jefnvk

Nope. Not in the case of my originally 6 speed 1989 Miyata Triplecross, at least.

7 speed fit on the hub just fine, the wheel went into the dropouts just fine, but in the small cog the chain was rubbing on the chainstay pretty good. Took a couple washers on both side of the axle to give me enough room.

Kontact

I can't speak to what is wrong with your Miyata, but 7 speed freewheels are designed to work with 126mm hubs and 126mm spaced bikes without modification. Your experience with whatever defect your Miyata was built with doesn't change the basic principle.

You can't blindly assemble any bike - plenty of things that should work correctly fail on certain bikes, even if they should not.

jefnvk

Which was exactly my point. I have a clear case where a 7 speed did not drop flawlessly into a 6 speed bike, you can't just make a blanket statement that it will work. It fit on the hub, it fit the rear end spacing, the chainstays were simply designed with a 6 speed in mind, and interfered with operation of the smallest cog in 7 speed.

What it looked like, before spacers were added. Chain just rubbed on the chainstay until I gave it a bit more room:

HTupolev

That's often true, but not always the case. It depends on how exactly the 6-speed hub was spaced, how tight they decided to make the clearance for the freewheel. 7-speed freewheels are slightly wider than 6-speed, despite the narrower cog-to-cog spacing. They'll always thread onto the hub just fine, and you'll generally be able to get the wheel to go into the dropouts, but there's not always enough room to the outside of the small cog for the chain to make use of the highest gear.

Kontact

That's not a frame problem, it is a hub problem. And maybe the hub problem is actually a spoke protector problem?

And you solved the spoke protector problem by moving the axle spacers around on the hub, so it really wasn't much of a incompatibility, just a minor issue that required a simple solution. You didn't have to modify the frame or replace the hub or wheel.

The OP's Trek is going to be the same way - if he puts a 7 speed freewheel on it will work with the current hub and frame.

John Nolan 

This happened on my 86 triplecross as well.

jefnvk

What? The spoke protector attaches behind the cassette to the spokes, it in no way affects how far out the cassette sits. I didn't adjust hub spacers, I added washers from the hardware store. A couple on each side (forgot if it were two or three). While it wasn't a vastly significant change, it was still a change that took an afternoon of fiddling to make work.

My point is, it simply isn't as plug and play as you made it out to be. It may take some reengineering, which may or may not be within someone's capabilities to make work properly and may not be modifications every bike shop is going to recommend.

Kontact

So now this is a cassette not a freewheel? I put a question mark after the spoke protector idea because some do fit under the freewheel, moving it to the right, but couldn't tell from your picture.


I didn't say it was "plug and play". I said "7 speed freewheels fit on 6 speed hubs and in 6 speed frames without any modification." You didn't need to make your hub wider, you needed to move one of the thin spacers from the NDS to the DS side, because 126mm hubs accept 7 speed freewheel at 126mm spacing, as do 126mm frames. We can argue about what "modification" is vs. "adjusting", but the point here is that any 126 frame/hub combo will work with 7 speed without respacing, adding parts or modifying the frame.

ksryder

You've been hijacking threads and picking pointless fights all over bikeforums AND paceline lately. What the hell is your problem? Do you even ride?

Kontact

It was suggested that the OPs bike couldn't accept 7 speeds. I said that it would, and some people disagreed with that assessment.

It was also suggested that 27" tubes are hard to find, and I posted evidence that 27" tubes are 700c tubes.


Which part was the hijacking?

jefnvk

Nope, that was a misspeak on my part, it is indeed a freewheel.

As to what it took for the chain to clear the frame, it was more than moving one thin washer from one side to the other. It took two to three washers to get me the clearance needed to fit the chain on the seventh cog, and the same on the other side to keep the wheel centered. Whether or not you consider that substantial, I personally consider it more than a simple task I would expect someone new to biking or a modern bike shop to do, and that is really all I have ever had to say on the matter. I'm out on this discussion, it has hijacked the original thread enough.

Kontact

Fair enough.

Part of the difficulty in talking about working on bikes is what people consider to be a "simple task" or not. Replacing a freewheel with a different model even of the same speeds is going to, at a minimum, require the ability to remove and replace the FW plus examine and adjust the derailleur stops and indexing (if any). For many, that is already outside of "simple".

For a bike shop, swapping 7 for 6 on a FW will involve all of that, plus the ability to change the axle dish as necessary - easy enough to do if you already have the FW tool in the bench vice. It's an extra two minutes work.

Should the average home mechanic have the ability to adjust a loose ball rear hub and shifting? I think so, but I don't get to decide. Should a bike shop treat mounting a 7 speed FW on a 126mm rear hub as a "project"? Absolutely not (in my experience as service manager). I would have done that sort of modification as the customer waits, as long as I wasn't already backed up. It is usually a quicker, simpler job than replacing the pads on a cantilever brake.


