Vintage Shimano compatibility question

[flydhest]

I keep a bike in my mother-in-law's basement in Ft Collins. My wife wanted to ride out here with me so we got an awesome late 90s Specialized Allez Epic. 7-sipped Shimano Ultegra. Great shape. Downside, need easier gearing. This is all on the cheap--bike was less than 300 bucks.

I found 7-speed Shimano MTB cassettes for short money and as much as 34 teeth.

Question: What is the biggest cog that is compatible with that era 7-speed Ultegra with a 53-39 crankset?

Thanks.

Side comment, one more bike for the wife makes me seem less crazy having "a few"

[PacNW2Ford]

I once ran a 30T cog with 7-speed 105sc on a Paramount. Usual caveats about hanger length, etc. apply, but it worked once

[Ken Robb]

Hmmm, I have a 7 speed triple on my MB-3 and it only has a 28 as the lowest cog. If you can find a deal on a crank with smaller rings that might be the way to go.

[gdw]

http://www.bikepro.com/products/rear_derailleurs/rear_der_table.shtml

The derailleur's total capacity is 28 but I've run a 13-28 with 52/38 chainrings without issues. You might be able to use a 13-30 cassette if you set it up carefully but the steps between gears might be annoying.

[jtakeda]

What kind of gearing do you need?

I have 2 7 speed cassettes here. I think one has a big cog in the back

[palincss]

I keep a bike in my mother-in-law's basement in Ft Collins. My wife wanted to ride out here with me so we got an awesome late 90s Specialized Allez Epic. 7-sipped Shimano Ultegra. Great shape. Downside, need easier gearing. This is all on the cheap--bike was less than 300 bucks.

I found 7-speed Shimano MTB cassettes for short money and as much as 34 teeth.

Question: What is the biggest cog that is compatible with that era 7-speed Ultegra with a 53-39 crankset?


I'd just put an 8 or 9 speed MTB rear derailleur on the bike, and use whatever 7 spd MTB cassette you like. I'll bet the 13-30 K cassette would do very nicely with that 39/53, and so would the 14-32 F cassette.

[classtimesailer]

I'd get a compact crank. Shorten or get a new chain and your done.

[pdxharth]

I have the early '90s gray 7 speed Ultegra 600 with a 30 tooth in the back. Shifts great; never had an issue. Haven't tried a 32.

Harth

[Tandem Rider]

Any of the older 7spd Shimano MTB derailleurs will index with the Ultegra levers if the Ultegra won't handle the new cog.

[oldpotatoe]

Any of the older 7spd Shimano MTB derailleurs will index with the Ultegra levers if the Ultegra won't handle the new cog.

As will shimano MTB 8s and 9s rear ders.

[flydhest]

So, MTB derailleur and a cassette with a 34 might be the ticket. A compact crankset wouldn't be bad but may be more expensive and harder to source.
Thanks everyone

[Ken Robb]

How low does she need? I'd analyze what gear ratios would be available across each cassette and ring across the entire range so she doesn't get stuck with what might be a low enough bottom gear but not have her favorite gears for regular riding/cruising.

[farmersam]

This probably doesn't help, but I have Ultegra 6600 with a 32. Had to replace my rear d駻ailleur to make it work, and my chain will fall off my front 39 on occasion.

[flydhest]

Ken, good point. The riding we tend to do here in CO is different from our riding back home. The climbs include some really steep sections (for those familiar with Ft Collins, Horsetooth Reservoir, especially Maniac) and flat land motoring is seldom above 20 mph. A 53-14 is going to be far more than enough top end gear. I think I am leaning to 14-34 cassette with a new MTB derailleur.

Anyone looking to unload an old Shimano MTB derailleur?