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Trek sizing(15 posts)

Trek sizingpkompath
Nov 2, 2001 7:29 AM
I've read somewhere about Trek's peculiar sizing. It seems that their frames runs a size smaller and that one should get fitted according to their top tube length. Yes or No?
re: Trek sizingTJeanloz
Nov 2, 2001 7:34 AM
Trek road bike sizing runs center-to-top of tube (as opposed to center-to-top of the seat collar). This is one of many sizing iterations used by various companies. It does make the frames run 'smaller' than similarly sized bikes that are measured center-to-center of the tube.

One should get fitted according to their top tube length regardless of how the seattube is measured.
Nov 2, 2001 8:44 AM
They do not measure to top of (top) tube. They measure to top of seat tube or even beyond, and that is what is so misleading, giving a much lower reach than for other bikes with similar top tube lengths (and I do not agree to just look at top tube, but rather to issue severe warnings to anyone not wanting a very big saddle/bar differential). Here is the proof:

Unlike for other companies, their standover stats happen to be correct, as many owners have verified. Let's take the 5200, size 56. Standover minus BBH = 79.3 - 26.8 = 52.5. Then ST length as measured c-t of top tube = 52.5/sin73.5 = 54.75, well short of 56.
Nov 2, 2001 8:54 AM
ET, I don't want to be rude. But I have personally measured, and verified the measurement of literally hundreds of Trek Bicycles. If we want to be very technical about it, Trek bicycles measure center-to-top of top tube with the exception of OCLV's, which measure center-to-top of seat tube with the aluminum collar removed- or approximately to the center of the bolt on the seat collar.

Now you're going to tell me that I'm wrong because the OCLV Time Trial bike is measured differently. You're right, it is. Get over your damn standover height argument already, its crap...
I have to add...TJeanloz
Nov 2, 2001 8:57 AM
ET, you're that guy who comes into the bike shop with mathematical proof that a 27" tire will fit a 700c rim, we tell you it won't, you call us morons because the math works, and then you complain when you can't get you're tire on...
not Scottish...Austin
Nov 2, 2001 11:08 AM
it's crrrop!
you must've had too much coffee todayET
Nov 2, 2001 12:13 PM
What do you think we're talking about when someone on this board asks about Trek sizing if not Lance's OCLV? Low-end aluminum? Of course OCLV! Not that it's my favorite source, but here is a quote from the August 2001 Bicycling magazine, page 51, on OCLV:

"Caveats: The frame is measured from the bottom bracket to the top of the seat collar, so they feel small--a 58cm feels more like a 56. Size yours by top tube length."

I don't deny that top tube sizing is more important than other considerations. But given that Trek's 58 is really a 56, or to view it another way, its top tube length is quite long for the given standardized seat tube length, I think it's disingenuous and misleading the way they size. I feveryone would use just c-c or c-t of top tube, it would be a simpler world; top of seat tube (collar) tells you nothing without more info. I can't understand why Your Bike Highness can't understand that. I'm not fixated on standover. What I am saying is that standover is a proxy for seat/bar differential, and at the least, if one has substantial clearance over a bike, be forewarned that the the drop to the bars will be more severe. I myself can easily handle a 4" drop. But there are many who are here or come onto this forum wanting their bars more like an inch lower than, or even equal to, their seat (there's some posts to that effect right now on the board). They ain't gonna get that with OCLV; they just ain't, certainly not with spacers in the standard threadless setup, or not without a ridiculously angled-up stem, if with that. I'd say about twice a month on average (until recently anyway), people would come on this board and say they bought an OCLV based on top tube and can't comfortably reach their bars or have neck/back pain due to the drop and find out that due to misleading sizing, they made a big mistake. Go tell them just size by top tube and what a piece of crap my standover argument is. Have a good day, TJeanloz; you used to be more civil.
Tell me...TJeanloz
Nov 2, 2001 12:33 PM
Please tell me that you don't believe a word they write in Bicycling Magazine.
just those wordsET
Nov 2, 2001 1:33 PM
since it was verified by many others.

One more thing: you have said yourself that you have ridiculously short legs as compared to your overall height--way out at the tail of typical build, so much so that in the past you have referred to yourself here jocularly as a "freak". No wonder you fit so well on a Trek, what with its long top tubes as compared to its standardized seat tube, and hence, by proxy, lower standover. Just don't expect the rest of the population closer to the mean to fit equally well on a Trek.
I am a freak...TJeanloz
Nov 2, 2001 2:15 PM
And that OCLV fits me as well as any stock bike ever will. However, despite my incredibly short legs, I can easily (albeit carefully) ride a 61cm bike without a real threat to my future children.
Your 56cm 5200,TJeanloz
Nov 2, 2001 10:24 AM
It was an interesting example, because I happen to own exactly that frame. Over lunch, I went home and reviewed my personal spec sheet- which has the intimate details of all of my bikes. I measured 54.52cm center-to-center on my OCLV. So if your 54.75 center-to-top measurement is correct, the tube is only 4.6mm wide. I recall it being wider than that...
vertical and horizontal fit equally important...C-40
Nov 2, 2001 10:03 AM
Sizing by top tube length and ignoring vertical fit isn't too smart. The majority of builders only change top tube length by .5cm for each 1cm of (stock) frame size. The vertical fit will suffer severely before a significant correction in horizontal fit is achieved.

The long torsoed rider could end up with a frame that he couldn't even standover if only top tube length were considered. I value my private parts enough to get the vertical fit correct. Correct vertical fit includes the proper head tube length, which is often ommitted from geometry charts.

I could easily ride a frame that was 2cm smaller than my optimum size (55cm c-t), by switching from a 110 to a 120 stem, but the saddle to bar height difference would then be too extreme. A high rise stem or lots of steering tube spacers would then be needed. Both look bad and are obvious signs of improper sizing.
Question ? ..breck
Nov 2, 2001 10:28 AM
Interesting you mention the 110 mm road stem. Was taught to size my road bike horizontal top tube frame using a 110 mm ~"parallel" to the ground stem. This seems to work perfectly for me riding an older 1996 so called 58 cm OCLV with the 110mm TTT Status 72 degree quill stem.

Is it your feeling that the ~horizontal 110 mm stem would be typically preferred for good fit. My bud Campy Man has made this claim. Always learning here :)

BTW, most charts do not take into account shoe size (length) either.
Am not really "chart" person and never really fully understood them, etc.

nothing sacred about a 110 stem...C-40
Nov 3, 2001 6:10 AM
The 110 length just happens to be in the middle of the commonly available 90 to 130 range and the size that happens to give me the best fit on most frames. It wouldn't matter to me if a frame required a 100 or a 120 to get the proper reach. I've used all of these lengths over the years.

The idea of sizing by top tube length implies that there is something wrong with changing stem size by 10mm to get the proper reach. I would much rather get the proper vertical size and fine-tune the reach with the stem, than get a frame that was 2cm too small or too big, just to use a particular length of stem.

Most stems are now angled at 80 degrees (or more), instead of the 73 degrees commonly used on quill stems. This helps to compensate for the lower stack height of threadless headsets and reduces the steering tube spacers required.
I'm 6-5 and long torsoed with a 62 cm OCLVElefantino
Nov 2, 2001 11:07 AM
I have a 110 stem and my seat is mounted smack in the middle of the rails.

What does that mean? I don't know. I've ridden a 60 cm OCLV too and it wasn't uncomfortably small.

Fit is important. A good, long ride to tell you whether that fit is right is even more important. Insist on one.