The main thing I was trying to get across is that there is no substantial reason the OP couldn't put 7 speeds on his nice Trek if he wants to. A good shop shouldn't charge too much for it, and a handy home mechanic can make the necessary checks and adjustments themselves. This is fundamentally different from trying to get different brands of index systems to work together, replacing a UG freehub body with HG, respacing a 126 frame to 130, etc.

hartmame

Just because he wouldnt do it doesnt mean it can't be done. I'm sure some updates would help. My brother rides a Fuji touring bike from '84 the only change he made was to change out the center chain ring that was only a few teeth different from the big ring. Actually, I think he took the middle ring and made it the big ring then purchased a new ring for the center that was more evenly spaced between the big and small. He said it makes shifting work much better. He was is still concidering making the small ring even smaller.

RobotGuy

Good thread, great advice. To the OP, I’m sure you know by now the bike is plenty good enough. About 8-9 years ago a friend was planning a bike tour from NJ down through the south east and into Louisiana. I gave him my ‘88 Panasonic DX3000 with 105 component group repleat with Bio Pace and a straight block 6 speed cassette. Immaculately cared for by myself of course.

Guess what. He made it and so did the bike.

LuckySailor

I think the bike shop owner is a prude. One could ride a single speed across the country if they wanted to. I'm not advocating that, but what you have will get you across the country. I'd seek out another LBS. really. I'll guess early 1980's on that bike. You mean to tell me that people didn't ride across the country 40 years ago? c'mon! Oh, by the way-in 2015, I rode across Canada. One of our riders, a 66 year old man rode across Canada on a 1988 Bianchi with a 2x6. His only issue came in Banff - his handlebar stem broke while riding! He managed to stop safely, and actually was able to find a new stem the next morning at the bike shop.

Kontact

There is certainly a difference between what is possible and what is efficient and sensible. But when I look at current touring bikes I don't see a great leap forward from the OP's bike. You don't need 11 speeds when you aren't setting a personal best and have a triple crank. It isn't any heavier than a Surly, modern racks will attach just fine, good 27" tires roll as well as anything else, the shifting will work just fine. This bike isn't an artifact from a bygone era but more of a standard that has changed little since it was made.

Mr IGH

1.) There's no difference between 27" tubes and 700c tubes. They come off the same production machines, they are the exact same size, the only difference is the box labeling. Don't pay a premium for 27" tubes, there isn't any advantage.

2.) Old touring bikes came with half step gearing, there's a ~10% difference between the outer and middle rings, the inner ring is the granny gear. Changing the chainrings on a half step chainring set with only 6 cogs in the rear makes lots of overlap. Use the google on half step gearing before screwing up your vintage bike's gearing.

3.) I rode half step gearing back in the day all over America and Canada and then again just last fall. My old tandem had it and I pulled it out to use. With 500 miles I knew I wasn't interested in going back. My GF thought I was driving a steam engine the way I was working those vintage SunTour bar-cons on half step gearing. Sold it to a enthusiastic millennial for $400 and upgraded to a tandem with 3x10 and brifters, never looked back. For me there's a safety issue, brifters allow me better control esp in tight spots when I need to shift.

HTupolev

On the other hand, in many cases, the "half step" original gearing was implemented totally wrong. If the OP's bike has 50-44-28 cranks alongside a 14-16-18-21-24-28 freewheel, which appears to maybe be the case, then it's basically 1-step and there's not much to lose by switching the middle chainring.

Kontact

Couldn't you just have bought a different middle chainring?

Macman11393

So I can buy 700c tubes and put them on my 27" frame without any issues? (just want clarification)

Mr IGH

27" wheels take 700C tubes without ANY issues, they are the same. Be sure to select the correct width and valve type, ignore the 27"/700c dimension.

Mr IGH

Screw half-step and friction shifting. I have a choice and I wouldn't have paid $500 for a used 80's era touring bike with friction shifting, freewheel and halfstep gearing. Faced with a similar choice, instead I purchased a used 1998 Santana Arriva for $180 and kept the crankset, seatpost and rear drum. I built a touring tandem with 3x10 exactly the way I wanted (wheels/tires/bars/saddles/gears/pedals/etc) for ~$1100 with brand new 3x10 brifters, wheelset, derailleurs, cassette, etc. Then I sold off my old 1986 era tandem with freewheel/half-set/friction shifting Arriva and extra wheelset. That put my out-of-pocket for a basic brand new Santana tandem set up exactly for me and my GF at ~$400 including powdercoat and Chris King headset (very few choices for headsets on these frame/fork combos). Easy peasy....

And the geometry on the new Arriva is much better than my old Arriva, handles much better, more comfortable for the stroker.

jefnvk

I looked into doing that with my Miyata before I just sold it. The issue was lots of old cranks took odd sized BCD, which finding even a used chainring for cost more than a whole new crank