Update 25 March: I have changed the gearing to a new 42-32-22 chainset, coupled with a new 7-speed megarange cassette, with 11-34t.

I have decided to lower the gears on my bike. Currently using a Biopace 28-38-48 chainset with a 7-speed HG cassette, 12-28. After doing some research here, I have decided I will swap both the cassette and the chainset. Am planning to get a 7-speed 11-34 cassette, and perhaps this chainset. My question is -- is this chainset compatible with a 7-speed set-up and 7-speed chain? In the description it mentions a "super narrow HG chain" -- which I doubt I am using!

Shimano Deore M510 Chainset

Description
HOLLOWTECH crank arm construction
OCTALINK BB mount
Hyperdrive compatible : Integrated design of the SG-X chainrings, SG-X front derailleur and HG chain provides a precise shifting action.
DUAL SIS compatible
Rear Speeds 9
Chainring Combination: 44,32,22T
Spider or Gear Arm: 4arm PCD(mm)
Crank Arm Length: 170mm, 175mm
Chain: Super Narrow HG for 9-Speed
Axle Length: Chain Line 50,113

Note: I can't find a Sugino here in a 170 length, so this is the next best thing.

No. According to the description, it has 9-speed chainrings which are narrower than 7-speed, so your current chain will rub (and/or not shift) on the front gears. Or if you get a 9-speed chain, it will be too narrow to fit the rear gears.

7- and 8-speed gears are a bit thicker (.5 mm or so) than 9- or 10-speed gears. The chains are designed accordingly.

Besides most tourers say the 44-32-22 gears are too low for road touring -- just fine for mtn biking.

Did you check aebike.com ? Any QBP online store should have the Sugino cranks.

-- Mark

The crankset will work. Cranksets don't have speeds. The "nine speed" sticker is just marketing. These marketing concerns have created a great deal of confusion about compatibility. This is intentional. Shimano hopes you'll get fed up and upgrade your entire drivetrain when you don't have to.

If you're replacing your cranks and cassette, you should probably replace your chain too unless it is very new.

Now, chains. Modern derailleur chains all (with the exception of Campy's ten speed system and maybe Shimanos, which I haven't measured) have the same internal width, which is what matters for backward compatability. So, any new chain specced for use on derailleured bikes that is labeled for nine or fewer gears will work with any drivetrain with the same or fewer gears. Upward compatability is more problematic because of differences in outside width and cassette spacing.

Oh, and I have, incidentally, experimented with a chain for a ten speed Campy drivetrain on a nine-speed Shimano system. It shifted well and didn't stick to the chainrings in spite of the .25mm difference (narrower) in internal width. So maybe the above rule can be expanded to include ten speed chains as well.

All that aside, the real compatability issue is your bottom bracket. You aren't likely to have an Octalink BB of the right width on your current bike.

So, what you need is either a) properly selected chainrings and maybe a chain OR b) a new crankset, probably BB and maybe a chain.

You could always just replace your chainrings, but then you need to match the spacing and BCD.

Whether the gearing is what you want is up to you, not some yutzes in a forum.

Ooops. Then my 'knowledge' was actually echoing Shimano's hype. I gotta admit I haven't actually done the different combinations, just going by what I thought I 'knew'. I think I'll stick to 7- and 8-speed comments -- my bad.

-- Mark

I run 7-speed Shmano components on all my bikes. I am a Luddite I suppose, but they work great and last a long time. Anyway, I would first check and see what your crankset BCD is (see article on Harris Cyclery site if questions). For years, Shimano MTB were 110 BCD on the outer rings and 74 on the inner. If you have that setup, then you can get a 24t inner ring and 36 midddle. Leave the 48 outer. Then swap your 12-28 cassette to either a 13-30, or a 13-34 which will give you plenty low gearing. No need to swap your crankset unless you have an odd BCD, in which case the Sugino XD600 would work with normal square taper bottom bracket like most older bikes.

I run 13-30 cassette and 24-36-48 chainrings, which gives 21-99 GI with the aforementioned chainrings - very versatile, however I did just buy a 13-34 to get even lower gearing on the 970, for trail use. The problem with using an 11t small cog is that you get bigger splits between gears - uncomfortably big gaps at the low end. With the 13t small cog and a 34t large cog, the biggest split is from 29 to 34, 5 teeth, which isn't too bad. The 13-30 is even better, only 4 teeth split (from 26-30) but not as low overall.

Thanks mtnroads, a very good post!

The number of gears doesn't matter much in real life-- it's the number usable gears that counts

Lots of riders have newer 9X3 gearsets with a top gear of something like 11t X 52t that only guys like Lance Armstong can use, so in reality, they might as well have an older 8X3 or 7X3 system.

Try a 13-34t rear cassette-- chances are that will do the trick without messing with the cranks.

Thanks everyone for your suggestions. I just fitted a new BB, so I wasn't keen on replacing it already to accommodate the Octalink which requires a different (Octalink) BB. I also just replaced the chain. The bike shifts beautifully, particularly under load, and I am very pleased with everything except the absence of low gears.

As for replacing the chainrings on my current set up, would you believe the Biopace chainset is *riveted*? There is no swapping out of rings, or I would simply have gotten a smaller inside one to replace the 28.

I have calculated the potential gearing based on keeping the current chainset and simply changing the cassette to an 11-34. While it is an improvement, it is only marginal. In fact, it only provides one new low gear, 28 x 34 (22 g.i.), and the next lowest gear is *higher* than the current lowest gear. So, the only way to deliver a real new low end is by changing the chainset.

