Hybrid Bicycles - Trek 8.4 DS - anyone else have noisy back brake?

I've been struggling with this back brake since I got the bike. It was noisy from the beginning, but I thought it would go away. Instead it got worse, and developed into a super-loud harmonic honk each time I hit the back brake. The Trek 8.4 DS comes with Hayes Dyno brakes so I contacted Hayes. Their support has been very responsive. Following their suggestion, I removed the glaze from the pads and tried to bed them in again. Last night I rode around the parking lot making hard stops and thought I was making progress. But, the harmonic vibration started showing up again. This morning, with cold brakes, the sound is coming back strong. I'm getting discouraged. A certain amount of noise is expected, but when people turn their heads to see what the problem is, it's too much.

Has anyone else experienced this? The Hayes tech indicated that a noisy back brake is a known issue, specifically with the 8.4 DS. I would love to find a solution to this problem that doesn't involve buying new brakes.

.... A certain amount of noise is expected...

Has anyone else experienced this? The Hayes tech indicated that a noisy back brake is a known issue, specifically with the 8.4 DS. ....

I don't think that a "certain amount of noise should be expected" as I have cheap tektro calipers and pads on avid discs and have absolutely no sound coming from them. Ever!

I have experienced the problem though with avid pads in avid calipers on avid discs but the noise went when I changed the pads to BBB.

I find it almost amusing that the Hayes Tech tries to indicate that the problem is specifically with the 8.4 DS.

I'd simply try to swap out the pads with a cheaper set, and see how you go.

EDIT...sorry obvious question...Have you taken the bike back to the bike shop where you purchased it so the mechanic there can have a go? That way it should be fixed up under warranty.

I see there is already a discussion going on about the same issue. Some fellow TREK riders... http://www.bikeforums.net/showthread.php/827949-Any-Other-Trek-8-3-Owners

(they're on 8.3's not 8.4's but I'm sure 0.1 wouldn't make much difference. ;) )

I've got an 8.4 but haven't had any problems with noisy brakes. Zerogravity also has one so maybe he has experienced this or knows someone who has. Sorry I couldn't be of any help.

On my 8.4, I only had the hydraulic DBs on the bike for 2 weeks before I happily changed them out for mechanical DBs. Anyway, I had no noise problems in that 2 wks. Sorry.
I do know how you feel, though. I get major squeels from my rim brakes on my MTB sometimes:( It's very annoying!

I have had my 8.4 for about 3 weeks and brought the bike back to the shop after a week and they adjusted the wheel and rotor and so far I have not had any noise since.

I have that issue. I sanded the rotors and the brake pads and it is still there. I even upgraded the brakes from Hayes to Shimano Deores(Not rotors) and still have the hum. I have concluded that they are the Hayes Rotors. I can live with the hum, but when it is time to replace them, i will be getting some Shimano rotors..more than likely the ICETECH rotors.

I took the bike to the LBS and the tech worked on the back brake while I watched. He sanded the pads, scuffed the rotor and made some other adjustments. He also cleaned everything with a special degreaser that doesn't leave a residue. He took it out to the parking lot and didn't hear the noise, as I suspected he wouldn't. The noise doesn't show up until the friction starts to increase in the brakes. I took it for a longer test ride (maybe 5 minutes) and as the brakes started to grab more, the sound came back. This is not a high-pitched squeal. It's a loud vibration that you can feel through the bike. When I got back, the tech heard the noise and said he would talk to Trek about warranty service. I left the bike there a few days ago. I'll call the LBS today to see what the plan is.

I have that issue. I sanded the rotors and the brake pads and it is still there. I even upgraded the brakes from Hayes to Shimano Deores(Not rotors) and still have the hum. I have concluded that they are the Hayes Rotors. I can live with the hum, but when it is time to replace them, i will be getting some Shimano rotors..more than likely the ICETECH rotors.

