Bicycle Mechanics - 7 to 9 speed mod

I'm getting ready to mod my mid 90's road bike from 7 to 9 speeds. Here's my shopping list, please me know if I'm going horribly wrong anywhere.

Crankset, sticking with a double but upgrading to 9 speed compatible. Thinking Stronglight 53/40 square taper.
Ultegra 3X9 bar end shifters, SL-BS77
Front derailleur, thinking FD-2300 (Should work even though it 8 speed right?)
Rear Derailleur, RD-3400 Sora, or RD-4500 Tiagra (is there much difference between these two?)
Cassette, CS-HG50-9 speed Tiagra (11-34T)
Freehub Body, Tiagra FH-4500
Chain, CN-HG73 LX

I guess the one the one real concern I have is the 34 tooth cog on the Cassette. Do I need to buy a long cage rear derailleur to avoid interference with the derailleur cage?

Thanks

Neither of the rear derailleurs you mention will accommodate a 34-tooth cog (they are rated for 27T), and you will need a "total capacity" of 36 teeth or greater to wrap the chain properly given the front and rear tooth ranges you specify.

The 3400 only has a max sprocket of 27T (http://bike.shimano.com/publish/content/global_cycle/en/us/index/products/road/sora/product.-code-RD-3400-SS.-type-.rd_road.html) and the 4500 only has a max sprocket of 27T as well (http://bike.shimano.com/publish/content/global_cycle/en/us/index/products/road/tiagra/product.-code-rd-4500-gs.-type-.rd_road.html).

The cassette you have picked has a max sprocket of 34T.

Another factor you need to look at in picking a new derailleur is total capacity. From the specs you give, you need 36T of total capacity. (http://home.earthlink.net/~mike.sherman/shift.html).

RK

EDIT: What he said

thats what I was affraid of but sure where to look. So I need to go to a 27T or switch up my derailleur. Thanks guys.

I'd try using your existing chain rings if there's nothing wrong with them.

For a short time, I was using a cottered crank set from an early 70's 10 speed (2X5) with a 9 speed cassette.

I just did a similar conversion with a Campagnolo group - as Bill said, try your existing crankset / front derailleur first it may work.

You might need a new axle and spacer to get under that freehub body. If not a new axle, you might been to make 'change' with the larger spacer that's on the new drive side. be ready to redish your rear wheel if you're not up for coldsetting your frame to 130mm.

Edit: OP, where in upstate NY? Need a hand?

I'd try using your existing chain rings if there's nothing wrong with them.

For a short time, I was using a cottered crank set from an early 70's 10 speed (2X5) with a 9 speed cassette.

That what started this whole mod. My front chainrings are shot and was initially was just going to buy a 7 speed replacement crankset. But then thought as long as I'm replacing parts might as well go all the way.

You might need a new axle and spacer to get under that freehub body. If not a new axle, you might been to make 'change' with the larger spacer that's on the new drive side. be ready to redish your rear wheel if you're not up for coldsetting your frame to 130mm.

Edit: OP, where in upstate NY? Need a hand?

The frame is already set to 130mm so I'm ready to roll there; and yes, I doubt I'm going to get away without redishing the wheel. I've never done it before but from what I've read I think I can do it without screwing it up. I'm not too far away, Syracuse. Thanks

The 3400 only has a max sprocket of 27T (http://bike.shimano.com/publish/content/global_cycle/en/us/index/products/road/sora/product.-code-RD-3400-SS.-type-.rd_road.html) and the 4500 only has a max sprocket of 27T as well (http://bike.shimano.com/publish/content/global_cycle/en/us/index/products/road/tiagra/product.-code-rd-4500-gs.-type-.rd_road.html).

The cassette you have picked has a max sprocket of 34T.

Another factor you need to look at in picking a new derailleur is total capacity. From the specs you give, you need 36T of total capacity. (http://home.earthlink.net/~mike.sherman/shift.html).

RK

EDIT: What he said

I took a look at that calculator but not sure how to calculate the rear derailleur requirements. I'm thinking if I back of to a 32T (which I think would still be plenty low gearing) I can use this:



Model Number
RD-M675-GS


Series
SLX


Shifting Action
Top-Normal


Mount Type
Direct Attachment


Maximum Sprocket
36T


Minimum Sprocket
11T


Front Difference
22T


Total Capacity
35T



Is there any disadvantage to using a mountain bike derailleur? Any advantage to medium vs long cage in this model?

