I've noticed a recurring theme in a bunch of the "what bike" type threads, and that is 8 speeds in back are acceptable, 9 is preferable- but avoid 7. Why is that?

More gears gives more versatility of matching your cadence to your actual conditions.

MOST current 7 speeds have a Free Wheel system instead of a Free Hub, which is MUCH better.

https://sheldonbrown.com/free-k7.html

The only decent 7-speed bikes had cassettes, not freewheels... and 7-speed cassettes are extremely rare nowdays. Having owned both (my current bike is 7sp cassette) I can say that freewheels bikes are not up to serious miles, I've bent several axles and broken numerous freewheels, and I'm not a big guy.

7-speed cassettes, however, work great if you can find them.

For the actual speeds, if you have a triple in front, then 7 in back is fine. If you only have 1 or 2 rings in front, then 9-10 in back makes more sense. I'm fine with 3x7.

So Freehubs now trump Freewheels, eh? The cadence thing I figured for those who are into fitness or competition wanting to maintain a targeted HR. But what about people who just want to get around without turning into a Cat 6 racer?

So essentially something like the Brodie Bolt is using modern technology, albeit bottom of the barrel, no?

Makes sense. I've noticed quite a few of the fitness orientated hybrids being upgraded from 7 to 8 speeds over the last couple of years.

As far as I know, Shimano doesn't make any new 7sp cassette hubs now. When they quit making them, then they're obsolete, if you get my meaning. I've actually thought about putting 7sp freehub bodies on newer Sora/Tiagra/105 hubs, and re-spacing the axle to give you a more centered wheel. Yes, it's possible, but at some point, they're probably going to stop selling parts for them.

Really, I should just switch to 9-speeds, but I just can't bring myself to do it. I can still get 12-32 cassettes.

I've got this new seven speed bike and it works just fine!

I doubt 7 speed cassettes are going to go away anytime soon!

https://www.trekbikes.com/us/en/bikes...tion/pure/pure

Has a Shimano TZ31 14-34 7 speed cassette!

Wanna bet?
https://techdocs.shimano.com/techdocs...&bmUID=jh66uac

MF is Multiple Freewheel.

Not necessarily.
I have emphysema.
I use 12-21 & 12-23 9 speeds on my two bikes.
It allows me to "fine tune" the maximum effort I can sustain without going into oxygen debt, while being able to go up or down a tooth or 2 as head/tail wind changes.
Wider spaced gears means I'm often in a gear that isn't quite right.
I don't have a car, so I simply have to be as efficient as I can on the bike.
Every little bit adds up, like tires aired to the max, crank length that works best for me, regular maintenance to make sure the wheels/crank spin as freely as possible etc.....

My new bike is 1x7 - on purpose because I think the 11-28 cassette is plenty of range. It's actually an 8-speed freehub with only seven cogs however, and 8 gears would be better than 7.

Huh? You have 7 on purpose but 8 is better?
You somewhat contradict yourself.

Many people are content with ONE speed. To each their own!

Once you go SS....

7 speeds ftw

The choices were 7,14,21. The point being, in answer to no1mad, "people who just want to get around without turning into a Cat 6 racer" can do it on seven gears without giving up that much.

But I'm just talking about 7 gears, not a 7-speed freewheel, which are two different subjects. Regarding the freewheel there may be issues with spacing, the size of the cluster, which relates to dropout width and it's lateral position in the wheel. If you start with just the 8-speed hub (even with 7 or fewer gears) those issues won't exist. I suspect that's why people say to avoid the 7-speed bikes - they might not be very compatible with most of the standard frames, wheels, clusters etc out there.

Maximum efficiency/cadence for the most part - big gaps in gear inches staggered between the biggest and smallest cog unless it's a racing cassette/freewheel. In addition to my 9 and 10 spd cassettes, I have a few bikes with 5,6,7 freewheels; no big deal. Just ride, don't worry about such nonsense.

Just found a batch of Shimano FH-RM40-7 hubs on ebay... hmmmm. They're Altus level and have loose bearings, but heck, they work fine. Might have to pick some up to future-proof my bike.

It is just technology. Model T's were two speed, new cars are six with overdrive.

You get more out with less in. Matches up the motor with the chassis.

I have two bikes, one is 7/3 the other is 8/3, both cassettes. The big
difference is the 8 has an 11t and the 7 a 13t. the chaining and the
large cassette cog are the same on both bikes. The 7 sp bike has
slightly smaller tires and runs in one gear higher most of the time in
the same situation. It is also a bit lighter, couple pounds.

7-speed cassettes are "extremely rare" now? Harris still sells 8 or so configurations (from Shimano), and several other brands make knockoffs.

I am in the process of hoarding 7-speed cassettes, because I think they're great.

- Scott

By "extremely rare" I mean Shimano no longer sells the HG70, which is what 99% of them used. The HG50 is just not as good (I have both) and SRAM isn't nearly as widespread.

I intend to keep my bike 7sp as long as possible. No reason to change unless I have to. If it gets to the point where I have to spend more money to keep it 7, then I may go to 9.

Seven speeds are ok by themselves and much better with a triple. You should be able to find a gear for almost any riding situation. You will find a
good selection of alternate cassettes available too. Some of us buy into to the bigger number is always better syndrome.

Hmm, so there's a difference beyond the color? The cassette on my bike (which may be original, for all I know) is still in good shape, but maybe I should step up my efforts to find more of them...