It may be more the model of the rotor. I have a Shimano M596 brake on the front and Hayes rotor that do not squeal, but I may have a different rotor design. The original brake was a mechanical Hayes MX4.

Let me know what they say at the lbs! I have had my bike (trek 8.3) since Christmas and since day one the brakes have squealed. Just been a lazy a^* and haven't gone. Maybe this week I'll take it in.

I called the LBS on the weekend and the tech said he hoped it wouldn't take more than a week to fix it. But, I'm not really sure what Trek is planning to do. I really hate not being able to ride the bike.

.... When I got back, the tech heard the noise and said he would talk to Trek about warranty service. I left the bike there a few days ago. I'll call the LBS today to see what the plan is.

This is freekin' pathetic that the "tech" at your shop can't give you a definite answer to what specifically is the problem. Talk to Trek about warranty service??? What does that mean? If you are not at fault with damaging it, your "tech" should be fixing it straight up. Once your problem is fixed, move to a different Trek Dealer. Your LBS "tech" is more suited to Wallyworld Bike tech work. BTW, since when did a bike mechanic become a "tech"?

The bike mechanic did try to fix it. I watched him go through the whole process. It didn't work. He said he would contact Trek about getting it fixed under warranty. From my understanding, it means Trek will send parts and the LBS guy will replace stuff until the bike starts working as designed. I don't know what parts they will try. This seems to be my only option at this point if I expect to get things done under warranty. It's stressful knowing I paid a bunch of money for something that's already in the shop. If they don't end up giving me a bike that works, I will certainly make my complaints known to them and to every friend and acquaintance who will listen, including blogs, Facebook, and anyplace else I can think of. But, until then, I will work with their process and keep my cool.

The bike mechanic did try to fix it. I watched him go through the whole process. It didn't work. He said he would contact Trek about getting it fixed under warranty. From my understanding, it means Trek will send parts and the LBS guy will replace stuff until the bike starts working as designed. I don't know what parts they will try. This seems to be my only option at this point if I expect to get things done under warranty. It's stressful knowing I paid a bunch of money for something that's already in the shop. If they don't end up giving me a bike that works, I will certainly make my complaints known to them and to every friend and acquaintance who will listen, including blogs, Facebook, and anyplace else I can think of. But, until then, I will work with their process and keep my cool.

You are being very patient and I wish you luck. There is nothing worse than making a purchase (expensive purchase in this case) and not having 100% satisfaction.

I have some good news to report. No more noisy back brake!!! The LBS worked on the pads and the rotor 4 or 5 times, and the noise still kept coming back as strong as ever. Trek ended up replacing the frame and it's all good now. I'm very happy with the bike, happy with Trek, and especially happy with the LBS for making sure I got a bike that worked.

The frame was replaced to quiet the brakes? I wonder what the issue was with the frame?

I wonder if something just needed to be greased. I did not think of this before but in automotive disc brakes, some grease is typically applied to the back of the brake pad to prevent squealing. I wonder if it was something like that.

My 8.4 is new and so far the rear brake is quiet. I can tell you that I had a Raleigh Talus 5.0 that had horribly noisy rear mechanical disc brakes that were replaced and still were awful, so bad that the shop took the bike back. I also had a Cannnondale with hydraulic disc brakes where the front brake was noisy, but not as bad as the Raleigh. I learned to live with it. Both sounded like the brake was under water and was scraping on the openings in the disc. So far this has not happened on my 8.4 DS, but it only has something like 100 miles on it so far.

This is not a normal squeal of brake pads. It is a very loud buzzing honk that vibrates through the entire bike. Over the course of their troubleshooting the LBS de-glazed the pads and scuffed the rotor about 5 times. They also tried new brake pads. None of this helped. As the pads would start to gain friction in the bed-in process, I would begin to hear an audible tone. As the process went on, the tone would eventually build into an extremely loud vibration that made the back brake essentially useless for anything other than waking the dead.