Compare all the parts at Retail + Frame spread , to getting a new bike, ready to go..

Is there any disadvantage to using a mountain bike dérailleur? Any advantage to medium vs long cage in this model?

For this specific example, yes. The M675 is 10 speed Dyna-Sys, this is only compatible with other Dyna-Sys components. You would need to look for a 9 speed RD / non Dyna-Sys component,

If you are looking at a 32T max on the rear, then a Shimano GS road rear dérailleur will work, although you may need to reverse the B screw,

RDER's have 2 things to be concerned about.
1 Min/Max cog sizes.
2. Chain wrap capacity
That is calculated by-
(Largest ring - smallest ring) + (Largest cog - smallest cog)
(53-40) + (32-11)
= 13 + 23
= 36

You can fudge a bit if you don't use the small-small combination, which would result in chain sag. Not dangerous, but "tacky" at best.

Rather than pushing a road derailleur's limits or hacking the B screw, just get a 9-speed MTB derailleur which will handle the 34T cog and wrap plenty of chain with ease, like this one: http://www.amazon.com/Deore-M591-SGS-Long-CageRear/dp/B0064QND30

Compare all the parts at Retail + Frame spread , to getting a new bike, ready to go..

It's no contest. I'm going to pick all this stuff up for around $300; new bike = $1100.

For this specific example, yes. The M675 is 10 speed Dyna-Sys, this is only compatible with other Dyna-Sys components. You would need to look for a 9 speed RD / non Dyna-Sys component,

If you are looking at a 32T max on the rear, then a Shimano GS road rear dérailleur will work, although you may need to reverse the B screw,

OK; Good save.

RDER's have 2 things to be concerned about.
1 Min/Max cog sizes.
2. Chain wrap capacity
That is calculated by-
(Largest ring - smallest ring) + (Largest cog - smallest cog)
(53-40) + (32-11)
= 13 + 23
= 36

You can fudge a bit if you don't use the small-small combination, which would result in chain sag. Not dangerous, but "tacky" at best.

If I go with the the long cage (SGS) MTB derailleur I can get 36. I'm going to do that plus down size the biggest ring to 32. So, I have enough total, plus a little extra.

New parts list:

Crankset, Raceface Cadence 39/53T
Ultegra 3X9 bar end shifters, SL-BS77
Front derailleur, thinking FD-2300 (Should work even though it 8 speed right?)
Rear Derailleur, Deore M591-SGS
Cassette, CS-HG50-9 speed Tiagra (11-32T)
Freehub Body, Tiagra FH-4500
Chain, CN-HG73 LX

New parts list:

Crankset, Raceface Cadence 39/53T
Ultegra 3X9 bar end shifters, SL-BS77
Front derailleur, thinking FD-2300 (Should work even though it 8 speed right?)
Rear Derailleur, Deore M591-SGS
Cassette, CS-HG50-9 speed Tiagra (11-32T)
Freehub Body, Tiagra FH-4500
Chain, CN-HG73 LX
One more comment, do you really need a 53x11 (130 gear-inch) high gear? Consider a compact crank (typically a 50/34 double) instead of the 53/39. It will give you a usefully lower low gear while sacrificing nearly nothing for the high gear which will still be 122 gear-inches.

Since you are using barend shifters that have friction front shifting, nearly any road front derailleur will work.

The frame is already set to 130mm so I'm ready to roll there; and yes, I doubt I'm going to get away without redishing the wheel. I've never done it before but from what I've read I think I can do it without screwing it up. I'm not too far away, Syracuse. Thanks

Well, if you get stuck or are up for a drive to use my shop, let me know.

I'm still a little confused- if the frame is already 130mm, I wonder if you're 7 speed because of a spacer on an already 8 speed freehub body.

One more comment, do you really need a 53x11 (130 gear-inch) high gear? Consider a compact crank (typically a 50/34 double) instead of the 53/39. It will give you a usefully lower low gear while sacrificing nearly nothing for the high gear which will still be 122 gear-inches.

Since you are using barend shifters that have friction front shifting, nearly any road front derailleur will work.

Pittsburgh!!! Home of the Dirty Dozen.

