Classic & Vintage - best gears for an 8speed cassette

Hi all,

i'm musing away today, and have another question to put to the forumites.

my gios has an 8speed 600/ultegra tricolor RD, with a double up front. The bike currently only has 7 speeds on the cassette due to whatever the previous owner felt was right, but i'm thinking of choosing a new set of ratios. i know this can be discussed (argued) until the cows come home, but here's a few things i'm dwelling on:

it's current little cog is still a 13T, i'd like to get that down to a 12T or even 11T for hammering it. However, at the other end of the equation it's got a 24T currently, and i wouldn't mind something even easier for the hills. I'm hitting a ride later this year with some notorious hills, and despite my training, i'd like to have a 'granny' gear for the later stages!

so, with an extra cog in there, what would be my best range options? given i want a big one at one end, and as small a one as possible at the other end.

can't be done? wishful thinking? can i up to a hyperglide cassette option? its on a ritchey wheel, its all circa late 90s i believe.

What are your chainings?
Also, I thought 7 speed cassettes couldn't convert to 8 speed but that could be an individual cirumstance that I have encountered. A 12-24 should be plenty if you run a 53/39 front.

Can you spin a minimum cadence of 100 in high gear for extended periods of time with your current setup? Unless you can, it makes no sense to go to an 11 or 12 in the back.

What hub are you running?

I have an 8 speed shimano 11x28 cassette. I use it on my cyclocross rig with a single ring up front and it provides a lot of options but sacrifices the finely tuned one or two tooth shifts.

remotelocal, What chainrings are on the crankset? The tricolor comes in at least two configurations, 53-42 and 53-39 are what I have. For the cassette a 12-26 works with a 52-42 for me.

Brad

my gios has an 8speed 600/ultegra tricolor RD, with a double up front. ...
...
it's current little cog is still a 13T, i'd like to get that down to a 12T or even 11T for hammering it. However, at the other end of the equation it's got a 24T currently, and i wouldn't mind something even easier for the hills. I'm hitting a ride later this year with some notorious hills, and despite my training, i'd like to have a 'granny' gear for the later stages!.

What cage is on your Ultegra RD? Short Cage? Long Cage?

If you're currently running a 24-13 and you're planning to go to a bigger Big and a smaller Small you need to consider the Capacity and the Max cog size limit of the RD.

It might just be easier to change your chainrings.

hey all, thanks for taking the time to reply. the chainrings up front are 39/52. All that needs changing at the back is the spacing. it's all go for 8 cogs, but the previous owner had it set up with 7. I had the bike given the once over at my LBS and the mech there asked if i wanted to add a speed on as there was the room and the RD allowed for it.

so i'm thinking a 12/26 might be the improvement over the 13/24 on there currently. basically looking for the easy option on the hardest hills if i run out of steam, and a slightly faster option at the other end. miamijim, i don't think i can spin 100 for extended periods on the 13T, but i still want a bit more acceleration at speed there.

You might even end up with fewer redundancies between your two gear ranges, if you pick your cogs and chainrings right.

"if you pick your cogs and chainrings right"... here's hoping. no promises... i think i'll leave the chainrings as they are, and just alter the rear cogs.

I'm running 12-28 with 52-42 in the front. Works good here in Orange County CA, lands of hills & headwinds.

that sounds reasonable, so i'd be really treating myself with a 39f > 26/28r for the worst of the hills? thanks merkel.