Upgrade to Disc Brakes?

[johnl350]

I was thinking about upgrading my '06 Spec Rockhopper to disc brakes...Does anyone know how much this will cost?...and if its worth it? TIA

[pirate]

I was thinking about upgrading my '06 Spec Rockhopper to disc brakes...Does anyone know how much this will cost?...and if its worth it? TIA

Here ya go... http://www.blueskycycling.com/product1630_70_-2007-Avid-BB7-Disc-Brake-Combo-Kit.htm

[Brizn]

..and be sure you have disc hubs. PS: that's a reaaaaally good deal on those brakes!

[johnl350]

..and be sure you have disc hubs. PS: that's a reaaaaally good deal on those brakes!

Does that mean I probably will have to buy new wheels?

[CRAIG2]

Possibly just hubs, and make sure to count your spokes first. Though, for the cost of parts (hubs) and labor (time to rebuild wheel using existing rims) it might be as cost effective just to buy new wheels.

[halfinch]

it'd probably be easier/more cost effective to find a new set of wheels and sell the ones you have or keep them as a spare rather than relacing the rims to new hubs.

[Brizn]

a cursory e-review of that bike shows that it may very well come with disc ready hubs. Check 'em out; see if they have a flange with 6 holes on the left side- this is where you'd mount the disc rotors.

[saxman]

It's also possible your hubs may be disc ready. That would make life nice and easy. I would agree that it would be best to just get a disc wheelset rather than replace the hubs and relace the wheel.

However, even with the inconveniences involved, the gains you get from switching to discs, even mechanical ones, far outweighs this. Discs are easier to modulate, give you more stopping power, and because they are located close to the hub, aren't subject to getting as wet or muddy as rim brakes get. As someone who has a terminal case of upgraditis, I say go for it. Once you start with one upgrade, though...you just can't stop!

[Brizn]

Discs ...give you more stopping power, ...I agree.. But I've always wondered how and why this was true.. or whether it's just a matter of perception. Physically speaking, (and all other noted benefits of discs aside) it should be much easier for pads to grab&slow a wheel at the largest circumfrence (ie the rim sidewall @ 26" in diameter), as opposed to a smaller one (ie a rotor @ 6" in diameter). I mean, from a physics stdpt, that's why you get bigger rotors for better stopping power, and bigger cogs for easier climbing.

:confused: :confused:

[punga]

I agree.. But I've always wondered how and why this was true.. or whether it's just a matter of perception. Physically speaking, (and all other noted benefits of discs aside) it should be much easier for pads to grab&slow a wheel at the largest circumfrence (ie the rim sidewall @ 26" in diameter), as opposed to a smaller one (ie a rotor @ 6" in diameter). I mean, from a physics stdpt, that's why you get bigger rotors for better stopping power, and bigger cogs for easier climbing.

:confused: :confused:
It's true about being the wider circumference giving you better stopping power, but disk calipers apply more pressure to a smaller range of movement to compensate.

The main benefit of discs is not having to worry about less than true rims giving you headaches on the trail and being fairly impervious to water, mud, etc.

punga!

[DaveG]

It's true about being the wider circumference giving you better stopping power, but disk calipers apply more pressure to a smaller range of movement to compensate.

The main benefit of discs is not having to worry about less that true rims giving you headaches on the trail and being fairly impervious to water, mud, etc.

punga!


I used to wear through sidewalls fairly regularly riding in avalon. Not a worry with disk brakes. Just replace the pads every once in awhile.

Dave

[jabberwocky]

I agree.. But I've always wondered how and why this was true.. or whether it's just a matter of perception. Physically speaking, (and all other noted benefits of discs aside) it should be much easier for pads to grab&slow a wheel at the largest circumfrence (ie the rim sidewall @ 26" in diameter), as opposed to a smaller one (ie a rotor @ 6" in diameter). I mean, from a physics stdpt, that's why you get bigger rotors for better stopping power, and bigger cogs for easier climbing.As Punga noted, disc calipers clamp with a force several orders of magnitude larger than rim brakes. If rim brakes clamped with even a fraction of the force of discs they would collapse the rim sidewall.