I talked with a guy from Hayes, the brake manufacturer, and he said he has seen this problem before and they have been studying it. They have many thousands of these brakes (Hayes Dyno) in production, and this problem has been only been reported in a few models of bikes, the Trek 8.4 DS being one of them.

If you look at the difference between the 8.4 DS from 2012 and 2013, the back brake is bolted on in a completely different place. This leads me to believe there have been problems in at least some of the 8.4 DS frames. Otherwise, why move it? My theory is, the brake somehow vibrates at a certain frequency when the pads contact the rotor, and my 8.4 DS frame vibrated at a similar frequency, which caused the vibration to amplify. I do know that sometimes if I reached back during braking, and grabbed the small frame tube attached to the brake (being careful not to kill myself in the process), the vibration would go away, and the brake would act and sound perfectly normal. So, it wasn't a problem with glazed pads screeching on the rotor.

In summary, I'm not saying everyone who owns a Trek 8.4 DS from 2012 is going to have this issue. But I did. I'm very glad the problem is solved. I went on two 10-miles rides and loved every minute. I highly recommend this bike to anyone who is thinking of getting one.

If you look at the difference between the 8.4 DS from 2012 and 2013, the back brake is bolted on in a completely different place. This leads me to believe there have been problems in at least some of the 8.4 DS frames. Otherwise, why move it? My theory is, the brake somehow vibrates at a certain frequency when the pads contact the rotor, and my 8.4 DS frame vibrated at a similar frequency, which caused the vibration to amplify. I do know that sometimes if I reached back during braking, and grabbed the small frame tube attached to the brake (being careful not to kill myself in the process), the vibration would go away, and the brake would act and sound perfectly normal. So, it wasn't a problem with glazed pads screeching on the rotor.


The 2012 and 2013 DS line are completely different. The reason to move the brake location is to better accommodate racks and fenders. The 2013 has been changed to be more oriented towards road riding. By tucking the brake into teh triangle, it's possible to use just about any rack rather than disc-specific racks.

I don't think that a "certain amount of noise should be expected" as I have cheap tektro calipers and pads on avid discs and have absolutely no sound coming from them. Ever!

I have experienced the problem though with avid pads in avid calipers on avid discs but the noise went when I changed the pads to BBB.

I find it almost amusing that the Hayes Tech tries to indicate that the problem is specifically with the 8.4 DS.

I'd simply try to swap out the pads with a cheaper set, and see how you go.

EDIT...sorry obvious question...Have you taken the bike back to the bike shop where you purchased it so the mechanic there can have a go? That way it should be fixed up under warranty.


Hi. I have an 8.4 DS that I purchased within the last 2 months and have the exact same issue. I thought after I had a few more miles on it and took it in for the initial service that I would mention it. I hope this isn't an ongoing issue. It is not only annoying (the sound) but has me not feeling overly confident about the stopping power if I get in a bad situation.

I took the bike to the LBS and the tech worked on the back brake while I watched. He sanded the pads, scuffed the rotor and made some other adjustments. He also cleaned everything with a special degreaser that doesn't leave a residue. He took it out to the parking lot and didn't hear the noise, as I suspected he wouldn't. The noise doesn't show up until the friction starts to increase in the brakes. I took it for a longer test ride (maybe 5 minutes) and as the brakes started to grab more, the sound came back. This is not a high-pitched squeal. It's a loud vibration that you can feel through the bike. When I got back, the tech heard the noise and said he would talk to Trek about warranty service. I left the bike there a few days ago. I'll call the LBS today to see what the plan is.


This is exactly the same issue I'm having as well..................please let us know what they tell you. Thanks.

This is exactly the same issue I'm having as well..................please let us know what they tell you. Thanks.

He already did. Trek replaced the frame.

