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Changing gearing on a road bike

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Changing gearing on a road bike

Old 09-14-13, 04:53 PM
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Zhaan
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Changing gearing on a road bike

I've owned a bike for a few years but I've recently been riding a lot more (car got wrecked --> carfree) and thus trying to learn more about bikes and bike repair.

My bike is a 1988 Centurion Ironman Master (Shimano 600 components), a triathlon bike. I bought it used from an LBS about five years ago, back when I didn't know *anything* about bikes. Although it's got some deficiencies as a commuter bike, it mostly works okay.

One of the more annoying problems is the gearing on the bike. It's a 14-speed, but I only use the lower 7 gears; the higher 7 gears are just too high, especially since I live in a somewhat hilly town and I'm often going up hills. The current gearing on the bike is 53 / 42 on the chainrings and 12-21 on the cassette.

So I went to my LBS today and asked if it would be possible to replace one of the front chain rings. I learned a lot from the fellow; he presented me with four options:

1.) Replace the 53 chainring with a 39; minimally effective. Cost: ~$25.

2.) Replace both chainrings, which would also mean replacing the crank arm. The new chainrings would be 50 / 34. To me, 50 doesn't seem much more useful than 53... Cost: $75.

3.) Replace the cassette. Because I've got a funky wheel (I can't explain the details, but as I understand it my bike was made between the transition from one type of wheel technology to another), he didn't think it would be possible to order a new cassette to fit my wheel. I would have to replace the cassette and the wheel. If I get a decent wheel, I think he said this would be $125-$150.

4.) He also gave me a second option for replacing the cassette. He happened to have an old cassette in his box of spare parts that he'd taken from a bike similar to mine. He said he'd have to take apart my rear wheel/cassette to know for sure if it'd fit my bike. The cassette he had was a 12-30. However, it has 6 rings rather than 7, so I'd have one less gear and I'd need to change my shifters from clicky mode to continuous mode (my terms, not his). I'm not sure what he'd charge me for this; I imagine not too much.

So, what would you recommend? Are any of these options a good idea? Which one will give me the most bang for my buck?

If I've left out any information, please excuse me! And if pictures would be helpful, I'm happy to take some and upload them.

Thanks for any opinions / information / anecdotes you have! Cheers.
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Old 09-14-13, 05:14 PM
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The trouble with throwing parts at old road bikes to lower the gearing is you can easily spend more than the bike is worth, especially having a bike shop doing the work. Another option would be to find an 80's or 90's rigid frame mountain bike on craiglist and sell your centurion. A mountain bike will have the lower gearing you need, and you can find them pretty cheap.
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Old 09-14-13, 05:20 PM
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Installing a 50 & 34 compact crank for $75 is a reasonable option.
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Old 09-14-13, 05:20 PM
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Post some pics of the bike (esp. the drive side) and you'll get some options. Hard to give advice when we have no idea what the parts are. Southern IN is pretty hilly so a triple might be in order. Also a 50/34 is pretty common for a compact and provides reasonably good gearing so I'd lean towards that option of keeping the bike; a triple might not run much more though and might be more to your liking.
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Old 09-14-13, 05:30 PM
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Although it can vary a lot, your bike is probably worth $175 or more if in lightly used condition, especially if the shop did a lot of work on it before selling it to you. If it does not fit your needs you may be best off selling it and buying something that does work for commuting.
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Old 09-14-13, 05:42 PM
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If you take off the rear wheel, and take good closeup pictures of the rear cassette and hub from a few angles, someone here may be able to determine what model it is. Then perhaps someone here or Ebay will have a similar 7 speed with a wider range.
The 50-34 crankset is also a good option.
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Old 09-14-13, 06:20 PM
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Originally Posted by grinningfool View Post
The trouble with throwing parts at old road bikes to lower the gearing is you can easily spend more than the bike is worth, especially having a bike shop doing the work. Another option would be to find an 80's or 90's rigid frame mountain bike on craiglist and sell your centurion. A mountain bike will have the lower gearing you need, and you can find them pretty cheap.
The problem with trying to use a MTB for road use is that you'll end up likely spending even more money on it than you would have fixing the gearing on the road bike. A rigid MTB still needs: tires, bar ends (for an extra hand position) and possibly a tighter cassette or large ringed crankset. And it's still going to be overbuilt for the purpose.

I agree with Barrettscv (even though I'm not a compact crank fan) that $75 for a compact crank is going to be the best bang for your buck.

