Brake Discs - How long should they last & how to true them?
Discussion
Afternoon all,
I've had my Boardman for 9 months, and covered around 1,300 miles on it.
Annoyingly, the front disc (the calipers are Avid BB7, so I assume the discs are too) is somewhat warped, so at the moment I have to choose between having bugger all braking power on the front, or having the pads rubbing against the disc.
Is this normal? In their defence, they've got to slow the best part of 140kgs of me, bike and fully laden panniers on a bad day, but on the other hand, as I'm only commuting on roads, I very rarely need to really haul on the anchors, so they've not been given a regular battering by any means.
Is there an easy way to straighten the disc? If I just loosen off the tension on the bolts attaching it to the hub and then move round the wheel tightening them back up to the specified torque, would that help?
It's frustrating at the moment!
I've had my Boardman for 9 months, and covered around 1,300 miles on it.
Annoyingly, the front disc (the calipers are Avid BB7, so I assume the discs are too) is somewhat warped, so at the moment I have to choose between having bugger all braking power on the front, or having the pads rubbing against the disc.
Is this normal? In their defence, they've got to slow the best part of 140kgs of me, bike and fully laden panniers on a bad day, but on the other hand, as I'm only commuting on roads, I very rarely need to really haul on the anchors, so they've not been given a regular battering by any means.
Is there an easy way to straighten the disc? If I just loosen off the tension on the bolts attaching it to the hub and then move round the wheel tightening them back up to the specified torque, would that help?
It's frustrating at the moment!
Afternoon KP,
You shouldn't be having any issues with the use you are giving the discs, but they do sometime seem to run out of true.
I'd just check all the 'disc to hub' bolts are tightened correctly, then if you use an adjustable spanner and slot over the disc and tighten gently then use it to flex the disc back/straight bit by bit until you feel it is spinning true with out rubbing the pads. You should then be able to take up some cable slack and have a sharper/closer brake biting point.
Oh, and just make sure the disc is actually running central between the pads.
HTH
Pete
You shouldn't be having any issues with the use you are giving the discs, but they do sometime seem to run out of true.
I'd just check all the 'disc to hub' bolts are tightened correctly, then if you use an adjustable spanner and slot over the disc and tighten gently then use it to flex the disc back/straight bit by bit until you feel it is spinning true with out rubbing the pads. You should then be able to take up some cable slack and have a sharper/closer brake biting point.
Oh, and just make sure the disc is actually running central between the pads.
HTH
Pete
If they are out of true, they are scrap.
You will never successfully straighten them.
Top Tip: If you have just come screaming down a hill and heated your pads up to orange hot, ride around for 20 seconds before coming to a halt. Those orange hot pads will stop a small section of the disc cooling down and will warp the disc.
You will never successfully straighten them.
Top Tip: If you have just come screaming down a hill and heated your pads up to orange hot, ride around for 20 seconds before coming to a halt. Those orange hot pads will stop a small section of the disc cooling down and will warp the disc.
Thanks guys. At around £25, I reckon it probably makes more sense to replace it than drive myself nuts trying to true it!
This, then, generates my next questions...
Given that none of the listings for rotors make any mention of the spacing of the bolt holes, can I assume that I can fit any 160mm 6 hole rotor as a replacement, or am I limited to Avid rotors?
If I can fit any, is there any significant advantage to the Hope floating rotors?
This, then, generates my next questions...
Given that none of the listings for rotors make any mention of the spacing of the bolt holes, can I assume that I can fit any 160mm 6 hole rotor as a replacement, or am I limited to Avid rotors?
If I can fit any, is there any significant advantage to the Hope floating rotors?
Raven Flyer said:
If they are out of true, they are scrap.
You will never successfully straighten them.
Top Tip: If you have just come screaming down a hill and heated your pads up to orange hot, ride around for 20 seconds before coming to a halt. Those orange hot pads will stop a small section of the disc cooling down and will warp the disc.
