Machka 

First, have you measured all your bicycles and put the measurements into a spreadsheet or similar document?

Second, what measurements have you done?

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I had a spreadsheet with the measurements for all my bicycles at one point, but then my hard drive crashed and took that with it. So I recreated it a number of years ago, but so far only have 2 of my bicycles on it. One day soon, I'll have to do the rest.

This spreadsheet was invaluable to me when Machak, my Marinoni Ciclo was stolen. He was a customised custom-built bicycle and was very comfortable. Having my spreadsheet of measurements meant that Rowan and I could select a frame to build up, and know that the frame would work for me.

We sat in the shop with the frame, my spreadsheet, and a measuring tape, and checked everything ... and then bought the frame because it was a very close match. If I had a complaint about Machak, it was that his top tube was a little bit too long ... and the new Hasa titanium frame has a slightly shorter top tube.

So, I measure the following things ...

• Seat Tube (Center of Bottom Bracket to Top of Seat Tube)
  
• Notional Seat Tube (Centre of Bottom Bracket to Level from Centre of Front of Top Tube)
  
• Top Tube (Center of Head Tube to Center of Seat Tube)
  
• Down Tube
  
• Seat Stay
  
• Chain Stay
  
• Nose of Saddle to Center of Handlebar
  
• Center of Seatpost (at top) to Center of Handlebar
  
• Handlebar Width (Center to Center)
  
• Crankarm
  
• Bottom Bracket to Top of Saddle at angle of Seat Tube

What do you measure? I'm wondering if there should be other things I need to add to my spreadsheet.

darb85

um ok

Machka 

Don't you measure your bicycles?

darb85

i Fit my self to the bike. Everything else doesnt matter. ive got bikes with different seat and head tube angles that throw off measurements. Measurements only mean something if you measure from the exact same spot everytime. SPecialized XY tool works for me and then I still go through a fit.

LesterOfPuppets

I don't bother with seatstay length, bar width, crank length really. Well maybe bar width when I get a used bike and wonder what size they are. All the cranks I've had have the size stamped on them.

I also measure BB drop thusly : Loosen QRs, run string along top of axles, measure distance from center of crank bolt to string, subtract 5mm (assuming 10mm axles).

Machka 

Yes. And you can do that with levels.


I figure if I'm going to spend a lot of money, time and effort to get a bicycle that fits, I want to know the measurements of that bicycle so that the next time I spend money on a bicycle, I am confident I am getting one that will work for me.

lazerzxr

I note my fit and record all measuements i need to recreate that fit if the bike is destroyed or stolen.

I have a spreadsheet which I use to compare frames. For example my specialized has a 17 mm longer horizontal top tube than my colnago but that doesnt mean the reach is 17 mm longer because angles and HT length are different. the reach is actually 8.8mm longer

Therefore my spreadsheet allows me to enter horizontal top tube length, seat tube length and angle, head tube length and angle, stem length and angle and bar reach, number of spacers and headset size, bar drop.

This allows me calculate very easily for a given frame, what bar and stem and spacers i will need to acheive the same front end position as my "known" good fitting bike in terms of reach and height. Thats reach, not distance to saddle which will depend on the saddle.

A lot of people think that a 17mm shorter top tube will result in you needing a 17mm longer stem to get the same fit but if you work it out that is not correct. I was able to walk in to the shop and tell them the frame size i wanted the stem length and number of spacers for a frame I had never ridden and know that it was right. When I got home and measured it in real life, it was exactly the same as my other bike.

It was a very useful tool when buying a bike. I was also able to show that no trek will fit me as good a my colnago as their TT are longer and the result is I end up with more spacers and a short stem with too much drop or just a very short stem. I proved this with a test ride of the closest fitting frame. It was fine but I wanted a 90mm stem as predicted

JaceK

weird... here I thought those specs published by manufacturers were the measurements.

BentLink

Park Tool has a bike position measurement method and recording form available. It has instruction, pictures, and things you need to document a bike that fits so you can transfer this to another bike or get it back when replacing components. I just started using it with my acquisition of a Peugeot this January, so I only used it a little.

Machka 

Do you just purchase common "off the shelf" bicycles? And what about fit ... like stem length, height of saddle etc.?

Machka 

I like that ... I'll have to print that form.

rollin

That's a great resource, thanks.

I have some scrawls on a note which is in my travel case.

8Lives

I came at this a little differently. My LBS has a couple of different measurement tools, but for my new Parlee we used the size cycle. Basically that gives you the two critical XY measurements - position of feet, hips, hands. Once you have your coordinates "in space" you should be able to fit from there.

snowman40

Test rides, bike fitting and communicating with the sales guy about what I like and dislike about my current bike. When I got my Felt, I told the salesman I didn't like the stretched out feeling I have on my Fuji (a tourer and it feels to big, even though it is the "right size") and the numb cornering feeling. A few test rides later, I got my Felt F75 and it fits like an old broken in pair of shoes, when it was assembled, the salesman (also the mechainic) put a shorter stem than normal. I spent more time at the fitting getting used to clipping in and out, adjusting the cleats, and doing other fine tuning adjustments (handlebar angle, really minute stuff). We A-B-A-C a lot, almost always ended up back at A.

