broomcorn

Before anyone yells, I searched and could not find any definite answer to my question, though I am sure it has been asked before. I am in the process of converting an old hybrid beater to a single speed, and need to know if a simple single speed cog will work, or if I need a freewheel. I want the bike to coast, not looking for a fixie. Does a fixed cog coast depending on the type of hub, or is a fixed cog always for a fixie?

Can I just use this:


Or do I need one of these?:


Here is a picture of the bike if it helps.



THANKS!!

Kayce

If the wheel is a 6 speed like I counted then it will be a freewheel. If its 7 it could be either. More than 7 its a cassette.

homebrewk

yuppers. And generally a fixed cog is a fixed cog no matter how you slice it.

Scrodzilla

The OP isn't looking to install a fixed cog.

As Kayce pointed out, if your wheel has a multi-speed freewheel ( I think it does) - instead of a cassette with individual cogs - all you may need to do is remove it and thread on a single speed freewheel. Either way, go to a bike shop.

homebrewk

+1 on the bike shop. And I know the OP doesn't want to ride fixed, just putting in my two cents (as usual).

jimmytango

Or you could save money. Break the chain, keep the links, loop the chain around the cog you want it on, ride as a ss, and then if you're on a super hilly road you have the option of throwing it back up on a lower ratio. Not as cool as a true conversion, but its more versatile. Best of all, it's sheldon approved. I saw the idea on his site a while back, but I can't yet figure out how to ctrl-c on my phone.

broomcorn

good idea, but I would also have to mess with the wheel to get the correct tension everytime I manually changed gears. rather just keep it simple with one dedicated gear, plus I'm currently in Florida, so no worries of hills here.

Dannihilator

I've had in my hands in the past an 8 speed freewheel.

Dannihilator

Heck, here's a 9 speed freewheel.

https://www.jensonusa.com/store/produ...Freewheel.aspx

flippin_bikes

As others said, you need one of those which will thread right on to your hub once you remove the old 7 speed freewheel using one of these if it has 4 slots around the axle:



If you have 2 slots around the axle, you need this:



Then, you will also need to respace your axle and redish the rim. That means that you have to take a spacer out of the side of the axle where that 7 speed cluster was and switch it over to the other side of the axle. Some rear wheels have multiple spacers in the axle that allow you to fiddle with the spacing. In any case, what is going to happen is that your rim will be moved over to the ride side (or drive chain side) of the bike. That will require you to redish the rim back to the left. Sometimes, you can get away with loosening all of the drive side spokes and tightening the non-drive side spokes.

Is your head spinning yet? This is generally not something the average person would be able to do successfully. You have to buy special tools and know how to fiddle with the axle and spokes. Then, at best, you might have a rear wheel that doesn't fail immediately because the spoke tension isn't correct. If you just ride around on the street, no jumping curbs, or otherwide abusing the wheel, it may be ok.

I second the recommendation just to use one of the cogs on the freewheel cluster and call it good.

If you want it nice, clean installation, get a single speed specific rear wheel. That is your most expensive option.

A mediium priced option would be to find a rear wheel with a cassette freehub body that allows you to use one of these:



You may be able to rummage around and find a good used wheel for $10-20. You can buy one of those cog and spacer kits for around $20.

Someone already posted a link to Sheldon Brown's singlespeed conversion how-to page. Good stuff there.

Robofunc

OP--selling derailleurs soon?

broomcorn

ok, so while the picture does appear to show a 6 speed, it is in fact a 7, I just went and counted a couple times to confirm. With that being said, can you really tell if it is a freewheel or cassette? I've read sheldons article and still can't tell what I got. There is no bulge in the body of the hub, but that doesn't confirm anything... Is there an easy way to detect, or are you guys sure it is a freewheel even with 7 gears?

GeoKrpan

Quote from the LooseScrews.com.
"An easy way to tell if you have a freewheel is to look at the spacers between the cogs. If the spacers get bigger in diameter between the bigger cogs, you are looking at a freewheel....... If all of the spacers have the same diameter, you are looking at a cassette......."

Suntour made 6 and 7 speed cassettes.

Simply for informational purposes, Shimano made 5 and 6 speed cassettes.

WeirdOddity

can you post a picture of the freewheel/cassette on the rear wheel taken out of the frame? it would help with identifying. i have a hunch that its a freewheel (thread-on), but not sure yet.

broomcorn

well if this is true, its a freewheel. When sheldon says "Unfortunately, the chainline is likely to only work with your granny gear unless you re-space the rear axle and re-dish the wheel.", what exactly does he mean? Why won't my chainline work with a new single freewheel?

hairnet

When you remove the freewheel you will see there are spacers along the axle between the hub and frame, this offsets the hub to make room for the gears. So, to center the wheel you will have to move spacers around to the other side of the hub. Re-dishing the wheel is how you re-position the rim to line up with the frame, which it won't after you re-space the rear axle.

To do these things you need to know how to overhaul a hub and true wheels/use a spoke wrench. If not, find someone who can teach you or take it to a bike shop.

GeoKrpan

Get a single speed freewheel, screw it on, and see how it works.
It's a hybrid bike with long chain stays which will make it more tolerant to chain line.
The SS freewheel isn't as deep as the 7 speed freewheel. It won't screw on as far which will help with the chain line issue. Using the middle chain ring will help too. You might be able to mount the big chainring in the middle chainring position.
LooseScrews.com has freewheel spacers for Campy freewheels. If there were such a thing for Suntour freewheels you could simply replace some of the cogs with spacers.

broomcorn

I couldn't keep the spacing the same and just sandwich the freewheel between spacers to get the right chain alignment? I guess its something you just have to go through to see it.

Also, if you re-dish the spokes to align with the frame, how the hell does a flip flop hub work if you flip the wheel to utilize the other sprocket (or is my understanding of a flip flop way off?)?

Thanks all, appreciate you spreading the knowledge!!

GeoKrpan

You don't have a flip flop hub, it's only threaded on the right side. A flip flop hub is threaded on both sides.
I suppose you could try and find some big washers to act as spacers but I'd just use the 7 speed freewheel as is.
Try the idea in my previous post, you have little to lose.
From the middle ring position any of the 7 cogs is usable so it should work.
Do not redish the wheel until you have given my idea a try.

hairnet

flip flop hubs are not dished

GeoKrpan

I've thought about this some more.
Use the 7 speed freewheel and the big chain ring. You will probably use one of the three smallest cogs on the freewheel.
The chain line on any of these with the big chainring will be fine.
Do it this way and it won't cost you anything. All you'll have to do is to remove the derailleur and shorten the chain.
When the the 7 speed freewheel wears out you can get a single speed freewheel or another 7 speed freewheel, either are cheap.
Those dropouts you have aren't very long. They won't allow much fore/aft movement to tension the chain. Keep in mind that a half link may be needed.

andrizzle

is that 100 percent? formula, novatec, etc...all dishless?

ps. great post flippin_bikes

hairnet

I should have said wheels, but yeah...

broomcorn

That's what I'm gonna do most likely. Stopped by an awesome bike shop today (https://www.maggieroses.com/5001.html) and got some great details. The easiest and cheapest is to use the existing freewheel, and eventually I will piece together a true single speed. Thanks for all the help everyone! Now I gotta take it apart somewhat to give the frame a fresh paint job.

lverhagen

If you go this route, be sure that you maintain good chain tension, otherwise the possibility of derailment is reasonable and can be quite a shock if it happens while hammering on the pedals. Good luck!

Cheers
lverhagen