You could swap the freewheel (your bike almost certainly doesn't have a freehub to accept a cassette, and even if it did it would have to be 7 speed) for a wider range one but you'd need a new chain and rear derailler to make it work well. You'd also be stuck with some pretty tall jumps between gear shifts assuming you went with something like a 14-34. You could do the compact crank and a more reasonable 13-28 if you wanted considerably lower gearing than your current (admittedly brutal) set up. The 28T large cog stands a good chance of working with your current rear derailler while the 34T would definitely not work. These are available new so there's no good reason to accept an unknown origin freewheel that could fail at any time, especially not one that's only 6 speeds.

Ideally in my opinion, you'd go with a triple crankset and either a slightly wider freewheel or stick with the same one. However, a triple crank will require a new front and rear derailler to deal with the multiple chainrings and extra chain wrap capacity. Your front shifter will work just fine and so would your rear as long as you stuck with 7 speeds. If you shopped around, you could find all the parts for less than $100 easily, less if you bought used.
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Old 09-14-13, 06:31 PM
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I assume your bike has a 7-speed freewheel, not a cassette, and your current 12x21 is by far, the worst choice for your riding conditions. 7-speed freewheels are still available and a 13x28 would be much more useful. As noted, you will probably need a new chain but everything else should work.

Here a suitable freewheel for only $20: http://www.amazon.com/Shimano-MF-HG3...eed+freewheels

As to changing chainrings, I assume you meant to say substituting a 39T for the 42T, not for the 53. That would make a useful but not dramatic difference.
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Old 09-14-13, 06:39 PM
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Originally Posted by HillRider View Post
I assume your bike has a 7-speed freewheel, not a cassette
Sounds to me like he has a uniglide freehub.


Originally Posted by Zhaan View Post
...

My bike is a 1988 Centurion Ironman Master (Shimano 600 components)

...

3.) Replace the cassette. Because I've got a funky wheel (I can't explain the details, but as I understand it my bike was made between the transition from one type of wheel technology to another), he didn't think it would be possible to order a new cassette to fit my wheel. I would have to replace the cassette and the wheel. If I get a decent wheel, I think he said this would be $125-$150.
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Old 09-14-13, 06:41 PM
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Originally Posted by HillRider View Post
I assume your bike has a 7-speed freewheel, not a cassette, and your current 12x21 is by far, the worst choice for your riding conditions. 7-speed freewheels are still available and a 13x28 would be much more useful. As noted, you will probably need a new chain but everything else should work.

Here a suitable freewheel for only $20: http://www.amazon.com/Shimano-MF-HG3...eed+freewheels

As to changing chainrings, I assume you meant to say substituting a 39T for the 42T, not for the 53. That would make a useful but not dramatic difference.
If the OP has a freewheel and not an "oddball" cassette (whatever that means), then this is the cheapest, most cost-effective solution.
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Old 09-14-13, 06:41 PM
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Originally Posted by IthaDan View Post
Sounds to me like he has a uniglide freehub.
That's what I'm thinking based on the mechanic's description.
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Old 09-14-13, 06:48 PM
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Originally Posted by bikemig View Post
That's what I'm thinking based on the mechanic's description.
Hmmm, I'm starting to lean towards this as well. In which case, swapping the freehub for a Hyperglide compatible version will solve a number of issues: http://sheldonbrown.com/k7.html#transplant

Having done this before, the cheapest way to a Hyperglide freehub is surprisingly buying an entire Shimano rear hub. As a bonus you get the compatible cones and dust shields to make everything work. You do have to be careful which hub you purchase as Shimano makes two common styles of freehub (and many more oddball styles). Based on my experience, you should be ok with a Shimano Tiagra 4600 rear hub: http://www.amazon.com/Shimano-FH-460.../dp/B005DUXUUY

Note that your rear wheel will now e 130mm OLD and will need to be re-dished. Maybe this wasn't the best suggestion!

Last edited by joejack951; 09-14-13 at 07:52 PM. Reason: Changed "don't" to "do".
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Old 09-14-13, 07:29 PM
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I think it sounds like a Uniglide too.
IF that's the case, get a 7 speed Hyperglide cassette.
A little bit of time with a file and they can be made to fit .
You'd still have to use the same smallest cog if it's a threaded on one-

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Old 09-14-13, 07:36 PM
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Originally Posted by joejack951 View Post
Hmmm, I'm starting to lean towards this as well. In which case, swapping the freehub for a Hyperglide compatible version will solve a number of issues: http://sheldonbrown.com/k7.html#transplant

