derek.fulmer

I'm wrapping up my Look AL 464 P frame build, and ever since I got the frame I have had a nagging thought that the frame is too small for me, even though I bought the largest frame they offer. The geometry on their site states it has a 57.5 seat tube and a 58.4 top tube. Which is fairly similar to a Specialized Allez I rode for a while and sold recently which was a 58cm. However, when I measure the top tube, c-c I get 55cm. I'm not certain how Look is calculating the 58.4 measurement.

Are track bikes, by their nature, supposed to be smaller compared to what you would ride on a road bike? I'm ~6'2.5" and have been riding 58cm bikes since I started riding.

Normally, I try before I buy, but with this frame I didn't have that option and I really wanted to build the frame from scratch.

For reference: https://www.lookcycle.com/media/uploa...EOM_AL464P.pdf

carleton

There is a big difference between 55cm and 58.4cm TT.

Measure the head tube length ("K" on the diagram) and compare it to the chart. That will let you know which frame you have.

derek.fulmer

It matches, 18.5. My concern is whether or not it is the correct size, but I guess I'll learn that once I'm on it. I just can't make sense of how I'm measuring 55 and they're stating essentially 58.5.

Dalai

Are you measuring from the middle of the steerer tube at middle of stem height to middle of seat post with the tape horizontal?

queerpunk

Yup, you have to measure horizontally. If you measure along the tube, it's likely cutting a shorter path from the head tube to the seat tube by being at an angle. Triangles. A top tube that is parallel with the ground (perfectly horizontal) is a hypotenuse, the long side of a triangle.

Here's a good tip for cross-bike measurement comparisons, though:
Different angles can mean that strict top tube measurements don't necessarily communicate everything. Imagine your Allez frame and its 58cm top tube. Now imagine that you buy a track bike that the same top tube measurement, 58cm - but it has a completely vertical seat tube. In order to get your saddle in the right position relative to the pedals, you jam your saddle way back, and all of a sudden that 58cm top tube is waaaaay too big for you.

(Similarly, imagine sizing from a road bike to a cross bike - the cross bike, with a lot more clearance 'under' the frame, may have a much smaller headtube compared to a comparably-sized road bike)

That's why companies are starting to publish geometry charts with "stack" and "reach." Stack is the vertical distance from the bottom bracket to the "top" of the frame (a horizontal line extending from the top of the head tube), and reach is the distance from that vertical line coming out of the bottom bracket to the center of the headtube. It makes these two measurements independent of frame geometry, and they're the only realiable way to assess measurements across different bikes.

Your bikes:
Stack = Allez 606mm, Look 567mm.
Reach = Allez 402mm, Look 417mm.

derek.fulmer

Center of seat tube to center of steerer tube.

derek.fulmer

That's a TON of really helpful info! Thank you.

I still plan to build the bike and train/race on it so I won't be able to post any photos until I at least have wheels so I can mock up my fit. However, based on what you just shared as far as stack and reach, etc. do you think maybe this Look frame is too small for me? Or are track bikes supposed to be slightly smaller than a road bike as far as geometry and fit go?

queerpunk

It depends on a jillion variables but if that S fits you then I thiiiiiink that the way that the Look compares is within the range of adjustment, as well as within the range of "a little bit closer and lower" that one might setup a track bike compared to a road bike.

The Look is lower. That's pretty standard for track bikes (easier to go from a mass start to a pursuit position). It's a hair longer. and that's fine, because you might ride your saddle a bit further foward in a track position. plus, stems come in lengths.

carleton

At 6'2.5", this frame could very well be too short for you.

It really depends on:

- Your body proportions (even, longer torso than legs, or longer legs than torso). (I have longer torso)
- How you set your saddle with regards to your bottom bracket. If you have a forward position, you are eating into your top tube length.

It's really hard to do this via text. A pic of you on the bike while on a trainer will tell us more.

Also, comparing road bikes to track bikes may not be the best way to go when a couple of centimeters can make a big difference.

derek.fulmer

I agree, it's difficult to do via text with no accompanying images. Unfortunately, it's the best I can do until my wheels arrive.

I have not done it for a while, so out of curiosity I input my measurements into Competitive Cyclist's fit calculator. I didn't realize I'm 188cm tall, so closer to 6'1"/6'2". Based on their fit calculator, I think I'm closest to the "Eddy Fit" and the "French Fit". I attached some photos of what the fit calculator kicked back.

Worst case scenario is that I build the bike, get some training sessions on it and realize its too small and then try and sell it then find a better fitting frame. (Can someone find me a Cervelo T1 in 58cm for less than $500? )


I knew this was a risk before buying but it was an end of season sale and I was high off of my first couple training sessions.

carleton

Stop right there

That guide was made for an online retailer to sell more road bikes online

That guide basically takes a hunch and makes it seem scientific. You ever read any of their product descriptions? You need to you need to put on waders to walk through the paragraphs of their creative writing bullsh*t.



