Changing gear ratios
 

Hello,


I'm looking for input and advice.


I have an older Cannondale R600. I've had it 20 years and it was at least 2 years old when I bought it. I am 57 years old and 6' 4" (193 CM). The bike frame is 63 CM.


The bike's gearing is fine for flats but when I hit hills, especially now that I'm getting older, I struggle, even in the lowest gear. The bike is geared as follows:

• Crank length is 175. Gears are 53/39.
  
• Cassette is 8 gears 23/13.
  

My local bike shop said the crank, chain and cassette should all be changed together due to wear but the price just isn't worth it on a bike this old. They said if I could find a used square taper compact crank which would be geared 50/34, that would help. I may just buy a new bike but hate to abandon this one as it has served me well. Looking online I see cranks and cassettes are not that expensive. However I see the cassette sizes are quite different than mine, 11/28, 11/30, 11/32 for example.


What would be the best approach to gearing this bike down without spending a lot of money? There is a local bike shop that helps you do the work yourself for a small fee so I'm thinking of going that route. Could I just go to a cassette that has more teeth than mine and be done? Change the crank as my bike shop recommended? Both?


Thank you in advance.


Steve

Excellent post. I understand how it can be hard to find a bike that works for you at 6' 4" tall. See what others say, but my hunch would be to replace the rear cassette and resize chain only. May potentially require a new rear derailleur due to different size gears.

E-bike is always an option for getting up hills as well.

The compact crankset is a good idea. It will not require any other parts except possibly a different bottom bracket cartridge, and for work, just a shortening of the chain and slight dropping of the front derailler. It will help quite a bit.

The problem with a bigger cassette is that your rear derailler may not be able to handle it. My guess from the original gearing is that it is a short cage derailler and the hanger on the dropout is short, too. Once you have to change the rear derailler, things can cascade expensively from there.

More radically, a 46/30 chainset should sort you for at least a decade. The cheap way to do that is to find a decent used 110/74mm BCD triple chainset and run middle and inner rings only. Again, no other changes except a shorter chain and repositioning of the front derailler. Specialties TA (Peter White Cycles in US, Spa Cycles in UK) makes every chainring you could ever want for 110/74 cranks. Or, look at the offerings of Rivendell Bikes if you want a tidy solution.

oldschoolbike

Your current low gear ration is 1.7:1. Most likely, your rear derailleur will handle a 13/28 cassette with no problem. That gives you a low of 1.4:1. I don't know what the hills in your neighborhood are like, but if you have long or steep, you're probably looking for something lower. Consider this phase one.

The least expensive phase 2 would be to purchase a compact crankset with 50/34t chainrings. You might need a new bottom bracket, too, but this is no big deal. This would allow you to use your current shifters, derailleurs and cassettes. The smaller chainrings would give you a low of 1.2:1. Unless your doing 1500 ft. climbs, this might be sufficient. Shimano Claris would fit the bill.

Phase 3 would involve shifters, crankset, cassette, and derailleurs, either a 2x10 compact double or 3x10 triple. Compact double would give you 50/34 up front and 11/34 in back, for a final low ratio of 1:1, a little more on the top end, and some closer steps in the middle. I recommend Tiagra 4700. the triple setup would give you 50/39/30 up front and 11/32 in back for a final low ratio of 0.9:1. I'd choose Tiagra 4703 for this.

I chose 10-speed cassettes because 11 or more would require a new rear wheel, upgrading to 9 wouldn't be worth the bother, and Shimano Tiagra 4700/4703 is really slick stuff. I guess you could also go Claris 3x8, but you're still going to need at least a new front lever and derailleur. I wouldn't bother. And if you're replacing the cassette, a new chain goes without saying.

IMO road chainrings last something short of forever, ie. 50,000+ miles. While it's bedtime to replace chains and cassettes together, it's not always necessary. SOP is to replace a chain but keep a cassette, only replacing that after a few chains. And nobody ever feels the need to replace chainrings when replacing the chain.

IMO the shop may be (I haven't seen the bike). It's likely that simply changing the cassette and (maybe) the chain will do the trick.

Just make sure the RD has enough capacity. If that's not enough, I'd consider a triple crank vs. compact double, but gear selection is highly personal, so take your time before changing anything past the cassette.

It's easy to get sucked into spending more than you plan on. It's like swallowing a fly. Before buying a bunch of new stuff, consider looking for a used bike set up the way you need and swapping stuff over.

IF a 13-23 was the factory cassette, I'm pretty sure you have a short cage RDER and it won't handle a larger cassette.