Having done this before, the cheapest way to a Hyperglide freehub is surprisingly buying an entire Shimano rear hub. As a bonus you get the compatible cones and dust shields to make everything work. You don't have to be careful which hub you purchase as Shimano makes two common styles of freehub (and many more oddball styles). Based on my experience, you should be ok with a Shimano Tiagra 4600 rear hub: http://www.amazon.com/Shimano-FH-460.../dp/B005DUXUUY

Note that your rear wheel will now e 130mm OLD and will need to be re-dished. Maybe this wasn't the best suggestion!
I like your way of thinking, but having a shop do all that gets expensive quick, I'd imagine. If it weren't for potential need to change derailleurs, getting a triple would sound like the best option to me. Still might be, but not the cheapest.
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Old 09-14-13, 11:05 PM
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Wow, guys, you really know how to make a newbie feel welcome! Thanks for all of your input.

Originally Posted by grinningfool View Post
The trouble with throwing parts at old road bikes to lower the gearing is you can easily spend more than the bike is worth, especially having a bike shop doing the work.
I had the same thought. Before I commit to any upgrades, I am going to head over to the appraisals forum with some pics of the bike and see if I can get an idea of what it's worth.

Originally Posted by bikemig View Post
Post some pics of the bike (esp. the drive side) and you'll get some options. Hard to give advice when we have no idea what the parts are.
I took some pictures of the bike but can't seem to upload them to the forum. I will look into this.

Originally Posted by bikemig View Post
Also a 50/34 is pretty common for a compact and provides reasonably good gearing so I'd lean towards that option of keeping the bike; a triple might not run much more though and might be more to your liking.
Would a triple necessitate a new front derailleur or any other new hardware? (It seems joejack951 is suggesting it would?)

Originally Posted by Homebrew01 View Post
If you take off the rear wheel, and take good closeup pictures of the rear cassette and hub from a few angles, someone here may be able to determine what model it is. Then perhaps someone here or Ebay will have a similar 7 speed with a wider range.
I don't quite have time to take it apart tonight, but I'll try to do that in the next couple days.

Originally Posted by joejack951 View Post
You could swap the freewheel (your bike almost certainly doesn't have a freehub to accept a cassette, and even if it did it would have to be 7 speed) for a wider range one but you'd need a new chain and rear derailler to make it work well. You'd also be stuck with some pretty tall jumps between gear shifts assuming you went with something like a 14-34.
Pardon my ignorance. Why would a new freewheel require a new chain / derailleur?

Originally Posted by joejack951 View Post
The 28T large cog stands a good chance of working with your current rear derailler while the 34T would definitely not work. These are available new so there's no good reason to accept an unknown origin freewheel that could fail at any time, especially not one that's only 6 speeds.
Again I have to claim ignorance. What is a 28T and 34T?

Originally Posted by HillRider View Post
I assume your bike has a 7-speed freewheel, not a cassette...
This is quite possible. I used the term cassette b/c that's what the guy at the bike shop used. I looked up the difference between a freewheel and a cassette, but I can't tell you which I have. (Given what the LBS mechanice said, and what Sheldon Brown's page says, and what Wikipedia says, a cassette seems to be the correct term.)

Originally Posted by HillRider View Post
As to changing chainrings, I assume you meant to say substituting a 39T for the 42T, not for the 53. That would make a useful but not dramatic difference.
You are probably right. The guy at the shop talked about replacing a chainring with a 39. He didn't specify which one. I assumed that it made sense to replace the 53, since I never use that one, but now that I think about it I see that it would make sense to replace the 42. Which leads me to think that's not the best option, 'cause I'd still have the 53 that I would never use.

Originally Posted by joejack951 View Post
Hmmm, I'm starting to lean towards this as well. In which case, swapping the freehub for a Hyperglide compatible version will solve a number of issues: http://sheldonbrown.com/k7.html#transplant

Having done this before, the cheapest way to a Hyperglide freehub is surprisingly buying an entire Shimano rear hub. As a bonus you get the compatible cones and dust shields to make everything work. You do have to be careful which hub you purchase as Shimano makes two common styles of freehub (and many more oddball styles). Based on my experience, you should be ok with a Shimano Tiagra 4600 rear hub: http://www.amazon.com/Shimano-FH-460.../dp/B005DUXUUY

Note that your rear wheel will now e 130mm OLD and will need to be re-dished. Maybe this wasn't the best suggestion!
Thanks for the links. Ah, what does "re-dished" mean? Would I need additional hardware besides the freehub? I'm assuming I'd need a cassette to go with it? Also, what issues does a Hyperglide freehub solve (besides better gearing)?