I thought if I go to a wider range on the rear with a 32T for low gear, I can stick with a standard crankest, and still have top end speed. Was afraid if I went to a compact crank I would loose that.

Well, if you get stuck or are up for a drive to use my shop, let me know.

I'm still a little confused- if the frame is already 130mm, I wonder if you're 7 speed because of a spacer on an already 8 speed freehub body.

What's the name of you're shop? I'll definitely stop in with or without the bike next time I'm down that way.

Well, if you get stuck or are up for a drive to use my shop, let me know.

I'm still a little confused- if the frame is already 130mm, I wonder if you're 7 speed because of a spacer on an already 8 speed freehub body.

Oh, and to answer your question; the frame has been "coldset" (hope I'm using that term correctly) to 130mm.

"My" shop is in my garage. I volunteer at the coop, RIBS, though.

53/11 versus 50/11 will only get you more speed if you have the power in your legs to drive it. Most riders use gearing to get speed, but also use cadence (rpm of the crankset). The speed you pedal has something to do with knee health and avoidance of injury even for young riders. A healthy cadence is in the range of 80 to 95 rpm. If you can turn a 53/11 at 80 rpm, you'll be going 30 mph. How long can you do that, in your experience? 50/11 is not much easier, being 28 mph.

30 mph takes about 400 watts for a 160# rider. 20 mph takes about 175.

Granted, riding feel (I like to pedal slow sometimes, like downhill) is part of it, but in terms of pure speed a compact at 50/11, 50/12, or 48/12 is going to get you where you want to go as fast as you can pedal, over the term of a ride.

New parts list:

Crankset, Raceface Cadence 39/53T
Ultegra 3X9 bar end shifters, SL-BS77
Front derailleur, thinking FD-2300 (Should work even though it 8 speed right?)
Rear Derailleur, Deore M591-SGS
Cassette, CS-HG50-9 speed Tiagra (11-32T)
Freehub Body, Tiagra FH-4500
Chain, CN-HG73 LX

I'd also go with a compact crank as long as you're buying a new one anyway. Personally I'd look for a Shimano Sora or Tiagra compact with the "new" external bearing BB system.

Keep whatever FD you have unless it's broken. It'll work fine with a 9S chain.

53/11 versus 50/11 will only get you more speed if you have the power in your legs to drive it. Most riders use gearing to get speed, but also use cadence (rpm of the crankset). The speed you pedal has something to do with knee health and avoidance of injury even for young riders. A healthy cadence is in the range of 80 to 95 rpm. If you can turn a 53/11 at 80 rpm, you'll be going 30 mph. How long can you do that, in your experience? 50/11 is not much easier, being 28 mph.

30 mph takes about 400 watts for a 160# rider. 20 mph takes about 175.

Granted, riding feel (I like to pedal slow sometimes, like downhill) is part of it, but in terms of pure speed a compact at 50/11, 50/12, or 48/12 is going to get you where you want to go as fast as you can pedal, over the term of a ride.

But cant I get the both of best worlds going to a mountain rear derailleur and a couple of low gears on the rear cog? I got the idea looking at a couple of CX bikes at the LBS and thought, why not. Is there a downside to a setup like this?

"My" shop is in my garage. I volunteer at the coop, RIBS, though.

do they have wholesale parts accounts with distributors?, what is their markup, to sell that stuff,
volunteers get something like an employee rate?

They do have a QBP account. The whole place is pretty disorganized, so there isn't a markup. To anyone. I guess it's just a perk for being a part of the coop. Nothing is sold there, it's a 100% charitable organization. The closest there is to an cash income stream is the donation box, and the 501(c)(3) tax forms that record a donation.

It's all funded through grants under the umbrella of a larger community organization here in Ithaca.

I'd also go with a compact crank as long as you're buying a new one anyway. Personally I'd look for a Shimano Sora or Tiagra compact with the "new" external bearing BB system.

Keep whatever FD you have unless it's broken. It'll work fine with a 9S chain.

Tiagra 50/34T and bottom bracket would run a little over $100. Would the 9 speed crank work OK with all the existing 7 speed stuff on the bike?

