with increasing performance (and you've been riding say a year or so), then the 40mm drop may not be a bad thing. A rider as experienced as Bernard Hinault put a 1 cm longer stem on his bike and dropped it 1 cm just before going out and winning a classic (Lombardy?) in a solo break, this after he'd been a pro for 5 or 7 years.

    Position is a fluid thing:
    http://sprinterdellacasa.blogspot.co...ive-thing.html

    Technically dropping the stem 40mm will also extend the reach a bit (just look at your head tube and go down 40mm - the headtube will be a few mm further away from the seat). Keep this in mind when determining fit.

    On poor LBS fit, I should also add that an LBS that looks desperate to sell an in-stock bike may steer you the wrong way. But a good shop with good credit and a knowledgeable staff will fit you well.

    hope this helps,
    cdr

  19. #19
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    I have maybe 1cm of spacers under my stem right now. I wouldn't mind a more aggressive fit. I'm more flexible, and I'm 24 so still pretty young.

    Is there a rule of thumb for how many cm of spacers you can have above the headtube before you say that the bike will never fit? I wouldn't mind starting with a taller stack and working it down further. I was just about to take out the last spacer on my current bike anyway so it will be as low as I can get it.

  20. #20
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    I live in vancouver yes! Many bikers and I do find it very comforting. I know that washington is one of the most commuter friendly states. :-)

  21. #21
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    Stem drop - with virtual top tubes, it's hard to tell what's right.

    Dave Moulton (frame builder) has an interesting chart on his blog relating to this (and associated commentary):
    http://davesbikeblog.blogspot.com/20...ebar-drop.html

    His numbers seem pretty good. I have a 53.5 + 13 top tube (66.5 cm total) and his chart says about 8.1 cm drop. My primary bike is about 5 cm drop to the top of the bars, I'm setting up a new bike that will be about 10.5 cm to the top of the bars. Basically his number is centered around my current bikes' setups. Very rough measurements as I used a roll of wrapping paper as a straightedge sitting on the seat.

    I know at the lower bar position I'll have some hand numbness issues after an hour or so of aggressive (i.e. in the drops) riding - usually only happens during races. However I think the lower position is better for power, aerodynamics, and sprinting. My goal is to rotate my pelvis forward on the bike. I might experience some earlier back stiffness (currently it takes 3-4 hours to get stiff) but since most of my rides aren't that long, should be okay. Ultimately if things don't work out, I can get a rise stem (80 or 85 degree) and get back to my original position.

    I have relatively shallow drop bars so the delta between the two positions is less than with a deep drop bar. This means riding the tops is still pretty low but the drops don't put me that much lower.

    If you currently have a stem that points up (80 degree, a -10 degree from perpendicular) you won't have as much "fiddle" room with a 4 cm shorter head tube. If you can take a side pic of the headtube, stem, and bar, that would help. Holding a ruler to it would really help.

    I attached a picture of one of my previous bikes (yellow frame, a Medium). I found the bars to be too high. This was my first compact frame and I bought based on top tube length, didn't take into account headtube length.

    I got the measurements of the Small, marked it off on the bike (note the short line across the headtube - that's where the Small frame headtube ends). I used an adjustable stem, rode for about 6 months on it, and figured out where I wanted to be - and the position in the picture was good. I measured the length from the "Sharpie-marked Small headtube" and found that a 13 cm stem 73 degree (-17) would work fine with a size Small frame. I bought a Small and it worked out much better. The grey bike is my current primary bike with a 5 cm drop from seat to top of bars. I included a picture of that too.

    If you have a lot of doubts, buying an adjustable stem helps a lot. My stem is a Ritchey 12cm adjustable and it's a great tool for experimenting with bar height. I think they're $70 from Excel. I just checked - they're $60.


    hope this helps,
    cdr
    Attached Images Attached Images

  22. #22
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    Re-read your question...

    Spacer height max is sometimes determined by manufacturer. Cannondale says 40mm max on their SystemSix (I happened to check the manual - I was wondering if they had a minimum spacer height like some companies have - Trek I think is one of them). I wouldn't go too much more than that simply because you have so much leverage on the steerer tube when you double or triple the stack height.

    cdr

  23. #23
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    One other LBS consideration - I wouldn't buy a bike without riding it first. Okay, that isn't exactly true since I have had custom frames made. But otherwise I want to take bikes I am comparing out for a long test ride - lot's of climbing and descending. they may look the same on paper, and have minimal geometry differences, but that doesn't mean they ride the same.

  24. #24
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    Does that spacer height max include the stem? Or is it spacers under the stem?

  25. #25
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    for Cannondale it's spacers under the stem. I think the stem is practically 4 cm tall by itself

    cdr

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