curiousabe

So I brought my vintage 80s de visini with camps trimomphe group set to the LBS to replace the chain ans the old regina 5bx 5 speed 14-22T freewheel a new Sunrace 6 speed 14-28T freewheel.

Once I picked up and rode the bike it made a very loud knocking type of sound, once every revelation on every gear when the crank was at around 2 o clock. LBS confirmed this and tried replacing to another brand new Sunrace 6 speed 14-28T. This one made the bike have the same sound so LBS mounted the original freewheel and the sound was gone...

According to LBS both the sunrace freewheela have manufacturing defects (seems a bit unlikely both do?).

So what to do? The bike has 127mm measured dropouts and the Trimomphe derailleur should be able to handle 14-28T 6 speed back and 52/42T front chainrings. I'm tempted to bring them a new shimano MF-TZ500 6 speed 14-28T freewheel but I dont know...

SurferRosa

New Sunrace freewheels do not make "loud knocking" noises. Sounds like a fairly simple issue that deserves greater attention than this particular bike shop can handle. Why not try to understand the issue yourself? The bicycle is a very simple machine, but it takes time and patience, things that maybe this bike shop doesn't have readily available.

beicster 

I have a 14-28 freewheel that I bought new in the last two or three years. I think it was a Sun Race but I am not sure. It had a loud knock in it as well. I took it off and it now serves as a paperweight in my home office. I replaced it with a vintage Sun Tour something or other (New Winner?) and the knock went away. My conclusion was the same as your bike shop's-Bad freewheel.

T-Mar

That ounds like a crankset issue, given that it makes it at the same point of every crank revolution.

HTupolev

It's been a few years since I've used one, but in my experience, they do. Or at least the 6-speed 14-28 ones that I use do. It's a consequence of a sloppy bearing assembly. Wear can lead to squeals developing alongside the knocking within a few hundred miles.
This has been an issue with every single Sunrace freewheel I've used.

This is why I generally stick to Shimano freewheels, despite their ugly big cogs.

steelbikeguy

I've had SunTour freewheels where the bearing cone loosened. This resulted in the outer body pivoting on the pawls, depending on which cog the chain was on. This resulted in a "thunk" twice per wheel revolution, and this "thunk" was a warning that the cone was about to completely unthread and let all of those 1/8" bearings escape to the street and never be seen again. Once the bearings were gone, the freewheel would no longer function and you would be a pedestrian once again.
Not a good thing.

In the OP's case, as noted, a noise that happens once per crank revolution is unlikely to be a freewheel problem. It could be a bearing problem, or the front derailleur smacking into the crank arm, or a multitude of other causes.

Steve in Peoria

curiousabe

Well I dont have neither time, tools or patiance, Im glad if I can get a few hours of spare time to actually ride the bike during weekends.

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To clarify and answer all the above:

• Knocking sound not present when switching back to the old Regina BX freewheel - should rule out crank issue
• Bearing problem should be present when using the old Regina BX freewheel but it is not
• With the two Sunrace freewheels it makes the same sound when holding the rear wheel firm and pushing the crank with your hands a few mm forward when crank is in around 2 o clock position, this does not happen with the Regina BX freewheel
• We ruled out the front derailleur smashing into the crank when I was at the store, also the sound seems to happen when crank is not in a position to touch the front derailleur

As a last resort I will purchase and bring an ugly shimano MF-TZ500 6 speed 14-28T freewheel to the store since they still have the bike.

tiger1964 

Another data point -- I have an IRD freewheel making such a noise, but probably not as loud. Hmm, when I coast or at least let up for a tiny fraction of a second, which implies the pawls then engaging a different part of the freewheel... it goes away, until the next time I coast (or maybe not, it's like Russian Roulette). I've developed the technique of a slight "stutter" in my pedaling when I encounter it. Too cheap to discard freewheel, and good luck trying to convince the manufacturer it's defective.

SurferRosa

Strange. I wonder why anybody buys them.?.

I have Sunrace 7-speeds on almost all of my bikes. They work fantastic. That's why I replaced my IRDs.

SurferRosa

In my limited experience, they're pretty good with replacing it if you email them. I did that once with IRD (busted pawl), and they quickly mailed me a brand new one (no packaging).

noobinsf 

Well, it looks like you participated in the diagnostic phase, so if you're satisfied and you trust the shop, there's no harm in putting the Shimano on if you need the larger rear cogs. Like SurferRosa, my only experience with Sunrace freewheels is with a pair of 7-speed units, and these have been fine for me. Shimano may be ugly, but they're reliable in my experience.

curiousabe

Wont have to convince anyone its mfr defect since the store confirmed it and I bought it from them together with the service of replacing

Yea I brought it back and they diagnosed it while I was there yesterday. Today they called me after trying a second similair freewheel and confirmed mft defect on both units simply stating "****y quality freewheel". Will give it a last shot with the shimano one.

SurferRosa

That's the only one to buy in my opinion, the all-chrome units, just like this one:

https://www.ebay.com/itm/294988240793?hash=item44aeab5799:gvwAAOSwpQpigyck

The 6-speed units like that are more difficult to find. You have to look up the model number on the Sunrace site, and then search the web for that.

