hotbike

Today, someone donated a bicycle to me (I'm holding it in trust for my bike club). It's a white, 21 speed, TREK 720, Ladies model.

I am trying to guess how old it is, but it has cantilever brakes. Most newer bikes have Vee brakes, so I guess it is not very new, but it is in very good condition.
The tires (tyres) are hardly worn at all. They are 26 by one and a half, I think. Diamond tread pattern.

Can anyone tell me what year this bike is?
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Second Thread Topic:
I rode nine miles this morning on my 21 speed Fugi. There was a clunk-a-chunk noise coming from the Bottom Bracket. I got home and then went out to the LBS, because I needed an 8mm hex key. Upon inspection, the left-side BB bearings had a slight problem: two teeth were broken off the retainer ring. So that accounts the noise.
My second question: Do you think I should just replace the bearings, or the cups? Everything looks fine and smooth, but there could be microscopic scratches I can't see?
The thought has crossed my mind that I should K-ball the newly acquired bike, to keep my old steed running, but I don't think I'll do that.

hotbike

Okay, I looked closely at the sidewalls of the newly donated bicycle, and they are Cheng Shins, 700 x 350 in size!

I've never had 700 wheels before. Thirty years ago I had some kind of cheap road bike, but it had 27 x 1 and 1/8" , IIRC. Then I got a mountain bike. I weigh 280 pounds, so I don't know if they will hold up under my weight.

Please, can someone tell me how old this bike is? It has 7 speed index shifting, with grip shifts, but it has cantilever brakes, which leads me to believe it is a little older.

It says "TREK" and "720" on the frame, and it also says "multitrack".

Metric Man

Does this help?

https://www.roadbikereview.com/mfr/tr...4_1607crx.aspx

ebr898

Hi, I just noticed your post, I spend most of my time in Classic/Vintage. Here is how you figure out what year of almost all the old Treks: Go to Vintage-Trek .com and look under the heading of models/years/colors https://www.vintage-trek.com/model_numbers1.htm and you should find your bike model.
The number 720 was used on an early road model, yours is the hybrid/cross bike from the 90's. An interesting note on the lugged Treks vs the Tig welded Treks in 1992, the lugged wieghed less.
The 700 series lugged frames up to about 1992 shared a common geometry with the highly reviered Trek 520 at least in the diamond frame.
I hope this helps you

HandsomeRyan

A new BB can be had for $25 or so. If you are concerned you can replace it entirely.

hotbike

Nope.

hotbike

No, I can't find it on this list. Maybe because it's a Ladies frame? I also had a TREK 800 Antelope, which I gave away in 2006, and I can't find it's color, which was red.
I kind of like riding a Ladies bicycle because I have a slight hernia; I feel a lot more comfortable mounting and dismounting a bike with a Ladies frame.

ANOTHER CLUE:
When I looked at the batteries in the blinkie, they said "best if used by JAN 97"... oh darn, the batteries had leaked too. I had to file the terminals clean, and put new batts in, and then only two of the three LEDs would light.

hotbike

The BB and its' races were clean, and showed no sign of pitting or gouging. I repacked with 11 bearings and no retainers. The retainers held only 9 bearings each.

Thank you.

hotbike

These are the pictures of the Trek, which the lady donated to the bike club.

Here is a close-up of the deraileur- maybe someone can verify the age of the bike by the deraileur?

kaliayev

The lugged 7XX Treks only came in the 750 and 790 models from 1990-93. The were also made at the Waterloo, WI plant as compared to the other models that were made in Taiwan. I recently purchased a 90 Trek 750 that I am building. It is a pretty sweet frame.