The mechanic at the LBS had to do quite a bit of testing so they could be sure it wasn't a problem with the brakes themselves. After all was said and done, Trek replaced the frame. My brakes work great. No noise. What a beautiful sound. :)

I have a 2012 8.5 that I bought late last summer. I have about 2k km on it now and the shimano hydraulic brakes are perfectly silent.

Im glad it all worked out for you.

He already did. Trek replaced the frame.

Yeah......got it.

The mechanic at the LBS had to do quite a bit of testing so they could be sure it wasn't a problem with the brakes themselves. After all was said and done, Trek replaced the frame. My brakes work great. No noise. What a beautiful sound. :)

Glad to hear things have worked out for you. I'm taking mine in to the shop while its still under warranty. Thanks.

Interesting that the brake position was changed this year. I called the shop where I purchased it today. I'm taking it in this week. Wish me well. ( :

Interesting that the brake position was changed this year. I called the shop where I purchased it today. I'm taking it in this week. Wish me well. ( :

As someone else pointed out, there could be other reasons for changing the brake position, such as making it easier to connect fenders. But, I think vibration issues also had to be a big factor.

I hope all works out well for you. I was patient and let them do what they needed to do for troubleshooting. But, I was also determined to get what I paid for. When you drop $900 for a bike, you expect it to give you an enjoyable ride. I was happy that Trek took care of me in that regard. I am very pleased with the bike now.

As someone else pointed out, there could be other reasons for changing the brake position, such as making it easier to connect fenders. But, I think vibration issues also had to be a big factor.

I hope all works out well for you. I was patient and let them do what they needed to do for troubleshooting. But, I was also determined to get what I paid for. When you drop $900 for a bike, you expect it to give you an enjoyable ride. I was happy that Trek took care of me in that regard. I am very pleased with the bike now.

Is your new frame the 2012 or 2013 frame? They are quite different.

My old frame was 2012 and my new frame was 2013. I actually liked the look of the 2012 better, but it's still a nice looking bike. I was just glad to get rid of the noise and make use of the brake.

I too have the same issue. A horrible vibration that makes you jump off the saddle and a noise loud enough to scare a child.
Have taken the Bike back today after also emailing Trek for advice.

Will let you know what happens.

I too have the same issue. A horrible vibration that makes you jump off the saddle and a noise loud enough to scare a child.
Have taken the Bike back today after also emailing Trek for advice.

Will let you know what happens.

How long have you ridden it before the problem arose?

If you look at the difference between the 8.4 DS from 2012 and 2013, the back brake is bolted on in a completely different place. This leads me to believe there have been problems in at least some of the 8.4 DS frames. Otherwise, why move it? My theory is, the brake somehow vibrates at a certain frequency when the pads contact the rotor, and my 8.4 DS frame vibrated at a similar frequency, which caused the vibration to amplify..

They didn't simply move the brake mount from 2012 to 2013, they re-did the entire frame. The 2012 has a frame "based on" a 29're frame and the 2013 has a proprietory frame dedicated to the DS model. If you compare the geometry, the 2013 frame differs in nearly every measurement -- and most of them are smaller. Riding them, the 2012 simply feels bigger and more substantial to me. So, I am NOT trying to suggest that the 2012 frame was not a problem with disks -- but that the redesign of the frame went MUCH further than just the brake mounts.

I got a Trek DS 8.5 Wednesday night and took it for a 40 mile ride the next day (yesterday). The Shimano hydraulic disk brakes were almost completey silent. But the LBS warned me that: "Disks go through different sounds as they wear in, first you may hear one sound, then it wil change to some other sound". So far, on just that one ride, I have not heard any sounds to speak of -- but I was riding it kind of gently trying to let things break-in...

My old frame was 2012 and my new frame was 2013. I actually liked the look of the 2012 better, but it's still a nice looking bike. I was just glad to get rid of the noise and make use of the brake.

My LBS speaks highly of Trek warrenty coverage -- that they go above and beyond with their warrenty coverage. Perhaps that is the difference between Trek and other brands?