Discs are the way to go for a mountainbike. More consistent through varying conditions, more powerful, better, more consistent modulation and are unaffected when a wheel gets knocked out of true. Also, pads last much longer and the so will the rims. I run Avid Juicy's with 7" rotors and EBC gold pads on my Turner, and I can easily modulate the brake to the point of locking the wheel with one finger.

[johnl350]

Thanks for yalls help. My bike is getting tuned up now but when i go pick it up i will ask if the wheels can be upgraded to disc brakes. I wish i had just bought them to begin with.

[macdaid]

Disks, gotta love em. Jus load'm 'n leave 'm.
They've got none of the maint. hassles of v's and all the benefits below....

Let the fun begin.


Thanks for yalls help. My bike is getting tuned up now but when i go pick it up i will ask if the wheels can be upgraded to disc brakes. I wish i had just bought them to begin with.

[Brizn]

Ok, got it. Yea i definitely understand all other superior aspects of disc.. was just curious about the physics.. now i understand: clamp force. aye.

OP: yea man, you could even call the shop where your bike is and have someone check 'em far ye'. "Are my hubs disc ready?--I can't remember."

[saxman]

Thanks for yalls help. My bike is getting tuned up now but when i go pick it up i will ask if the wheels can be upgraded to disc brakes. I wish i had just bought them to begin with.

..and therein lies the real fun of owning a bicycle that can readily adapt to upgrades. Anything you wish you had on your bike, most of the time, you can upgrade so you CAN have it. Don't fight it. Upgraditis is only harmful to your wallet.

[starcitymtb]

...I can easily modulate the brake to the point of locking the wheel with one finger.

I have a question, I have too much modulation and about half life on my pads. I went to The Bike Lane to have my brakes bled thinking adding more Hydraulic Fluid might be the answer but it wasn't. It did help stiffen up my lever but I still have to apply a good amount of pressure to lock up the rear wheel. Are you really able to lock up the rear with minimal pressure?

Would the next trouble-shooting action be changing the pads? Maybe they have been contaminated or something.

[DaveG]

I have a question, I have too much modulation and about half life on my pads. I went to The Bike Lane to have my brakes bled thinking adding more Hydraulic Fluid might be the answer but it wasn't. It did help stiffen up my lever but I still have to apply a good amount of pressure to lock up the rear wheel. Are you really able to lock up the rear with minimal pressure?

Would the next trouble-shooting action be changing the pads? Maybe they have been contaminated or something.

Clean with alcohol, and re-bed in the brakes. If they're contaminated this usually solves the problem.

Dave

[starcitymtb]

Clean with alcohol, and re-bed in the brakes. If they're contaminated this usually solves the problem.

Dave

Nice. Good call. Right under my nose. Never thought of lightly scuffing the rotor and pads.

I assume rubbing (isopropyl) alcohol will work. Maybe even ascetone (sp?). Unless someone says otherwise, those are the only choices I have at the house.

I might even try starting with Simple Green on the caliper and pads to start. Thanks!

[drewdane]

Thanks for yalls help. My bike is getting tuned up now but when i go pick it up i will ask if the wheels can be upgraded to disc brakes. I wish i had just bought them to begin with.
There's a good chance the '06 Rockhopper comes with disc-compatible wheels. (edit: D'oh! I really should read the whole thread first!)

[jabberwocky]

I have a question, I have too much modulation and about half life on my pads. I went to The Bike Lane to have my brakes bled thinking adding more Hydraulic Fluid might be the answer but it wasn't. It did help stiffen up my lever but I still have to apply a good amount of pressure to lock up the rear wheel. Are you really able to lock up the rear with minimal pressure?

Would the next trouble-shooting action be changing the pads? Maybe they have been contaminated or something.As Dave said, clean the rotors and scuff the outer layer off the pads and rebed them. I actually clean my rotors with a random orbit sander with 100 grit sandpaper. :)

Pad choice may be a factor. I've never ridden a stock pad I really liked. Most aren't bad, but aren't great either. The EBC gold pads I run are sintered metal. They grab harder than organic pads, but they generate more heat (and wear the rotor faster). In fact, they cannot be used with brakes that use mineral oil as a brake fluid (Shimano and Magura) because the fluid isn't capable of absorbing the heat and will boil. I compensate for the heat issue somewhat by using larger 180mm rotors. With the setup I run, I can easily use my pointer finger only to lock either wheel, but I also have great modulation.

