RoadBikeReview.com's Forum Archives - General


Archive Home >> General(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 )


TJeanloz: Trek sizing(7 posts)

TJeanloz: Trek sizingET
Nov 6, 2001 2:46 PM
I just wanted to clear up the OCLV sizing issue, especially since it keeps coming up. You say you have personally measured, and verified the measurement of literally hundreds of Trek Bicycles. You also say that other Treks measure c-t of top tube, but that OCLVs measure center-to-top of seat tube with the aluminum collar removed-or approximately to the center of the bolt on the seat collar. And you also say that you yourself measured your own Trek 56 OCLV to be 54.52 c-c.

I'll point out that if that number were true, then it would be around 56 c-t of top tube, and so much much higher to top of seat tube. And one look at an OCLV shows that the seat tube comes up quite a bit.

Many OCLV owners here have in the past also carefully measured their seat tubes, and in fact did so for all of c-c, c-t of top tube, and various c-seat tube combinations. Admittedly, though, they did not have your qualifications. They all came out that a Trek OCLV size 56 is more like a size 54.2 c-t of top tube, if memory serves me. So my point simply was that, even with correct top tube fit, the mislabelling of sizing results in a standover quite a bit lower than on a real 56 c-t bike, making the handlebars, and hence the reach, lower, and some will find they have trouble with this. I'm not just spitting out useless math formulas for nothing, and I even ride too--I did a 50-miler on Sunday. You can pooh-pooh the math and me, but it really comes in handy in figuring out one's reach needs. Litespeed gives real c-t of top tube numbers. You can take them, the printed STA and BBH, use your high school geometry, and wa la, out pops the exact standover given in their own stats. Kudos to LS for giving correct standovers, unlike many companies. But bear in mind that if one has only around 1.5" (as measured to a tight inseam ala CC) of clearance (small by today's standards), then with a straight-angled stem there already will be around 3" of seat/bar differential, and that with 4 cms of spacers. Add another couple of cms to the standover, and for someone who needs the seat and bars close to level, you have a recipe for disaster.
or just ask Trekkenyee
Nov 6, 2001 3:14 PM
I've asked them about their sizing before. They say the frame is sized to the top of the seat tube...
measure at the store...C-40
Nov 6, 2001 5:59 PM
If I was in the market for a Trek, I'd go to the local dealer and measure one of the bikes on the showrom. This would eliminate any questions in about 5 minutes. If the store's floor was reasonably level, a plumb bob could even be used to get a set-back dimension, to calculate the STA.

One of the most revealing dimensions that's so often overlooked, is head tube length. This length will immediately tell you how much head tube spacer or stem angle might be required to get proper bar height. I would expect a true 56cm frame to have at least a 140mm head tube length. The head tube length changes almost one to one with frame size.

For what it's worth I have exactly 1.5 inches of standover clearance (in bare feet) on my bike. With an 80 degree stem and no head tube spacers, I have 10cm or about 4 inches from the top of the saddle to the brake hoods (where my hands rest). This measurement is more relavent than the top of the bars, since it's where your hands spend the most time. The bend of some bars places the brake hoods significantly lower than the top of the bars. Deda and Easton bars both permit the brake hoods to be placed close to the top of the bars and minimize the distance to the top of the saddle.

Using low-profile pedals like speedplays also reduces saddle height and the saddle to brake hood height difference.
I did that onceET
Nov 6, 2001 8:38 PM
Snuck in the tape. At the least, one could stand the OCLV of known size next to another company's bike of similar nominal size and compare; an inch or so difference will be noticeable even by eyeballing.

Anyway, I think we all are in agreement that Trek OCLV measures to the top of the seat tube (somewhere way up there) as opposed to top tube, making the 56 c-t of st more like 54 c-t of tt. Tell me I'm imagining it, but when I see cyclists on OCLVs, their position even on the hoods always seems to look way low; too low.

The numbers for your bike sound reasonable and confirm what I'm saying. I'll add that you should consider your official standover clearance to be that as measured with your shoes on (you'll be wearing them when you ride, won't you?); use the rough but good enough estimate of an additional 2 cms over CC inseam for shoes and cleats. Comes out, then, that you have over two inches of clearance, leading to the 4" drop.
get over it alreadysheesh
Nov 7, 2001 6:19 AM
nm
get over it alreadyjtolleson
Nov 7, 2001 7:01 AM
Yep, this Trek sizing squabble has definitely devolved into getta-life-land.
Trek OCLV sizingChen2
Nov 7, 2001 6:54 AM
Measurements from my '98 56cm 5500:

c-t seat tube 56cm
c-t top tube 54cm
c-c top tube 52cm
tt length 56cm
stand-over with 23mm Axial Pro's 78cm

Just the way I like it.

-Al