Point

While looking at my ca. 1987 Trek in the garage, I figured it's time to get it rolling again as something to take to the in-laws during visits and as a backup to my main ride. To make it a budget upgrade, I was going to replace the 6 speed freewheel with a 7, then use 8 speed Claris brifters with the last click locked out by the derailler stops. I'm also aware that a new derailler may be in the future, but if this works I'll let it go. Has anybody done this and what's your opinion of the Claris? It would be a lower component than I normally would use, but if it works for the intended purpose.....

zukahn1

I would say going with the Shimano 7 speed Brifters curently availbe and a nice 7speed hyperguidle type freewheel and a 8 speed chain would be a better choice. And more likely to work good with the Shimano light action stuff which is likely currently on your bike.

Point

Not light action - Shimano 600. The reason I'm looking at new Shimano Claris is the only 7 speed brifters available are the bottom of the line, and also use the thumb lever. Claris offers the same action as current brifters. I'd actually consider an 8 speed freewheel, but I'm somewhat concerned about breaking axles, after advice Sheldon Brown gave me some years ago.

hueyhoolihan

in '95 i rode from SF Ca to SD Ca to Florida to Bar Harbor Me. on an 8-speed freewheel. i weighed about 160 at the time and was loaded for touring. never had a problem. wore the thing out and had to get a new freewheel, to my surprise i couldn't find an 8 so used a 7 for the rest of the trip. i wouldn't worry about it.

zukahn1

This era the the Shimano 600 was light action type just a bit nicer which can make it a bit twitchy when you mix and match.

SkyDog75

According to Sheldon Brown's site, the spacing from cog to cog is different on 7-speed and 8-speed clusters -- 5.0 mm versus 4.8 mm. I'd suspect the difference might be enough to cause less-than-ideal shifting performance if you use 8-speed shifters on a 7-speed cluster without somehow accounting for that difference.

As an alternative, you could use a pair of Shimano ST-A070 7-speed brifters. Yeah, they're Shimano's low end gear, but it should match up more accurately.

Point

I'm hoping that the spacing will be close enough to work, maybe not perfectly, but acceptable. Hopefully split the difference on the upper and lower ends and maybe the floating pulley will be able to accomodate the difference. I really don't want to go down the full 8 speed road, since that would entail a new derailler with adequate throw. The old 6 speed should cover the 7 cogs. The ST-A070 brifters would probably work, but I really don't like the thumb button.

nfmisso

A WHOLE lot better with 7 speeds that a trimmed 8 speed shifter.

e_guevara

Claris is good. Shifting action has improved a lot thanks to trickle-down technology from the upper-level groups. Even 2300 and 3300 is better than my 12-year old Sora shifters.

However, as previously stated, cog spacing is different for 7s and 8s, therefore the shifters pull different lengths of cable per shift.

I once was building up a bike with 8s 2300 shifters. Unfortunately, I didn't have any more 8s cassettes in the parts bin but had two 7s cassettes. So I cobbled up an 8s cassette using one cassette and took one cog from the other cassette. The lockring did engage onto the freehub. When I tested it, shifting was sloppy from the second cog up.

mconlonx

I've built bikes with both 2300 and Claris 8sp shifters. I really like the Claris shifters. While everyone fawns over the latest, greatest Dura Ace, Ultegra, Di2, etc. stuff, I'm a big fan of trickle down tech and was chuffed when Claris showed up.

Also built a frankendrivetrain for a friend using Microshift 2x8 shifters and he loves it. I really like the action, preferred them over 2300, consider them on par with Claris.

e_guevara

Speaking of Microshift, their SB-R472 is a 7s shifter with paddles (not thumb shifters). Their ergonomics are nice, and they're good for the money. Don't know where you can get hold of them though.

ThermionicScott 

In practice, Shimano 7- and 8-speed are close enough in spacing to be interchangeable -- as long as you don't have major flaws like a bent derailleur or hanger. There is a generous amount of tolerance at this gear spacing. Heck, in my tinkering, a 6-speed shifter can index cleanly over 5 cogs of a 7-speed cassette, and those standards are much farther apart.

e_guevara

It depends on what you have. There are some 6s freewheels (Suntour for example) that have the same c-c spacing between cogs with 7s (5 mm).

The OP could try adjusting the RD to shift onto the most cogs "cleanly", but I doubt it'll ever shift without much chatter especially on the extreme ends of the cassette.

ThermionicScott 

Yep, in this case, the 6-speed shifters (5.5mm), RD, and 7-speed cassette (5mm) were all Shimano parts. I bet if you'd had a complete 8-speed cassette in your earlier example, it would have worked beautifully -- so much depends on having the right spacing between the first two cogs. I bought one of Shimano's cheap 14-28 7-speed freewheels for a project bike, and was dismayed that I couldn't get the indexing to work -- it could either be adjusted to work over the 4 smallest cogs, or the 6 biggest. Turned out that the center-to-center spacing between the 14 and 16T was 6mm! I wonder how many of them left the factory like that.

e_guevara

If I had an 8s cassette then, I wouldn't have gone the "8-cog cassette with 7-speed spacing" route. And that's what I eventually did - buy a standard 8s cassette.

That's a bummer. Would have been good if you could dismantle the cogs on the freewheel.

RaleighSport

I feel your pain, I was running ancient RSX brifters for a while on my 600 tri color drivetrain, but I ended up getting those black plastic tourney brifters. and I was surprised how well they work and how comfortable they are. They are mostly plastic though, and the gear indicators do bug me.. but nothing a little electrical tape can't hide.

fietsbob

Its OEM parts on these:CrossRip - Trek Bicycle
maybe time to buy a new bike.. to get all the kit at once..

ThermionicScott 

Yeah. If I had a freewheel vise (or something like it) I'm sure could twist off the first cog and substitute a different spacer. As it was, I just decided to throw away the wheel (it sucked anyway), and replace it with a nice used 7-speed cassette wheel. Everything worked beautifully after that.