Lets talk brakes..
- Thread starter davidj
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Re: Re:
Yep you had to be very gentle with the lever if not it was either off or on!
JamesM":30xrkl6p said:kyle888":30xrkl6p said:I assume they'd been bedded in as at first i wasn't that impressed then they got way better.
I run a 203mm front
Far better modulation than some avid elixers I've tried out wheelieing etc
I had some elixr 5's (180/180), I wasn't going to mention it but I didn't think they were any better than my XT V's in the dry. The elixrs were pretty grabby, good for doing skids
Yep you had to be very gentle with the lever if not it was either off or on!
Osella
Senior Retro Guru
Re:
Not very many manufacturers of brakes or forks suggest 180mm for XC tho..
There's also a wide variation in expected surfaces, weight and relative stopping/slowing distance.
A 6.8kg racing bike + 65kg rider in a race on tarmac/cobbles, is a different stopping/slowing proposition to a 9kg MTB (and this is for XC!) on loose and importantly often changeable surfaces where the turns are often sharper, the inclines (usually!) much steeper and the track possible narrower (depending on pack riding, of course).
Rubbish brakes (Hayes, Avid) are also rubbish brakes. You can try Hayes discs, get bad fade and dismiss all discs - try some Maguras or Shimano's and I'd suggest a very different experience will be had! You'd find the same with cheap V's or cantis vs good sets though. Pads too make a massive difference.
Yes, on long descents discs may heat up & fade (it does depend how you use them though, they are better used for slowing down, not for maintaining a speed, just like car brakes) but equally they will not rub through your rims, and they are very unlikely to ping up into your tyre or into your spokes - so there are good & bad sides to each.
Discs are not faultless, but we are talking overall balance of +ve/-ve.
Not very many manufacturers of brakes or forks suggest 180mm for XC tho..
There's also a wide variation in expected surfaces, weight and relative stopping/slowing distance.
A 6.8kg racing bike + 65kg rider in a race on tarmac/cobbles, is a different stopping/slowing proposition to a 9kg MTB (and this is for XC!) on loose and importantly often changeable surfaces where the turns are often sharper, the inclines (usually!) much steeper and the track possible narrower (depending on pack riding, of course).
Rubbish brakes (Hayes, Avid) are also rubbish brakes. You can try Hayes discs, get bad fade and dismiss all discs - try some Maguras or Shimano's and I'd suggest a very different experience will be had! You'd find the same with cheap V's or cantis vs good sets though. Pads too make a massive difference.
Yes, on long descents discs may heat up & fade (it does depend how you use them though, they are better used for slowing down, not for maintaining a speed, just like car brakes) but equally they will not rub through your rims, and they are very unlikely to ping up into your tyre or into your spokes - so there are good & bad sides to each.
Discs are not faultless, but we are talking overall balance of +ve/-ve.
A 180 or 185 was XC or was proposed for general riding. It seemed at the time to be more like motorcycle in that they also use a big rotor on front and a small behind.
The rear was there to balance the stopping power but it seemed that both together would cause a skid so the front was always a bit bigger.
Same way the early brakes looked like a blacksmith made them. They werent wholly sure what would work so erred on the side of what they knew would, and i think that early association has stuck
Time and usage has proven a 160/160 to give a balanced brake.
A little more on the front if youre a little heavier(and arent we all :shock or the bikes heavier or even if its an incline, where the weight and gravity also acts against the slowing force on the front rotor.
I went Canti- Canti/ceramic -V's -V's Ceramic to Hope discs in about 1998. Been hope discs since then on a 185/165 set up. I personally liked the larger front as it made the bike look meaner
The rear was there to balance the stopping power but it seemed that both together would cause a skid so the front was always a bit bigger.
Same way the early brakes looked like a blacksmith made them. They werent wholly sure what would work so erred on the side of what they knew would, and i think that early association has stuck
Time and usage has proven a 160/160 to give a balanced brake.
A little more on the front if youre a little heavier(and arent we all :shock
or the bikes heavier or even if its an incline, where the weight and gravity also acts against the slowing force on the front rotor.I went Canti- Canti/ceramic -V's -V's Ceramic to Hope discs in about 1998. Been hope discs since then on a 185/165 set up. I personally liked the larger front as it made the bike look meaner
dyna-ti":etf2dofu said:Osella":etf2dofu said:
Of course you are taking into account Hopes swop from Closed to Open systems
Its simple really. A disc that goes between two plates with about a mil's clearance.greencat":etf2dofu said:
You spin the wheel- Does the rotor wobble ?
If so bend the rotor till true.
You know the rotor on its mount is straight and true
Pads. Do they retract as they do ?
What im getting at is if all the component parts are functioning as they should, then nothing should rub.
It is a fiddle but perseverance will get you there.
Im assuming youre referring to cable discs as opposed to hydraulic :? But either way, if the system is functioning correctly, there should be nothing making a noise :?
