Freewheel Size - Speed?

[5MinuteMajor]

I have been noticing lately that when I go down some steep hills I can outpedal my bike in the highest gear and only achieve a top speed of about 34 Mph. I have noticed that the professionals in the tour de france can achieve faster speeds on their sprints and can get up to 60 Mph downhill. I am assuming that the only way they can do this is because their rear cassette is smaller than my bikes and the front cassette is bigger. Can you actually buy different sized cassettes / freewheels that suit your skill level? If I was to buy an $8000 bike would it have bigger gears than say a $500 bike?

 

[artemidorus]

Yes, you can buy different cassettes, chainrings and cranksets to match your fitness level and climbing/descending needs. An $8000 bike had better have exactly what you want on it! (Expensive bikes don't tend to have gearing that differs from cheaper bikes, at least in the drop bar bike market).

 

[Camilo]

I have been noticing lately that when I go down some steep hills I can outpedal my bike in the highest gear and only achieve a top speed of about 34 Mph. I have noticed that the professionals in the tour de france can achieve faster speeds on their sprints and can get up to 60 Mph downhill. I am assuming that the only way they can do this is because their rear cassette is smaller than my bikes and the front cassette is bigger. Can you actually buy different sized cassettes / freewheels that suit your skill level? If I was to buy an $8000 bike would it have bigger gears than say a $500 bike?

The cost of the bike makes no difference in gearing. It simply depends on the size of your front chain wheels and rear cassette sprockets.

High (fast speed) gearing depends on the size of your big front sprocket and smallest rear sprocket. If you want to maximize your highest gear, you want to have the largest available front chain ring and the smallest available rear sprocket. The maximum / highest possible commonly available is a 53 tooth front ring and an 11 tooth rear sprocket.

What do you currently have? THis would tell you if you can improve on that.

You can also improve your ability to pedal effectively at higher and higher cadence. This takes some practice and concentration on being smooth and in control.

Also consider that downhill speed depends a LOT on how aero your bike is and how aero you can get your own body while going fast. Even pros get to the place where they can't pedal effectively any more and they get aero and coast.

 

[BCC1]

Is it possible to change the rear without changing the front and get a noticeable difference. I am on a compact now and do not want to switch to a standard, but I notice I am a little too strong for my current gearing. If so how much adjustment in the derailer will be needed, while I am not a bike mechanic, I know how do do some fine tuning.

thanks

 

[daveryanwyoming]

Originally Posted by BCC1 .

Is it possible to change the rear without changing the front and get a noticeable difference. I am on a compact now and do not want to switch to a standard, but I notice I am a little too strong for my current gearing. If so how much adjustment in the derailer will be needed, while I am not a bike mechanic, I know how do do some fine tuning.

thanks

Yes, changing rear gears does not require any changes up front.

And yes, if you're not currently running an 11 or 12 tooth small cog on your cassette then you can get more high end gearing by swapping cassettes. Most folks couple a compact (50/34) crankset with a cassette with an 11 tooth top cog, typically something like an 11-25 or 11-27 as those still give you a lot of low end climbing gearing but fit standard road short cage rear derailleurs.

FWIW, a compact crank coupled with an 11 tooth small cog in the rear typically gives you more high end gearing than most off the shelf bikes sold with standard (53/39) cranksets coupled with 12 tooth small cogs. Specifically:

53/12 = 119 gear inches
50/11 = 123 gear inches

So yeah, swapping your rear cassette is typically all you need to do and there shouldn't be any need to readjust either derailleur with the cassette swap.

-Dave

 

[An old Guy]

Originally Posted by BCC1 .

Is it possible to change the rear without changing the front and get a noticeable difference. I am on a compact now and do not want to switch to a standard, but I notice I am a little too strong for my current gearing. If so how much adjustment in the derailer will be needed, while I am not a bike mechanic, I know how do do some fine tuning.

thanks

It is doubtful that you are too strong for your gearing. (I use a 14-25 in the rear and a compact on the front. I can do 30 on the flat.) But you can buy cassettes for the back. 11-21 seems to be popular with the stronger riders. I don't know what they do with the 11,12, or 13.

You should not need to change anything except the cassette. You need a tool for that - but the tool is cheap. And you can mix and match the cogs to give you gears to go up the hills as well as down the hills.

---

I am so embarrassed. I rode up a hill with a stronger rider (11-21 & 53-39) last week. I shifted into my 34/19 for the steep section and hit 600w waiting for him to pass. I held 450w to the top of the steep section waiting for him to pass. I looked around and saw him at the bottom expressing deep disgust toward his rear derailleur. Just so embarrassing.

Much better to just lack the gearing.