Thanks for that halfspeed.

So. . . a new Octalink bb is about £22. This Deore chainset is on sale for £34. A new megarange cassette is £18. So all in I am looking at an outlay of £74 or about 150 bucks. It's more than I would like to spend but a marginal price to pay for the comfort enhancements. Yesterday's hilly 40 miles through St. Patrick's country in County Down was the clincher: low gears good!

Just found a Shimano Deore M510 22/32/44 hollowtech 4 arm 9 speed tapered chainset for £56. It's more expensive than the other £34 Deore chainset but would save me buying an Octalink BB for £22.

The LX M571/2 22/32/44 is £70.

Any insights pro or con re using the Octalink with my set-up?

My inclination is to keep it simple and conserve my current (new) bb which is the square style.

Alternately, I could go mad and get the TA Zephyr chainset for £125.

Although the tech weenies will tell you otherwise, there is nothing wrong with square taper as long as the cranks are installed correctly.

Yeah, I hate any BB that isn't square taper (and not the Campy one either). Othewrise you end up with all this ISIS, Octalink 1, Octalink 2, and who knows what else systems that won't go together.

But I'm a simple guy who has enough trouble fixing bikes without adding problems like new fangled BB upgrades

As I said, you're =supposed= to be confused. I always have to double check my facts when I post on this stuff and I still get some details wrong sometimes.

The "safest" way is to always upgrade everything together from kits. Unfortunately, it's costly and you don't always get the combinations you want.

A good tool for the compulsive tinkerer is a decent dial or vernier caliper (digital for the mathematically challenged) for taking actual parts measurements. One that measures both SAE and metric is preferable for bicycle work.

I agree. A cassette change is the only change you should make at this time and see how that works out for you. My guess is, chances are, that's all you need...:)

My touring bike is a 7-speed Schwinn Transit from the mid-90's...those hybrid days. Even though I'm thinking of building up a LHT, I have alway liked this Schwinn. Sometime back the LBS swapped out the rear cassette for a 14-16-18-20-22-24-34 and kept the 28-38-48 crank rings.

Unless you are really screaming for speed, I can recommend the 14-34t cassette and suggest you keep the front cassette. Anything smaller than 14 on back could merit a crank set. The gap is a little wide going to the 34 tooth, but it is only for the worst and longest climbs, of which we have some good ones in the Texas hill country. However, if most of your touring and riding were in flatter country you might want to speed things up some.

My mindset is that I don't want to walk, ever, if I have a bike to ride. I find that when I "give up" and go to the lowest gear that I can spin my way up any hill, it just takes time. On a three day tour last month I had one 15 mile stretch of only three hills and it would take 1-2 minutes to go down, keeping the speed to about 20 mph, but take me 10-15 minutes to climb back up. This was with about 50# of gear on the bike, and I weight 220#.

All said, I'm happy with my decision to keep the crankset. If I changed it I would probably try to go to an 11-34t cassette.

Interesting suggestions about just switching the cassette. Thanks.

We have a lot of hills here, and climbing them yesterday my knee started to get sore. I don't want to hurt my knees. There were a few hills where my cadence in my lowest gear was much, much too low. I would love it if the 34 solved my problem.

With the current 28t on the cassette, I have a lower gear than I would have if I switched. I would have the new 34 in its place (for 22 g.i.), but lose the current 28 x 28 (27 g.i.) in favour of a 24 x 28 (29 g.i.)

As I mentioned above, just swapping the cassette only gives me *one* new useable gear, and replaces its sibling with a higher next gear. That's what makes me think it will take a new megarange cassette PLUS a new crankset / chainset.

But, switching the cassette is a logical start. It makes a good first step, from which I can evaluate if further improvements are needed.

I have a loaded tour coming up in Scotland and hear the area is quite hilly. I'd like to get my gear dilemma sorted before this trip so I can test it and make any adjustments in time.

LollyPop:

Perhaps I left out a little very important info, which I repeat from some of my other posts. I am 54 and have had 6 knee surgeries, including a ACL-reconstruction when I was age 48. With my low gearing, what knee pain I have is not caused by climbing in a low gear. It's caused by football in my youth, softball accidents, hopping out of a pickup bed, old age, loose joints, twisted and torn cartilage, osteoarthritis...yada yada.

Glad to hear you are still on the bike after all that knee trauma! Thanks for the suggestions.

I'd turf the biopace. I'd keep it as a wallhanger, since it is right up there with space pens and Bricklin cars. But there are plenty of good cranksets out there for reasonably low bucks that would give you a better low gear, without having to open up the spacing on your freewheel.

There comes a point when the range is good but the spacing is always so wide one rarely feels comfortable in a given gear. Anyway spinning would probably help as much as lower gears, and biopcace is supposed to be bad for that though I haven't tried it... I also find spinning helps my exploded knees.

One of the things I find with my current gearing which is 8 speed 11-30, is that when I fire off that large ring, I do a looney toones for a moment where my feet flail, and the bike slows down to a wobble seemingly going briefly into reverse. some of these systems with another four cogs of jump must be really something.

I'm thinking of giving a half step system a try since it should tighten in my gears, though I don't think I could use it on a bike I also comuted on.

Peterpan is right---its Looney Tunes for a brief moment. And, if by chance the derailer is out of adjustment and it shifts past the cog....get ready for a stop and a rollover, which happened once to me when I first put the big gear on back. I can get up any hill with the 34t ring, but note that I also refer to it as my "give-up" gear.