Harold Bridge

I have a Campag equipped Mariposa with an 8 speed Mirage hub/cassette & a 50/39/28 triple. It originally had a 26 inner ring. But I found it difficult to keep the chain on that ring if it changed at all. In view of the fact that Campag's smallest inner ring is a 30 one must presume they knew of the problem. But I would like to get my bottom gear back to where it was by replacing my 26 sprocket with a 28, but don't know where to get one. I can also replace my 22 sprocket with the 23 that was on there originally.
The original sprockets were; 14,15,16,17,19,21,23,26. But I found the 21 & 23 could just as easily be a 22 & that gave me space for the 18. That allows a 73" gear without crossing over to top cog x 39 ring.
Can anyone lead me to a 28 cog for a 1998 Mirage 8 speed cassette?
Harold Bridge, [edit by Joe]Removed ph number for privacy reasons[/edit] (Port Coquitlam, BC, Canada)

D*Alex

Have you considered going to a bike shop???

Just a thought.......

pat5319

I think the biggest cog the Mirage rear derailleur will handle is a 26 - check the Campagnolo website.

One other thing to consider- the "ramps" on the sides of the cog, to aid in shifting, are spaced sequentially form cog to cog. If you change cogs around and "mess-up" the sequence, your shifting will suffer.

Ride Well Geared
Pat

MichaelW

Torelli.com are distributors for Marchisio. I use their cogsets on a Mirage 95 system, and their 28t cog works fine. In addition, you can select and replace individual cogs.

Harold Bridge

1.Have you tried a bike shop? I was hoping for an address I could try. Around here if ain't current it ain't stocked.
2.Concerns about the ramp on a 28 not matching the existing cog set? I changed the orginal 14,15,16,17,19,21,23,26 to:
14,15,16,17,18,19,22,26 & noticed no difference in the gear change efficiency. I imagine that by changing the 22 & 26 to 23 & 28 the gear change won't suffer. The ramp concerns are focused on racing I think. If I should give racing another go I won't be riding that bike anyway.
3.Mirage 8 not taking a 28? The very first Campag chain tensioning gear I had in 1952 was claimed be suitable for up to 26 teeth. In 1956, on my first Alpine tour, I ran a 28. The only thing was I couldn't be on the 44 ring when using the 28, I had to be on the 36 ring. But that's the idea anyway. The original swinging parallelogram gear didn't really handle enough chain for Alpine gears.
So, I still need a lead to a bike shop.

MichaelW

The ramps on Marchisio are not quite as sweet as on Campys own cogs, esp since the cogsets are not matched, but they work quite well enough.
My Mirage system came with Campy 12-28 cogset, and the mech is rated to 28, but they stopped producing that one shortly afterwards.
Check out torelli.

lotek 

Harold,

I seem to recall having some large mirage type cogs
laying around the house. I'm sure my wife wouldn't
mind if I got rid of some stuff
Let me check on size (not sure if they're 28s)
and if so we can discuss where to send em!

Marty