Best freewheel option to lower gearing?
 

Hi folks!
I just picked up an 86 cannondale SR 600 road bike, some of you probably read about it already as I was showing it off in C&V. Anyway, it's a sweet bike but it's geared a little high for my wimpy legs riding in the Colorado front range (I never new my legs were so wimpy until I got this bike). The bike currently has 42t and 52t chain rings has a 6 speed Suntour freewheel with the largest cog having 24t. I have already ordered a 39t chain ring to replace the 42t which should help but I figure I might as well get a different free wheel on order as well. So what would my best option's be as far as free wheel replacement (make, model, cogs sizes, online vender etc)? Also what about a 7 speed free wheel, how would that work out (the frame is aluminum)? My goal is to lower the gearing so that I can ride long distances comfortably in the hills, without sacrificing shifting or riding performance. BTW, the derailleurs are Suntour sprint, the current cranks and chain rings are Suntour Superbe Pro, and it's all friction shifting. Thanks in advance for any input.

The Sprint technically has a max cog size of 26T -- you may be able to push that and run a 14-28 Shimano freewheel ($15). 6-speed would mean no goofing with the frame, so that would get my vote. (The 7-speed version of that freewheel adds a pointless gear in the middle for a 20-22-24 stretch.)

Also seconding the 14-28. Much less fuss than the 14-34 which needs MTB derailers and has a huge jump. I don't particularly have an opinion about 6 vs 7 speed, but the 6 is 14, 16, 18, 21, 24, 28. The 7 is 14, 16, 18, 20, 22, 24, 28. The 39t will help, but it may not shift well without a ramped and paired 53t chainring, although people have done crazier jumps with half-step and granny setups.

for 7-speed I like the SunRace 13-28. the progression of cogs is much better than the Shimano 14-28.

Thanks for the replies, I guess I'll just wait for the 39 tooth chain ring to arrive and see how much difference that makes, then I'll probably end up trying one of the shimano 14-28t freewheels if (when) it's still not geared low enough. I hate to start messing with things on this bike as the original components are so nice but I don't have much choice if I want to actually ride it.

You are missing the point of the "Mega Range" freewheels, especially when it comes to a traditional double and mountain climbing. The large jump is a bailout gear for a non-optimal gear selection. Going from the 24 tooth gear to the 34 is a large(ish) step, but it can be the difference between making it up a climb while pedaling vs walking the climb. Having a low gear that you can bailout to can be more important than having a smooth range, especially if the range is limited.

As for the crank, lots of us have used unpinned and ramped chainrings for a very long time. We managed to make shifts just fine.

"86 Cannondale" That says friction shifting to me. It means you don't have to worry about fancy chainrings or which rear derailleur will work.

If it was my bike, and I was looking for a serious hill climb gear, I'd go for the "Mega range" freewheel and a different rear derailleur. Since you want to keep it (sort of) original, I'd look for a Suntour Cyclone long arm rear derailleur if I could find one or even a classic VGT. Otherwise a basic Shimano mountain bike derailleur will function just fine. Messing around with a 28 biggest cog vs. a 24 biggest cog is only a baby step. It might give you the range that you're looking for but I doubt it.

Being an un-racer, I've developed my own philosophy about gearing. When I'm on a basically flat surface I like to have lots of gears spaced closely together so that I can make minute adjustments for wind conditions or small inclines. Once I get into the hills I want big gaps so that I can feel the difference when I shift. I don't want to have to shift too often either because every shift causes me to lose momentum. There must be a reason why the mega range freewheels and cassettes have been as popular as they are for such a long time. It might be because there are lots of folks like me.

I agree with the folks recommending a Shimano Mega-Range freewheel. You will need a new rear derailleur to handle the 34-tooth large cog and the additional chain wrap, if you want to keep the vintage look you could pick up a vintage Shimano Deore on Ebay.

Going from 42 to 39 is a pretty small change (7%). You will probably still want a larger freewheel.

I agree which is why I just bought a 14-28t freewheel from my LBS. I paid a few dollars extra rather than buying online, but that's ok, they also were kind enough to remove the Suntour freewheel for free.

