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-   -   7 speed cassette on an 11 speed hub? (https://www.bikeforums.net/bicycle-mechanics/1009322-7-speed-cassette-11-speed-hub.html)

ollyisk 05-19-15 03:10 PM

7 speed cassette on an 11 speed hub?
 
Backstory: I've got an Eddy Merckx Super Corsa. It has 600 hubs with older Mavic rims. To say the wheels have seen a lot of use would be an understatement (the braking surface is about done), and I recently broke a spoke on the rear wheel. Instead of buying new rims (can't be mismatching, now, can we?) and paying someone to relace them, it would seem buying a new set of wheels would only cost marginally more money and drag ol' Eddy kicking and screaming into the 21st century.

However, I've failed my attempts at google-fu and I'm at a loss--I can't seem to find anyone that has shared their experiences (horror stories?) of trying to stick a 7-speed cassette on an Ultegra 6800 11-speed hub. It would seem that to pull this off, I'd need 6.5mm worth of spacers behind the cassette. This seems a bit excessive to me. Has anyone done this? Should this not even be attempted? Should I just replace the freehub body (something I've never done, if we're being honest) with a 10-speed freehub (or potentially the freehub on the 600, if that's even possible)?

Should I just change my indexed 7-speed DT shifters to friction and stick an 11-speed cassette on there?

So many questions, not really sure what to do here. I'm relatively comfortable doing my own wrenching, but I've never changed a freehub body, so there's that.

Thanks for any help!

CafeVelo 05-19-15 03:20 PM

Freehub should fit with spacers, the wheel won't fit on the bike though. You could spread the rear triangle but why bother?

bikemig 05-19-15 03:20 PM

You have two different options. One is to keep the bike as is and simply rebuild both wheels around the old hubs. If you think the hubs are near the end of their service life, then find some good quality used shimano hubs. Alternatively you could go with a freewheel based set up and find a seven speed freewheel.

The other option is to go with a modern wheelset which will be spaced at 130 mm (your old bike is probably spaced at 126 mm). It's no big deal to do this but you may want to talk to a shop. Then you can go 8-9-10-11 on the back. Your downtube shifters won't index. Also you will probably find that friction shifting with 10-11 on the back is a less than happy experience. Personally I'd go for a new 130 mm wheelset and go for 8, 9, or 10 on the back with new downtube shifters matched to your set up.

A bike shop can take you through this without too much hassle.

nfmisso 05-19-15 03:27 PM

Peter White has some 7 speed hubs, scroll down this page: Custom Wheel Building

to:
Seven Speed Shimano 105 SC (almost) Wheelsets

ollyisk 05-20-15 03:31 PM

The rear is spaced to 130mm, I believe it's a 91 model. The hub is a 130mm HG (but UG compatible) 600 Tri-Color. To my surprise, there were no spacers behind the cassette.

The hubs are in working condition, but I can buy a new wheelset with modern Open Pros, Shimano 6800 hub, of decent build quality (according to reviews) for what it would cost for me to have wheels rebuilt around the hubs (in the 200ish euro range). I love my Eddy, but I don't want to spend $800 on a new wheelset with old parts, I'm not that much of a purist geek :)

My concern is putting 6.5mm of spacers behind the cassette. Is that an invitation to tragedy? Maybe I'd be better served putting an 8 or 9 speed hub on there and switching my DT shifters to friction mode (since apparently 10 and 11 don't play nice, according to bikemig)?

squirtdad 05-20-15 03:52 PM


Originally Posted by ollyisk (Post 17823226)
The rear is spaced to 130mm, I believe it's a 91 model. The hub is a 130mm HG (but UG compatible) 600 Tri-Color. To my surprise, there were no spacers behind the cassette.

The hubs are in working condition, but I can buy a new wheelset with modern Open Pros, Shimano 6800 hub, of decent build quality (according to reviews) for what it would cost for me to have wheels rebuilt around the hubs (in the 200ish euro range). I love my Eddy, but I don't want to spend $800 on a new wheelset with old parts, I'm not that much of a purist geek :)

My concern is putting 6.5mm of spacers behind the cassette. Is that an invitation to tragedy? Maybe I'd be better served putting an 8 or 9 speed hub on there and switching my DT shifters to friction mode (since apparently 10 and 11 don't play nice, according to bikemig)?

Why not go with the new wheels, put an 8, 9 or 10 speed cassette on and matching indexed down tube shifters? if you go 8 speed you can get tiagra downtube shifters. other wise probably need to go to durace.

ollyisk 05-21-15 03:01 AM

Yeah, was actually thinking about that this morning. Perhaps it came to me in a dream! The only problem with getting Dura-Ace DT shifters is getting matching Dura-Ace brakes, cranks, derailleurs...!

Guess this is probably my safest course of action. Thanks for all the help/advice y'all.

