Why 6 speed instead of 7?
 

I was looking at a 6 speed freewheel I have here and a 126mm Nuovo Record high flange hubset that I will be building. I was just thinking...why wouldn't I want to throw a couple spacers on the driveside, dish it slightly and buy the new freewheel for $13 while I am building it anyways?

Why would one choose 6 speed over 7 for friction shifting other than to compromise with a wheel they don't want to respace?

The 7 might require, as you point out, redishing the wheel. Actually usu. a 1 mm spacer does the trick if the chain is hitting the stay when going from 6 to 7 and you don't really need to redish. So I agree, go with 7 and enjoy the xtra gear.

I don't see that many 7-speed freewheels around.

You need to see my shelves in my basement. Andy

Check the frame inside surfaces of the drive side first, if blacksmith end as the Italians were known for, a few things to watch but with the extra spacer described earlier, only other thing is many 7 speed freewheels set the largest cog just a wee bit closer to the spokes, rear jockey cages need to be reviewed.

The wider you space a freewheel hub, the higher the chance of breaking an axle. In my experience, anything over a 5-speed results in occasional broken axles. A 7-speed is pushing the envelope. Personally, I push that envelope and endure an occasional broken axle as a result of my desire to stay "vintage" while at the same time wanting more gears.

I have a 6-speed on my Raleigh Super Course. A 7-speed freewheel did fit on the wheel, but then the smallest cog rubbed on the chainstay, so I stuck with the 6-speed.

If my memory is correct, I once replaced my 6 speed freewheel on a 126mm hub with a 7 speed suntour new winner compact. The spacing was the same as the 6 speed. All I had to do is replace the chain afterwards. ..worked like a charm.

Another reason is that the 7 speed freewheel may not give you an extra gear where you really need/use it.


For example, if the 6 speed FW is 13-15-17-20-24-28 and the 7 speed is 13-14-15-17-20-24-28, while that 14 makes sense from a gear-inches perspective it may not help at all if you don't go that far down on the cogset very much. So, worth looking into.

Both [MENTION=57478]repechage[/MENTION] and [MENTION=45515]rcc[/MENTION]ardt make good points.

Just because the wheel fits in the frame with a 7 speed block, doesn't mean it fits. Some frames taper back to the center faster than others. Some are "relieved" enough to have room for the chain to move from the smaller to the next sprocket.

My 1983 Colnago had the clearence.

The 6 speed:
[IMG]https://c1.staticflickr.com/4/3680/1...5bd8dea5_k.jpgP9161258, on Flickr[/IMG]

The 7 speed:
[IMG]https://c1.staticflickr.com/8/7357/1...6b58a02d_k.jpgPA121374, on Flickr[/IMG]

Right. On paper 5-speed and Ultra-6 fit 120, and normal 6-speed and 7-speed fit 126, though not all freewheels are spaced the same. I have 7-speed on all my 126 bikes, and none have clearance issues. And you can buy a brand new HG Sunrace 7sp freewheel for about $12. I have one on my Masi.

If you ride in Flatlandia, it does not make for a strong aurgument for climbing the gear ladder. But really, the choice in this matter is where are you going to ride.

Whether or not a 7 cluster will fit depends on three factors: frame, hub, freewheel. When 7v freewheels were introduced, the idea was to fit the gears in the current standard space allotted for 6 cogs. Some setups were just a bit tight and so some people started to add a mm more space. You aren't as likely to run into as many clearance issues until you start with components that were designed for indexing...Those components got a little wider to optimize spacing for shifting, etc and the already tight clearances were crowded a bit more...

Because more is often not superior to less. ;)

There's been some good information posted so far. 6 speed was a much longer lived standard than 7 speed, and it may be easier to make it work. As has has been pointed out, even though they in theory both use 126 OLD spacing, 7 speed sometimes needs to be fudged a bit wider to make it all fit. This was a common headache for mechanics around 1990 or so, when people were converting. If it fits, there's really no reason not to run 7 speed, except possibly historical correctness.

Just to add a bit: 6 speed was essentially standard and ruled for at least a decade, from the late 70s to the late 80s, followed by a transitional period when 7 spd was introduced, at first in the top end models. By the time 7 speed was the de facto standard, it really only had a couple years as king before 8, 9 and even 10 speed systems started to be introduced.

6-speed is lighter, more aero-dynamic and gives your bike better balance.

We're talking vintage here, folks. Just take only what you need. It's enough drama to swap the 5 speed crit cogs to a 6 speed for a climbers delight event ;)

https://c1.staticflickr.com/9/8736/2...ff8294a7_c.jpg

https://c1.staticflickr.com/8/7495/2...e47a4942_c.jpg

More speeds are usually better than fewer but there may be mechanical problems that make it hard or impossible. There can be diminishing returns.

I like lots of closely-spaced, evenly-spaced gears. Lots of them. But all gearing systems present compromises, and sometimes just a few gears suffice. Sometimes only one suffices.

CA, is that 30 tooth what you were riding at The Dare last year?

Interesting point. I happen to live in Flatlandia (TM), and with its long flat windy stretches, I like multiple gears to get into some sort of steady cadence. But when I'm in hilly France or Italy, the circumstances change so often that I only actually use four or five gears. Might be down to my lack of experience, though.

Thats correct, Doc. It's all I had available and in keeping near period correct. Yet even with the set-up and greatly exceeding chain wrap (slight risk if inadvertently shift big-big) it was still a challenge. We sure had some grimacing fun and looking forward to meeting up again.

Fairly quick and an easy solution, had to pull the Campy axle and swapped to a longer one from a Gipiemme hub plus add a spacer. Also removed the dropout adjuster screws that allowed clearance for the big cog and pulley. Its now back to the original configuration.

--- Now that I think of it, might use this same 6 speed to better match a mid-80's build w/ Triomphe stuff from Robbie. Should have no worries in chain wrap. It's kind of a funky project with an '84 Olympic and Coor's classic, Grewal's popularized ARCO paint theme.

I'll just reinforce the point that some 7 speed freewheels are wider than others and will need more spacers on the drive side of the axle in order for the chain to clear the dropout in the small cog. For example the 3 Sachs 7 speed freewheels that I have are a couple millimeters wider than the 2 Dura Ace freewheels I have.
Brent

Whew, glad I'm not the only one. ;) I think most people just didn't bother to get a bike with 128 spacing, so they had problems. I'm using 6-speed Suntour Accu-Shift 3000 shifters, with no problems. It has to be that off-normal spacing. :D

I have a Shimano 6 on my '71 International and a Shimano 7 on my wife's '77-78 Super Course. I'm likely to try a 7 on the International some day, for the same reason [MENTION=152773]noglider[/MENTION] cites: I like the close ratios for maintaining my cadence. I run Ultegra 10 on my Mercian and it's a pleasure.

My take is, a given configuration is not better generally, but as several posters mention or imply, there are pros and cons that must be weighed case by case.
I have settled on 6-speed as my sweet spot, given the vintage of frames that I like and like me back, not to mention my penchant for half-step plus granny gearing with my <patent pending> ;) natural progression 13-28 freewheel layout.
Regarding frame adaptability, one of my original 6-spd bikes recently swallowed a 7spd freewheel between the dropouts with no complaint or modification, as I converted it to 2x7 brifters for my son's benefit.