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6-speed, 7-speed, 8-speed, 9-speed, 10-speed?

This article is also available in French

Cassettes | Chains |Chainrings | Cranks | Derailers | Hubs | "Road" vs. "Mountain" | Shifters | Wheels

Bicycle Gears: 6-speed, 7-speed, 8-speed, 9-speed, 10-speed?

Component manufacturers like to sell you lots of new parts, even if you don't need them. This has led to much confusion as various parts are labeled as if they are incompatible with other parts even though they are actually usable with little or no problem.

The following parts only are "speed specific":  

• Indexed Shifters These need to have the correct number and spacing of detents ("clicks") to match the system they'll be used with. (Friction shifters have no compatiblity issues, they work with everything.)
• Cassettes It is really the cassette that determines how many speeds you have in back.

  Campagnolo/Shimano 8-speed cassettes have different spacing , so you can't generally get good indexing using a Campagnolo 8-speed wheel with a Shimano shift system or vice versa.

  With 7-, 9- and 10-speed systems, the sprocket spacing between brands is close enough that it rarely causes any difficulty in practice.

  For perfect matching, you might substitute different spacers or use a Jtek Shift Mate pulley adaptor.

  See my "Spacing Cribsheet " for more details on this.

•  Chain As you go to more sprockets on the cassette, you need a narrower chain. However, using a narrower chain with an older system rarely presents any problem. Thus, you can use a "9-speed" chain with a 7-speed or 8-speed system, or a "10-speed" chain with a 9-speed system. Since the chains designated for more gears are usually more expensive and don't last as long, this is not the ideal approach, but it's perfectly workable.

But What About...?

 Derailers -Rear

Within a given brand/style of rear derailer, all "speed numbers" are generally interchangeable. This applies to all indexable models, basically everything manufactured since the late 1980s. There are a few exceptions:

• Campagnolo's first attempt at indexed shifting, "Syhchro" was designed to work with their older derailers, but the cable travel was too short and cable tension too high for reliable indexing. In the early 1990s they abandoned the Sychro system and redesigned everything around a longer cable travel. I don't know the exact year of this change, but I believe it happened at the same time as the move from 7-speed to 8-speed.
• Campagnolo made a very slight change in their indexing in 2001. Supposedly you need to use 2001 or later shifters with 2001 or later rear derailers, but the difference is so small that it doesn't matter in practice.
• Shimano Dura-Ace models from 1996 and earlier (pre "9-speed") need to be used with matching shifters. See my Dura-Ace Interchangeability Page for details.
• Sram has two different derailer systems.

  Most SRAM derailers are fully interchangeable with Shimano systems.

  SRAM "ESP" derailers and shifters (generally designated by a decimal model number: 7.0, 8.0, 9.0 etc) can only be used if the shifter and rear derailer are both ESP systems. As long as you match the shifter and derailer for "ESP-ness" they're otherwise interchangeable with Shimano standards.

Derailers-Front

Front derailers don't generally care how many gears you have in back though models designated for higher numbers of speeds may have slightly narrower cages , so they might be a bit more fussy in adjustment/trim when used with wider chains.

Front derailers are generally 2- or 3-chainring specific.

• "Triple" front derailers generally work OK with double chainrings.
• "Double" front derailers will generally work with triple chainrings, but shifting from the small to the middle chainring will require some care and skill. In fact, you may need to upshift all the way to the big chainring, then jump back down to the middle.

See my Front Derailers Article and Derailer Adjustment Article for more details on this.

 Wheels/Hubs

There's considerable interchangeability amoung hubs . If you're upgrading from a system with fewer than 8 rear sprockets to one with more speeds, you may need to concern yourself with the frame spacing. See my Frame Spacing Article for details on this.

Old Style Thread-on Freewheel Systems

The threading on these older hubs is generally interchangeable except for some very old French units. If you go from a 5-speed freewheel to a 6- or 7-speed freewheel, you will usually need to add some spacers to the right end of the axle between the cone and the lock nut. Once you have done this, you'll also need to re-dish the wheel to bring the rim back to the centerline.

Campagnolo Cassette Systems

Campagnolo 8-speed cassettes used a slightly different spline pattern from the current pattern used for 9-and 10-speed systems.

8-speed Campagnolo cassettes will not fit on newer "9-speed" and "10-speed" hubs.

9- and 10-speed Campagnolo cassetts will not fit on 8-speed hubs.

It is theoretically possible to upgrade Campagnolo 8-speed hubs with newer cassette bodies, but in practice the parts don't generally seem to be available.

Shimano Freehub Cassettes Systems (and copies.)

In general, all Shimano Cassette Freehubs will work with all Shimano cassettes, any number of speeds. There are a very few exceptions:

• 7-speed hubs won't normally accept 8-, 9- or 10 speed cassettes without modification. Click here for details.
• 7-speed cassettes fit fine on 8- and 9-speed (and some 10-speed) hubs if you put a 4.5 mm spacer onto the body before the cassette. Click here for details.
• Older "Uniglide" Freehubs (including all 6-speed units) won't accept modern cassettes without modification. The last Uniglide Freehubs were made in the 1989 model year. Click here for details.

  These older hubs can usually be upgraded to work with modern Hyperglide cassettes by replacing the Freehub body. Click here for details.

• Some Freehubs are not designed to accommodate cassettes that include an 11 tooth sprocket. Click here for details.
• 2005 Dura-Ace hubs with aluminum Freehub bodies won't work with anything but 10-speed cassettes. Click here for details.
• Capreo hubs and cassettes only work together. Click here for details.

