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Post by goffski on Aug 21, 2015 14:33:14 GMT
Pads are easy enough to change but never tried to drain them (took it into a shop for this). Not really sure if you're meant to just swapped the pads over without draining etc. They still work anyway!
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Post by lenodd on Aug 21, 2015 14:44:04 GMT
When I say reliability, I think I mean long term operation, servicing and parts / maintenance, but no experience of servicing or owning them (my MTB is just that bit too old), so I'm just thinking aloud. I do know that not a lot of effort goes into changing brake cables and blocks at present, a bit of regular rapid cleaning and occasional lubing is all I do - I've no idea about how discs pan out. yeah, I get you, but anything that increases braking performance and adds to longevity of wheels sounds like a good thing. For a winter bike its getting towards the top of my list.
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Post by jimc on Aug 21, 2015 14:53:57 GMT
I've got hydraulic discs on my MTB and they're by far the best brakes I've used on a bike, even though the Avids get slated in reviews for not having enough power, I can lock the back wheel at any speed and you wouldn't need much power on the front to launch yourself superman style. They're also been maintenance free so far - I'll need some new pads soon, but I don't think they're anywhere near need a fluid change.
As a contrast I've got single pivot Weinmann callipers on my old bike and they're just about useful as a stopping mechanism and that's with modern blocks!
So my next modern road bike will have discs, but that purchase will be dependent on wearing out the T5 which isn't likely to happen for quite a while!
The other thing to take into account is that disc wheels need to be laced differently to rim brakes, often with 32 hole hubs too, so there's extra weight too outside of the rotors and callipers.
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Post by ianmoss on Aug 21, 2015 14:54:17 GMT
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Post by wardy99 on Aug 21, 2015 14:55:22 GMT
Simple question ... simple answer? Just to throw my two-penneth in. All disc brakes are not equal. I've got cable pull disc brakes on one bike & hydraulic disc brakes on another. All else being equal, the stopping power of the hydraulic disc is FAR superior to a cable pull. In my experience, the difference between a cable pull disc brake & a standard rim brake (with good quality pads) is negligible.
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Post by Radchenister on Aug 21, 2015 14:59:58 GMT
When I say reliability, I think I mean long term operation, servicing and parts / maintenance, but no experience of servicing or owning them (my MTB is just that bit too old), so I'm just thinking aloud. I do know that not a lot of effort goes into changing brake cables and blocks at present, a bit of regular rapid cleaning and occasional lubing is all I do - I've no idea about how discs pan out. yeah, I get you, but anything that increases braking performance and adds to longevity of wheels sounds like a good thing. For a winter bike its getting towards the top of my list. Wet kills rims and equals poorer performance, no debate there, can't say it bothers me when out on the winter bike though, but then I target dry spells and use the turbo if it's too grim; this winter I rode flat long loops rather than hills if it was wet on the roads come the weekend, so as to reduce wear, this knocked the wear issues back a fair bit - I simply don't get the same rim wear issues on the dry one with Koolstop blocks, I'm now having issues with wearing out the Fulcrum bearings more than the rims, the latter are barely different to new. My T3 is now on the bargain basement original groupo again and I think of it as semi disposable in terms of parts, if I went for a winter training bike with discs, chances are I'd have a better spec winter bike than best bike, that's not going to happen - so we're back to whether I buy them for the best bike or not. I think commuting is a different issue, as safety, reliability and longevity are bigger issues, you're on the bike a lot, rain or shine, rolling in rush hour, so it makes more sense there to me.
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Post by Radchenister on Aug 21, 2015 15:16:16 GMT
I saw that GCN video this morning ianmoss - it's the reason I posted this thread ... personally I don't buy into the very rough science ... great guy that Simon is, he's obviously got puny ex pro arms / grip strength ! More seriously, I'd have to have a play, test them back to back myself, to see if the precision and modulation really made any practical difference; I can lock wheels already in the dry, so not convinced that the discs will be beneficial there, even though they're reporting a slight benefit, I'm not so sure - as for the wet, yep, kind of getting the idea that it takes a second or two to rub off the damp with blocks and they're not working as efficiently / consistently so pads have a head start but not sure if you can't just grip harder to rein that back in. I can still lock up almost immediately in all but torrential rain, so yet to be fully convinced on the difference - I often rub the rims a bit at the start on a long descent to pre-empt any dampness lag and also get a feel for the power needed early, rubbing them again a bit further on to keep surfaces active sometimes helps as well. Don't get me wrong, I think discs are definitely going to be better but how much better, I'd like to try for myself.
