Shimano SF-1200 Single Speed Freewheel (20Tx1/8 1 Speed)

Ordered this for the well known quality assured with Shimano products. Came in factory box and in excellent condition. Very happy with seller. Arrived before estimated delivery date. Highly recommend.

Gave it five because it's typical Shimano quality. My original 18t was clicking loudly, so I replaced it with an lbs 18t fw, but it was noisy too, so bought this one (lbs doesn't stock it) and added 2 teeth as I live in a hilly town. The 48-20 gives me good speed and I can still make the hills and, IT'S QUIET.

I love that it's silent, but it's frustrating that it's more-or-less impossible to remove without a very uncommon freewheel tool

I like this freewheel it is simple and was easy to install. Please ignore all the other people who say it is permanent once you put it on for it isn't. I have worked in a bike shop for 3 years and have built bikes from scratch. With most bike repair you need a specific tool to do the action you want. If you need to remove this freewheel you can buy this tool : https://www.amazon.com/Park-Tool-Head-Gear-Lockring-Wrench/dp/B002PTVDP0/ref=sr_1_33?keywords=park+tools+wrench&qid=1565800043&s=gateway&sr=8-33. Or you can just go to a bike shop and ask for the tool and they should let you do it yourself. Overall a great single speed freewheel!

This is a very nice freewheel for my single speed. I was broke and needed a bike so I hijacked a front 50t sprocket off of another bike of the mountain variety and adapted it for use with some single speed cranks. So to get the gear ratio I wanted, I got this 20t rear freewheel. It is very smooth when riding and doesn't click when coasting. Be sure you know that is for 1/8" chain as opposed to 3/32". You MUST have a freewheel tool to take this off so don't mess around with it on random wheels if you don't have the tool. This is not for a fixie bike. Fixie bikes need a separate cog that is stationary. This one spins. Make sure you know what you are getting and I can guarantee you will be satisfied with this purchase.

Replaced 16t cheap freewheel that came with bike. Got done with the best ride I have done in a while immediately after installing. 20t works great for elevation with a 48t up front. The 18t fixed gear is just not fun on long descents and would of been a little much today climbing and the 16t amongst being cheap was just out of the question on the climb. The freewheel body has a much larger diamter than last freewheel so I was concerned I was going to top out way too fast, sure enough this wasnt the case because its all relative to the bearing size??? Which should mean it will last a while. I really like this product and hope this helped somebody. I have received a lot of help reading these reviews in the past. It has a larger diamter I had to buy a new chain $12SRAM chain at LBS. Took out the wrong link and suffered for a minute but all in all it was well worth it. Note that it uses a two prong freewheel tool opposed to the four prong I used to take off the last one, had to use a piece of pipe on a crescent wrench. Heads up you dont need a tool to install it. Just thread it on there hand tight and the bike does the rest.

I bought this POS for my single speed bicycle, and it resulted in a weak gear ratio, so I figured it was no biggie, as I could just remove it, return it and install a 16 tooth freewheel instead.Ends up that it's impossible to remove without destroying it. Took it down to my trusted local bike shop, and even if you have the stupid $25 tool designed for this thing, it still will probably strip and damage the 1/8 inch notches designed for extraction beyond repair.Do not buy this product if you ever intend to remove it without destroying it, or if you're experimenting with different single speed gear ratios, and are thinking you might be able to return it for a different size.They need to update the product description as non-removable. Very disappointed with Shimano on this one. I mostly blame myself for not researching it better, but still.

Pros: Good quality unit. I've managed to destroy several others. I'm also a fan of how quiet it is. This may be a negative for some as some kids like the loud clicking types.Cons: Doesn't use the common tool to remove and even the frail Shimano two-prong wrench won't remove it without frustration after you've ridden it hard making it very tight.