[starcitymtb]

As Dave said, clean the rotors and scuff the outer layer off the pads and rebed them. I actually clean my rotors with a random orbit sander with 100 grit sandpaper. :)

Pad choice may be a factor. I've never ridden a stock pad I really liked. Most aren't bad, but aren't great either.

I went to town on these things tonight with the sand paper before I read your post. FYI, 220 Grit doesn't do crap to hardened rotors. I was afraid to use anything more corse but I will go to the medium paper now that I know you are using a Dewalt on yours. Maybe even break out the Dremmel.

I was able to get to the pads though and that changed things a bit. The brakes definitely grabbed more but not to your standard. If this doesn't work, I saw on Blue Sky they had some Hayes replacement pads. I think they are semi-metallic also. That may be just what I need.

I can't wait until I feel more comfortable with my braking power. Don't get me wrong, I am not into power slides or grinding up switchbacks but I would like to be able to slow my roll when I need to. Most my braking is up front and I am not having any problems up there. I just hate to get some high speed wheel suck on a fast downhill because my rear brakes aren't working. Know what I mean???

[BikerMiker]

Rear brakes suck because when you brake, your bike slows down, you slow down less and all of your weight shifts forward. And what is forward of you on the ground still in contact (hopefully) with the ground? That's right, your front wheel. All of your braking forces transfer weight and therefore traction to your front wheel. Under hard braking, your rear brake is useless as you are REALLY weighting that front wheel. Just a bit more weighting of your front wheel (ie: harder braking) is called 'drilling your head into the dirt.'

Rear brakes work the way that physics wants them to. That being said, swap out to smaller rotors in the rear and learn how to use front and rear brakes differently.

There's a reason why we practice getting our butts behind the seats. It lowers your center of gravity and makes you less likely to pivot around that front hub, drilling yourself into the dirt, head first.

Power comes from the lack of flex in the system: cables stretch under load, housing compresses under load, brake posts flex under load, rim sidewalls compress, brake pads deform, brake arms flex. With hydraulic discs, you have fluid delivering the power, free from compression, a caliper that is rock solid (no flex) and a braking surface made of solid steel. No flex in the mounting system either. People who like cable actuated discs are missing most of the advantage in the power delivery system. Not to mention that you are more likely to get your cable/housing contaminated than a closed hydraulic system.

mike

[starcitymtb]

Rear brakes work the way that physics wants them to. That being said, swap out to smaller rotors in the rear and learn how to use front and rear brakes differently.


mike

Mike,

My issue is that it has been a real pain in the arse getting the same braking power out of these hydraulics versus the weight/convenience/performance ratio from my V brakes. I was running Avid V's that you couldn't tourque the wheel out of their grips.

What worries me is when I get to my trails back home. I want to be able to keep the bike speed under some control at the speeds I am running on these downhills. Just to give you some idea of the issue, at stand still and on level ground, I can engage the rear brake with full pressure and force the rear wheel to turn by pushing the bike backwards. Forwards, not so much but to me still a failure.

As for rides, I am behind the saddle on some shorter and steeper runs, but on longer sustained downhills I stay more in an attack position where my rear hovers just behind the saddle so it can rise and hit my bottom when decending. At these speeds, using too much front will cause wheel suck and your front to dive down on you in the corners. It really is a balancing act between the two levers but I certainly know that the front is much stronger than the rear.

With that said, I am still concerned about the performance. If these things require so much energy to stop, there must be something causing the performance failure. The question is this product failure or mechanical failure. I am running 160mm rotors in both front and rear. Maybe I can stop by with the bike but this will be the fourth bike store that I have brought in for the problem.

Maybe just start small and get some new brake pads. hmmph.

[BikerMiker]

I'd love to take a look at it. If you are getting zero power at the wheel, there couldn't be too many things wrong. What brakes do you have? If you are dumping simple green and other stuff onto the rotors, you probably have contaminated pads and a greasy rotor.

