Bicycle Mechanics - 7 to 9 speed upgrade...

first, the bike: 13-year old mountain bike

o.k., i know that this is not fiscally wise, as "you could get a new bike for less."

i don't want a new bike. what i do want to know is:

when changing from 7 to 9 speed components, can i use:

1. my existing crank with new chainrings? or will i need a new crankset?
1a. if i need a new crankset: square taper, isis, or hollowtech? why?

2. my existing front derailleur?

You need a new rear hub, cassette, chain, front derailleur, rear derailleur,cranks and shifters. You may need new brakes (V) if your shifters and brake levers are integrated. You can re-use everything else. Not close to an economical upgrade unless you find used components.

I did that to my '84 road/touring bike. You also need to bend the chain/seat stays to reform the frame to handle the extra width and keep the wheel aligned. My lbs owner used to build bikes and had the tools. He didn't charge anything. He also moved the front brake pivots so I could use V-brakes.

New moutain bikes are so superior to the oldies, I presonally wouldn't do it. My reference is my 91 & 2000 mountain bikes compared to my new 2003. However, I'm happy I did the touring bike.

Al

heres what you do: take off the back derailluer, and throw it away. Do the same with the front. Get wheel spacers and a 16t cog, take off the big and little rings on the front chainring. fix the chain to fit the new setup. Now you have a single speed. then, go get a new geared bike. Now you'll have two bikes for the price of one.

The accurate answer to your question depends on a lot of things.

1. First measure between your rear dropouts. Many bikes with 7-speed cassettes were built with 130mm dropouts. If yours is 130, that's a good thing. If it's an aluminum bike with 126mm dropouts, I'd forget the whole thing. I'd spread the stays on a steel frame in a heartbeat. You might have to realign the right dropout. Your mountain bike probably has 135mm dropouts so you're good so far.

2. If your bike has a spin-on freewheel, you will need a whole new 9-speed rear wheel. If you have a cassette, you will need a new freehub body. The "A" conversion method is to buy a 9-speed axle set, especially if you had to spread the dropouts of a steel frame. If you rework your rear wheel, you will also have to redish it.

3. You will obviously need a new 9-speed cassette and chain.

4. Your rear derailleur will work fine. The rear derailleur guides the chain from the middle.

5. I've been told that an 7-speed front derailleur will work on a double but I've never done it and I'm a little doubtful. The front derailleur guides the chain by the outside so cage width is a factor. I've not been successful in getting a 7-speed front derailleur to work with 9-speed STI shifters on a triple but the unmodified crankset worked swell once I installed a 9-speed front derailleur with the slightly narrower cage.

6. Assuming you want to retain your index shifting, you will obviously need new 9-speed shifters.

New mountain bikes are so superior to the oldies? AL, what bikes do you mean?

Exotic hardtails like Ritchey,Moots,Fisher,Breezer,Mountain Goat etc are great, the frame geometry has not changed much, the use of Ti is great.
The quality of the frame builders skill is paramount.
My bike is not a robot built Japanese factory bike.
If I choose to replace it with a frame of the same quality of materials, design integrity and built by hand- I'll pay a $1000.
It will be the same bike- The parts,mechanics of a bike have made great advances.
Basically I mean a 1990-$500 dollar old mtb is junk,
A hand built top dollar frame will be fine.
My 1992 has a sloped top tube- It was designed by a pioneer of bike building.
Robots didn't get onto that common until 95? or so.
I believe Brodie started doing this 93-94 or so.
If its old and not worth it, why did Rocky Mountain buy Ritchey proprietary metal for it's bikes?
Because it's better.

This argument can go to other manufacturing-
Are old sports cars garbage cause there old...no.

An electronic device with machine built circuit boards is not better than hand soldered. It's simply cheaper to manufacture.

The beauty part about a robot manufacturing something is that a robot lacks one simple thing: human nature. A robot is not able to be hungover, tired, drunk, stoned, coked up or pissed off. It can make as good as or better than human welds. Most likely, hand built is a much better way to be, but i will go with the proven quality of the good, although robot built, names like Trek, Specailized, GT, Giant, e.t.c.

P.S: Gary Fisher is run by Trek

New moutain bikes are so superior to the oldies, I presonally wouldn't do it. My reference is my 91 & 2000 mountain bikes compared to my new 2003.

define "superior." my bike is a lugged steel hardtail; i don't think anybody makes those anymore, and i prefer the ride to any other (mountain) bike i've test-rode in the past six months. i don't need (or want) rear suspension, front is just fine.

the rear dropouts are 135mm; i already have a "new" (9-speed) wheelset.

the bike has been variously upgraded throughout the past decade, but the drivetrain is getting old. pricing out cassette, derailleurs, crank, chain and shifters, total cost will be about $250. which is a hell of a lot less than a (decent) new bike.