My LBS works hard to be sure his riders are happy riders. Perhaps Trek does the same?

I too have the same issue. A horrible vibration that makes you jump off the saddle and a noise loud enough to scare a child.
Have taken the Bike back today after also emailing Trek for advice.

Will let you know what happens.

How did your repair go?

It will be a year that i had my DS 8.4. I rode it last night for teh first time in a few months and had forgotten about the brake squeal..which is non existent on my Rumblefish. I have SLX Brakes and XT Icetech rotors on my Rumblefish while my 8.4 has Deore brakes on Hayes Rotors. I now firmly believe and confirm that the Hayes rotors are the noisy suspect. Still stops on a dime(which is what is important anyway) but just NOISY.

It will be a year that i had my DS 8.4. I rode it last night for teh first time in a few months and had forgotten about the brake squeal..which is non existent on my Rumblefish. I have SLX Brakes and XT Icetech rotors on my Rumblefish while my 8.4 has Deore brakes on Hayes Rotors. I now firmly believe and confirm that the Hayes rotors are the noisy suspect. Still stops on a dime(which is what is important anyway) but just NOISY.

You may want to check those brakes: I have a 2012 DS 8.5 and the brakes are Alivio. Actually Trek didn't publicize that -- they just gave Shimano part numbers. When I got the bike, I checked the part numbers stamped on the calipers and levers and checked them on the Shimano website. When I bought the bike I thought it was all Deore and SLX stuff. But, when I looked up the part numbers, only the shifting components are Deore and above. The hubs, crankset and brakes are all Alivio...

Again, Trek didn't make that obvious. Actually they kind of hid it by using part numbers instead of group names. They publicized the group names for all the Deore and SLX components but then just gave part numbers for the cheaper stuff.
... tricky Trek ...

I like the bike and I would still buy it. But I wish Trek hadn't tried to slip that stuff past me. It feels dishonest.

I posted earlier is this thread that I haven't had the noisy brake problem but guess what cropped up yesterday. I noticed that it would start as I gradually applied the rear brake and would stop if I applied the brake hard and quick then went back to the gradual application. I guess I will take it back to the dealer on Wed. It's funny that it is happening only on the back brake which might lead someone to believe there is a problem with the way it is mounted to the frame.

You may want to check those brakes: I have a 2012 DS 8.5 and the brakes are Alivio. Actually Trek didn't publicize that -- they just gave Shimano part numbers. When I got the bike, I checked the part numbers stamped on the calipers and levers and checked them on the Shimano website. When I bought the bike I thought it was all Deore and SLX stuff. But, when I looked up the part numbers, only the shifting components are Deore and above. The hubs, crankset and brakes are all Alivio...

Again, Trek didn't make that obvious. Actually they kind of hid it by using part numbers instead of group names. They publicized the group names for all the Deore and SLX components but then just gave part numbers for the cheaper stuff.
... tricky Trek ...

I like the bike and I would still buy it. But I wish Trek hadn't tried to slip that stuff past me. It feels dishonest.

I actually UPGRADED to Deore brakes from the stock Hayes brakes. I did a write up a while back and listed that as one of my upgrades. I originally wanted an 8.5 but it wasn't available at the time at my LBS and i loved the 8.4's paintscheme better.

http://www.bikeforums.net/showthread.php/810620-A-few-goodies-on-my-DS-8-4-and-the-bike-is-SOLID!?highlight=Trek+8.4

