Changing to a more agressive rear cassette. Do you need new shifters too?

[vegasbabee]

I'm getting to be a pretty powerful rider and I'd like to switch out my rear cassette on my Allez from the stock 12-25 to maybe a 11-23.

Can I just order a new cassette and have my LBS pop it in, or are there other things you need to do too?

 

[punkerfinger]

I'm getting to be a pretty powerful rider and I'd like to switch out my rear cassette on my Allez from the stock 12-25 to maybe a 11-23.

Can I just order a new cassette and have my LBS pop it in, or are there other things you need to do too?

You should be able to order it and pop it on. You may need to remove a link from the chain to give you the proper wrap, but with an overall change of only one or two teeth, it's unlikely that it will be a problem. Also, depending on how many miles you've got on the chain/cassette, you may need to replace the chain altogether. Chains and cassettes wear together, and if you try to run a badly worn chain on a new cassette, there will be problems with the them interfacing properly. You will definitely not need new shifters.

 

[gclark8]

Vegas...

I guess this is the new bike... ?? Why change? Maybe your cadence is too low?

The chain should be ok, its only a few weeks old.

Your rear casette is an 8 speed, no need to change anything else unless you want to upgrade to 9 or 10 speed, then its big bucks...

What are the sizes of the chainrings on the front?

 

[vegasbabee]

Vegas...

I guess this is the new bike... ?? Why change? Maybe your cadence is too low?

The chain should be ok, its only a few weeks old.

Your rear casette is an 8 speed, no need to change anything else unless you want to upgrade to 9 or 10 speed, then its big bucks...

What are the sizes of the chainrings on the front?

52x42x30. I'm absolutely spinning when I go down hills, yet I don't top 30MPH. I have a 36" inseam and was thinking about getting longer cranks too. I'm a big boy.

 

[gclark8]

OK, understnd,
ask the LBS about Shimano Triathlon Cranks and Chainwheels, they come long (175-180?) and big (54-55), and should still be available in 8 speed, probably only 2 chainrings, also front derailleur may need to be lifted.

 

[bikeguy2004]

52x42x30. I'm absolutely spinning when I go down hills, yet I don't top 30MPH. I have a 36" inseam and was thinking about getting longer cranks too. I'm a big boy.

Your high gear is a 52 X 12, assuming you have 700 X 23C tires at 30 mph your cadence should be approximately 88 rpm. If you spin your cadence up to 110 rpm, you will be moving approx 37 mph.

So… if you can’t get to 30 mph with a 52 X 12, I have to disagree, that you aren’t “… absolutely spinning…” My fastest while still pedaling (down hill) with a 52X12 is 43 mph and my cadence was close to 130. For ME that was absolutely spinning. My Polar 725 records my cadence during my rides, and my average cadence is generally in the mid 80’s, and my typical max cadence is generally something like 105.

I use an Excel spreadsheet to calc gear ratios vs speed. The web link below can help too.

http://sheldonbrown.com/gears/

If you do switch to an 11 rear cog, you will only need to spin at approx 81 rpm for 30 mph. I’m not sure I need any thing smaller than the 12, since the 52 X 12 is a gear large enough for me…

I suggest working on cadence (spinning more) rather than changing the cassette or the chain rings as others have suggested.

I’m 6’4” with an inseam close to yours and I ride 175 cranks. You can probably ride 180 cranks (I know I could) with you leg length, BUT… the down side is the longer the crank is, it gets harder to spin faster. And… I’m not sure you can get cranks longer than 175 for a triple. If you had a double I know you can get longer cranks.

And if you do buy a 11-23, I see no reason to take out any links in the chain.

http://www.parktool.com/repair_help/FAQchainlength.shtml

 

[gclark8]

I must now ageree with bike guy.

After checking your previous posts and your link to the bike http://www.cyclingforums.com/showthread.php?t=235274

CASSETTE Shimano Sora, 8-speed, 12x25t

Shimano do not make an 11-23 in 8 speed.

Now try to bring the seat forward a little (19-25mm), maybe by using a zero offset seat post and try a 100mm stem instead of that really short one. That will bring your cadence up more easily.

 

[boudreaux]

I must now ageree with bike guy.

After checking your previous posts and link to the bike
, Shimano do not make an 11-23 in 8 speed.

They use to make an 11x21. One could probably be scrounged up or a custom cassette in 8 speed is easy enough to cogb together.

 

[vegasbabee]

I must now ageree with bike guy.

After checking your previous posts and your link to the bike http://www.cyclingforums.com/showthread.php?t=235274
Shimano do not make an 11-23 in 8 speed.

Now try to bring the seat forward a little (19-25mm), maybe by using a zero offset seat post and try a 100mm stem instead of that really short one. That will bring your cadence up more easily.

That will bring your cadence up more easily.
__________________
Really? how does that do that? I thought more offset gives yiou more power, according to Greg Lemond.

 

[RC2]

52x42x30. I'm absolutely spinning when I go down hills, yet I don't top 30MPH. I have a 36" inseam and was thinking about getting longer cranks too. I'm a big boy.

As the OP said, you should be able to do mid to upper 40's mph with a 52x12 w/o killing yourself... quick feet is the trick. Work on your >100 rpm rhythm, it's fun...learning to spin in the 125+ rmp range w/o wobbling like crazy makes 90-100 cadence childs play. Or get the 11.

 

[cydewaze]

As the OP said, you should be able to do mid to upper 40's mph with a 52x12 w/o killing yourself... quick feet is the trick. Work on your >100 rpm rhythm, it's fun...learning to spin in the 125+ rmp range w/o wobbling like crazy makes 90-100 cadence childs play. Or get the 11.

