Any good 7spd drivetrains out there?

[sethschmautz]

I noticed that Jr's rear derailleur looks a bit twisted after our ride yesterday and there is definitely some added drag in the system. The bike (Cannondale Cujo 20) has a Shimano Tourney 6/7 speed derailleur with a 7 speed cassette. The tourney derailleurs are pretty inexpensive but they don't strike me as great quality either. Anything out there that is a bit better quality? I'm considering upgrading his twist shifter to trigger shifter also.

Any suggestions?

Seth

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[XXX-er]

before replacing a DER is it the DER thats twisted or is it just the hanger a little bent?

Often the der hanger gets pushed inwards from stuff hitting it or the bike being put down on the der, eye balling it from behind will tell you if the der pulleys are out of line with the cog set

You can replace the hanger or just bend it back with a cresent wrench until the pulleys line up

[toast2266]

7 speed systems have essentially the same spacing as 8 speed systems. You can just get an 8 speed shifter / derailleur and set the limits so that one gear isn't used. There's probably better quality options in the 8 speed realm.

[El Chupacabra]

Is current-day low-end 7-spd (Tourney) the same spacing as late 80s/early 90s higher-end 7-spd (Deore LX, XT)? If so, I may have some old 7-speed stuff in the parts bin that would work.

[doebedoe]

Is current-day low-end 7-spd (Tourney) the same spacing as late 80s/early 90s higher-end 7-spd (Deore LX, XT)? If so, I may have some old 7-speed stuff in the parts bin that would work.

In most cases, yes, spacing is the same. Or it is so close to not make a difference. Of course, there are exceptions.

[teledad]

Aside from Dura Ace, all 6-7-8-9 speed Shimano rear derailleurs are compatible (same cable pull).

[XXX-er]

good 7spd is like jumbo shrimp or military intelligence,

at least not since the latest greatest 7spd replaced the latest greatest 6spd because who wants high end 7 spd when you can have a der that goes to 11 ?

BUT that ^^ is only compared the best of the best available now days cuz even an entry level der shifts pretty good, I still rock Deore light-action on my bar bike, it still works the way it did 33yars ago but that is not near as good as the cheapest der you can buy nowdays ... before you try and fix something make sure its actualy broken

[sethschmautz]

Thanks all. I'm take another look at it this week. The cage looked to be pretty tweaked when I examined it yesterday and I think the extra drag was the chain rubbing against part of it. It is certainly possible that it's the hanger, or both.

Toast suggested that 8 spd might be an option and somebody else suggested that 7/8/9 speed uses the same cassette spacing. So...I could theoretically upgrade him to 8 or 9 speed?

Seth

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[Eluder]

Toast suggested that 8 spd might be an option and somebody else suggested that 7/8/9 speed uses the same cassette spacing. So...I could theoretically upgrade him to 8 or 9 speed?

Seth

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You will need to pay attention to the length of the freehub body. The original 7 speed freehub bodies were shorter than the 8/9 speed versions. That doesn't mean your kids freehub won't take an 8 or nine speed cassettes... often time spacers are used to make the 7/8 speed cassettes work on the more current longer free hub, unless its actually a freewheel, most current bikes sold with seven speeds in the rear are actually freewheels not cassettes. If all you want to do is upgrade the derailleur a 7 8 or 9 speed derailleur will work with the rest of the existing components... this is likely the easiest option.

[chadr2]

You will need to pay attention to the length of the freehub body. The original 7 speed freehub bodies were shorter than the 8/9 speed versions. That doesn't mean your kids freehub won't take an 8 or nine speed cassettes... often time spacers are used to make the 7/8 speed cassettes work on the more current longer free hub, unless its actually a freewheel, most current bikes sold with seven speeds in the rear are actually freewheels not cassettes. If all you want to do is upgrade the derailleur a 7 8 or 9 speed derailleur will work with the rest of the existing components... this is likely the easiest option.

I've got an 8 speed cassette, trigger shifter, and free hub body I'd be happy to part with. I tried to do the upgrade on my daughter's bike last year only to realize that she had a freewheel instead of a cassette. These parts are just gathering dust, so if you're interested shoot me a PM and I'd be happy to send them to you for beer money and shipping.

[sethschmautz]

Chad,

That would be stellar. Looking at the specifications on Cannondale's website, it sure looks like I have a cassette and freehub. I will verify tonight at home. That's a massive hookup. Thank you.

Seth

[Dantheman]

Anything 11-xx is going to be a cassette hub. Freewheel cassettes with a smallest cog that's less than 14t are pretty uncommon. Disc freewheel hubs are also pretty uncommon.

[teledad]

Shimano used to make an 11-34 7-speed freewheel (HG50 Megarange) but yeah, they're pretty uncommon (and discontinued now).

If you do upgrade to an 8-speed cassette you should replace the chain, the OEM one is only speced for 7 speed.

[XXX-er]

BTW if the der hanger is bent

you can instal a new der and it still won't shift right

[sethschmautz]

It actually shifts alright, there is just extra drag when spinning the pedals and the dealer cage appears to be twisted/not parallel any longer. I think it's derailleur, but I agree that it might be the hanger.

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[sethschmautz]

Cassette and freehub.

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