robertj298 

Picking this up tomorrow night. I love the smoke on the water paint scheme but was wondering if Centurion took a step backwards going to Suntour components from Shimano on the Expert in 1989?

canklecat

Nah, the Suntour GPX group is just different, not worse or better.

The brakes look nifty but are not user friendly to adjust spring tension and alignment. The trick is to cut the cable housing length jussst right, then secure it with bar tape up front and the cable housing braze on guide in the rear. Otherwise, zip ties help secure the housing so it centers the calipers and pads.

DiaCompe BRS 500 (550?) were the best brakes in feel, braking power and ease of adjustment. The GPX isn't in that class.

Accushift is picky to set up, but sweet once it's dialed in.

Try a SunRace chromed 13-25 MFR30 or 13-28 MFM30 7-speed freewheel. Combine with a KMC Z72 chain. The index shifting RD will be perfect. The only sound will be the clicking of the downtube shift lever.

With the original Suntour Alpha freewheels there's a distinctive ker-chunk sound to the rear derailleur, especially going from larger to smaller cogs. I get the best results with plain narrow chains, rather than the fancy Z72 or Z50.

If you have trouble with chain drops on front derailer shifting, set the FD very slightly askew. And the Vuelta SE Plus ramped and pinned big ring is excellent and shifts better. Costs around $25 and worth it. I use Vuelta 50 ramped and pinned big ring, and 39 plain little ring. Good combo with either the 13-25 or 13-28 SunRace freewheels.

BTW, don't use a 14T smallest cog freewheel on the '89 Ironman Expert. There isn't enough clearance for the dropout to make full use of the adjustable horizontal dropout. The chain will rub the paint. Just a quirk of that model.

canklecat

Also, best stuff I've found for cleaning those white brake hoods? LA's Totally Awesome Grill and Oven cleaner. Costs a whole dollar at Dollartree. It's pump spray, mostly ammonia and degreaser, not caustic aerosol can oven cleaner. I use it for cleaning my skillets after frying too. Really breaks up oils and fats, better than Dawn dish soap.

markwesti

I have no idea about the Suntour switch . However if you switch to black cable housing and route it correctly , the bike will look much nicer .

texaspandj

Possibly a lateral move,
HOWEVER, if it came with Shimano's equivalent to that (105), you wouldn't have to change a thing.

canklecat

That Ironman looks mostly original and in great shape. The original white cable housings may still be good enough to continue using for awhile. New cable housings didn't improve the braking on mine. It did improve shifting a bit, but that's just a small loop of housing around the RD. Dribbling some lube like Boeshield T9 down the cable/housing will improve it a bit.

Personally I don't care for black cable housing on the white/blue smoke Ironman. Looks funky. I have some since it was on sale for $7 a 20 foot roll at REI. But eventually I'm switching the Ironman back to white housing. Just looks better to me. I have blue on it now, but the blue doesn't quite match and it's cheap crappy SunLite housing, which compresses way too much. I'm switching to Jagwire housing, white for the Ironman, yellow for the purple Trekenstein. Can't deal with mushy feeling brakes.

fleslider 

I think it was more a matter of looks, since in 1987 Shimano Sante, was introduced and then in 1988 Shimano 600 Ultegra was out, and they seemed to be the popular with painted modern looking componentry. for 1989 105 looked the same as it did in previous years. but Suntour had the GPX which was similar quality level to 105 but was painted components that they thought was the new look.

just my $0.02.

Narhay

The GPX on my 89 works ok but not seamless. I have a few hundred km on it so not thousands of miles like others but enough to have an opinion. I would give it a 6.5, maybe 7/10. The indexing works, then it sometimes searches or needs a bit more persuasion to shift, then it works for miles upon miles, then back again. You will also need the suntour accushift spaced freewheel so be sure it isnt worn or it may be difficult to find a compatible replacement. The brakes arent great but new pads with adjustable holders are a must. The front derailleur needs more trimming than I usually like.

I would have preferred a Shimano 600 tricolor set on mine but so be it. I do like the bike very much but the groupset is just average and slightly unrefined in my eyes.

