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13/29 to 12/29 change possible?(9 posts)

13/29 to 12/29 change possible?steveF
Jun 8, 2001 8:50 PM
Am currently running 13/29 and miss the 12. I use the "medium cage" derailleur recommended by Campy. I have an unused 12/25 cassette. Is it possible to swap out the 13 to the 12? If so, does chain length need to be adjusted?

Being naive in other ways as well, why aren't mtb-type "V-brakes" used on road bikes? Do they stop too fast? Thanks!
possible, but....C-40
Jun 9, 2001 6:46 AM
Jumping from a 12 to a 14 isn't a great idea, and the shifting might not be the best.

You should not have to adjust chain length, unless you have it set up very loose in the 13/39 combo (which you don't use). If two or more teeth are changed (like from 13 to an 11), the chain might need to be shortened. It takes a change of four teeth to equal the minimum pair of links (1 inch) that can be removed from the chain. (Although 2 cog teeth equal 1 inch, the chain only wraps half way around the cog, thus a 4 tooth change equals an inch change in chain length).

V-brakes are bulky, not aerodynamic, and have more stopping power than needed. A V-brake equipped road bike wouldn't stop any faster, the tires would just lock-up easier. A bike (or car) stops fastest when the tire are close to lock-up, but still rolling. You also have no steering control of a tire that isn't rolling.
you'll miss the 13...C-40
Jun 11, 2001 9:22 PM
If you switch to a 12 and give up the 13, you'll miss the 13, maybe even more than the 12. Try learning to spin faster. I've wound my 53/13 up to 40mph (125rpm).

The 12-25 cassette is one of the best choices for all around use, unless you're regularly doing long climbs, where the 29 may be required. If you're doing mainly short climbs, standing in a 25 tooth gear may be an option to using the 29.
re: 13/29 to 12/29 change possible?xyz
Jun 11, 2001 8:49 AM
C-40 is wrong. The only problem you may have is the Outside Diameter of the lockring may be to big to be compatible with the smaller diameter of the 12 cog. Campy makes several lockring diameters. It depends upon if you have an 8, 9, or 10 speed cogset.

Also, road bikes don't use V-brakes for 2 primary reasons:
1. V-brakes calipers mount to the frame on individual internally threaded studs ("brake bosses") that road bikes don't have (or need - mtb do for clearance with fat tires and mud)
2. Road levers don't have enough cable travel to properly actuate the brake calipers.
YOU are wrong!....C-40
Jun 11, 2001 8:31 PM
As a long-time campy owner, I know for certain that Campy has one lockring diameter for both 12 and 13 tooth cogs and a smaller size for the 11 tooth cog. I have one of each. It does not matter whether the cogs are 8, 9 or 10 speed, the lockrings fit any of them.

There are also two different lockring thread sizes, one for the new oversize aluminum axle hubs, and the one for the older steel axle hubs, but they both work with all campy cogs.

As for V-brakes, your answer is equally uninformed. You've got the situation backwards. The studed mounts aren't on most road bike forks, because no one needs the more powerful V-brake on road (racing) bikes.

Lots of touring (road) bikes and tandems have forks with studed mounts (front and rear) for cantilever or V-brakes. With larger tires and heavier loads, these bikes can make use of the V-brake power.

The only accurate part of your answer is in regard to the difference in brake lever cable pull. If you really want to use V-brakes with road levers, there are adapters available to change the amount of cable pull. This is a common mountain, touring and tandem bike problem. People want to switch from cantilevers to V-brakes, but don't want to trash their old levers. The adapters allow road or old cantilever levers to be used with V-brakes.
YOU are wrong!....xyz
Jun 12, 2001 8:36 AM
Jeez - lighten up. Maybe you got me on the lockring. How can "two diffrent lockring thread sizes" work with ALL campy cogs. I am not "uninformed" about V - brakes. The original post asked about V brakes on a road bike. I answered him. Road bikes don't have brake bosses. He did NOT ask about touring bikes or tandems.
lockrings...C-40
Jun 12, 2001 5:00 PM
I'll try to be "light", but I hate to see someone who's obviously misread a question and has little experience with bike mechanics, tell me I'm wrong.

Lockrings thread into the cassette body. The required thread size is determined by the cassette body. Campy had to change to a slightly larger thread diameter when they redesigned their hubs, and began using a larger diameter aluminum axle, instead of the traditional 10mm steel axle (that Shimano still uses). The lockring thread size has nothing to do with the cog size, since it does not thread into it.

The flange diameter required on the lockring does depend on the cog size. 12 & 13 tooth cogs require the large flange, and the 11 tooth requires a smaller diameter (or the chain will rub on the lockring). Both flange diameters are made in both thread sizes (four posibilities). Hopefully this response has been clear and polite.

You obviously missed the point of the V-brake question. You answered why V-brakes can't be fitted on a road bike, which is obvious, if the frame and fork don't have mounts for them.

The requestor wanted to know why V-brakes aren't used on road (racing) bikes. If V-brakes were advantageous on a racing bike, that's the type of mounts that the manufacturers would put on them. I answered the question asked. The V-brake does serve a purpose on non-racing road bikes, as I pointed out. Avid even makes a version that works directly with standard road bike levers (the Shorty 4). You'll find this model on many touring and tandem road bikes.
yes, I'm using one right nowfreespirit
Jun 12, 2001 12:43 PM
I have that setup right now. Use: 12-13-14-15-(17-19)-(21-23)-(26-29)

Use the 12 lockring.

This setup works perfectly fine, but with a bit of a jump from the 15. Just use the small ring to fill in, though.

This is for 10 speed, of course.
fyi, check this outfreespirit
Jun 12, 2001 12:44 PM
Campy's site shows the cogs:

http://www.campagnolo.com/uk/loader.html?top=top_flash.html¢er=pro_doc.html