7 speed cassette compatibility

Michael Falk

I've read quite a bit of information at SheldonBrown but I'll seek an opinion here.

My old Cannondale road bike, that I rarely ride & is bit high geared for me, I'm thinking of putting on one of my spare 7sp atb cassettes (13-28 or 13-30) instead of its current 13-23. I have a good old XT rear dérailleur to replace the current short arm Shimano 600 dérailleur. I'll keep using 52-39 chainrings. I have downtube index/friction shifters.

Will there be any problems doing this (especially cassette compatibility)? Are the short chainstays likely to produce any problem with this wider range gearing?

Thanks, Michael

priory

in early 90's I moved to a hilly area, had a shimno 105 short arm 7 speed set-up.
I put 28teeth cassettes on without problems, then 32 teeth which did click a bit as they went round because the derailleur wheel would be practically in contact wth the cog. It did work , though, even with the short cage. The clicking was worse when the chain was new, then became unimportant.
Not all old 7 speed shimano type cassettes use the same spacing if I remember rightly, but you would have difficulty finding a part that old. I used to use dt shifters on friction setting so that the gears could be found by feel and I used 7,8,9 speed whichever was to hand..

so you might save yourself some trouble by first just puttind on the new bigger cassete and see if it works.

Michael Falk

Thanks for that info.

It seems like I won't have a problem at all with the dérailleur, I won't use larger than a 30 tooth cog. I have the old XT dérailleur anyway, so I might use it. I can't really see any disadvantage about using it, just a slight weight increase.
I'll see how it goes.

bigjim

I've put a 7 speed 34megarange cassette on my bike that is sora equipped with STI's. Works great with the existing rear mech.