RobbieTunes

I'm only guessing, but I think they wanted to go 7sp vs. the "new" 105's 6sp. The dark colors were in, i.e. the tricolor, but they couldn't very well put tricolor on the Expert. Suntour was gasping a bit by then, having excelled at friction but missed the boat launch on the indexing.

I long ago figured out the secret to aligning the calipers so the cable housings make no difference whatsoever in adjustment, and I like the hidden spring calipers and the brake levers are average,. Black hoods would have been a plus.

On the FD and RD, I rate them even with the 105, but the RD is so limited in range, when you add in the 52/42 crankset, well, not a lot to fall in love with, unless racing. GPX hubs are very smooth, and I'd take them over 105, but definitely not over 6400.

One thing about GPX: when it shifts, you know it. Put that group on a carbon frame and you'd have an echo to match the Grand Canyon.

I do like a GPX group, if even only for the aesthetics, but it's a workhorse in my experience if the RD is lubed once in a while. I always hated the brake pads and switched to polished Tektro holders/pads right away. That kind of classes it up.

The group looks great on the Smoke on the Water Ironman, no so great on the Black Dog, but it looks pretty classy on some other colors, like dark red and yellow. I put a set on a Centurion Facet and gave the bike to a budding pro. She still has it. She's told me more than once that people mistake it for tricolor.

fleslider 

If i remember right Shimano took 105 to 7 speed in 1989 i think 1051 was the #PN . (not to be confused with 105SC. which was 1055 (1990)) so not sure why they went GPX

canklecat

texaspandj

My guess as to why they went to gpx is to help keep cost down.
Shimano was hitting it's stride and it was reflected in price.

T-Mar

After Shimano introduced SIS and Accushift failed, it was normal practice to keep one or two SunTour models in the lineup, just in case SunTour bounced back. If you totally dropped SunTour and the market suddenly reversed in SunTour's favour, you'd be last on the list to have your order filled by SunTour and would get least favourable pricing.

So the question became, what SunTour group did you want to spec? In 1989, SunTour introduced, four new road groups, GPX, Olé, Edge and Blaze. These were first of the 2nd generation Accushift groups and manufacturers were cautiously anxious to see if SunTour had finally gotten index shifting right. Blaze and Edge were entry level groups, still only 6 speed and competing with Shimano's new and expanded Exage series. For full range manufacturers this was their meat and potatoes price range and most considered it too risky to spec Sun Tour. Olé was SunTour's answer to Santé, though at a lower price level and the boutique styling was still a questional market. GPX was up against New 105, which, while upgraded to 7 speed, was into it's 3rd season and the oldest of Shimano's groups that was in direct competition with one of the new SunTour groups. Consequently, many considered it to be Shimano's weakest market segment and the logical point of attack to test the new SunTour groups. As result, GPX appears to have been the widest spec'd of the new SunTour groups. To name only a handful, besides the Centurion Ironman Expert, it was also spec'd on the Fuji Roubaix, KHS Triathlete Pro, Giant Allegre and Miyata 1100A.

Personally, I'm not a big fan of GPX. I still prefer Shimano New 105. GPX was definitely an improvement and rivals New 105 but I find it lacks durability, particularly in the derailleur pivot seals. I seen too many come through the shop that have been incredibly worn and sloppy. Then there's the whole incompatibility and availability issue for replacement parts, when things do break or wear out. Finally, there's my preference for freehubs, which GPX didn't receive until 1990.

So, was it a mistake to spec GPX on the Expert? In hindsight, I'd say it was. However, at the time, it made sense not to put all your eggs in Shimano's basket and this was the logical market segment to spec a new SunTour group, given the relative age of the Shimano competition.

RobbieTunes

Maybe on production dates for '89 models being in 1988, or maybe Suntour gave them a good deal, trying to get a foothold in the indexing market. Maybe because they had a relationship back in the Elite RS/Turbo days, I dunno. I've often wondered that myself. It would have been a lot simpler to just go 105. For us, on this side of the market, anyway.

RobbieTunes

Take the plug out, get out your allen wrenches AND your cone wrenches.

Now look at what pivots and what doesn't, and what needs to be tight and what doesn't.

It helped me on these, and then on 105's, as well. Of course, then dual pivots came out and it was all moooooooooot.