Changing Gearing for the hills?
 

I have a 1990 Davidson Impulse with a Shimano 600 Gruppo. My chainrings are 52 and 42 and my biggest cog on the 7 speed rear cassette is 24 teeth. My goal is to get the lowest gearing that I can reasonably get to flatten out the hills of Austin,Texas for my 52 year old legs.

What combination of cassette and chainrings could I get that would function with the Shimano 600 deraileurs?

Should I change deraileurs? If so, what kind should I get? Could I find a good used set on ebay?

Could I change to a triple ring in front? Would that make a lot of difference?

changing to a tripple is a great idea for getting up hills

Being about your age and doing most of my riding in Southwest Travis County, I can appreciate your problem. There are several different ways to go, but on a bike similar to yours, I found the best fix was a compact crank. You should be able to keep everything else if you go this way.
http://www.jensonusa.com/store/produ...+Crankset.aspx
If you want to go a little more vintage in appearance, you can go this way:
http://www.jensonusa.com/store/produ...t.aspx?sc=FRGL

I recommend a visit to Sheldon Brown's website...

http://www.sheldonbrown.com/

If you just get a triple, even the very common 52/42/30, you'll have a much lower gear than you do now, 34 inches versus 47 inches. If you just get a compact 50/34, it won't be so low; you'll get 38 inches. With either one you can go a lot lower by going to a rear cassette or freewheel (forgot which one your bike uses) with a big cog in the 30 or 32 tooth range. That will get you (for the triple and compact respectively and the 32) 25 inches or 27 inches (not very different!). Depending on how hard your hills are, you might want to go even lower as you return to riding - 19 inches is a practical "lowest possible gear," needing you to come up with a 24 front and 34 rear. This is possible with some triples, but impossible with any normal compact double.

I'd suggest getting a triple that can take a granny ring as small as 26 teeth. It will give you the most flexibility. My brief recollection of Austin is that the hills are steep. You might need all that extra depth, but only you can say.

+1

If i got a triple chainring, would I have to change my front derailure? What cranksets should I consider?

I have read that the largest rear cog the 600 will support is a 28 tooth. If I got a triple should I change to 28 tooth cassette?

You can get either the triple or the 28T rear cog. If you want a seriously low bottom end, do both. The real question is how much lower you need to go. I am content with the 42/26 low or nearly-equivalent 38/23 low on my road bikes, but I know lots of folks who want something lower. If your spider will take 38T and your rear derailleur will take 28, the inexpensive change from 42/24 to 38/28 will definitely be noticeable and MAY (or may not) be enough.

Finding my Bianchi's original 52-42/13-23 gearing a bit stiff, I dropped the entire range by 10% by getting 47-38 chainrings.

This is Austin, not Boulder. While we have some fairly steep hills, they are hills, not mountains. Most hills aren't more than a mile long. You can go with a triple, but it is going to involve a lot of work. You might be able to use the old FD, but that is questionable. You will have to replace the RD. The existing one won't handle all the extra slack.
Unless you have pre-existing knee problems a 34t front and a 24t rear should get you up 95% of the hills in Austin. Going to a 28t rear will probably get you up the rest after you get your engine properly tuned.

I might have to agree with kid, in a year or two you might not need that bottom end--depends upon your riding. This year I'm experimenting with not going below 42x21--but I'm not 52 either, and I don't live in your neck of the woods. Then again, the last couple of years I used my 30T chainring quite a bit.

What about swapping the 42 for a 38 (39?), and maybe a new freewheel (cassette?) going up to 26 or so. I don't know the chain takeup, but I think you're going to swap lots of parts if you go much further. How much are you willing to change?

I also like the idea of the compact crank. Can your knees taking standing for the hills?

I'm old and decrepit, and I find 34x28 just a touch _too_ low for steep mountains.

Maybe you should borrow a bike and test some gears out on your steepest hill before you get too far into it.

Where can I get smaller replacement chainwheels for my Bio Pace crankset?

Compact cranks, get a cassette up to about 28. Cheap, easy, and works pretty well.

When your legs turn 62, think about a triple.

Such a stud! :innocent: Spoken by someone in his 40s? :rolleyes:

As a 52 year old too heavy weight, who basically has to park the bikes from December 1 to April 1, I give thanks for my triples, :love: especially at the beginning of the season.

Currently I use and abuse dear ole granny once or twice on each ride. As the season progresses I'll visit granny less often, keeping that 30 tooth in reserve for the steepest hills--- but always grateful for her presence.

And as far as the rear freewheel or cassette is concerned, the bigger the inside cog the better! :eek:

Vonfilm, listen to your legs on your hardest climbs when you are in the poorest condition or fatigued. If they say to your head, "I need more low end," then go for it--- swap the cassette or move to a triple. Remember, you are not Lance--- none of us are (even if Robbie thinks he is :p)! :)

http://i125.photobucket.com/albums/p...Drivetrain.jpg

In 130 BCD the smallest Biopace ring is 40t. 110 will get you down to 36t (I think but am not sure), but the biggest will only be 50t. As to finding them, you have to scrounge or get them off the 'Bay.

