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I am a total bike novice, I can ride them but have never done much as far as maintenance. Recently, I got my old bike out of storage, it is a 1991 Trek Multitrack 700, and I want to know if I can "restomod" the bike.

The chain, chainrings, cassette, and crankset are all fairly rusty but the derailleurs are both fine. Aside from that both of the wheels need to be replaced.

Do I need to replace the chainrings, cassette, and crankset with contemporary parts? If I install new components, how would I know that they'll fit? Would contemporary parts not get along with a new wheel?

And if I wanted to install a new gear change mechanism, would I need to get new derailleurs?

  • Only you can decide if the effort and money spent are worth it, some people would advise against and just buy a new/used modern bike that's doesn't require maintenance out of the box. You might also want to check out relevant forums like retrobike.co.uk instead. – Klaster_1 Aug 20 '17 at 6:30
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    Ride it as-is for a few months and see how you get on. The only thing I'd change straight away would be the brake pads, because they go hard with age and stop working so well. Tyres could also perish in storage, so give them a close inspection. – Criggie Aug 20 '17 at 12:31
  • How to upgrade: You buy another bike. One cannot have too many bikes, despite what one's spouse thinks! N+1! – RoboKaren Aug 25 '17 at 3:33
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Cranks and chainrings are made of aluminium, which does not rust. You'll probably be fine with cleaning them and new cassette and chain. This isn't that expensive any more. From quick googling, your bike uses 7-speed cassette, which are still available.

Upgrading to modern parts would require replacing all transmission components, shifters, derailleurs and the rear wheel. This will be expensive and probably not worth the trouble.

  • I think ojs is pretty solid on this for recommendations. FWIW, The Shimano 200GS crankset comes with steel biopace chainrings on this bike stock according to the 1991 trek catelog: vintage-trek.com/images/trek/91/1991TrekCatalog.pdf That actually bears pretty well as steel chainrings tend to wear a bit slower than aluminum ones. If anything I would try tossing a fresh chain and cassette (you should be able to find a compatible one cheap) and ride it. – Benzo Aug 24 '17 at 15:37
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    I actually found the same catalog when writing this. I had the same cranks on a Kuwahara, but no idea about chainring material. I just remember that it wasn't the cheapest bottom of barrel series so they might have been aluminium but not necessarily. The more memorable part was that cranks, brakes and brake levers all had thick plastic coating. – ojs Aug 24 '17 at 16:45
  • @Benzo I had a similar steel crankset on an old Raleigh (92, I got it a couple of years ago). It had done pretty well (much less rusty than screws etc. on the rest of the bike). I only replaced it because one of the pedal threads truned out to be ruined. – Chris H Aug 25 '17 at 12:49
  • +1 for the advice, even though in the early 90s steel was used for many components that are now Al. – Chris H Aug 25 '17 at 12:49
  • Even a steel crank set may only be superficially rusty. And could be restored to a nice and useable state. – gschenk Aug 26 '17 at 14:04
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Upgrade from say a 7-speed to a 10-speed (because you have 3 discs in front) without changing anything is a double question : 1. Does your rear derailleur is compatible ? Meaning : is the cage length long enough and does it have sufficient amplitude. 2. 10-speed chainings are thiner than 7-speed in order to avoid friction on the front discs.

You have an example with the Shimano 640x group (great stuff btw), the rear derailleur is the quasi exact same design but when the 6400 one is a 6-speed, the 6401 can handle 7 to 8 speeds just as easily provided you mount a thiner chain.

This is a technical spec problem from the time, if the 10-speed chaining was very rare (or inexistent) at the time, you would have to calculate derailleur amplitude from a 6-speed point of vue. So now that 10-speed chainings are available, if your discs are thin enough (usually they are) you can pass the 8 speeds on the bike just by changing the chain.

It's theoretical from a MTB point of vue but it's a Roadbike reality.

The morale is here that it's not because it's old that it's obsolete, sometimes au contraire.

I upgraded a 70's roadbike with a 90's group, my main problem was that some setting screws were not designed for ulterior frame modifications which impose a workaround (basically a longer screw and adaptation of the stop).

The thing is, what is your desired upgrade ? 1. If it's "the same thing but younger" it should be fairly easy because things have not changed dramatically between the 90's and today (less than between the 70's and the 90's) 2. If it's "more performance at all costs" it could be tricky because it means changing at least the chain, cassette and shifters but also eventually the rear-derailleur and front discs (if they are too thick you will have some nasty friction).

Concerning the shifters, unless you have good old fashioned friction ones (this kind : https://images.jet.com/md5/f636d8a5af21fce219fa5fb3809f6198.1500) it could be tricky too because if it's an indexed system, provided that you stay in the brand and that you keep the same number of speeds you can certainly be lucky (because it's more of a cassette issue in reason of the system, indexed shifters provide differential tension which is calculated from the inter-speed space which is proprietary).

You don't have this problem with friction shifters because it's an analogic device that does not care at all how many speeds you have (because if you tend the cable all the way you will span all your cassette anyway). Same thing for the front.

This is why (I'm sort of lazy this way) I systematically use friction shifters, it's bit tricky to use at first when not accustomed but you get the coup de main pretty fast.

But if you have now a 7-speed indexed shimano transmission, upgrading the shifters with newer 7-speed ones should not pose problems.

  • I would worry about a 7 speed hub not supporting a 10-speed cassette, as I think the 8/9/10 share the same width of hub body width. I think it's a few millimeters smaller for 7 speed. You would likely need a new wheel if you want more cogs on your rear cassette. – Benzo Aug 24 '17 at 15:41

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