Cheap route- Get a low level Shimano RDER such as this-
https://www.amazon.com/Shimano-Acera...LwhvD_BwE&th=1
And a cassette with a 34T largest cog.
You most likely will have to lengthen the chain, so it may be easier to just get a new one and shorten to fit if needed.

A 9 speed offers more options, but would also require a 9 speed shifter (s?) and chain.
That's often a good option if you HAVE to replace the R. shifter.

EDIT-
IF this is your bike, you should be good up to a 28T cog.
https://www.bikepedia.com/Quickbike/...%20&model=R600

There are a few different ways to get what you want, some of which have already been mentioned.

If it were me, and assuming I really liked the frame and am willing to invest to make it work, I would do either of the following:
1. New groupset altogether - look for used 10 speed - with a 34x32 climbing gear. It's a big investment but it'll make the bike slightly more modern.
1.b. Ok if I'm on a budget, then go with what others said, which is to get a 50/34 crankset (with BB if needed), a 32t cassette, and a longer cage rear derailleur to accommodate the 32t cassette. You will also need a new chain. Everything should come to under $200 from the used and AliExpress market.
2. New groupset altogether but make it a 1x flatbar bike. You'll need new stem and bar, rear shifter, rear derailleur, and cassette (and new chain). You can keep the current crank and use the existing middle ring. You save the crank cost but spend on a new shifter. Should also come out to under $200 if sourcing parts from AliExpress.

What 8 speed derailleur EVER was limited to a 23t low cogs?


@siearly If your chainrings are in reasonable shape and you don't want to spend a lot of money, a cassette that goes to 28t might be enough. However, there are no Shimano/SRAM compatible 13-28 cassettes. You would go with 11-28, or use some of your old cogs to make a custom cassette.

For a few dollars more, you can just replace your rear derailleur with a long cage mountain type, keep the crank you have and go up to a 32 or even 34t cassette. Derailleurs are pretty inexpensive.

There are new hollow spindle 2-piece cranks (sort of like Hollowtech II), crank with rings, and external bottom bracket bearings, for the price of just a couple chainrings, $65 with steel rings and I think $5-8 more for aluminum rings. This has been a great upgrade from square taper spindle BBs, especially for road; Some MTBers prefer internal cartridge BB, as the seals are further away from the crank arms, so no grinding of dirt between the two, as with external bearings they are right up against the crank arms. My favorite has been out on amazon for a long time, still on ebay, it's 50/34 on 5x110mm BCD. If you need lower than 34, you'll need a 110/74 BCD triple and I have not seen them aftermarket with hollow spindle at the deal I got, but they may be out there; I wanted a 5-arm spider just for aesthetics, 4-arm spiders are much more common now. 170mm is typical, not all are available with longer arms.

Also, the quality of cheap derailleurs has improved a ton in 25 years, you can probably get a decent one for $25. With your wheel size, you have tons of room for a long cage. I use a mid-length GS cage because I'm on 20" wheels and a long cage would drag on the ground. You can get by with a GS, I think you'd only need a long cage for a full triple range, and/or a megarange cassette for lower lows.

I'm old, and sometimes run out of gas climbing hills while standing, so need a 21 gear inch low to crank my way up sitting. To also have sufficient high of 85 gear inches, I need 400% gear range. You might want a higher high typical of road race bikes.

You have an 8-speed. More means changing the brifters. Perhaps the wheel if you cannot find a compatible cassette. But if you find that 110/74 BCD crankset, you now have a lot of options, for both now and the distant future. (As a 71 year old, I have witnessed many gear lowering since I was your age.) You will be able to find chainrings for that crankset for a long time. Many, many bikes were built using it. With different bottom bracket spindle lengths, itis incredibly versitile.

A plan that starts cheap and never gets too far out of hand would be to get that 110/74 BCD crankset (there are a lot of used ones out there) and a 28 tooth cassette with whatever small cog you can get. Now the fun starts. Go to an online gear calculator. (There are threads on BF with lots of info on the best, easiest ones.) If your present high gear is good, then an 11 or 12 tooth small ring can be used with a smaller large chainring to get the same high gear. (ii tooth, you'd be looking for a 47 tooth large chainring. Going to a much bigger big cog means the cassette spacing will get much bigger and you will find that your favorite flat ground gears aren't there anymore and the jumps are much bigger. So, play with that calculator, looking for large and small chainrings that give you the low and high gears you want with that cassette - and have as little duplicate gears as possible. You may well find you can get most of those favorites with slightly odd shifting pattern and still have a high gear that suits your needs and a low gear that works for your legs.

And in time, that low gear will no longer be cutting the mustard, so to speak. Brace yourself. Now triple time is coming. You'll need a new bottom bracket, probably derailleur, perhaps a new front shifter (a good, not very expensive option is to keep your brifters and just add a bar-con front shifter. But you already have the crankset, the building block.