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Post by Radchenister on Aug 21, 2015 15:21:50 GMT
Good input wardy99 - I suppose there's a danger that if manufacturers of low spec bikes stick on any old system, just because disks are what people have been told they need, then the set up could be getting more complicated for no particular benefit. That said, I wonder if there's likely to be a point when there's no longer any real choice on new bikes? ... 3, 5, 10 years?
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Post by william39 on Aug 21, 2015 15:38:18 GMT
Changing the subject slightly. With regards to rim wear, if your wheels don't have indicators (Mavic Aksium) how do you measure it? Doing lots of long alpine descents I imagine mine are quite worn as braking performance is getting poorer but I don't have another wheelset to slip in to see if there is a difference braking wise. I'm currently debating whether to order a set of 501s for winter or just run the Aksiums into the ground and get a more expensive set next year.
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Post by Radchenister on Aug 21, 2015 15:55:23 GMT
Could try to use calipers on the rim and check thickness that way (find local garage / engineering shop - take tyre off, pop in, ask nicely, they'll do it in seconds); I rebuilt my rear Aksium when it went quite bowed, pads can also rub a groove in. I didn't measure thickness on mine through, they just looked odd and felt dodgy to the touch, a mate's old Dura-Ace wheels (that I've got here for repair) have worn much more than mine though, they've worn so much they started to collapse slightly in one spot near the outer edge but haven't actually failed, you should be able to tell by eye and touch if you give them a close inspection. You're a prime candidate for rim wear failure though with all those hairpin turns to brake for on long fast descents, best not take too many risks stretching them out, if in doubt then replace. What I find curious, is everyone always says you brake harder on the front (true when digging the front in with a car or motorbike) but both mine and my mate's rims wore most on the rear (believe this is normal for most)- either there's more force going through the rear (when people stretch arms and hang out back when braking hard) than people give credit for, or perhaps they just get more gunked up?
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Post by Deleted on Aug 21, 2015 16:05:06 GMT
Could try to use calipers on the rim and check thickness that way (find local garage / engineering shop - take tyre off, pop in, ask nicely, they'll do it in seconds); I rebuilt my rear Aksium when it went quite bowed, pads can also rub a groove in. I didn't measure thickness on mine through, they just looked odd and felt dodgy to the touch, a mate's old Dura-Ace wheels (that I've got here for repair) have worn much more than mine though, they've worn so much they started to collapse slightly in one spot near the outer edge but haven't actually failed, you should be able to tell by eye and touch if you give them a close inspection. You're a prime candidate for rim wear failure though with all those hairpin turns to brake for on long fast descents, best not take too many risks stretching them out, if in doubt then replace. What I find curious, is everyone always says you brake harder on the front (true when digging the front in with a car or motorbike) but both mine and my mate's rims wore most on the rear (believe this is normal for most)- either there's more force going through the rear (when people stretch arms and hang out back when braking hard) than people give credit for, or perhaps they just get more gunked up? Pretty sure the rear rim wear is down to more grime from the road. Giving mine a wipe down after an outing the back one is always the dirtiest.
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Post by Rocket on Aug 21, 2015 16:29:17 GMT
Radchenister my take is the front lifts debris for the rear to catch so the rear has more grinding paste to wear with. My rear rims have always worn more than the front and like yourself I'm a motorcyclist so the front always does the most work for me. In my case I believe this is also why almost all of my punch-ers have been in the rear tyre.
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Post by Radchenister on Aug 21, 2015 16:42:05 GMT
Most likely. Rear tyres always wear more, reckon that's down to load when seated going mainly through the rear as don't think it's torque and cornering like on a big bike (?). As for braking, I'm uncertain what's happening, although I reckon hanging off the back (like most of us do when braking hard), probably adjusts the relative weighting more than on some vehicles - reckon it's probably more evenly spread than for cars / motorbikes, what proportion front to back is something I'd be interested to know more about, I'm assuming it's likely a pretty dynamic thing.
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Post by Rocket on Aug 21, 2015 16:52:51 GMT
Rear tyre wear is definitely torque for me as I weigh nowt My current GP4000s front tyre has done over 9,000 miles and still has life left. It's wearing on the shoulders rather than the middle but back tyres are shot after 4,000 miles with a squared off profile down to the carcass. Weight distribution when braking on a bicycle has a massive effect on front/rear brake use as even the lightest riders weighs many times more than the bike. I notice Planet X do a disc and conventional version of their RT90 bike. The increase in weight for the disc version is not massive but the price increase is.
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Post by derekv4 on Aug 21, 2015 17:35:14 GMT
Having only bought a new bike last November I won't be getting an n+1 anytime soon, especially since I still think it is the best thing since sliced bread.
Do I wish my current bikes had disc brakes? Every single time I ride it in the wet, especially when descending in the wet!
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