I agree that you are probably overgearing the bike. Here is a gear calculator I use with your proposed gearing and another with a 50/34 compact crank and a hypothetical 12/28 cassette compared. Unless you are an extremely strong rider gearing over 110 gear inches is wasted and your remaining gears are stretched thinner than is optimum as a result.

http://www.kstoerz.com/gearcalc/compare/?link=1&lbl=1&tsid1=2&igbbid1=1&cogs1=11,12,14,16,18,21,24,28,34&rings1=53,39&ighid1=1&tsid2=2&igbbid2=1&cogs2=12,13,14,15,17,19,21,24,28&rings2=50,34&ighid2=1

Pittsburgh!!! Home of the Dirty Dozen.

I thought if I go to a wider range on the rear with a 32T for low gear, I can stick with a standard crankest, and still have top end speed. Was afraid if I went to a compact crank I would loose that.
Yeah, that was yesterday and it was snowing here!!

You won't loose any top end that mere mortals can use. A 53/11 is what Tour de France riders use for time trials. As Road Fan noted, a 50/11 combination gives you 30 mph at 80 rpm and 36 mph at 100 rpm. Almost no non-professional rider needs more than that, or even that. As for fast downhills, it's probably faster to tuck in out of the wind and let the bike run than to try to pedal at those speeds. A compact will give you more usable gears at no sacrifice.

7-speed and 9-speed bodies IME use different seal arrangements between the body and the axle.
For a road bike, (not seeing much dirt) it's not a big deal, but I've always preferred to go for a donor wheel to get the full set of pieces that'll line up as intended all in one go.

... Unless you are an extremely strong rider gearing over 110 gear inches is wasted and your remaining gears are stretched thinner than is optimum as a result.

+1
If the OP wants both top end to be able to stay on power, even during serious descents, and crawler gears, consider a triple instead. That's the way to go for both range and user-friendly tight spacing.

I'm getting ready to mod my mid 90's road bike from 7 to 9 speeds. Here's my shopping list, please me know if I'm going horribly wrong anywhere.

Crankset, sticking with a double but upgrading to 9 speed compatible. Thinking Stronglight 53/40 square taper. Ultegra 3X9 bar end shifters, SL-BS77 Front derailleur, thinking FD-2300 (Should work even though it 8 speed right?) Rear Derailleur, RD-3400 Sora, or RD-4500 Tiagra (is there much difference between these two?) Cassette, CS-HG50-9 speed Tiagra (11-34T)Freehub Body, Tiagra FH-4500Chain, CN-HG73 LX. I guess the one the one real concern I have is the 34 tooth cog on the Cassette. Do I need to buy a long cage rear derailleur to avoid interference with the derailleur cage? Thanks

Seems like a lot of complexity and cost to gain two gears? Worse case, have you considered selling the old completely disfunctionality bike you have now and buy a new one that fully meets your wants?

Well I was going to 9 speed primarily to get a few low gears on the rear. Lots of hill around here and thought some low gearing would make sense. But the consensus seems to be, skip the mod to 9 speed and just buy a compact crankset. Maybe that's what I'll do first and see how it rides before going further.

Thanks for the input everyone.

I had the same thought for a different reason: I want to eliminate the bar ends and install some brake lever/shifters. Not really concerned with the 7 speeds vs 8-9-10. Any thoughts from the collective wisdom?

Another option is to start with friction shift on the Dt and a 9speed wheel/cassette/chain. If you like the extra range, move it all around from there. IF you buy smart used, you'll be able to recoup most of the changeover if you don't like it.

I had the same thought for a different reason: I want to eliminate the bar ends and install some brake lever/shifters. Not really concerned with the 7 speeds vs 8-9-10. Any thoughts from the collective wisdom?
Certainly it can be done but it's an expensive change as brifters are generally the most expensive single item of any component group. Also, the rest of the components must be compatible with the brifter's indexing as there is no friction option.

Google "Kelly Take-Offs" and "Retroshift" for a look at ways to mount downtube or barend shift levers on conventional brake levers. These are both lower cost options with nearly (but not quite) the convenience of brifters.

Certainly it can be done but it's an expensive change as brifters are generally the most expensive single item of any component group. Also, the rest of the components must be compatible with the brifter's indexing as there is no friction option.

Google "Kelly Take-Offs" and "Retroshift" for a look at ways to mount downtube or barend shift levers on conventional brake levers. These are both lower cost options with nearly (but not quite) the convenience of brifters.

Wow,,, those Retroshift brake lever shifters are pretty cool.