It fits so perfect, is comfortable, and really really fast!

kleinboogie

Just goes to show you, no matter how retentive you are there's always someone else more so. Yeah, I measure all kinds of stuff especially when I was deciding which TT frameset to get. I compared the P3, Siice and 8 different Chinese models side-by-side. For my bikes I record in a notebook I keep on my bike stand all the fit measurements. Great park document and it's "cute" how they use a board to get a straight line. I use two laser levels mounted on tri-pods. GL

Machka 

Very interesting ... you've taken it further than I have with the angles, but I've been tempted to do that too. And very interesting results when you use it to purchase a bicycle. That's one of the most significant things I've used the measurements for ... I can go in and buy a frame and be confident it will work for me.

Rowan

I suppose only for dudes like you with plenty of cash to buy the latest off-the-shelf bling bikes.

But some of us also are into older bikes for which the manufacturers' measurements have disappeared off the net.

There also is some degree of confusion or disagreement over how frames should be measured, especially with the advent of compact frames. There then needs to be, in our case, a standardised form of measuring the notional top tube and seat tube lengths, especially as the "base data" bikes had or have frames with level or almost level top tubes.

There is a tendency for some published measurements by manufacturers to blur the method of measuring the top and seat tubes.

lazerzxr

They are the measurements but you have to use them correctly to compare two bikes.

As i said 17mm shorter top tube does not mean 17mm less reach. Almost all manufacturers quote horizontal top tube length measured from centre line of seat tube to centre line of the top of the head tube. They also quote head tube length

If you look at the sketch you can see that frame B with shorter top tube also has a shorter head tube. Therefore to calculate the the change in reach you need to take off the 17mm but then add on the reach associated with dropping 20mm at 73 degrees. This can be a significant change in reach particularly if comparing a high end race bike with a tourer for example. Then you need to consider the height of the headset on both bikes and the spacers used which all adjust height and reach sometimes as much as flipping a stem or changing length by a size or two.

Then factor in bar reach, stem angle and reach, and you can compare the fit of your known bike and another (details taken from online tables) without ever even seeing one in the flesh. Of course you need to know your current bike dimensions and this is only half the story as you need to make sure your seat is in the right place too. Bikes come with different set back posts and often the manufacturer is more interested in telling you the post is carbon than telling you it has 20mm set back where last years model had no set back etc.

By the time you get into different frame angles and wondering just how many spacers you need bla bla bla you will find a spreadsheet is very useful. Like I said, I just walked in the shop, told them exactly what i wanted, no questions asked and nailed it firts go with identical fit to my other bike



I am a super geek tho

rollin

Correct

Machka 

A little update on this ...

When we ordered our Bike Fridays, they asked us for measurement details on the bicycles we currently own, and on which we currently feel comfortable, so that they could build us a bicycle that fits.

So Rowan and I both updated our spreadsheets with the measurements of several of our bicycles, and we added more columns for specific measurements that Bike Friday asked for.

Those spreadsheets have been a useful reference ... for our titanium bicycles, for our touring bicycles and for our Bike Fridays.

Bandera

Well done, a proper Old School methodology.
I include BB height, pedal/shoe info, KOPS, reach/drop and bar type as well.
I've logged my build details since the 70's and transferred the data to a spreadsheet w/ serial # and pic for insurance purposes as well as fit.
When I built my last two bikes I used the data to replicate my fit: bang on w/ no guesswork, wasted time or component $.

-Bandera

dalava

If you are only concerned with fitting all bike the same way, assuming you are going to use the same crank arm length, then you only need to know:

- saddle top to bb offset (verticle)
- saddle tip to bb offset (horizontal)
- bb to hood offset (v)
- bb to hood offset (h)

All other measurement can be either derived from these or doesn't matter in term of fit. There are other measurement contributes to how the bike feels, such as bb height or tube angles.

I normally keep the manufacturers stack and height and other geometry measurement for each bike, and then keep these measurements for fitting. I measure each bike by having the front wheel against the wall, and measure everything by the subtracting the distances measured to wall or ground for the offsets.

wphamilton

I do keep a spreadsheet with the standard measurements, plus stem length and effective top tube. But then those don't uniquely specify my particular fit to the bike, so I also have a saddle to hoods measurement. From the wide part of the saddle center, straight forward to intersect the line between the hoods. Since that's really what the reach is. Then also from the saddle top at the sitbone area to the pedal top with the pedal at the furthest extension. Which you could calculate with your other measurements along with set-back, but it's easier to just measure.

bt

stack, reach, seat tube angle, done.

dalava

Not done.