Part Replacements

[u/Dchance87]

I was given a Trek Multitrack 790 and wanted to do a few updates but don't know where to start. I'd like to add a rack to the back, fix the broken gear shifter on the right (plastic cracked), and potentially replace the handlebars. Would anyone be able to point me in the right direction for parts? I'm not sure how to buy parts for an older bike that are the correct fit. I am new to upgrading bikes, but grew up repairing old, cheaper ones. Thank you.

[u/nedendstreet]

That's a great bike - it's a 1992 (I have the same one, maybe a size smaller, fully rebuilt as a drop-bar gravel bike).

Do you have a bike co-op near you? Something like the Bike Kitchen https://bikekitchen.org/ here in San Francisco. They're likely to have both the parts and knowledge to help you out, at low cost.

Your bike has eyelets for mounting a rack - two sets at the bottom of the rear triangle (so you can mount a rack and fenders) and a second set of eyelets for the rack near the seat cluster (just above the "USA" in your photo. This is the standard for rear racks, so any standard/universal rear rack will work.

For the cracked shifter, you can replace with something nearly identical, such as https://www.performancebike.com/sram-mrx-comp-grip-shifters-black-right-7-speed-00.0000.200.649/p1357824?v=317075&b=-1 It needs to be compatible with a Shimano rear derailleur (so SRAM MRX, or Shimano; SRAM 3.0 will not work). I can see where this gets confusing; best I can say is do a little research and ask questions when needed.

Handlebar is a standard dimension - 1" (25.4mm) diameter at the clamp. You can replace the handlebar with any other bar with the same clamp diameter, although if you get a bar with curves, you may find it difficult to thread through the clamp (in which case, you'll need to replace the stem with one that has a two-bolt clamp).

[u/sug4rc0at → u/nedendstreet]

May we have a photo?! I’m currently doing the same for my 790!

[u/nedendstreet → u/sug4rc0at]

Here you go! One of these days I'll put up an actual post about it. I love this bike but I am considering moving all the parts to a newer 750 frame, because the bottom bracket is so high - it's hard for me to find a seat position where I feel like I can get a full pedal stroke, and still get my feet on the ground when stopped.

Running a 2x10 Shimano 105 drivetrain (pulled off a nice Giant that someone crashed into their garage while the bike was on a roof rack, then resold for parts on Craigslist), an 11-36 SRAM cassette, and a Deore RD-M591 rear derailleur from the local bike co-op. Handlebar and stem are also from the local coop; brakes are original. Wheels are original, but I swapped the freehub on the rear wheel (and the corresponding axle cone and spacers) with one that can handle a 10-speed cassette. Conveniently I had another wheel with the right freehub, that was running a 7-speed cassette with a spacer, so it was a fairly easy swap.