You aren't supposed to touch brake pads and rotors. If you get stuff on your pads/rotors, you have to dump 'em and start over. That's the manufacturer's answer anyway. If you touch the rotors, the grease from your skin makes bad things happen, same with the pads. It's a good idea to run your QR on the non-disc side of the bike so you don't grab the rotor to close the QR.

Scuffing the rotors happens from riding. I've never had to do that. If you get a few good rides on 'em when new, the pads 'bed in' with the rotors. Sound sexy. Basically, your pads are not that flat or even so the first few rides makes the surface of the pad more uniform and you can get more pad hitting the rotor, making braking better.

I think that you have some severe contamination issues. I'll look at it free of charge if we can hook up and meet at the shop. Count on new pads at least.

mike

[starcitymtb]

I'd love to take a look at it.

mike

I will try to come in Wednesday this week. That gives me a day or two to schedule a "client" for lunch. HA HA. Thanks for the advice. See you Wednesday but no later than Thursday.

Ken

[BikerMiker]

I can meet you there on Friday, but I work from home so I'm rarely there.

Just let Bega or Dave know that I'm supposed to look at it. They can take a quick look as well. There's a pretty good chance that they'll see something as well. I'll check it out on Friday, although it's supposed to be in the 70s that day... Hmm...

Where do you live or work? I can always meet you somewhere else. Just lemme know.

mike

[starcitymtb]

Where do you live or work? I can always meet you somewhere else. Just lemme know.

mike

I live in Alexandria but work in Lanham. Other end of the world from you but its all good.

Like you said, it is suppose to be nice on Friday. I was planning on going home to get some riding in. I am racing in the Dirty Dawg race at Mountain Lake on 1 April back home and don't have much between now and the race. It should be fun to try and race through there with all the single track and downhills. Supposedly it is the highest MTB race in the East Coast. Going to need my brakes to work!!!

What I am going to do is call the shop. I am starting to think more and more that the pads are contaminated and need to be replaced. I also think they are organic so what I may do is change to the semi-metallics.

I have Hayes HFX Mag XC on this bike. Does City Bikes carry Hayes Semi-Metallics?

Thanks!

Ken

[pepelkod]

If you got oil/grease on your pads a quick solution to get them back is to bake them on the grill. I tried everything else on mine (boiling, soaking in brake cleaner etc). The only thing that worked was cooking them at super high heat.

Put them on an *outdoor* grill. (The smell is bad). The will hit some temperature, smoke for a few seconds then stop smoking. Turn off the grill and wait. I have some on my bike that have been grilled and have had no other ill effects. BTW, this will get them back to 75% or better, but nothing is like a new set of good brake pads. I just use this technique because Im cheap.

-D

PS. I got this idea from some link posted here to an auto tuning website. So people do the same with car brake pads.




I live in Alexandria but work in Lanham. Other end of the world from you but its all good.

Like you said, it is suppose to be nice on Friday. I was planning on going home to get some riding in. I am racing in the Dirty Dawg race at Mountain Lake on 1 April back home and don't have much between now and the race. It should be fun to try and race through there with all the single track and downhills. Supposedly it is the highest MTB race in the East Coast. Going to need my brakes to work!!!

What I am going to do is call the shop. I am starting to think more and more that the pads are contaminated and need to be replaced. I also think they are organic so what I may do is change to the semi-metallics.

I have Hayes HFX Mag XC on this bike. Does City Bikes carry Hayes Semi-Metallics?

Thanks!

Ken

[DaveG]

If you got oil/grease on your pads a quick solution to get them back is to bake them on the grill. I tried everything else on mine (boiling, soaking in brake cleaner etc). The only thing that worked was cooking them at super high heat.

Put them on an *outdoor* grill. (The smell is bad). The will hit some temperature, smoke for a few seconds then stop smoking. Turn off the grill and wait. I have some on my bike that have been grilled and have had no other ill effects. BTW, this will get them back to 75% or better, but nothing is like a new set of good brake pads. I just use this technique because Im cheap.

-D

PS. I got this idea from some link posted here to an auto tuning website. So people do the same with car brake pads.

Same principle. I personally have never contaminated a pad that badly though.

Dave

[starcitymtb]

I just use this technique because Im cheap.

-D

PS. I got this idea from some link posted here to an auto tuning website. So people do the same with car brake pads.