Now hopefully my gearing will be low enough to manage the hills

I don't think I'm missing the point. I'm saying that a Megarange freewheel will need a new rear derailer, and possibly a longer chain. It is a lot more hassle than a 14-28. The point about the big jump is because you don't gain more low gears. You gain one very low gear at the expense of another low gear. If 14-34 were spaced 14, 16, 18, 21, 24, 28, 34 it would be a lot more useful.

As for the crank, the shift quality is considerably worse with the bigger jump without ramps and pins or properly timed teeth. It works fine with 52/42, but mismatched chainrings need to be eased into the shift and often require more overshifting. I never said you can't do it. I said the shift quality is degraded.

You may need a longer chain so that your bike can handle being in the 52 x 28. If it's too short, nasty things can happen.

It's always a good idea to involve the local shop.

Brad

hmmm.... thanks, hadn't thought about that. I don't plan on ever being in that gear combination but there is good chance it might happen unintentionally (less chance now that I'm aware of it).
I'll look into the issue. I am going to do some research, but is there a quick and easy way to find out if I need a longer chain?


thanks all for your thoughts

If you don't have a workstand hang your bike by it's saddle so the rear wheel is in the air. While turning the crank with your hand, gently try to shift into the big/big. If it won't go, you need a longer chain.

If it was my bike, I'd skip the test. To me, new freewheel = fresh chain. Then I size the new chain using the big/big method.

Thanks, the derailleur doesn't seem overly stressed at all in big/big gears (looked at sheldon brown and a couple other sites). I'll just keep the original chain, the beauty of this bike is that it has essentially never been ridden, so the chain is like brand new. The original owner told me he only rode it once, it's seems to be true as the braking surface on the rims along with everything else looks unused. He probably didn't ride it because he lives in some hills and the bike is geared so high, he said he liked riding his mountain bike better.

Have you considered getting a 9 or 10 speed wheel? Really. As long as you have 126 spacing you can squeeze in a 130 spaced wheel in it. (I just checked your post, Cannondale is probably the most difficult from that era). Anyway, if it is possible, you'll find that shifting is much smoother, quieter, easier and once shifted doesn't rattle between gears. 10 speed wheels are typically lighter too. You'll need a 10 speed chain too, but the front chainrings should be OK. As long as you have friction shifters the derailleurs don't matter, any one will work.

Modern cassettes are as important as the brifters in current setups. It is the ramps on the cassette and the chains that ride them that make the shifts so easy. Without them indexing would work but would never be smooth.

Just keep your old wheels for show if you want to keep the bike original. I have 2 bikes like this now and have converted two others. Both of mine are from 1981. I still have all the original parts, but one I've really just semi modernized, while the other is all original Campy SR pantograph Italian steel, except the 9 speed chain. The old wheels are still in my basement right next to the bike, with the modern Campy Vento 10 speed wheels.

Prying open a stiff alloy frame like a C'dale is nothing I want to do with every Puncture repair..

I'm ok with freewheels on a condition reliability..
I toured Europe several trips 13~34t freewheels . (50,40,24t crank )

built up a set of wheels , rear one an old Phil Wood Hub

since the axles are so strong It was a trouble free wheel ,

not something I would expect from a typical 10X1 threaded QR axle hub .

I'm not sure where you live but, as you can see, I live where turkey lurkey lives, i.e. the Colorado Front Range. I've lived here for about 45 years and, more importantly, I've ridden here for 35+ years. I know a little about the terrain and the altitude. Out on the flats, a 28 might work well enough but once you get up here, a 34 tooth low, especially when tied to a 39 tooth chainring makes the difference between riding up a hill and walking it.

On the other hand, having a big jump to a gear that you won't be using that often isn't all that bad. I used to ride a very similar gear selection back in the 80s and 90s. Mine was a 5 speed, however. You had a close gear range for most flat riding and then a bailout for climbing. I even toured on the same freewheel.

Your gear ratios do make a bit more sense but finding one can be a problem. Freewheel selection is somewhat limited. You kind of have to take what you can get.

I'd say slightly worse. A 52/40 shifts just fine without ramps and pins. I ran them on all kinds of bikes for many, many years. A 52/39 isn't significantly different.