I could never do much over 90-95 without the bike feeling like it was going to jump off the ground. Guess I'm a pedal masher for life.

 

[53-11]

I'm getting to be a pretty powerful rider and I'd like to switch out my rear cassette on my Allez from the stock 12-25 to maybe a 11-23.

Can I just order a new cassette and have my LBS pop it in, or are there other things you need to do too?

You have an 8 speed, so finding an 11T cassette will hard unless it is an 11-28 mtn cassette.

I know Vegas is flat so that granny chainring with 25T cog is pretty much overkill.

I'd suggest switching to a regular 53/39 crankset. If you really want the 180mm (I'm 6'2" and I use this size) you don't have that many "cheap" options though.

P.S. Going from a 53-12 to a 53-11 is a pretty big jump (mainly due to air resistance in the speed range you'd be using it).I can still think of a lot good decents that 53-11 would be fun to riding around around in Vegas though.

 

[Alpha]

52x42x30. I'm absolutely spinning when I go down hills, yet I don't top 30MPH. I have a 36" inseam and was thinking about getting longer cranks too. I'm a big boy.

I have 52-42-30 cranks with a 12-25 cassette. I can hit 46-47 mph. In your original post you stated you are getting powerful. It would seem to me you have more power than speed. You can go up hills fast with power but can't turn the cranks at a high rate. This is why you can't go faster than 30 mph.
I would think it is not the equipment on your bike.

 

[gclark8]

This has been an educational topic for me.

I have looked at the need for speed (52/11,12,13) and hill clinbing ability (30/23, 25,27) and decided now I am a little stronger, (swim training), I can try a 13-23 and remove my stock 12-25. This will give me the "missing" 16 & 18 for headwind training that I miss so much with the 9 speed.

If this works ok, it means there is no need to spend money on a Ultegr 10 upgrde for a 2004 model bike (SR81), I will put the upgrade money into a new bike in 2006. (I have already bought my new bike for 2005, the Trekking bike)

Excellent topic Vagas...

 

[vegasbabee]

I have 52-42-30 cranks with a 12-25 cassette. I can hit 46-47 mph. In your original post you stated you are getting powerful. It would seem to me you have more power than speed. You can go up hills fast with power but can't turn the cranks at a high rate. This is why you can't go faster than 30 mph.
I would think it is not the equipment on your bike.

I'm 6'2" 200lbs and I had a 31" vertical jump in high school , was a discus thrower, and I could leg press the whole damn unviersal machine for several reps. I was never fast ,however.

Is there some way I can transform my power into speed? Longer cranks, bigger gears, etc.?

 

[gclark8]

Is there some way I can transform my power into speed? Longer cranks, bigger gears, etc.?

No! Its not about equipment!!

Learn to spin, get that cadence up to 90 or better. OK, buy a computer, a Cateye Australe 8 will do it, but learn to spin.

 

[artmichalek]

No! Its not about equipment!!

Learn to spin, get that cadence up to 90 or better. OK, buy a computer, a Cateye Australe 8 will do it, but learn to spin.

It's not about equipment, it's about muscle fibers: [size=-1]www.sportsci.org/encyc/drafts/Adaptation_endurance.doc

[/size]You don't "learn to spin". Not everyone reaches their peak power output at 90 rpm. Some are higher, some are lower. If you feel comfortable and efficient at a lower cadence, then don't waste your time trying to "learn" how to pedal faster.

 

[Doctor Morbius]

I'm 6'2" 200lbs and I had a 31" vertical jump in high school , was a discus thrower, and I could leg press the whole damn unviersal machine for several reps. I was never fast ,however.

Is there some way I can transform my power into speed? Longer cranks, bigger gears, etc.?

Hate to say it but it's probably just going to take more conditioning. I'm fairly strong when it comes to leg presses as well, but unfortunately that doesn't transfer into sustained power on the bike.

People that genetically favor instantaneous burst strength (discus, vertical jump, heavy leg presses) have a higher concentration of Type I fast twitch muscle fibers which fatigue much faster than slow red twitch fibers. When I was a young lad I had a decent 100 yd. and 220 yd. sprint, good strength with weights and a good broad jump compared to most. However, when it came to endurance activities I pale in comparison to my red twitch bretheren.

 

[Doctor Morbius]

It's not about equipment, it's about muscle fibers: [size=-1]www.sportsci.org/encyc/drafts/Adaptation_endurance.doc

[/size]You don't "learn to spin". Not everyone reaches their peak power output at 90 rpm. Some are higher, some are lower. If you feel comfortable and efficient at a lower cadence, then don't waste your time trying to "learn" how to pedal faster.

I agree with this 100%. Riders should train at the cadence that feels the most comfortable for them within a certain range. It is at that cadence that they will be able to produce the most sustainable power on the bike. Sprints are the exception but that is not sustainable power.

I don't know what cadence Magnus Backstedt uses but I have serious doubts that he's a 115 RPM kind of guy!

 

[gclark8]

I note the comments above, however it can be done.

Buy the Computer with speed and cadence, install it on the rear wheel & cranks, buy a mag/wind trainer. Practice every day on the trainer, 10 min, start where you are comfortable, the next day add 5 rpm, do that new speed for a week, next week, add another 5rpm, until you reach 90, the second week that you are at 90rpm add a minute, eventuallly you will spin at 90 for 30 min, then its a piece of ****! You will do sprints up to 105-110 quite easily then. I did it this way it took me a year, 6 days a week.

Another useful item is a heart rate monitor. Set the load on the trainer and the gear ratio on the bike to give you 65% max heart rate at the training cadence.

Be patient, this will work.