The beauty part about a robot manufacturing something is that a robot lacks one simple thing: human nature. A robot is not able to be hungover, tired, drunk, stoned, coked up or pissed off. It can make as good as or better than human welds. Most likely, hand built is a much better way to be, but i will go with the proven quality of the good, although robot built, names like Trek, Specailized, GT, Giant, e.t.c.

P.S: Gary Fisher is run by Trek

I bet robot welds are fine, but having a guy who may not even ride design something in auto CAD and pass it off as pro-gear?
Racers make good designers, they understand the stresses and what the bikes going to be put through.
The old guys raced and busted their stuff, went and re-designed...on and on.
I feel I'm lucky to have a hand built bike, I cannot afford a new horse so I run the best old beast I can.
HT like road do not need major design changes.
Alu FS is quite a different matter.
I will probably buy a Trek as my next bike as they are a great deal.
I doubt it will be better than my retro-racer though.

Under the best-case scenario, you will need only a 9-speed chain and a 9-speed cogset, but this assumes that you have a cassette, rather than a freewheel, and that your shifter will work in friction mode. As I believe Sheldon has mentioned, you can probably go from 7 speeds to 8 by using a 9-speed chain with cogs and spacers from a 9-speed cassette.

first, the bike: 13-year old mountain bike

o.k., i know that this is not fiscally wise, as "you could get a new bike for less."

i don't want a new bike. what i do want to know is:

when changing from 7 to 9 speed components, can i use:

1. my existing crank with new chainrings? or will i need a new crankset?
1a. if i need a new crankset: square taper, isis, or hollowtech? why?

2. my existing front derailleur?

The real question is what will the nine seped gain ya? The gearing range of a 7 speed is more or less equivalent to a 9, just slightly bigger jumps between gears.

I tinkered with the though of upping my trusty 7 to a 9. One I sat down and figured out the ranges, it just didn't seem worth the cost.

Just my two cents.

The real question is what will the nine seped gain ya? The gearing range of a 7 speed is more or less equivalent to a 9, just slightly bigger jumps between gears.

I tinkered with the though of upping my trusty 7 to a 9. One I sat down and figured out the ranges, it just didn't seem worth the cost.

Just my two cents.

basically, both my freewheel and rear derailleur are worn pretty bad; they're the only part of the drivetrain that haven't been replaced over the years, and the bike just doesn't shift as well as it used to. changing the cables didn't help, and it's been impossible to find replacement parts of the same quality, so i either have to live with the crappy shifting or upgrade.

basically, both my freewheel and rear derailleur are worn pretty bad; they're the only part of the drivetrain that haven't been replaced over the years, and the bike just doesn't shift as well as it used to. changing the cables didn't help, and it's been impossible to find replacement parts of the same quality, so i either have to live with the crappy shifting or upgrade.

There's also the enjoyment and satisfaction of thinking it through and doing it. Beats the heck out of watching "Survivor" on television. If you try to justify everything purely on an engineering basis, you'd never hang pictures in your house and making babies would take less time.

I find that I appreciate closely spaced gears more on flat rides than when riding in the hills. When I'm grinding up a hill, when I shift I want to feel a significant difference. When I'm riding on the flats, I like to have a lot of closely spaced gears so that I can find one right in the sweet spot.

define "superior." my bike is a lugged steel hardtail; i don't think anybody makes those anymore, and i prefer the ride to any other (mountain) bike i've test-rode in the past six months. i don't need (or want) rear suspension, front is just fine.

the rear dropouts are 135mm; i already have a "new" (9-speed) wheelset.

the bike has been variously upgraded throughout the past decade, but the drivetrain is getting old. pricing out cassette, derailleurs, crank, chain and shifters, total cost will be about $250. which is a hell of a lot less than a (decent) new bike.

That's wonderful! I referenced my basis for the comment and said I wouldn't do it. I think you should.

AL

basically, both my freewheel and rear derailleur are worn pretty bad; they're the only part of the drivetrain that haven't been replaced over the years, and the bike just doesn't shift as well as it used to. changing the cables didn't help, and it's been impossible to find replacement parts of the same quality, so i either have to live with the crappy shifting or upgrade.

Which level components are they? 7 speed freewheels (or do you mean the cassette) are fairly common still. All that may be wrong with the derailleur is something a good cleaning could probably rectify. Maybe replace the guide and tension pulleys. I tore down, cleaned, lubed and tuned my rear derailleur, was amazed at how well it acted afterwards.

Not trying to dis your wanting to change, I just like keeping old things running well. Kind of a challenge.