Interesting thread!!! I also have a 2012 Trek DS 8.4, and it has the same rear brake issue!!! It makes an extremely loud noise that seems to emanate from the frame of the bike!!! This issue started right after I purchased the bike! Unfortunately I left on an extended vacation with the bike out to Mammoth Lakes, California a week after I bought the bike. Once I started riding the bike on down hill paved trails the noise began and was so loud it was embarrassing!!! It does seem to emanate from the frame!!! The LBS was unable to help, they sanded the rotor, it helped for about ten minutes...they cleaned the rotor, another ten minute fix!! I took the bike to a LBS in Carson City NV. and left it with them for a week! They replace the rotor, cost me $65.00, when I got back to Mammoth the bike still had the same problem!!!
I'm now back in Phoenix and dealing with the LBS where I purchased the bike!!! They swapped front and rear bake pads, which didn't help!!! I've emailed both Trek and Hayes, they initially pointed fingers at each other!!! At this point I think it is a frame problem!!! Hayes even suggest mounting a rack on the back of the bike to dampen the vibrations caused by the rear brake!!! The LBS has ordered new pads, it's been two weeks already and I'm still waiting!!! They said Trek send the wrong pads!!!!
I'm holding Trek responsible for the problem!!!! When first contact they told me to contact Hayes!!! I now see that this was a known problem that they should have acknowledged and owned up to!!!
At this point I'm still waiting for new pads, which I'm sure won't solve the problem!!! I think I want my money refunded, this bike is a lemon!!!!

Interesting thread!!! I also have a 2012 Trek DS 8.4, and it has the same rear brake issue!!! It makes an extremely loud noise that seems to emanate from the frame of the bike!!! This issue started right after I purchased the bike! Unfortunately I left on an extended vacation with the bike out to Mammoth Lakes, California a week after I bought the bike. Once I started riding the bike on down hill paved trails the noise began and was so loud it was embarrassing!!! It does seem to emanate from the frame!!! The LBS was unable to help, they sanded the rotor, it helped for about ten minutes...the cleaned the rotor, another ten minute fix!! I took the bike to a LBS in Carson City NV. and left it with them for a week! They replace the rotor, cost me $65.00, when I got back to Mammoth the bike still had the same problem!!!
I'm now back in Phoenix and dealing with the LBS where I purchased the bike!!! They swapped front and rear bake pads, which didn't help!!! I've emailed both Trek and Hayes, they initially pointed fingers at each other!!! At this point I think it is a frame problem!!! Hayes even suggest mounting a rack on the back of the bike to dampen the vibrations caused by the rear brake!!! The LBS has ordered new pads, it's been two weeks already and I'm still waiting!!! They said Trek send the wrong pads!!!!
I'm holding Trek responsible for the problem!!!! When first contact they told me to contact Hayes!!! I now see that this was a known problem that they should have acknowledged and owned up to!!!
At this point I'm still waiting for new pads, which I'm sure won't solve the problem!!! I think I want my money refunded, this bike is a lemon!!!!

The bike is an awesome bike. The Noise issue is HAYES. Get rid of the rotor and u will get rid of the noise. PERIOD. I find it kinda ridiculous that Hayes suggested mounting a rack to lessen vibration...SERIUSLY??? Does that even make any sense??? ANyway, you are entitled to your opinion. Good luck with selling your bike.

So, really the frame was the issue. Glad that it worked out for you!

I have a 2012 8.5 that I bought late last summer. I have about 2k km on it now and the shimano hydraulic brakes are perfectly silent.

Im glad it all worked out for you.

+1 -- the Shimano hydraulic disks on the 2012 DS 8.5 are about the lowest level Shimano makes (Alivio)-- but they are quiet and very smooth and effective.

But, if it were ONLY a frame issue the Shimano disks on the 8.5 would be squealing as well. Perhaps, it is the Hayes rotor creating a vibration that gets amplified as it carries up through the frame....

Got my 8.4 back today and the brakes aren't noisy but I was thinking what zerogravity said about the rotors. I have a second set of wheels with 29 x 1.9 tires on it for sandy rides and those rotors aren't noisy at all (they aren't hayes rotors). I think I will swap the rotors from the spare set of wheels and see what happens. I'll post my findings later in October since I'm going to be out of commission for a couple of weeks starting early next week and won't be able to ride.