Chainrings/Cranks

Old Chainrings, New Chains There is a lot of confusion about the compatibility of narrow 9- and 10-speed chains with older cranksets. Shimano says you should replace the inner chainring(s) with specially designated 9- or 10-speed ones, but then they're all too eager to sell you stuff, whether you need it or not.

These chainrings have the teeth slightly farther to the right than the older chainrings to work a little better with the narrower chains. There is no difference whatever in the crank spiders.

The manufacturers also concerned about clueless users. The worst-case scenario is that you will be riding along with the bike in its highest gear (large front, small rear) and then for some bizarre reason shift down in front before downshifting in the back. (There is no shift pattern in which it is reasonable to shift in this sequence.) If you do shift this way, there's a small chance that the chain might "skate" over the edges of the teeth for maybe half a turn.

In practice this "problem" almost never materializes. Many, many cyclists are using 9- and 10-speed chains with older cranksets and having no problems whatever.

>New Chainrings, Old Chains

Going the other direction, using wider chains with chainrings intended for narrower chains is not generally a major problem if there's only a one or two generation difference. The only problem you might run into is that the chain will be more liable to rub on the inside of the bigger cbainrings in the small/small crossover gears, gears you shouldn't be using in any case.

"Road" vs. "Mountain" Cassettes, Derailers and Hubs

When discussing cassettes, the terms "Road" and "Mountain" are marketing terms, not technical ones.

• "Road vs Mountain Cassettes

  Cassettes come in various gear ranges, and the ones where the sizes are close together, with no really large sprockets are commonly referred to in marketing-speak as "road" cassettes. Wide range cassettes, with larger sprockets are commonly called "mountain" or "MTB" cassettes.

• "Road" vs "Mountain" Rear Derailers

  Similarly, derailers come in long, medium and short cage versions. Shimano designates them: SGS (long), GS (medium), and SS (short.) The short cage ("road") ones only work with narrow range ("road") cassettes, because they don't have enough capacity to take up chain slack for use with a wide range cassette. Short and medium cage derailers are also limited in terms of the largest rear sprocket that they can clear without having the jockey pulley rub on the sprocket. Generally, SS & GS rear derailers won't work properly with rear sprockets larger than 30 teeth.

  Long-cage (SGS) derailers have greater takeup capacity, and work with all types of cassettes. Long-cage derailers are commonly called "mountain" derailers currently, though in the past, this style of derailer was known as a "touring" derailer. (The marketeers retired the use of "touring" as a buzzword in the late '80s when mountain bikes became the hot item.)

• "Road" vs "Mountain" Front Derailers

  While rear indexing is the same for all recent shifters/derailers, Shimano fronts use a different amount of cable pull for drop bar vs straight bar controls.

  An additional complication is that "road" front derailer cages are shaped to fit well with a 52-53 tooth big chainring, while most current "mountain" front cages are shaped to fit witha 42-44 tooth big ring.

  This makes it difficult if you want to use a "road" crankset, with full-sized chainrings (52, 53 top) with straight handlebars, or if you want to use a "mountain" crankset (42-48 tooth top) with drop-bar STI shifters.

• "Road" vs "Mountain" Hubs

  There is no interchangeability issue between "Road" vs "Mountain" cassettes and hubs as long as the number of sprockets matches.

  Although "Road" and "Mountain" hubs are no different as far as cassette fitting is concerned, they are different in terms of overall spacing. "Road" hubs generally use 130 mm spacing, while "mountain" hubs are 135 mm.

  "Mountain" hubs will likely be slightly better sealed against dirt and mud than "road" hubs, but this is rarely an issue in practice. The wider 135 mm spacing will generally result in a slightly stronger wheel due to reduced dishing of the spokes.

	Center-to-center Spacing	Sprocket Thickness	Spacer Thickness	Total Width
"Regular" 5-/6-speed	5.3 mm	1.85 mm	3.5 mm
Sun Tour "Ultra" 6-speed	5.0 mm	1.85 mm	3.15 mm
Sun Tour "Accushift" 6-speed	5.5 mm	2.0 mm	3.5 mm	30 mm
Shimano HG 7-speed	5.0 mm	1.85 mm	3.15 mm
Shimano IG 7-speed	5.0 mm	2.35 mm	2.65 mm
SRAM Freewheel 7-speed	5.0 mm	1.8 mm	3.2 mm
Sun Tour 7-speed	4.8/5.0 mm	2.0 mm	3 x 2.8 mm(L) 3 x 3.0 mm(H)	31.5 mm
Campagnolo 8-speed	5.0 mm	1.9 mm	3.1 mm
Sachs 7-speed & 1997 8-speed	5.0 mm	1.8 mm	3.2 mm
Sachs 1998+ 8-speed	4.8 mm	1.8 mm	3.0 mm
Shimano 8-speed	4.8 mm	1.8 mm	3.0 mm
SRAM Cassette 8-speed	4.8 mm	1.8 mm	3.0 mm
SRAM Freewheel 8-speed	5.0 mm	1.8 mm	3.2 mm
Sun Tour 8-speed	4.8/5.0 mm	2.0 mm	3 x 2.8 mm(L) 4 x 3.0 mm(H)	36.5 mm
Campagnolo 9-speed	4.55 mm	1.75 mm	2.8 mm
Shimano 9-speed	4.34 mm	1.78 mm	2.56 mm
SRAM 9-speed	4.34 mm	1.8 mm	2.54 mm
Campagnolo 10-speed	4.12 mm	1.7 mm	2.42 mm
Shimano 10-speed	3.95 mm	1.6 mm	2.35 mm

See also my article on Derailer Adjustment on this site.

Britain's Cyclists' Touring Club Website has a good article on derailer gearing.

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