So, given the limited knowledge that I've given you all about my bike (I'll see if I can take it apart and get some pics soon), it seems like about half of the opinions are leaning toward a new crankset and half toward a new freehub.

Given that you don't know a lot about my bike or where I live, how many usable gears would each option net me? (My apologies if this is a completely unreasonable question / very difficult to determine.)

Again, thanks for all of the information you've given me. It's a mite frustrating that I know so little about bikes, but I'm glad to be learning all of this.
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Old 09-15-13, 05:12 AM
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Originally Posted by Barrettscv View Post
Installing a 50 & 34 compact crank for $75 is a reasonable option.
That sounds like a real reasonable price to me.

Here's what to look for:
Figure out what gear you like to ride in on a dead flat road with no wind. With the new compact crank you want that gear ratio to be made up of the 50 chainring and a middle rear cog. That will give you a couple of trim gears each way for riding on the flat and you can save the 34 chainring, which will be quite a bit lower than your current 42, for up hill.
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Old 09-15-13, 05:32 AM
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Originally Posted by Zhaan View Post

Pardon my ignorance. Why would a new freewheel require a new chain / derailleur?


Again I have to claim ignorance. What is a 28T and 34T?

Hi,

The "T" indicated teeth. A 28T has 28 teeth.

A new rear freewheel with a wide range may exceed the capacity of the rear derailleur. Some road bike rear derailleurs are designed for racing and only fit a 13-26 freewheel. Other rear derailleurs designed for touring bikes can fit a 14-34 freewheel. The overall diameter of a freewheel is determined by the number of teeth, a 34 tooth cog on a 14-34 freewheel will have a larger diameter than a 24 tooth cog.

We would need to know what make and model rear derailleur you have to determine what will fit.
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Old 09-15-13, 06:10 AM
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Originally Posted by Barrettscv View Post
Installing a 50 & 34 compact crank for $75 is a reasonable option.
It will get you a gear 20% easier, which is significant. If we identify the type of cassette/freewheel you have, and you feel you just need a couple easier gears, then swapping to a bigger cog in back is probably the cheapest. Cogs and chains wear out, so you may be close to needing replacements anyway.

For comparison, ride in your 42x17, then swith to 42x21. That is also 20%. So if you go with a 34t up front, it will be like the same jump between 17 and 21, but even easier. The equivalent of keeping your 42 and getting a 26 in back.

The "right" gearing is hard to tell from here. Do you feel like you just need 1 or 2 more lower gears to be comfortable ? Or is it so bad you think you need radically lower gears ?
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Old 09-15-13, 09:47 AM
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In the light of Michael's $75 compact crankset post, this may not be the cheapest option, but I've had good success using 48T and 39T chainrings on a standard crankset like yours:



The 48T big ring is far more useful than a 53T (for me) and climbing is a little easier with the small inner ring. The Sugino 48T runs about $30-35 online.
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Old 09-15-13, 10:53 AM
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Originally Posted by Barrettscv View Post
Installing a 50 & 34 compact crank for $75 is a reasonable option.
That's really cheap for a compact crank... plus labor plus maybe a new BB - those old Centurians may have been before the low profile cranks came out.

Anyway, another option MIGHT be, to put on a single-speed crank with a 34t... lots of cheap options there to give him a 1x7 drivetrain.
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Old 09-15-13, 11:44 AM
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You could consider to going with a "mountain double." I am finding them in the 30/42 configuration (or close to that number of teeth) if I remember correctly. Shimano makes them, as well as others I'm sure. This one is more than you'd probably want to spend, but it gives you an idea. You may have issues with the width of your chain though so check into that (beyond my expertise).

http://www.performancebike.com/bikes...400182__400182
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Old 09-15-13, 12:01 PM
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himespau 
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Just talking out my butt here, but could he get something like this: http://www.amazon.com/Shimano-FC-M36...9267722&sr=1-2 for $28, remove the inner ring, pair it with a bottom bracket like this: http://www.amazon.com/Shimano-Square...t+square+taper for $20, and call it a day? Sure the bottom bracket is smaller than is optimal than the one for the crankset, but that would bring the rings in closer and allow him to use the FD he has. Of course he'd have to pay for labor and many shops might not be happy about hanging internet parts on bikes, but maybe he could bring that idea up to his mechanic and see if they could do that for $100 or so with parts they ordered fromQBP. Seems like it'd give him more usable gears and a better range for what he's wanting to do than a 50-34 compact crankset.
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