Rear Cassettes What Sizes are best?

[SCOOBA STEVE]

On my training wheels i have a 12-25 rear cassette, and it works well with my 39 & 52 chain rings. I have just bought some race wheels and got a 12-23 cassette with them and i find it a real pain, due to the the fact that "i am always changing between the two front chanrings to get the best gear". I just wish i could get up to that 19 tooth gear but the Shimano manuels say not to use the large chainring with either of the TWO largest rear gears and the small chainring with the TWO small rear gears as this puts too much twist on the chain. I don't know how true this is. It is a ULTEGRA cassette, is it possible to pull it apart and change some of the larger gears?

 

[Mercxstrom]

i always use the large chainring with either of the TWO largest rear gears and i have no problems... and i use shimano... if it makes noise some adjustment and you are ready to go

 

[maarten]

Originally posted by SCOOBA STEVE
On my training wheels i have a 12-25 rear cassette, and it works well with my 39 & 52 chain rings. I have just bought some race wheels and got a 12-23 cassette with them and i find it a real pain, due to the the fact that "i am always changing between the two front chanrings to get the best gear". I just wish i could get up to that 19 tooth gear but the Shimano manuels say not to use the large chainring with either of the TWO largest rear gears and the small chainring with the TWO small rear gears as this puts too much twist on the chain. I don't know how true this is. It is a ULTEGRA cassette, is it possible to pull it apart and change some of the larger gears?

Doesn't it go 19-21-23 so your 19 isn't even one of the 2 outer gears? riding big ring and your 21 will only make your chain stretch and give you a less efficient power transfer.

I Race depending on the route 11-20 or 21 at home 11-23 or 25 in my new home country. In belgium I barely use somethoimg smaller then 50*17 or 52 *18.

 

[filtersweep]

11-21 or 11-23

 

[DanBB]

I use 11-21, works well for me

 

[jitteringjr]

My cross bike was an 8 speed 13-26 so when I bought my new bike, I was worried about the new cassette (11-23) being to tight for my weak legs. However, the second gear on the 13-26 was a 23 so I only lost the one gear. It took less than a week to get used to it and now I am fine with it. It is nice having the 11 for the decents too.

Also, on the old Sora double and the new Ultegra double, I have never had any problems riding any gear combination.

 

[gregg v.]

Any thoughts on 12-25 cassettee coupled with a 42-52 crankset? I've read that this way of shifting from a ring to another does not result in such a great change of development, so it is not needed to make multiple cog up or downshifts to compensate that great difference. I'm building out my new frame and I'm thinking about going in this direction. Any thoughts on this set-up?

 

[hermank]

I use a 25-12 cassette (10speed campy) with a 53/39 in the front. It works well for me. I use my 53 with my 25 at the back, but only for short hills. With longer hills I downshift in the front and use the 25/23/21 at the back to keep the cadence high.

 

[big_h]

On the tandem we use a 12-25 Ultegra with the 14 removed and a 17 after the 25. On front we use a 55-39-32. This combination works well for two oldies

Keep those wheels spinning !!!!

Big H

 

[big_h]

Oops it should have been a 27 after the 25!!!! Sorry!!!!

 

[Daremo]

When I was in shape, 11-21, 53/42.

Now that I'm not ...... 11-21. 53/39.

We have plenty of hills, but nothing over two or three miles long.

And I would rather grind the big gears, suffer, and climb faster than get up the hill comfortably but slowly .......... just me, that's all.

 

[shaneo]

12 - 21 to train

11 - 21 to race

 

[petal666]

Originally posted by shaneo
12 - 21 to train

11 - 21 to race

12-21 all the time (very occasionally 12-23 if BIG hills are involved.)

 

[shaneo]

Originally posted by petal666
12-21 all the time (very occasionally 12-23 if BIG hills are involved.)

totally agree with your comments.....throw on a 23 for big hills....always helps to have an ace up your sleeve.

 

[pfrichar]

Originally posted by SCOOBA STEVE
On my training wheels i have a 12-25 rear cassette, and it works well with my 39 & 52 chain rings. I have just bought some race wheels and got a 12-23 cassette with them and i find it a real pain, due to the the fact that "i am always changing between the two front chanrings to get the best gear". I just wish i could get up to that 19 tooth gear but the Shimano manuels say not to use the large chainring with either of the TWO largest rear gears and the small chainring with the TWO small rear gears as this puts too much twist on the chain. I don't know how true this is. It is a ULTEGRA cassette, is it possible to pull it apart and change some of the larger gears?

I like my 12-23 best. I also have a 12-25 and an 11-23, plus I just outfitted a time trial bike with a 12-21.

In a 12-23 you have middle gears of 13-14-15-16-17, so it is easiest to find the right gear. I do use the 53x19 combo to no ill effect. But any lower (21 or 23) and I get rub. My mechanic says it's best not to use those extreme positions.

 

[holli]

Mostly I use 12-21 cassette because I got four of them for free last spring I use also 11-21 cassette on my Shimano wheels but I don't use those wheels too often. 12-23 cassette is good to have when racing over big hills, 23 works well if you get dropped. 53x12 is big gear enough for me, I need bigger gear when the speed stays over 60km/h for a long time.

 

[nhorscro]

Anything that has a 16 somewhere in there!!
At the moment I'm using a 12-23, and I have a SRAM road 12-26 that I will mount sometime soon.

 

[SuperDaveK]

I've got a 12-22 with a 52/42 up front.

I've got a 12-25 for the serious hills but I find the 22 enough for most everything.

I used to run a 13-23 when I used 9 speed and had a 54/42 ring set up front.

 

[bikerchas55]

The big-big and little -little combos will wear out your chain, your chainrings and your cassette at a very accelerated rate.

 

[Roy Gardiner]

Originally posted by SCOOBA STEVE
...training wheels...12-25 ... 39 & 52...race wheels...12-23 ...a real pain, due to the the fact that "i am always changing between the two front chanrings to get the best gear". ....is it possible to pull it apart and change some of the larger gears?

AFAIK you can pull the cassettes apart, but can't necessarily buy the cogs you want In the Good Old Days all 5-speed freewheels were custom made and your LBS had individual cogs for sale. Business opportunity for aftermarket replacement cogs here, someone?

If you're Campag (don't know about Shimano) there's only certain quite limited combinations available, and many of them only in the expensive groupsets.

I fix it by varying the chainrings; for instance, on my work bike (which is always heavily loaded!) I have a standard 12-23 10sp but with a 48 outer ring, enabling me to cruise comfortably at 20mph on 48x17 or 16.

On the road machine, 39x53 12-25 10sp is perfect. 53+12-about 19 for crits, the 39 + large cogs for mountains in Mallorca. BTW (small plug for Campag) on the large ring all 10 work well, on the 39 all bar the 12.