Measuring a Trek for size?

[Catrin]

I know that different bike manufacturers measure their bikes differently. Does anyone happen to know how Trek measures their bikes? I am 99% certain what size my Trek is, but would like to confirm that as someone might be interested in it.

Thanks!

[indysteel]

There's likely a sticker on the bike indicating its size. Check the down tube or seat tube. IMO, that's verification enough.

[Catrin]

There's likely a sticker on the bike indicating its size. Check the down tube or seat tube. IMO, that's verification enough.

I removed the stickers long ago I will measure the down tube, thanks!

[OakLeaf]

No, she just meant the sticker might be on the down tube. The measurement is supposedly of the seat tube. But with the sloping top tubes these days it's all about imaginary lines.

Prop the bike upright and use a plumb line to measure the distance from the center of the top tube where it joins the head tube, to the floor. Record this distance.

Now, find the place on your seat tube that's the same distance from the floor as what you just measured. Mark that spot with a piece of tape, then measure from that spot to the center of the bottom bracket.

That's as close as you'll get to the manufacturer's frame size.

[Trek-chick]

It looks like the seat tube is measured from the center of bottom bracket to top of seat tube. This is based on diagrams I saw on their geometry charts from their website.

[OakLeaf]

If it says center-to-top rather than center-to-center, I'd do it the same way I just outlined, but start measuring from the top of where the top tube joins the head tube. Even in the old days, the measurement was based on the top tube, because different manufacturers allowed widely different amounts of tubing above that level to support the seatpost.

[kmehrzad]

If you subscribe to Adventure Cyclist magazine, there's a great article towards the back of the current copy (I received it yesterday) that discusses and shows what to measure on a bike when sizing.

[Cataboo]

It looks like the seat tube is measured from the center of bottom bracket to top of seat tube. This is based on diagrams I saw on their geometry charts from their website.

This is how I've always measured bikes - and it usually matches whats on the specification pages from manufacturers...

It's a bit less complicated than Oakleaf's method.

Center to top of the seatpost lets you know how far you can drop the seatpost - with the sloping top tube of the trek, center to center of the seatpost measurement probably doesn't matter all that much. There is going to be plenty of standover - but whether or not you can put your seat where you need it to be is necessary. There are lots of mixte frames that will fit me just fine for top tube length and standover height - but their seattube (center to top) is longer than where my seat usually is.

[Catrin]

So I would just raise the seatpost to the mark that says "this high and no higher" and measure from the bottom bracket to the top of the seat tube. That seems simple enough. I will also use Oakleaf's suggested method and see how they compare

Thanks for the tips - from the base measurement I took this morning it may actually turn out to be a 17 inch bike - which would explain why it is too big for me and I know someone who might be interested in it IF it is a 17 inch I need to make very certain though - I now wish I hadn't removed that sticker.

[indysteel]

So I would just raise the seatpost to the mark that says "this high and no higher" and measure from the bottom bracket to the top of the seat tube. That seems simple enough. I will also use Oakleaf's suggested method and see how they compare

Thanks for the tips - from the base measurement I took this morning it may actually turn out to be a 17 inch bike - which would explain why it is too big for me and I know someone who might be interested in it IF it is a 17 inch I need to make very certain though - I now wish I hadn't removed that sticker.

Maybe I'm just totally confused, but I think you just measure the length of the seat tube from the center of the bottom bracket. Leave the seat post out of the equation. In looking at Trek's geometry page, this is indeed how they measure the bike. The seat tube--if it is indeed a 15--should measure 15 inches from the center of the bottom bracket.

http://www.trekbikes.com/us/en/bikes...th/fx/76fxwsd/

[Catrin]

Ooops, I was obviously confused Thanks! This makes perfect sense.

I just called the LBS from which I purchased it and they confirmed that it is a 15 inch, so now I know. I am going to measure it anyway just to do it, but now I don't have to rely on my trusty measuring tape.

[tulip]

I was going to suggest that you look at your receipt or call the bike shop where you bought the bike, but you figured that out already. I hope you sell your bike soon.

[Catrin]

If you subscribe to Adventure Cyclist magazine, there's a great article towards the back of the current copy (I received it yesterday) that discusses and shows what to measure on a bike when sizing.

Adventure Cyclist?!!? This sounds interesting...that sound you just heard was me firing up the search engine

[kmehrzad]

Adventure Cyclist?!!? This sounds interesting...that sound you just heard was me firing up the search engine

It's a great magazine, my favorite in fact. They'll send you a sample copy if you'd like.

http://www.adventurecycling.org/mag/