If you go to a 40-39t small ring up front and a 13-30 cassette you should be able to wind up most anything.

Can I use other makes of round 130 BCD chain rings with my 600EX crankset?

Absolutely! 130 BCD is 130 BCD regardless of who makes the chainrings.

Here's a great place to start looking. I see they have 39 tooth 130BCD chainrings.

http://www.loosescrews.com/index.cgi...id=27942125751

And some good choices on Freewheels as well.

http://www.loosescrews.com/index.cgi...id=27942125751

I'm still not sure what the OP is willing to swap out. Changing from a double to a triple is most likely going to require a rear derailleur change too; not sure about FD.

I think a compact will require a longer RD too. I have mediums and long cages on all the bikes I built. My wife's bike has a 32T freewheel, too. Once you commit to a long cage, you can go up to 34T in back with a freewheel.

It is for this reason that I find a triple just too many gears to mess with. When you need a granny, you need a granny. Otherwise I'm in 50/17 or thereabouts. All those other gears are just a waste of time and weight.

I dunno; I kinda like the granny so as to avoid a wide range cassette. Big gear jumps are fine going up a hill, or on an MTB; but on road rides I like to trim the gear inches in as fine of a step as possible.

Science is right, three chainrings is more to think about than two, but 99% of all riding is done in the middle and big rings. The granny is usually just there for the ride.

I think the OP needs to select his approach based on how good HIS legs actually are, not what a bunch of Internet guys who have never even seen him ride, make recommendations based on how strong his legs SHOULD be.

If he has to change it in a year (perhaps triple to compact), that's his call. But I think it's far worst to tell him there's no way he'll need a triple, when the fact is he might, and how would we know?

Many compact users become irritated with the large jump in effort between the two chainrings. Double shifts are very common, and I for one can get tired of it.

Believe me guys, I need the lowest gears that I can get. When I was 20 years old and 135 pounds, I never had this problem. At 52 and 230pounds, I need all the help I can get. I have lost 25 pounds in the last 2 1/2 months.

I have been perusing Ebay for triple cranksets and I see come inexpensive Campagnolo units called Mirage, Veloce, Race Triple. Are these good? Would it be very difficult to use them on my bike. I know it would involve changing a lot. I am just not sure what. It is certainly confusing.

Maybe I was a little quick and to the point on my post, but my intentions were honorable...
1-At his weight, his legs are stronger than he thinks. I'm optimistic about his abilities.
2-Going from double to triple is often more relief than a person needs, and more work to do.
3-Staying double (a compact or a ring swap) is more often than not a good remedy.
4-Cassettes/Freewheels make a big difference, especially if you've not ridden taller ones.
5-As he's losing weight, he's gaining in fitness and leg strength proportional to loaded bike weight.

My hunch is that our Texas friend, with a wider range freewheel and dropping some teeth in the front, will realize he has a little more power than he thought. I don't know if he's using clipless pedals or not, but I always advise folks to try three things before going to a triple:

a-Anticipate the hills and don't get caught playing catch-up.
a-Mentally turn hills into "pull" sessions; think about pulling up and smoothly staying the course.
b-Get clipless pedals. We can debate that, but it works for me and others.
c-get tall in the rear.
c-get shorter in the front

:innocent:


If that fails, then by all means, go to a triple. I feel it's just worth a shot at a more comprehensive approach, both in technique, equipment, and components. I've seen it work in several situations, all with riders who were on the way down from substantial biking weight, and on the way up in fitness level. Most of them can now outclimb me, any day. There is a lot of power in legs that once carried a lot more weight. Unless the terrain absolutely demands it, it's more convenient to try it step by step than go triple. You may have to, but my advice is to give your legs a chance to show you what they can do.

I'd start out with what's simplest and cheapest:
1. 39 or 38 tooth chainwheel
2. Freewheel with 28 or 30 tooth big cog - available at Harris Cyclery

You'll want the 39 or 38 tooth chainring with a triple anyway, should you eventually go with that.

I have a 39/28 combo on my old Centurion. It works well up Bouldin Ave, never tried it on something steeper like Redbud Trail. I did use a MTB triple back when I used to ride around Westlake back in the 80s.

Just tossing it out, but what about another bike, with all the gears that you wanted? Not to replace this bike, but something you don't have to mess with. I mean, if you are planning on losing 100lb (or even just 50), I think you're going to find a big change in your hill climbing performance, and you might not want to leave your bike in this changed status. [Then again, you might like it this way.] I took a quick look, and I'm not sure if FD's are the same between triples and doubles--sounds like the RD would probably need an upgrade too.

Have you priced a 40T chain ring (38?) and maybe a new freewheel (cassette?)? 12-28, or 13-28, something like that, given the RD 28T limitation. Might need/want a new chain too at the same time. I'm guessing it'd only be $100, give or take, for such changes; but obviously we're not talking about suddenly deeper gearing with this change. 42x24 is about 47 gear inches, while 40x28 is 39 gear inches, or about 17% change. That's like a couple of gears, and I don't think it'll cost that much to try out.