Bike measurements, making an order!
Hello guys, This seems to be the right forum,
I am in contact with a bike manufacturer and would like to order some bikes. They supplied me with their measurements for a frame that can be fitted with flat bar or a road drop bar.
After they sent their measurements, I tried to make sense on what is the range of heights each size would fit. I requested their help and they sent me the following ranges in CM. Can some one confirm if these bikes actually fit the ranges supplied by this manufacturer.
Please Fill in Expected Rider Height in Yellow Cells
Size Seat Tube Top BB to F/Hub Head Rider Minimum Hieght Rider Maximum Hieght
XS 44 440 505 574 95 155 165
S 47 470 520 576.7 95 165 172
M 50 500 530 578.6 95 170 175
ML 53 530 545 589.2 125 175 180
L 56 560 560 590 155 178 185
XL 59 590 585 615 185 185 190
The last two columns (Cyclist Height Ranges) and the last two rows (L & XL sizes) were added later after I requested more bike sizes and expected human height ranges.
I really appreciate your help!
Here is a link to a google drive spreadsheet that you view and comment on and edit.
If the data above is mixed, the link is better to view.
I really do not want to order bikes for my clients that does not meet their sizes!
Bike measurement Graph
I have included the bike mesurement graph if it helps, you can check it out in the same link.
Not sure where to start, but are you a bike dealer with a storefront? Do you ride a bicycle? If you do and understand how and why your bike fits you, you can compare your bicycle that presumably fits you and your height to the chart. For me, I think your chart gives a small but plausible size.
But the problem I see is the focus on rider height. Seat tube length combined with its angle (with some other numbers) gives you standover height, which is a factor in deciding it the bike is tall enough or too tall for the rider's leg length. The TT length, combined with seat tube angle, has a lot to do with the bike being in the right range given the rider's torso length, arm length, and degree of lean while riding. There isn't a bike dimension that is directly based on rider height.
You or presumable this manufacturer has made assumptions about the proportion of leg to torso that the rider brings, and that might not fit your clients. And if your clients expect you to deliver a bike with a superbe fit, you don't have the options with this line of bicycles to accomplish that, unless you are an expert fitter, have good fitting equipment, and have ready access to a whole selection of different-size parts (such as stems) to use to set up the bikes in detail for every client. You also have to do this in-person, not over the Netz.
It would be nice to help more, but I'm not sure how to do that.
Thank you for your thoughts! I currently help a dealer to order these bikes and we have a humble storefront where we plan to display the different sizes for people to test ride. Also, we plan to sell online for those who do not have access to bike shops, we also plan to offer renting programs.
I am a cyclist and have been riding road bikes and other types. I always thought frames are standard and conventional until I realized there are compact frames sizes also! Are these frames above considered compact?
I know that road bikes are the hardest bikes to fit, but these bikes are low end and we want to meet beginners demand. We will not help much with fitting, measuring inseems, etc. We might consider getting extra stems.
We have customers that will be ordering online after checking the table, can I at least expect the ranges to be correct for most people?
As you said, I am not looking for an exact fit, but are the ranges displayed in the table seem logical? For exampls, the ratios between the seat tube and top tube seem are not the same as "Giant Bikes".
The questions again:
Are these frames above considered compact?
can I at least expect the ranges to be correct for most people?
Would size be different for a flat bar bike vs drop bar for the same rider?
Originally Posted by Road Fan
Whilst true a bike sized based on height is better than say just inseam.
If your average it won't matter, but average bike sizes fit people based
on height better than inseam, i.e. a person with longer legs and shorter
torso, or shorter legs and longer torso is better off with a bike based on
height than too big for the former and too small for the latter based in
inseam, the error being the implied height from inseam and so then
the front to back dimensions that will also suit the rider.
Copy off the other guy's paper, just like in school..
bike geometry in the standard bike form is pretty well resolved.
look up other brand's data offerings..
proportion of leg to torso is a variable thing in people, women, more so .. height is a combination of both..
Good luck ..
Last edited by fietsbob; 07-17-13 at 06:52 PM.
In a road frame "compact" usually refers to the top tube having a steep slope down from the head tube. It doesn't have anything to do with size selection, except that a bike shop can supposedly fit all customers with a smaller number of frame variants in stock. The only exception is if you size a bike based on stand over height. On a road bike I consider SOH and personally I have an upper limit, but it's not the main consideration.
Originally Posted by RoadSurfer
A former engineering bud who now manages a bike shop (much more happily!) showed me how several of his major brands (i.e. Giant, Trek, et cetera) all provide sizing charts, but the sizing guidance varies from company to company. It's very possible for a person to take a Small in one brand and a Medium in another. The way these bikes will fit your customers will have somethign to do with how the company thought fitting should "work" on a customer's body. Without the expertise to second-guess such a set of assumptions by the manufacturer, combined with the lack of intent to measure and fit the customer yourself, I don't think you have much choice but to go with what the company tells you, at least to start out.
A sufficiently bad fitting can result in pain or at least rider discomfort, and some would say to injury. An affected customer might see you, the retailer, as liable. Do you want to stand in front of a judge and say "I didn't know how to fit, so I thought this one would just be ok so that's what I told her?" I'd want to at least say "I'm an authorized dealer for XX brand and I followed manufacturer's guidelines as I got my business kicked off, depending on the expertise the bike company said they had. I made a point of getting all of the available manufacturer literature and studying it."
And, find a class in bike fitting to attend, intended for dealers, if you don't have experience helping friends and family. Most of my experience comes from self-fitting, helping friends and family (never shy about expressing their opinion of my results) and studying this on my own. Being an engineer by training I'm pretty quick dealing with the procedural and quantitative sides of it, and I get "help" from my friends in the people side of it.
All this said, I haven't had a lot of friends needing help with hybrid or city-type bikes, unless they wanted to upgrade to a road frame.
If I were to go work in a bike shop, I'd try to get the available training in fitting, regardless of my experience.
As I said before, your chart gives a plausible fit for me. I can't say about other road riders. We're usually a picky bunch!