Patriot

I am going to be building some fast Hybred/Road bikes for some friends of mine having their mid-life crisis. They want double cranks, not triples, so who am I to argue? Thus, I will slip some Compacts on there, as they don't know the differance.

Anyway, with some 50/34 compacts, I am debating on 12-25 or 13-29 cassettes. Opinions?

My wifes bike has a 34/25 low end gear, and it seems pretty darn good for most climbing. So, I was thinking 12-25. Maybe not?

With 12-25, I know a small cage der will work. However, if I go 13-29, what would be best, medium or long cage? Opinions?

hi565

Isn't it hybrid?

Patriot

What is it with the slam on spelling? Am I just a target for this? I guess so. Ok, I stink at speeeeling. Just answer the freakin' question, Genius!!!

iansir

If you are worried, go for the 12-27 for that extra 'umf' to get up the hill. Will work with normal deraileurs.

zakk

+1

hi565

jokes jokes!!!


sorry I was just playing around.

chipcom 

You say these guys are in a mid-life crisis, but nothing about their physical condition or cycling experience. I'd go with the 13-29 to give them more low range. I'm pretty sure a medium will work just fine.

kahn

MID-LIFE is controlling. You live in an area with very hilly terrain. Go for the lowest you can get and your friends will appreciate it now and into higher than mid-life.

Patriot

Campy cassettes, Chorus doesn't come in 12-27, but I can get it in 13-26 or 13-29. I figure, I'd go 13-29 to get the best low end.

So, medium cage should be ok then. Any other opinions?

Tree

As far as the 13-29 goes even a short cage will work. I use one on mine and also consider that I'm using 53/39 up front. You just need to make sure the chain length is precise. I can even go big-big if I brain fade and not mess things up. If you want to be safe go with the medium cage though.

Edit: I didn't consider the small/small combo with the compact crank. Better go with the medium cage. It will work fine.

TrekDen

+ another vote here
34 / 29 @ 80rpm = 7.9 mph / Gain Ratio = 2.4 / Gear inches = 31.7
34 / 27 @ 80rpm= 8.1mph / Gain Ratio = 2.5 / Gear Inches = 34.0
This is with 170mm cranks & 700 x 32 tires
Info from Sheldon Brown's site.

AnthonyG

Patriot,

Your wifes bike has 650c wheels with 23c tires hasn't it?

This will mean that a 34 /25 combo will be slightly lower on her bike than on a larger wheeled bike. To calculate wheel size in inches its as easy as adding the ISO wheel size to the ISO tire size and dividing by 25.4 to get inches.EDIT: ISO wheel size plus ISO tire size x 2! (metric)

650c x 23c is 24.3 inches, 700c x 25c is 26.45 inches, 27 inch x 1 inch (630x25c) is 26.75 inch and 700c x 28c is about the same at 26.7 inch.

then its just chainring divided by sprocket multiplied by wheel diameter to get gear inches.

Regards, Anthony

Patriot

Anthony G,

Good point. I thought of that earlier, which is why I am leaning towards using the 13-29 cassette now. So, I guess all I need to know is, which der is best? From what I've read, the medium cage should be fine.

Grasschopper

34-29 is going to be silly low. 13-26 will be plenty of cassette IMO. 12-25 is probably plenty

chipcom 

Silly low for someone who is in decent shape and rides & climbs fairly regularly, but do we know this about these fellers? Patriot?

Grasschopper

I know a 34-27 is just about the same gear as 30-25. I NEVER used that gear on my triple and I was 230 at the time. 34-29 is going to be silly low.

chipcom 

I see folks here that need to use 26-34 to climb little bumps! I guess I just don't have any faith in the physical condition of the average non-cyclist.

AnthonyG

I'd go for a low bail out gear. I've calculated that 34 to 29 x 700-25c would be 31 gear inches. Its low but not that low. Its a sensible option in my view.

I thought I would never use the low gear on my triple setup but one day I nearly bonked through lack of food and I had a big hill to get up and I was sure glad that I had it to use.

Regards, Anthony

bbattle

The top Trek FX fitness bikes are doubles with Shimano 105 cassettes in the rear. I'll be getting my wife a step below that, which is a triple with a Deore LX mtb. cassette. It has the 34 "thank god, I'll climb anything" cog on it.

I've got a compact with a 12-25 and I climbed my Monte Sano today in 34-23 through most of the "tough" part (~9 degree) part, then went to 34-19 for the 5.6deg. remainder of the climb. And I'm 40 yr. old with 5 months of road bike riding experience. If this helps you decide, great. If not, go for the mtb. cassette/derailleur and your friends will think they can drop Lance when climbing. Shimano does have a 12-27 cassette; though it sounds as though you are going Campy since you've mentioned 13-29.

When you say "hybrid", are you meaning front suspension fork and upright geometry?

Patriot

No, ,my friend basically wants a road frame bike, with carbon forks, and 700x28c tires, and some nice strong wheels. However, he wants MTB handlebars, and shifters. Easy enough to do. He is close to 50yo now, and needs to get into shape, so I think the 13-29 is probably best for starting off. He can always upgrade later. He's around 220# I think.

kahn

You obviously have perfect knees and don't need "silly low" gearing.

I wish mine went lower than 26 gear inches made with a 26 front and 27 rear. There are hills and then HILLS and rolling and then ROLLING.

These legs hike up 4,000 vertical feet in 4 miles in about 2 to 2.5 hours but pushing a gear is JUST different on that cartilage.

bbattle

Check out the Trek Pilots or the Trek FX 7.7FX. The 7.7 comes with a 50-36 double and Ultegra cassette, most likely the 12-25. The 7.6FX has the 105 cassette. Bontrager Race or SSR wheels carbon forks, flat bars.

The Pilots are even more road setup but have the sloping top tube and have flat bar versions, too. Some of the Pilots have the S.P.A. rear suspension for a softer ride(Hincapie used this on his Paris-Roubaix win)

Actually, looking at the Pilots and the FX bikes I'm having a hard time telling the differences in the frames. And since they put flat bars on both bikes it's hard to say what the differences are. The Pilots of course, are classified as road bikes, not "fitness" bikes, so your mid-life crisis friends should appreciate that.

(I'm getting the 7.5FX WSD for my wife. I'll probably get an adjustable stem or try to match the angle of the stem on her hybrid; she hates to be leaning over, though I think she may accept a little bit, just a bit.)

simplyred

Put 11-21's on them.
They'll be like - omg, cycling's too hard I give up...

then you can ask "oh, how's cycling going?"
response: "sucks dude, i give up.."
Patriot: "oh.. sorry, who's riding those bikes now?"
response: "no one... want them?"

Patriot

^^^ I could never be so cruel.

ggg300

a short cage will work...
Why campy?
Shim has a nice 9 speed 12-27...
Sram has a nice 9 speed 12-26...
If you went 8 speed you could get a 11-28 from sram...nice too.