That's not true, I've had lots of success truing a brake disc with an adjustable spanner. Maybe they're not perfect, but you can easily prevent rubbing.You will never successfully straighten them.
Top Tip: If you have just come screaming down a hill and heated your pads up to orange hot, ride around for 20 seconds before coming to a halt. Those orange hot pads will stop a small section of the disc cooling down and will warp the disc.
Park even do a tool for it...
takes 2 mintues and is certainly worth a crack.
Having said that Avid discs do have a very bad reputation generally so if you're looking for an excuse to upgrade to Shimano this is it.
Rob_T said:
This might sound like complete overkill but I would be tempted to upgrade to 203mm discs. You will need to get a disc brake adaptor as well. I found the braking with the larger discs much more progressive and assured. Luckily they look great as well.
This is a CX bike used for London commuting, not a DH bike used in the Alps! 
I have, however, decided that there are far nicer looking shiny bits, so need to know if they'll fit!
Kermit power said:
Rob_T said:
This might sound like complete overkill but I would be tempted to upgrade to 203mm discs. You will need to get a disc brake adaptor as well. I found the braking with the larger discs much more progressive and assured. Luckily they look great as well.
This is a CX bike used for London commuting, not a DH bike used in the Alps! I have, however, decided that there are far nicer looking shiny bits, so need to know if they'll fit!
These are the ones I have: http://superstar.tibolts.co.uk/product_info.php?cP... They're been great. They do the adapter too (http://superstar.tibolts.co.uk/product_info.php?cPath=57&products_id=359)
Change of plan!
I think I'm going to go for a pair of these.
£99 per wheel including rotors and pads, then flog the BB7s on eBay.
Reviews on the web are great, and one of the guys in my LBS has them on his bike and was recommending them over and above anything they themselves sell, which can't be bad!
I think I'm going to go for a pair of these.
£99 per wheel including rotors and pads, then flog the BB7s on eBay.
Reviews on the web are great, and one of the guys in my LBS has them on his bike and was recommending them over and above anything they themselves sell, which can't be bad!
You can true the rotors by hand - I've done it on my old bike after a bit of an excursion into the undergrowth. They only have to be out-of-true by a tiny fraction to cause rubbing.
As they are true-able by hand, they are also un-truable by hand!
I guess that what I'm saying is, be careful when operating the quick release on the front wheel that you don't hold onto the rotor to use as leverage to close the QR skewer, or resting something against the rotor when locking them up in your garage/shed/bike-store/kitchen or when piling a kit bag on top of the wheel in the boot of the car etc etc... not accusing you of doing such a thing of course, but shows how easily they are bent if you apply forces in a direction the rotors weren't designed to take.
I certaily agree that you immediately need to go out and buy a new bike, but this time, don't even consider anything under £5k!
As they are true-able by hand, they are also un-truable by hand!
I guess that what I'm saying is, be careful when operating the quick release on the front wheel that you don't hold onto the rotor to use as leverage to close the QR skewer, or resting something against the rotor when locking them up in your garage/shed/bike-store/kitchen or when piling a kit bag on top of the wheel in the boot of the car etc etc... not accusing you of doing such a thing of course, but shows how easily they are bent if you apply forces in a direction the rotors weren't designed to take.
I certaily agree that you immediately need to go out and buy a new bike, but this time, don't even consider anything under £5k!
Kermit power said:
Change of plan!
I think I'm going to go for a pair of these.
£99 per wheel including rotors and pads, then flog the BB7s on eBay.
Reviews on the web are great, and one of the guys in my LBS has them on his bike and was recommending them over and above anything they themselves sell, which can't be bad!
I'd be interested to hear your thoughts when you get them.I think I'm going to go for a pair of these.
£99 per wheel including rotors and pads, then flog the BB7s on eBay.
Reviews on the web are great, and one of the guys in my LBS has them on his bike and was recommending them over and above anything they themselves sell, which can't be bad!
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