BFisher

Guys, defects do get through in mass production. I had a knocking Sunrace freewheel here a while back. Brand new.

I contacted Sunrace, and the rep asked for a short video of the issue. I provided, and he sent me a new freewheel right away, no more questions asked.

What did I find when I opened the freewheel? Two different size pawls, one silver and the other black. The main body looked like it was made on equipment that was long past it's useful life, just very, very rough. Lots of slop all around.

I have other Sunrace freewheels that have been fine.

If the issue is your freewheel, Sunrace will likely replace it.

Chombi1 

Had an NOS Regina FW that knocked on me too.
Turned out to be a defect with the FW body the outer body was hitting the inner one at a certain point of its revolution. It was easy. Basically, a high spot where the two halves were rubbing.
I just knocked down the area with a grinding stone bit on my Dremel Drescher knocking was eliminated.
It's a relatively easy fix, as long as you are able to break open the FW with the right tools.

curiousabe

Just brought the lbs a new MF-TZ500 6 speed 14-28T freewheel since they didnt stock these, lets see if this ine works better.

Just too bad its ugly as hell...

SJX426 

Not intending to be judgmental but if the freewheel is/was the problem, how can the sound be always at the 2:00 position of the crank? We are talking changing gear ratios! does the sound only occur on only one sprocket and one chain ring?
Does the freewheel "wobbulate" when the wheel spins (typical)? Conceivably, the chain could be displaced during one revolution of the freewheel causing the chain to rub on the FD when on the largest sprocket.
Are the pins on the chain properly inserted where the chain was "broken?" Recently I was hearing a ticking sound once every revolution of the chain. The master link was for an 8-speed chain but mounted on the 9-speed chain. The link was wider and would hit the FD in the right configuration.

T-Mar

Personally, I don't think they are ugly. Regardless, you'll almost certainly forget the aesthetics, once you experience the quantum leap in shidting performance over the old Regina.

dddd

As one who loves installing certain of the SunRace chromed freewheels (7-speed for me), I have seen a couple of problems turn up on a few of the perhaps ~30 of them that I have installed.

The "tick tok" knocking is the most-common problem in my experience, always fixable by tightening the bearing adjustment (removing the locking cone, sanding down it's back-side seating surface, cleaning the threads and re-installing with Loctite).

[[[[[[[[[The cog-retaining ring needs to be removed first, so one needs to fashion a removal tool using 1/4" flat steel stock for twisting it off and then back on again. I used the handle of one of my older chain whips for this purpose, a few minute's time tuning up the width dimension of the end of it using a bench grinder and file.]]]]]]]]]

Removing metal from the locking cone is irreversible, so if you go too far with the sanding, the freewheel becomes a paperweight since the needed shims are not usually available, other than by cannibalizing another (perhaps worn or rusted) SunRace freewheel.

The freewheels were fine after my readjustments.

I also had a couple of SunRace freewheels come in that were from a batch where the factory over-packed the body with grease. These freewheels would not turn freely enough to use, and removing the excess grease required soaking the freewheels and giving them a spin each day for a week, with lots of time wasted. Thankfully this was a little over ten years ago!

The 13-25t and 13-28t, 7s chromed models are the cat's meow for performance riding around here using indexed levers!

curiousabe

It might have been in more place, we only diagnosed it together for like 5 min before they were closing the shop and I left my bike overnight for them to try another freewheel the next day.

Not sure if the freewheel was wobbulating. Didn't look like the chain was rubbing FD though.

Regarding the chain, I would very much belive it was properly inserted since the poor guys had to switch freewheel like 6 times haha.


Ugly!but do you weren't joking regarding the shifting, I had to look down multiple times when shifting to visually verify (even though I felt it) that it had actually shifted haha, so quite and smooth!





Super helpful, thanks!

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Brought the bike back from the lbs today with the cheap and ugly shimano freewheel. Knocking sound is gone, the shimano freewheel is a lot quite (the sunrace one was IMO way to loud) and it shifts so smooth and quietly together with the new Izumi chain. Wax also flying by all the commuters who were struggling uphill on the big hill back home

pastorbobnlnh 

I've also have had great experiences with Sunrace customer service. Glad that curiousabe had a great final outcome.

dmarkun

dddd, this fix worked great for me! I have a new Sunrace 5 speed that clicked and had a bit of play. I left the freewheel on the wheel and removed the lockring (removal is CW). Mine had 2 indents for a pin spanner but very tight so I used a punch and hammer to loosen and then the green Park spanner tool. I sanded the backside of the lockring (which is also the bearing race) on 3M Wetordry 220 with oil for about 30 seconds and tightened it up. Play was gone and so was the click. I noticed a shim in there - it was just a bit too thick. I sanded in 10 second sessions with test fittings in between. Great post, thanks!

merziac

@curiousabe, @T-Mar, and all,

Fully agree on the fugly Shimano Mega billboards.

You have to lean in a bit but well worth it.

5 minutes on the bench grinder mounted wire wheel and the ugliness is gone, burn the branding off and the metal blends right in with the rest, do the backside and your golden.

Still not a fan but they do work well and I have accumulated several that have come with acquisitions along the way so free is good.

You could probably use a sharpie too......