Changing from 27 1-1/4 wheels to 700c

The wheels that came with my Miyata One-Twelve are Sansin and the local
shops tell me they can't find replacement cones so I'm looking forward
to modifying my bike to accept 700c wheels. I realize that there's a
much better variety of tires available in 700c, too.

The front should accept 700c with no modifications, it appears, because
I can readily drop the (admittedly poor type) brake pads down the 1/4
inch or so required. However, the back brake pads may not extend low
enough. I believe I can probably work the parts with a rat-tail file
perhaps 1/16 inch to work around that limitation.

I found a couple of 700c wheels that look very nice, one front and one
back. The cones look fine and the rims and spokes are great. In fact the
spokes appear to be stainless steel. I'm really impressed.

The rear 700c wheel, however, has a 7 sprocket freewheel, whereas my
Miyata was furnished with a 6 sprocket Shimano and Shimano index
shifting and derailer components. Can I use this 700c wheel? Can I use
it with it's present freewheel? It looks very different from the 6
sprocket and 5 sprocket freewheels I've seen. There is a lot of
variation in the way the teeth were machined. I have to think that the
tooth system was computer generated and designed somehow. It says this:

Shimano Interactive Glide 2 Japan
Lock 40N.m

Thanks so much for any help.

Dan

Dan Musicant wrote:
The wheels that came with my Miyata One-Twelve are Sansin and the local
shops tell me they can't find replacement cones so I'm looking forward
to modifying my bike to accept 700c wheels. I realize that there's a
much better variety of tires available in 700c, too.

The front should accept 700c with no modifications, it appears, because
I can readily drop the (admittedly poor type) brake pads down the 1/4
inch or so required. However, the back brake pads may not extend low
enough. I believe I can probably work the parts with a rat-tail file
perhaps 1/16 inch to work around that limitation.

Assuming this bike uses the older type of brake attachment with an
external nut (10 mm wrench size) the best place to use the rodent
extremity is to re-shape the hole in the frame's brake bridge a bit so
that you can pivot the caliper downward a skosh.

I found a couple of 700c wheels that look very nice, one front and one
back. The cones look fine and the rims and spokes are great. In fact the
spokes appear to be stainless steel. I'm really impressed.

The rear 700c wheel, however, has a 7 sprocket freewheel, whereas my
Miyata was furnished with a 6 sprocket Shimano and Shimano index
shifting and derailer components. Can I use this 700c wheel? Can I use
it with it's present freewheel? It looks very different from the 6
sprocket and 5 sprocket freewheels I've seen. There is a lot of
variation in the way the teeth were machined. I have to think that the
tooth system was computer generated and designed somehow. It says this:

Shimano Interactive Glide 2 Japan
Lock 40N.m

That's not a freewheel, that's a cassette Freehub, the very much
superior modern system that has made the old thread-on freewheels
obsolete.

See: http://sheldonbrown.com/free-k7.html

The different shaped teeth are indeed computer generated, a feature
known as "Hyperglide" and it yields a drastic improvement in shifting
smoothness.

See: http://www.sheldonbrown.com/k7.html#hyperglide

This cassette won't index properly with your 6-speed shifters, but you
can probably switch the shifter to friction mode.

The better solution would be to replace your shifter with a 7-speed unit
of some sort.

See: http://sheldonbrown.com/harris/derailers.html#shifters

Note, you should also replace the chain when you switch to the new rear
wheel. I particularly recommend SRAM chains for this application,
either the PC48 or PC58.

Sheldon "Upgrades" Brown
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