There are a lot of factors that go into gear selection, and there are other things I would do before getting a megarange. I regularly have to cycle up 15-20% grades measured with an inclinometer. I find the megarange jump wholly unpleasant, and there are times I feel that the 34t would make you more tired at the top than the 28t. Bailing out into 34t mid climb is also not a great experience. The 24-34 gap is large enough that you can't really train to get stronger by trying to stay in a higher gear for longer, since you're 2 gears up. I've done my share of experimenting to climb better. If the grades are that bad, and the legs that weak, I would more readily buy a cheap 42/32/22 MTB triple and a Tourney derailer set or rip them off a cheap MTB/hybrid, and still pair that with the 14-28. The gears are reasonably spaced since it is missing the 11-12-13 cogs found on higher speed cassettes.

Ask me why I wouldn't just ride the MTB, that that's because cheap suspension and knobby tires rob two gears from you, and make you even more tired by the top since you have to put out the same power for longer.

I don't know if you're trying to be silly by implying that 39x28 is a gear for the flats. It is my opinion that the megarange freewheel is a bad solution, and only exists to share tooling with the nicer and more sensible 14-28 freewheel. If I have to change the entire rear end of the drive train to fit the megarange, I would rather replace the entire drivetrain just to avoid the megarange and end up with a superior range of gears. Slapping a megarange on a bike to me is a half-baked bodge job and a band-aid fix. I would only consider it if there was nothing else you had to change out.

I'm just going to have to disagree with you on the chainrings. I don't like how it shifts. I never said you can't do it, I just said it degrades the quality, and I can't say I like it.

Using Sheldon Brown's GI calculator to compare bottom gear:

39 42
41.0 44.2 (25T)
36.6 39.4 (28T)
30.1 32.5 (34T)

The OP will determine if the 39T/28T is satisfactory. The ~32% decrease in GIs using the 39T/34T from his OEM 42T/25T is hard to ignore tho'. The 34T will require a mountain bike RD and a new chain (longer) and will be about as good as it can be. My sister has a mega range cassette and while I find the upshift from the 34T quite abrupt, it's a good bail out gear.

Brad

My back yard, base elevation about 6000ft:
http://www.mycoloradolife.com/Pictur...do-Springs.jpg

Again, I have no idea where you are riding so it's hard to compare. Let's start with the fact that Colorado doesn't do 15 to 20% grades much. We have to deal with snow and ice on a regular basis and a grade that steep isn't a grade so much as a bobsled run. I've ridden in the east a fair amount so I'm familiar with steep grades and I wouldn't want to tackle any of them in a 39/28 gear.

In Colorado, the other thing that we are dealing with that most of the rest of the country isn't is altitude. Colorado's lowest altitude...3317 feet...is higher than most of the rest of the country's highest altitudes. Our mean elevation is 6800 feet. While I can climb those 15 to 20% grades in other parts of the US, a climb like that at our altitude is much, much, much more difficult. We just don't have the air pressure for it.

A 39/28 is a good all around low for areas that are flatter and lower altitude but not the Colorado Rockies...not if you want to have knees when you are old. I agree that I would change the drivetrain on turkey lurkey's bike. I go to at least an 8 speed rear cassette in an 11-34 range. I'd probably go to a triple as well. That would require a new wheel, new cassette, chain and derailers and would get pricey real quick. But that's not what he is asking for.




That's Pike's Peak, by the way. From the middle of Colorado Springs to the top of the mountain is an 8000 foot elevation gain in 11 miles...as the crow flies. And if you are going to find any 15% grades in Colorado, Colorado Springs would be a good place to go looking.

Yes Pike's Peak! Though I am not trying to imply that I am riding up Pikes Peak all the time, I haven't yet. I do plan to this summer but there is a good chance I will ride my low geared hybrid bike. I do however live at the base of the front range mountains in front of Pikes Peak and ride all over those hills regularly, and anytime I ride into the springs (everyday) I have a good 1 - 2 mile (depending on route) climb to get to my house. Crescent Cycle may very well be a strong climber, good for him. I will give the 39/28 gearing a try for awhile and if its not low enough or if I decide to do some centuries or something with the bike I can always make more drastic modifications later. That gearing is close to some of the sport/touring bikes I've had from the 80's and I have managed with them, but anything beyond 25 miles or so in the hills and I start getting pretty tired and start to wish I had lower gearing.

BTW: Beautiful weather we've been having here in the Springs, I'm sure it has been nice in Denver as well!

Lower gearing = more teeth in the back and less teeth on the chainring.


With a lot of chain-slack to control and take up .. you need a long cage RD.