With the amount of time and money we spend on our bikes, there is no substitution for good ole' American ingenuity! I am going to try that when I get home. Thanks for the tip!

[jfoley]

camping stove works well too... whatever you use to heat them, do it gently and let the pads cool slowly. a couple of years ago we tried to cool a set of pads faster by dunking them in a pot of water and the shock of rapid cooling of the two different materials (pad & backing) caused them to come apart.

Same principle. I personally have never contaminated a pad that badly though.

Dave

[johnl350]

Thanks for yalls help. My bike is getting tuned up now but when i go pick it up i will ask if the wheels can be upgraded to disc brakes. I wish i had just bought them to begin with.

Ok I picked my bike up yesterday and the wheels that are on it now are not disc brake compatible. Im going to call on Wed to get a quote on some new wheels for my bike that i can put the brakes on. What should i expect to pay for some new wheels? Everywhere i look all i find are real expensive ones. I am hoping not to have to spend more than 150 or 200 for new wheels. Im also trying to see if its worth it to spend probably around 400 for new wheels and disc brakes for my bike when i only spent 600 for my bike brand new. I really like my bike and dont want a different model so i dont want to buy a new one but feel kind of stupid paying so much just to get disc brakes...although i do think the upgrade would make my bike much better. Let me know what yall think. Thanks for your help.

[ride-n-fall]

I really like my bike and dont want a different model so i dont want to buy a new one

You said all that needs to be said right there. Liking and being comfortable on the bike you have is, in and of itself, a perfect reason not to buy a new bike, but instead only upgrade the brakes.

Nothing wrong with taking a good bike making it better. Kind of like taking a sad song and making it better . . .Remember to let her into your heart . . . Then you can start to make it better . . .

It's one of those days.

[starcitymtb]

Ok I picked my bike up yesterday and the wheels that are on it now are not disc brake compatible.

John,

Not to crush our LBS but you can go online to JensonUSA, Nashbar or BlueSkyCycling and find some decent XC wheelsets for right around $100.00. You will have to buy rotors for them but it will be a bit cheaper. They even have complete packages for upgrades including all of this.

If you are just going to run mechanicals, you can use your levers. If you run hydraulics, you'll need to get the complete set of levers and calipers but they are relatively easy to install.

Good luck!

With everyone getting back on their bikes though, I'll bet you can call around to some of the sponsors on this site and find a good deal. Nothing replaces customer service especially when you have a problem.

[Dirt]

Not to crush our LBS but you can go online to JensonUSA, Nashbar or BlueSkyCycling and find some decent XC wheelsets for right around $100.00. You will have to buy rotors for them but it will be a bit cheaper. They even have complete packages for upgrades including all of this.


As a wheel builder for the last 29 years, I'd just say that you get exactly what you pay for when you buy inexpensive wheels. Machine-built wheels have gotten amazingly cheap these days. In fact many of the deals that you see on the internet are significantly cheaper than what it costs to buy the parts.

I'm sure there are folks who have had machine built wheels last. I've seen so many die young that I can't recommend that people buy them.

At those kind of prices, it is really hard to resist the machine-built wheels. Just realize that there is the real possibility that you'll be working on them or having them rebuilt some time soon.

Sorry. That's my inner bike snob showing its ugly face again.

Pete

[DaveG]

As a wheel builder for the last 29 years, I'd just say that you get exactly what you pay for when you buy inexpensive wheels. Machine-built wheels have gotten amazingly cheap these days. In fact many of the deals that you see on the internet are significantly cheaper than what it costs to buy the parts.

I'm sure there are folks who have had machine built wheels last. I've seen so many die young that I can't recommend that people buy them.

At those kind of prices, it is really hard to resist the machine-built wheels. Just realize that there is the real possibility that you'll be working on them or having them rebuilt some time soon.

Sorry. That's my inner bike snob showing its ugly face again.

Pete

Everytime I get suckered into buying machine built wheels because of the price they fall apart on me. If you get a machine built set pay a bit of cash to have somebody competent retension them before using them.

Dave

[luvdatrails]

If you are just going to run mechanicals, you can use your levers. If you run hydraulics, you'll need to get the complete set of levers and calipers but they are relatively easy to install.