FastJake 05-21-15 07:10 AM

If you're fine with 7 speeds, and it seems like you are, I would simply re-lace the hubs to new rims and fresh spokes (but I build my own wheels.) This way you can keep all the equipment on your bike and keep the period correct hubs. You can even get some period correct rims if it makes you happy.

You won't have any issues putting a 7-speed cassette on an 11-speed freehub body but you will have a wheel that is dished far more than necessary and substantially weaker than your 7S 130mm wheel. I would not go this route. In my opinion an Eddy Merckx "deserves" a nice wheelset and throwing a cheap 11S wheelset on there with a 7S cassette is a hack way to do it. If nothing else, at least keep the original wheels in case you ever sell the bike.

70sSanO 05-21-15 08:36 AM

There are no issues with spacers on a freehub. There is an added benefit is that you can slightly improve your chainline depending on the width of the spacers.

Since you are pretty much open to everything, my personal opinion is to start with a cogset or cassette and build from there. Figure out what your ideal gearing would be. If it is 8 then that is the way to go... 9, do that etc. If you really want to stay with 7, stay with that. Personally, I would try to find a good used wheelset off of ebay. A 7403 or a 7700 freehub will give you 130mm and you won't have that funky DA unique crap that isn't compatible with anything. Plus DA hubs will make you forget about your 600s pretty quick.

I would think that with some diligence you would be able to find a very nice used wheelset for around $300. I have built my own wheels, but for some of the ebay wheelsets, I can't buy the parts individually for what I have paid for a complete set. You just have to do your homework, research, and ask questions. Good luck.

John

Dave Mayer 05-21-15 11:23 AM

Here are some considerations for your task:
  • A 11-speed compatible wheel is substantially inferior for what you want to do relative to a 7-speed wheel. The 11-speed wheel, due to the width of the freehub body, has much more dish and spoke tension differential than a 7-speed wheel. The drive-side spoke tension is double that of the non-drive, which leads to an inherently weaker structure. To try and overcome this deficiency, manufacturers have to execute tricks such as 2 x 1 lacing patterns and extra heavy rims to provide support. For 7 speeds, you actually want a 7 speed rear wheel. It will be stronger, more stable and lighter.
  • You do not want 7 or 8-speed Dura-Ace anything. Maybe the front hub or the last generation brakes. But the shifters, derailleurs and freehubs are completely orphaned and incompatible with anything else that Shimano made before or since. There is a reason why this stuff clutters up Ebay.
  • A standard bike shop will provide no help. Their only motivation will be to sell you a new bike. You are on your own.
Recommendation:
Replace the rim on your existing wheel. Just the rim - keep all of the spokes except if they are broken or gouged for some reason. I have used the same spokes for 4 successive rim replacments on one wheel. Find a rim with the same ERD as what you have. Should cost around $50. Tape the two rims together with a few pieces of electrical tape. Transfer the spokes over one by one from the old rim to the new. This will take about an hour, during which you can listen to the Giro. Truing and final tensioning - you may want a pro for this.
Overhaul your old hub and apply fresh grease and oil for the freehub.

RoadGuy 05-22-15 12:23 PM

If you like DT shifters, I'd rebuild the existing wheels or build a new set of wheels with 8-speed 130mm hubs. I have a set of Shimano BL-400 8-speed DT shifters (sold as unbranded or with groups) and they work fine. I upgraded my 1990 Trek 1100 from 7-speed Suntour drivetrain and 126mm drops, to 8-speed Shimano drivetrin with 130mm drops with the Shimano BL400 shifters. Natural alloy finish (goes well with RX100, RSX, silver 105, and Ultegra groups), not a bright polished finish. Index only, no friction setting on the right shifter.

Initially, after installing the new 8,8,10-speed rear wheel with a 7-speed cassette and 4mm spacer, I removed the spacer and installed a 8-speed cassette because I did not care for the excessive space between the 7-speed cassette and the spokes (was concerned about the chain dropping in between if a overshift occurred). The huge gap between the largest cog of a 7-speed cassette and the spokes on a 10 speed wheel with a spacer would be unacceptable to me.

ThermionicScott 05-22-15 02:06 PM


Originally Posted by RoadGuy (Post 17828783)
Initially, after installing the new 8,8,10-speed rear wheel with a 7-speed cassette and 4mm spacer, I removed the spacer and installed a 8-speed cassette because I did not care for the excessive space between the 7-speed cassette and the spokes (was concerned about the chain dropping in between if a overshift occurred). The huge gap between the largest cog of a 7-speed cassette and the spokes on a 10 speed wheel with a spacer would be unacceptable to me.

That would bother me a lot, too. Having a wheel with all that extra dish, and then throwing it away by not even getting the benefits of extra gears. If I ever acquire a bike with 130mm spacing, I'll make the leap to 8-speed, or build up 7-speed wheels with 4mm extra on the NDS to even out the tensions.


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