Having tried it, don't expect a 9 speed chain to shift acceptably with the old 7 speed cranks. The spacing is too wide, there are no ramps or pins and the the rings are too wide for the chain.
I converted a 7 speed hub to a 9 speed a while ago. It was an expensive Hadley hub so it was worth the effort. I wouldn't recommend it for a basic Shimano unit.
Seven speed is fine equipment, just a little heavier than 9. I don't think a mix of the two will shift as well as the original.

Which level components are they?

XT


7 speed freewheels (or do you mean the cassette) are fairly common still.

no, it's a freewheel, not a cassette. if it was a cassette, i'd probably just stay 7-speed.


All that may be wrong with the derailleur is something a good cleaning could probably rectify. Maybe replace the guide and tension pulleys. I tore down, cleaned, lubed and tuned my rear derailleur, was amazed at how well it acted afterwards.

Not trying to dis your wanting to change, I just like keeping old things running well. Kind of a challenge.

i really think it's shot. it's on its 3rd (4th?) set of pulleys, has been overhauled several times in its life, and no longer hangs perpendicular to the ground (not a bent hanger, that's what i checked first).

argh. typos.

You need to assess what is wrong with your current drivetrain.

Freewheel

I would say "if it ain't broke, don't fix it". the freehub and cassette has a basic advantage: the axle is stronger. On the other hand, unless you do lots of loaded touring, ride through a lot of potholes or are very heavy, you are probably OK. It should be easy to see if your freewheel is still in good shape: the chain should sit in round depressions, not in "stretched Us".
There is also another advantage to a cassette for riding off the beaten track (like loaded touring): it's easier to remove a cassette than a freewheel on the road. But again, at home, it's not a real problem. Cassettes are also easier to swap if you like to change your gearing according to terrain.

So, if you never had any problems with broken axles or with replacing a spoke on the road, and if your rear wheel and freewheel are good, don't change them. BTW, find a shop that deals with used bikes and repairs: you will have plenty of freewheels to looks for. If no local sources, look at http://www.sheldonbrown.com/harris/.

On the other hand, if you are having problems with the wheel (bent rim, rash of broken spokes...), break axles often, have shot bearings, want to swap cogs on the fly... than a new wheel might be warranted.

Derailleur
I can't do a long-distance diagnostic, but it looks to me like you have a worn out derailleur. I had that problem with a 20-year old derailleur (50 000 km), where the pins that were holding the parallelogram had loosened. Basically, the derailleur cage was so loose that I could grab it with my hand and shift it by 1-2 gears. A new derailleur solved the problem.
If you get a new derailleur, I think your 13-year-old indexed shifters will work with a modern derailleur (Alivio, LX, XT... whatever you want to pay). If not, they will work in friction mode.


If you upgrade

If the frame is AL, you can't spread it so you should stick with a 126-mm OLD wheel. In practice, that means a 7-speed freehub. You could use 8-speed-on-7 by reading http://www.sheldonbrown.com/k7.html

If you change the wheel, you may or may not need a new derailleur. If it is good, I _think_ indexing specs are the same as today. If so, it would work with current indexing on an 8-speed cassette... or with a new shifter on a 9-speed cassette.

A 9-speed chain (and drivetrain) works flawlessly with a 7-speed or 8-speed crankset, at least in friction mode. I have head a few people it doesn't work quite as well with STI (i.e. indexed front shifting) and others say it works fine.

I would suggest you leave the front end as is. Keep your current derailleur (if it works fine) and current front shifter. If you want to change the front shifter too, then try it first with your current derailleur. Whether it works or not depends on which standard it was designed for, alas. As for "9-speed crankset", the only real difference seems to be with the inner chainring: different position of the teeth relative to the ring's thickness. But why buy one or more new rings unless they are needed?

Regards,

first, the bike: 13-year old mountain bike

o.k., i know that this is not fiscally wise, as "you could get a new bike for less."

i don't want a new bike. what i do want to know is:

when changing from 7 to 9 speed components, can i use:

1. my existing crank with new chainrings? or will i need a new crankset?
1a. if i need a new crankset: square taper, isis, or hollowtech? why?

2. my existing front derailleur?


I just finished upgrading an old steel MTB frame from 7 speed to 9 speed. It did not make economic sense, but that wasn't really the point. I ended up upgrading everything, so that the only original items on the bike are the seatpost, seatpost collar, and frame. This was an abandoned bike and it was fun to bring it back to life. I ended up learning a lot from the experience, and I had a blast tearing it down and rebuilding it.

To answer your questions, there was an older thread in this forum about using old cranks with a seven speed system. I think there were conflicting opinions. That being said, I picked upa square taper Deore crankset to replace the STX that was on the bike for $40. It is a pretty nice crank; although I do not have a season of riding on it yet.

I am not sure about the derailleur. I picked up a new Deore derailleur too, for cheapo money. The nice thing about the deore derailleur, is that it is top pull or bottom pull, and has shims to fit multiple tube widths.

Enjoy your rebuild.