Unfortunately, fit usually comes down to trial and error.

derek.fulmer

Trial and error it is, then!

I'll take my lashings for using the fit calculator thusly.

Quinn8it

Also not perfect... But probably as good as a fit calculator gets:

Tiemeyer Cycles, Inc. :: Custom Bicycle Frame Builder

carleton

Yup! That one is better than the Competitive Cyclist calculator. Notice how, not only does it have different measurements for Track frames...it breaks Track into 3 styles of frames: Points, Pursuit, and Sprint!!

For those who don't know, that is the calculator that Mr. Tiemeyer made for his website. He'd instruct clients to use it. Then he'd send out technical drawings and have the client take the drawings to a local bike fitter to input the measurements into a fit bike. The client would then get on the fit bike and see how it felt before any welding took place. That way they could feel the geometry before they commissioned Tiemeyer to start building the custom frame.

It's a really, really smart system.

Quinn8it

very little changed for me between doing that fit calculator, seeing a local fitter and building my Tiemeyer..

also that calculator puts me on my current size DF3, which i have since been fitted on by Nate.. and its correct.

its worth adding that Tiemeyer tends to fit with a shorter stem.. so assume any TT measurements are allowing for a 100mm stem

sickz

actual top tube length c-c would be longer (the hypotenuse) than the virtual top tube length of 584.9mm.

derek: your measurement is most likely intersection to intersection, and not center to center. if we tack on half of the diameter of each tube we roughly end up to the distance you've measured.

584.9mm - 550mm = 34.9mm

eyeballin' the image the seattube appears to be about 1" diameter (25.4mm), w/ the headtube 1.5" diameter (38.1mm). the center of each is roughly half of their diameter because of the angle of intersections.

but if we take half and add them together we'll get: 9.05+12.7=31.75mm. add that to the 550mm gives us: 581.75mm. take into account all the visual error on my side =P and that's most likely where the last 3.5cm disappeared to.

derek.fulmer

Received my deep v wheels today and could finally start mocking up my fit. Here are two photos, one with me on the tops and one in the drops. 110 stem, 44cm road bars, setback seatpost. No cranks on yet.

Hopefully these help you all give feedback on not only the fit, but the size if the frame and if it's correct for me.

carleton

It may work. Your back angle is kinda high.

I'd try a 130mm stem before getting a larger frame.

derek.fulmer

What's the reasoning behind that, Carleton?

carleton

The wind is your biggest opponent out on the track.

A longer stem (or top tube) will extend your hands and cause your back to lay your back down.

Compare your photos to photos of riders that ride the events you like and you'll see.

EDIT:
Bro, this is what we are striving for.



Anything less than that is unacceptable :-|

carleton

I want to express that, like and off-the-rack suit, it'll be fine for what you need it to do.

We (the internet) (and I personally) can get caught up in finding the absolute best fitting frame ever...and it still won't make a significant difference in race results.

Here are the frame sizes that I've ridden over the years:

2009: 58cm
2010: 57cm
2011: 57cm
2012: 57 & 58cm
2013: 56 & 58cm (didn't race much)
2014: 58cm (didn't race much)
2015: Looking to buy a 60cm

All of my TT times were in the same area. So, don't feel like you won't be your best. Have confidence. You'll be fine whatever frame you use.

queerpunk

Yeah, I thiiiiiiiink you're in the range of adjustment, but somebody your size can and should probably-definitely be riding longer stems. So I agree with Carleton.

When you get your cranks, slap 'em on and take a 30-second video of you steadily spinning. That will be more helpful than a still.

Quinn8it

yep-
you can't set up the front end until you set up the back end, which you can't do until you get cranks on it.
Having a set-back post doesn't really tell you anything about where your saddle is set.
I have to use a set-back just to get my saddle 2cm behind the center of the bottom bracket. But that has a lot to do with my saddles clamp able area and my weirdly short legs.

i would start by setting the saddle at the same height and distance behind your BB as your road bike, a minimum of 5cm set back, likely way more based on your height.

Then you are setting the front end based and arm extension, back angle and hip angle.. That's when the video becomes important. As that's the only way to judge hip angle and it will make you settle in to the actual position that you sit on the saddle while pedaling

In in addition to a longer stem you could get more reach and drop by switching to Track Drops.. That would also get you off 44cm bars!

queerpunk

Yup. I have some very rad very sprinty 36cm B123s if you are interested in 'em, Derek.

derek.fulmer

I'm hesitant to install my cranks incase I decide to exchange the frame. I wouldn't want to have greased the threads and then not be able to send it back. I'm going to try and grab a 130mm stem today and post more photos.