Trek 520, general frame size question

ea1958

I can stand flat-footed over a 23-incher barely touching the top-bar, or a 21-incher with 1.6 inches to spare. Is there a consensus as to which is the better way to go? Thx.
Eric (newbie)

Scotty_Dog

Proper fit really has little to do with your clearance over the top tube, especially with a touring bike like the 520. The length of the top tube and the length of the seat tube are the most important factors. The following link for bike fitting is easy to follow and works well for me, but there are hundreds of other useful fit links as well. Do a search and click to your heart's content. Your local bike shop should also be able to determine your correct frame size, but it's usually nice to then purchase a bike from them in return for their time and hospitality.

http://www.coloradocyclist.com/bikefit/

ea1958

OK. Thanks for the link. They say .67 * Inseam for the C-T (Trek 520 sizing). That makes it the 21" frame for me

Scotty_Dog

Do not disregard the top tube length! Make sure your upper body is not cramped on the 21" frame. Stem length and saddle fore/aft position can only shrink or stretch the cockpit so much.

ea1958

OK, I'll try and be cognizant of it when testing bikes. At 5-11, I am a little short in the legs and a little long in the torso/arms. I hope that the stock frame fits, as I carry my wallet near my legs (i.e. it's short!). Thx.
Eric

nun

The best thing to do is to ride a couple of sizes if you can. There are probably as many sizing philosophies out ther as riders, but I think they break down into 3 main catagories

1) The agressive/speed approach puts you on a bike with 2 to 3 inches of stand over clearance. The seat post os way out and the bars a well below the saddle

2) The touring/audax style gives you about an inch standover, and puts you on a frame a few cm bigger than the agressive style. Consequently you can get the handle bars higher and lessen the weight supported by your hands.

3) The "grand dad/mom" or kiddy style. Handle bars way above the seat, back almost straight.

Style 1) is very prevelant as most cyclists go for speed and aren't putting in 50 to 100 miles day after day. The inside leg*.67 method is geared to this style. I'd suggest you go with style 2) and shoot for a handle bar position level with the seat. The Rivendell website has some good thoughts on this

http://www.rivbike.com/html/bikes_framesize.html

and there's a good fit calculator here too.

http://www.competitivecyclist.com/z...ALCULATOR_INTRO

I just went through the process of buying a new bike and here's what I did.
Firstly make sure you know where the manufacturer measures from an to. It will be from center of the bottonm bracket to either the top or the center of the top tube. There will be 1.4 cm difference between the stated frame size depending on the method used. Below I use center to top

1) I'm touring so I want style 2)
2) I measured my Pubic Bone Height, usually a couple of inches longer than you pants inseam. My pant inseam is 30", my PBH (up to the bone) is 32", or 81cm
3) I'm 5'10" so I have a slightly long torso wrt my PBH.
4) Now measure the saddle height on your current bike, mike is 28" or
71 cm.

Now we can calculate
Take 10cm from your PBH, this should be within 1cm of your saddle height.
If this is so you measued right and you're riding in a good position.

For me PBH = 81 and 81-10 =71 so I'm ok.

Now take 15 or 16 cm from your saddle height so for me its 71-15 or 16
so I'm in the range of 56 to 55 (53.5 to 54.5 center to center).
If you are long torsoed like me I'd go for the bigger size of this range so
you don't feel cramped on the bike. Its more important to give up a cm or so in standover so that you feel comfortable actually riding.

scituatejohn

The Trek 520 has a rather low handlebar height, so I would go with the 23 if you are more comfortable with it.

It seems that you are in-between sizes, and since Trek doesn't offer a 22, then the Trek 520 might not be the best bike for you.

I don't like the low handlebar aspect of the Trek 520. You might ask your bike shop if they can build you up a 54 or 56 cm Surley Long Haul Trucker for a similar price. The LHT has more sizing options (every 2cm instead of every 2 inches), and it has a longer head tube and an uncut fork that will allow a much higher handlebar position.

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John McCarthy

nun

I agree that the 23 might be better. At 5'11 with a long torso it will probably be a better fit in the top tube. Also you'll have a good chance of getting the saddle and bars level. If you carn't do this with the stock stem tou can always switch it out for a longer one.

ea1958

The 56cm Surly LHT frame is about .3" taller than the 23" Trek 520. It is the only one that I have actually stood over and it felt a touch tall (the 54cm Surly takes 26" wheels, which I don't want).

I'll try and find both the 21" and 23" Trek 520s to test ride. Thx.
Eric

scituatejohn

What's wrong with 26" wheels? I would think that they would be preferable because they are stronger, and there are more rim and tire options.

__________________
John McCarthy

daveornee

I agree with your sizing ideas and the Surly Long Haul Trucker (LHT) may even have other attributes that are better than Trek 520 such as gearing choices that are more realistic to loaded touring. Surly LHT has reasonably long chain stays for heal/pannier clerance and they even make good quality racks for loaded touring.

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David Ornee, Western Springs, IL USA

daveornee

http://sheldonbrown.com/frame-sizing.html
http://www.peterwhitecycles.com/fitting.htm
I think there is good amount of wisdom and experience in these two sites.
I also suggest that you find a dealer that carries something other than Trek for touring bicycles. I think that Surly Long Haul Trucker with 26" or 700C wheels are great alternatives. If your size ends up with 26" wheels, you shouldn't shun the bicycle for that reason. I toured across the USA 4 times on a BG (Bruce Gordon) BLT with 26" wheels. 26" tires that are suitable for touring are widely available. On my tour from Chicago to Anchorage, Alaska and back I was happy that I was on 26" wheels as the tire choices for the roads I encountered where much more suitable.
If you tell what area you are located near, we could help you with dealers who address loaded touring options.

__________________
David Ornee, Western Springs, IL USA

ea1958

I already have a plane ticket to London for late April 2006 (with a 2 month return). I've traveled a good bit by bus, boat, and train and I am hoping the biking will be both more economical and better for seeing the in-between spots.
I don't know why I am under the impression that the 700 wheels (and I'm now confused about what the 700 units are?... what they measure?) are more efficient for getting down the road. I'm very much on a budget, but I live in the north central Florida part of the world (Ocala National Forest).

ea1958

Well, I do see that the 700 is millimeters (tire diameter). I was thrown off by the 'c' designation that often follows it, which I take now to be a tire type. Any input on the general performance differences between 26" and 700mm appreciated. I am back to considering the 54cm LHT as well.
Eric