When my rear brake started making the honking noise, I brought it back to my (excellent) LBS. They put some kind of anti-squeak stuff on it and worked for a time, but the honking is coming back. Going to wait for it to get very bad and then bring it back and see what they say.

I would find it hard to believe it is the frame, but someone here or in another post had this issue and Trek eventually replaced the bike, which suggest the frame might have something to do with it.

Update, the product the bike shop used was "Squeal-Out"

When my rear brake started making the honking noise, I brought it back to my (excellent) LBS. They put some kind of anti-squeak stuff on it and worked for a time, but the honking is coming back. Going to wait for it to get very bad and then bring it back and see what they say.

I would find it hard to believe it is the frame, but someone here or in another post had this issue and Trek eventually replaced the bike, which suggest the frame might have something to do with it.

Update, the product the bike shop used was "Squeal-Out"

I think to clarify a bit, the frame was not replaced because of the squeeling of the brakes. It was changed COMPLETELY as in evolution just like cars are changed every few years or so. If it were just the brakes in the rear, one would think only the rear triangle would have been replaced but it is no so. The top tube, bottom tube, Longer steerer tube for a more upright and less aggressive position, pretty much everything was replaced/changed because the brand was evolving. If you look at the 2013 frame, it looks nothing like the 2012's and i highly doubt all this was changed because of some brake noise. I can live with the noise..as long as the bike stops that is all what matters to me as well as the bike's comfort. Going down a dirt downhill with ruts at 44+ MPH and having the bike hold up and stop when needed to surely doesn't make the bike a lemon. Ride the bike, enjoy it, get your exercise, and enjoy it some more. Would a little noise really stop you from riding? Riding both My DS and my Rumblefish at the same trails 4-6 times a week at about 70 miles a week would and should result in the same rear brake noise. The only difference between the two are the rotors. I have had both Avid and Icetech's on the RF and no squeel. I think i ride more aggressively on my RF just because i have 5" of rear travel and still..no noise. Im curius of what Choc reports..im curius and intrigued.

Just to let you know that my LBS got into contact with Trek after I suggested that there may be an issue with the frame after reading this forum. Well after 2-3 weeks they came back and said that Trek have agreed to replace the whole bike for the 2013 model. Still dont have it back due to Trek forgetting about it and the LBS then having a moan at them. Will get it back next week :)

Thanks to these posts my problem hopefully is now sorted, I even like the 2013 better than the 2012 despite the frame being slightly thinner in diameter.

Just to let you know that my LBS got into contact with Trek after I suggested that there may be an issue with the frame after reading this forum. Well after 2-3 weeks they came back and said that Trek have agreed to replace the whole bike for the 2013 model. Still dont have it back due to Trek forgetting about it and the LBS then having a moan at them. Will get it back next week :)

Thanks to these posts my problem hopefully is now sorted, I even like the 2013 better than the 2012 despite the frame being slightly thinner in diameter.

That's great! It's good to hear that Trek is standing behind their bikes and looking out for their customers.

I think it was on a thread in the 50+ forum where somebody pointed out that most bikes -- including name brand ones are all manufactured out of a few Asian factories -- which tends to make them all pretty much the same. But, the difference is: how does the "Manufacturer" stand behind them if there is a problem? From everything I have heard, Trek tends to do a pretty good job along those lines...

But again, I really do not think the frame was the problem: if it was the DS 8.5's would have a squealing problem as well. But they don't -- probably because they have Shimano brakes rather than Hayes...

It will be a year that i had my DS 8.4. I rode it last night for teh first time in a few months and had forgotten about the brake squeal..which is non existent on my Rumblefish. I have SLX Brakes and XT Icetech rotors on my Rumblefish while my 8.4 has Deore brakes on Hayes Rotors. I now firmly believe and confirm that the Hayes rotors are the noisy suspect. Still stops on a dime(which is what is important anyway) but just NOISY.

So, did you solve this problem by swapping out the Hayes rotor with something else?