Cable being the problematic way of approaching this problem, though the solution they were looking for has more to do with cost and mass production, than stopping ability or ease of set up and use
It suggests that a system designed with one fixed pad, is really just a pointless exercise :?
The part about enjoying the ride discs or v's or cantis has to be the real point here. Admittedly i enjoy the muddy tracks on michellin runr 1.4 slicks. No brake helps there , in fact best leave well alone
Glazed rotors cause squeaking :? as do contaminated pads. Both of which are easily sorted and the former id recommend folk do more often than not :?
Rotor best deglazed using some wet and dry sandpaper, and any residue can be burnt out the pads using a blowlamp, only just to burn off the solvent, i have watched people try to weld them to the bench
Thanks for the tips. My problems are typically pads/pistons not retracting fully after extended use i.e. a long down hill (front/back) and so dragging slightly (sometimes for the remainder of the ride). Also frame shuddering honking on the back (even with brand new pads/discs) after about 20-100 miles.
I have run hydraulic Deore/Deore XT (had several different sets of Deores all with the same problems from new) and once spent an entire weekend following every tutorial I could find to try to cure the above. I now suspect it's simply heat build up/glazing related and I want a quiet to ride bike that doesn't need babying with constant maintenance so back to Vs it is.
Compare what you are suggesting above (and repeat every 20-100 miles) with slotting a new set of XTR style v-brake pads in every few months and the occasional barrel adjuster twist. One job takes approx five minutes every few months, the other takes at least half an hour at least a few times a month.
Still have a disc brake equipped bike, but it rarely gets out now I've got a v-braked one. Tend to only use it if the other is out of action/the missus is on the Add-1 (a trailer trike) as it has the mount already in place and I think the extra braking power is useful when I have extra weight.
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A few pointers for disc purchases
Avid and their 'composite' pistons - plastic, seizing left right and centre. I dont know whats in the current stuff but that was a big pain a few years ago
Hoses expanding under pressure
Cold weather - levers touching the bars before the brakes would even engage
Hot weather - those same brakes being unusable for a time after being dragged out of hot sheds
Calipers expanding under braking - not a lot written about this but they do. Not heat so much but the mechanical pressure pushing the calipers apart. Coda used to be one of the worst leaving the brakes pretty much useless.
Glazed pads
Wonky discs
Contaminated pads - disc brake cleaner isnt going to sort that either
My best set were the original Hope levers with the adjustable reservoir - I used these levers with all manner of calipers
And the fact that there are two completely incompatible fluids used, DOT and Mineral oils.
ISO, flat mount, post mount fittings - ISO that no one bothers with and so on....
Avid and their 'composite' pistons - plastic, seizing left right and centre. I dont know whats in the current stuff but that was a big pain a few years ago
Hoses expanding under pressure
Cold weather - levers touching the bars before the brakes would even engage
Hot weather - those same brakes being unusable for a time after being dragged out of hot sheds
Calipers expanding under braking - not a lot written about this but they do. Not heat so much but the mechanical pressure pushing the calipers apart. Coda used to be one of the worst leaving the brakes pretty much useless.
Glazed pads
Wonky discs
Contaminated pads - disc brake cleaner isnt going to sort that either
My best set were the original Hope levers with the adjustable reservoir - I used these levers with all manner of calipers
And the fact that there are two completely incompatible fluids used, DOT and Mineral oils.
ISO, flat mount, post mount fittings - ISO that no one bothers with and so on....
Interesting, we are still talking best system as we were in the '90's, I have great v-brakes, even better I feel are my old Magura rim-brakes on my Marin back end. However, even on short black runs and longish hill descents here in Scotland, they do make life interesting when things get fast. I ride an older rigid, a fat bike and a retro f/susser.
My oldish Hopes, and modern cheapo discs, stop more consistently than my rim brakes, and I have just weighed them against acera, lx and Marin v's....... disks seem 10-15 % heavier, but with lighter rims may on be closer on weight.
I find the consistency when I hit water/mud/snow/alps favours discs, especially lately, where I have had water freezing on my rim brakes, on high hills leading to zero braking.
I must say, I do remember buying the first 2 sets of TransX v's in Cardiff Cycle-logical, and them telling me I would rip the front of my Kona, exciting days........
My oldish Hopes, and modern cheapo discs, stop more consistently than my rim brakes, and I have just weighed them against acera, lx and Marin v's....... disks seem 10-15 % heavier, but with lighter rims may on be closer on weight.
I find the consistency when I hit water/mud/snow/alps favours discs, especially lately, where I have had water freezing on my rim brakes, on high hills leading to zero braking.
I must say, I do remember buying the first 2 sets of TransX v's in Cardiff Cycle-logical, and them telling me I would rip the front of my Kona, exciting days........
Re:
I came across this article the other day, pad wear might be an issue for longer "road" rides:
http://www.bikeradar.com/road/gear/arti ... deo-44489/
I came across this article the other day, pad wear might be an issue for longer "road" rides:
http://www.bikeradar.com/road/gear/arti ... deo-44489/