I've wondered about this a lot, considering a set of mechanicals. Is this true most of the time (using your existing levers)? I didn't like the thought of upgrading to discs to also mean shifters too. (XT 8 speed on bike 1 and XTR 9 speed on bike 2).

[starcitymtb]

I've wondered about this a lot, considering a set of mechanicals. Is this true most of the time (using your existing levers)? I didn't like the thought of upgrading to discs to also mean shifters too. (XT 8 speed on bike 1 and XTR 9 speed on bike 2).


All you need to install mechanicals are the calipers/rotors. Your current lever whether it be an integrated system or not, will work. You will have to add a lower housing on both the front and back plus new cables but that is it. I was toying with that very idea on my other bike but ended up with hydros!

[starcitymtb]

Sorry. That's my inner bike snob showing its ugly face again.

Pete

Don't apologize for experience. That is what is great about this forum is that riders can take in information, apply it to their needs and riding style, and make a more informed decision.

The caveat is I am sure that there can be too much information that can bog down LBS employees with a guy going through hyperbole and uncessary situations.

I have had friends who have bought wheelsets from the internet and threw the rim tape on and off they went. A couple have had very bad experiences with that. None were the lower end wheelsets either but stuff like Mavic SLs going out of true and ending up bending the rim.

Like posted earlier, if you buy something as important to your bike as a wheelset, get the tension checked by your LBS.

[Dirt]

Like posted earlier, if you buy something as important to your bike as a wheelset, get the tension checked by your LBS.

I wish it was as simple as just checking tension. Though wheel building machines have improved greatly over the years, many, if not all, skip vital steps in the wheel building process that doom their wheels from the start.

1) They rarely prep the spokes correctly. Spoke threads need a prep that provides an element of lubrication and also adhesion in order to really build well. Linseed oil is my personal favorite.. dip the spoke threads in it, wipe most of the excess off, then let them sit over night. Blue locktite works well. DT, Wheelsmith and others also make spoke prep. This not only helps in the building process by reducing spoke twisting, it also makes trueing down the road much easier.

2) The rarely lubricate the nipples. (Craig2: please insert an off color remark here.) A tiny drop of Phil Tenacious Oil applied at the base of the nipple and then cleaned off after the building process goes a long way to insuring that spokes tension up evenly and helps prevent the nipples from deforming. (Craig2: You can have fun with that line too.)

When I've been asked to make a machine built wheel work like a hand-built wheel, the process involves completely dismantling the wheel, replacing the nipples, prepping the spokes, and then building the wheel up as though it was hand built. Even then the wheel isn't quite as good as if I'd started from scratch.

Again, that is a nitpick on my part. I learned wheel building from a 70 year old mechanic who was about as crusty and cranky as you can imagine. Though I'm more open minded to innovations in spokes, nipples, hubs and rims, I'm somewhat alarmed that I'm rapidly becoming as crusty and cranky as he was.

Pete

[starcitymtb]

I wish it was as simple as just checking tension. Though wheel building machines have improved greatly over the years, many, if not all, skip vital steps in the wheel building process that doom their wheels from the start.

1) They rarely prep the spokes correctly...

Pete

Funny... my buddy bought a wheelset from one of the foremetioned internet sites. He couldn't wait to get them on his bike and on the trail. We were flying down a trail that had a hard banked switchbank at the bottom and POP! He was on the ground. We dusted him off and checked if he was okay. I thought his tire came off the rim.

When we looked the rear tire, every spoke on half the wheel had become loose and collapsed the rim. The wierdest thing I have ever seen. Don't know if it was the nipples or the spokes but there was certainly something wrong with the way the wheel was set up.

[johnl350]

Thanks again for all of your help. I ended up ordering the Shimano Deore Disc Wheelset w/ Sun Ds-2 Rims and the Avid BB7 disc brakes. I think i will like them alot better than the v brakes i have now.

[starcitymtb]

Thanks again for all of your help. I ended up ordering the Shimano Deore Disc Wheelset w/ Sun Ds-2 Rims and the Avid BB7 disc brakes. I think i will like them alot better than the v brakes i have now.

Congrats John. That is the combo I was thinking of all along. Good luck. I know you'll be happy!