Difference between a trek 500 and 520
 

I have a 1983 trek 500 that I have been setting up for touring (triple, rack etc). I have looked at the vintage trek site and it appears the geomety is the same for the model 500 and 520. Am I missing something, or are the frames the same? Is there a reason the 520 frame sells for a premium?

Looking at 1984... the head tube angle is different, and as I would have suspected, the 520 has a longer chainstay length and wheelbase. This is the norm for a touring bike for heel clearance with panniers and stability when loaded.

The 520 also had some additional braze-ons. Perhaps differing by year, but I believe an additional set of bosses for a water bottle under the down tube, and a low rider mount on the fork. In addition it probably had double eyelets front and rear, and I don't know if your 500 has them.

The 500 is a sport bike, and will not be ideal for touring, but if you have no issue with heel strike, and get everything mounted that you need, then you should be fine. Especially so the more lightly loaded you tour.

Trek being what they were, models evolved as the years went on. The x20 complete bicycles were usually touring bikes: 520, 620, 720. In different years they shared frames with other 5xx, 6xx, or 7xx bikes. A 500 would usually be a sport bike or sport-tour bike, where the 520 is set up as a touring bike.

Early on Trek had two frame geometries, three materials, and dozens of build kits. As they went on the frames became more specialized.

Models changed a lot from year ot year, even in frame details like rake. Not all 500s would ride like all other 500s, over the years.

Road Fan

I rigged up a mid-80's Trek 500 for light touring. The neutral handling made for a very pleasant ride. Great for day trips!

Here's a pic taken in the North Woods of WI:

http://farm3.static.flickr.com/2366/...52b78ea358.jpg

And I had a 510. Definitely a road bike, not a tourer at all.

I think this refers to my bike. The 1983 brochure (vintage trek site) shows the geometries to be identical. Same wheel base, same angles, same chain stay length. The 500 has only one position for a bottle cage.

Nope. I bought my '84 model 520 new, and I still ride it every day. It came with a single bottle cage braze-on, single dropout eyelets, no low rider mounts on the front fork. It has canti bosses and rack mount bosses front and rear...