robertj298 

Picked this up today and it seems to be in great shape except for the RD cable being frayed and the problem with the RD shifter.
When I turn the D ring on the shifter it turns but doesn't click and the red dot which I assume changes to one of the 3 settings doesn't move at all.
Does anyone know any shops in the Columbus or Toledo Ohio area that specializes in vintage bikes? Here are some photos of the bike.

canklecat

Nice condition, nearly identical to mine.

I'm literally eating pizza right now as I write, but I'll take a look at my GPX shifter later to refresh my memory of the three settings. There's one for standard Suntour Accushift index shifting, one for some other index shifting standard, and friction mode. I wouldn't bother with friction mode, other than curiosity. The GPX shifter friction mode was an afterthought, with poor feel compared with earlier good purpose-designed friction shifters.

Definitely gotta replace that shifter cable loop before doing anything else. No point trying to adjust the shift lever until the cable is replaced.

If there's an REI or good local bike shop nearby you can buy just enough cable housing to redo the whole bike for a few dollars. They can even cut it for you. Just bring in the old cable housing and they can use it as a guide for cutting fresh cable housing. Add some new cables. And offer a tip or buy some extra stuff at the regular shop price as a thank-you. I never leave my LBS without buying a little something.

Classtime 

That is a nice bike (frame). I got an 89 IM frame to replace my son's TREK 560 that he crashed and destroyed. The PO kept the GPX group for another frame. I put the Shimano 600 from the TREK on the IM with some Open Pros laced to the 600 hubs. It is an awesome riding bike. Don't mess with the shifter until you remove that bad cable. It is possible that someone already tried to use/adjust the shifter with that frayed cable and destroyed the innards of the shifter. Cross your fingers. Remove the cable, squirt some solvent/liquid wrench/WD40 at the shifter and see if that helps.

Pompiere

I don't know of any shops that specialize in vintage bikes, but there are a couple that I know have been around awhile that may be able to help you out. Wersell's in Toledo has had the same owner for may years, so would have been around when your bike was made. Also, at Spoke Life in Elmore, their main mechanic Mike has some older bikes of his own and always takes an interest when someone brings an old bike in. There used to be a bike co-op called Toledo Bikes, but their web site is dead, so I'm not sure of their status.

wrk101

You have to loosen the attachment bolt, move the red dot to the position of your choice, and then tighten it down. Suntour in that era had some goofy positions on their shifters, I tend to google it every time I run across it.

RE = standard indexed shifting

UL = Ultra 7 speed shifting for Ultra 7 narrow freewheels.

P = Friction.

Crazy to have a DT shifters with two different indexing options.


Getting a shop with the knowledge and interest to work on vintage stuff? I've never found one. Most shops prefer the latest/greatest/wizzbang stuff. I've had shops tell me no bike over five years old was worth working on as they are functionally obsolete.....

May be able to find a forum member in your area, as they are "everywhere".

RobbieTunes

Once it's fixed, outrun everyone.

ryansu

Not sure if you have searched You tube but I am often surprised how much vintage bike content is on there, maybe RJ the bike guy did a video on GPX shifters. I would never be able to afford this hobby without doing my own, slightly more than adequate, wrenching. On pre 1995 bikes its actually pretty straightforward even for a ham handed mechanic like me, Knowledge+Patience+time+beer+remembering to walk away and calm down when things go south, means I can get most jobs done.

Very nice IM OP have fun with it.

TXsailor

I have the identical bike. My GPX stuff worked pretty good but can be a bit finicky. I switched the freewheel to a 12-28 Suntour to help with hills and put a Sram PC 850 chain. It needs to be a little longer to make up for the larger cog. It was quieter and shifted good. After about 1000 miles I have decided to change it up for riding RAGBRAI so I am switching it to 10 speed on the rear and a triple on the front. I am using Shimano down tube shifters and Utlegra brakes. This will be the second Ironman I have done this way. In fact I am robbing the triple off the other one and switching it to a DuraAce crank. I love the way these bikes ride & handle and with a little more modern drive trains they are even better. BTW there is another thread that most of us Irongents post on https://www.bikeforums.net/classic-v...aint-jobs.html

TXsailor

Here is mine shortly after I bought it

ThermionicScott 

Seems goofy, but I think it makes sense in context. SunTour had invented 5.0mm Ultra spacing years before and knew that more cogs were the future, but standard-spaced 6 was still firmly entrenched. And I'm sure quite a few people had both 6- and 7-speed wheels in their collections that they might want to use. So what to do? A shifter that could accommodate both (along with a friction mode for anything else) starts to sound like a nifty idea. You could swap wheels without also needing to swap shifters and cables!

Shimano faced the same thing, but their solution was a little plastic shim that allowed their 7-speed shifter to index a 6-speed. Judging by how rare those are now, cyclists must have been content to stick with 6- or 7-speed Shimano on a particular bike in the end.

robertj298 

I put a new cable on and it shifts but not so accurately.For some reason it wants to click 8 times instead of 7 for 7 gears

ramzilla

I'm thrilled that you got such a nice bike. Get a new set of shifter cables for that thing. Chunk the RD in a bowl of diesel or mineral spirits and let it soak for a couple days. Put it back together and have fun riding it. DIY and save some $green$.

robertj298 

Well after changing the RD cable and a little adjustment it seems to shift ok. Sometimes it skips second gear and goes into first and you have to click it twice to shift from 7th to 6th. It is loud when you shift. I think I would actually prefer friction shifting. My old Lotus had suntour blueline shifting and once I got used to it it was smooth and quiet.

canklecat

@robertj298: Try a SunRace chromed MFR30 13-25 or MFM30 13-28 freewheel, and KMC Z72 or Z50 chain. It'll fix those nagging shift issues. Seriously, no more ker-chunk shifting. The lever will snick-snick into place.

Or, stick with the original Suntour freewheel but get a new KMC narrow chain, like the cheap Z7 "narrow" chain. It'll settle that annoying "hunting for the cog" clatter.

For now I'm back to a Suntour freewheel, mostly because I wanted to try the 13-26 to go with the 50/39 chainrings on my Ironman. It's good and helps on climbs on hot days with tired legs, just a little more easy spinning than the SunRace 13-25, without going overboard into the 13-28 that I use on the other road bike with 52/42 chainrings. But the Suntour freewheel is slightly pickier about chains and setup. It kerchunks again, while the SunRace freewheel and KMC Z72 are quiet and smooth.

Be sure the drivetrain is clean, including the rear derailleur pulleys. And the cable and RD are adjusted. Later I'll attach a screenshot of some basic tips for quickly adjusting the rear derailleur.

A set of inexpensive Tacx sealed bearing pulleys polished off my GPX setup. It's so slick and smooth I wouldn't go back to the original sintered bushing bearings. Costs about $15 or less on Amazon and worth it. The Tacx pulleys won't improve the already good Shimano Centeron pulley, but did help the Suntour GPX RD.

RobbieTunes

Hmm. You may be going past zero, if that makes sense.

robertj298 

Maybe it's meant to be that way? When I shift into 7th gear the shifter will move back and extra click and if I move the shifter forward it will stay in 7th gear