Now, that second step is a place where there is room to save bucks. You will know long in advance it is coming. So when that sweet derailleur shows up at a decent price you can grab it. And so on. When you don't need it tomorrow, bargains happen.

My circa 1989 cannondale racer, I think also a 600, when I swapped in a triple crank after 15 years, the double front derailleur worked fine on the triple.

Are you proposing replacing all the components on hisbike except for your brake calipers to accommodate a triple crank?

For now, the triple crank with two chainrings. A new cassette and same derailleurs. Years from now and many miles later, yes, the triple. (Maybe he can master the art of not aging. My advice is for a plan based on my experience.)

A good plan. But taking off the big ring means he'd need shorter chainring bolts, maybe just spacer washers. I think he should just buy a decent triple and leave it intact, using just the smaller two rings if that's all he needs. Think of it as a stylish chainguard.

I’m your height and age and I’ve been riding triple chainrings since my twenties. Kudos to you!

That said, do you have a bike co-op near you that sells used parts? Or maybe an ex-mechanic (like me) who modifies bikes for the simple joy of swapping parts? Either way would lower the cost of modifying your bike.

I've been upgrading two vintage bikes this one. One is a new to us Santana Tandem and the other is a Gary Fisher MTB.

In both cases I have changed the drivetrain.

My experience has been that changing the crankset or the FD results in huge difficulty finding a combination of crankset, FD and shift lever thy work properly. The upgrades to the rear are easy, even if they require changing the cage on the RD or buying a new RD. You will be able to find a combination that works.

Your lowest gear is a 39-23 which is about a 1.7 ratio. I'm a little older than you and find I need a 1:1 ratio, but like a 0.75 ratio. A 41 largest tooth cassette would give you a 1:1 ratio and fit right on.

Shimano Deore Derailleurs are in the $35- 75 range on Amazon. 8-Speed 11-42 Cassettes are in the $45 range.

Wow, lots of good information. I have a lot to think about. I appreciate knowing all the options. I do have a local bike coop that will help me work on the bike and sell me used parts, they just didn't have the crankset. Thank you to everyone who responded.

Yes, that is my bike! Nice to know all the equipment/specs.

Suggest you consider a new Tiagra level crankset and bottom bracket, same arm size, now on sale for around $105 at Performance Bike: Shimano Tiagra R460 Crankset (Black) (2 x 10 Speed) (Hollowtech II) (175mm) (48/34T) - Performance Bicycle (performancebike.com)
That will make a significant difference.
However, while changing the crank, you might as well go further and replace the cassette and chain. SRAM makes a fine cassette in 12/28 (note that your freehub may not accept an 11 tooth small cog as your bike was produced during a period when not many bikes used them) and while Performance sells them for $78, you might be able to find a better price elsewhere: SRAM PG-1050 Cassette (Silver) (10 Speed) (Shimano HG) (11-32T) - Performance Bicycle (performancebike.com)

SRAM also makes my preferred chain, which Performance has for $7.50: SRAM PC-830 Chain (Silver) (6-8 Speed) (114 Links) - Performance Bicycle (performancebike.com)

The RD on your bike can absolutely handle a 28 tooth large cog. So, using this example, for around $200 you can keep the bike that fits you so well AND have the gearing you need. It's the same gearing I use on many of my own bikes (and I'm 72). I'm only using these examples from Performance because they were easy to find.

Questions? Just keep asking. Lots of good advice here.

That 13-23 tooth count suggests to me that you may have a freewheel, not a cassette.

Because of all those 8 speed freewheels Cannondale used?

It's a cassette.

I'd start by replacing your 13/23 cassette with a SHIMANO CS-HG200 8 speed 12-32 cassette (or something similar), a new chain and a proper size derailleur. This doesn't have to be an expensive change, and alone will reduce pedaling effort by 28% giving you an extra 2 - 3 lower gears.

if its the original chain rings, then it might be a good idea to do them too. A popular road bike double like a 50/34 might do the trick. Reducing pedaling effort by another 13% and insuring you drivetrain is up to spec. Aside from a new derailleur, which isn't expensive this is just normal maintenance.

You can't put 50x34 chainrings on a 130BCD crank.

Perhaps there is something close, or lower that will work If the crankset is good. The point being using an worn out chain ring with a new chain and cassette isn't a good idea. Even the same size new ones might be fine with a 32T large rear sprocket.

The bike has a RX100 crank according to the specifications page linked above. 130/74mm bolt pattern so the smallest chainring is 39 teeth. (38 teeth if you want to hunt one down.)