Viewing 33 posts - 1 through 33 (of 33 total)
  • Disc brake at rear, v brake up front….why not?
  • SiB
    Free Member

    Building up a rigid ss scandel and whilst looking for carbon forks wondered why nobody has disc at back and v up front….v brakes cheaper than disc (yes, I know bottom end disc brakes are cheaper than some v brakes, easier to install, no bleeding issues or sudden loss of power mid ride, cheaper to fix and easier to maintain….and Im sure there must be a few more ‘incentives’ to use v.

    For gnarly downhill and the heavy hitters I can see why it should be disc on both but for me on my ss rigid scandel I cannot see it making too much difference on my XC rides?

    Yes, it would look a bit odd and obviously not as powerful as disc but then that surely helps the people who say ‘try not using the front brake much’ for a smoother ride and prevent OTB incidents, some might even say to make you a better rider/better line chooser to leave fron brake alone

    Discuss

    ir_bandito
    Free Member

    ‘try not using the front brake much’ for a smoother ride

    Who says that?

    Why do all cars and motorbikes have bigger brakes up front?
    In fact, why do most mtbs have bigger (and better) brakes up front?

    Because you control your speed with your front brake: it does a greater proportion of reducing your speed as when you brake, your weight is distributed more over the front. If your back brake is more powerful, you’ll just lock it up as the back wheel is “unweighted” and skid, losing traction and damaging the trail.

    V-brake only forks may be cheaper than discs, but you’ll wear your rims out sooner…

    mintimperial
    Full Member

    Your front brake is much more effective at stopping you than your rear brake. You should therefore use your front brake much more than your rear. A powerful rear brake will just lock your rear wheel and make you skid, a powerful front brake is very hard to lock up and is much better at slowing you down effectively. All other things being equal it would be far better to have a disc on the front and Vs or cantis on the rear rather than the other way round, and you do sometimes see bikes set up like this.

    So, “people who say ‘try not using the front brake much'” are silly and you should ignore them cos they’re talking rubbish. 😉

    mrmoofo
    Full Member

    Why would you want to do that?
    As mentioned above the centre of effort is behind the front brake. Hence it is way more efficient. On a motorbike, I very rarely even touch the rear brake – it makes a pillion’s ride more pleasant , so who cares 😉
    A disc at the front an Vs at the back would work – and was how we rode bikes back in the embryonic days of Hope disc brakes … but unless it is for the road, I wouldn’t know why you would bother TBH

    avdave2
    Full Member

    I have disc front and v rear on my rigid bike, can’t think for the life of me why you’d ever want to run it the other way round. V brakes are a pain in the neck in mud and if you want the simplicity of them a bb7 will do a much better job. I’d get my frame modified tomorrow to take discs if it didn’t also involve the cost of getting the Rohloff converted.

    garage-dweller
    Full Member

    Are you mad?

    Reasons as above and it would be aesthetically worse than not lining up tyre logos with valve holes.

    alpin
    Free Member

    not even worth commenting on, is it?

    SiB
    Free Member

    I remember reading a thread on here where folk were saying they rode better when front brake had broken, realising what their bikes ciould actually do when go faster and how much better they could ride when not constantly dabbing front brake……but I fully understand whjat you’re saying.

    Bit confused on one point though….if I had to pull on one powerful brake as hard as possible to come to a stop I would alwaysd chose the back one, done it with front one once and ended up OTB flat on my back! Would have much rather used the back and skidded to a halt!

    M1llh0use
    Free Member

    1/10 – poor trolling.

    SiB
    Free Member

    BTW, I’m taking all your comments on board, just cant get my head round it! And I will be going for 2 x disc so dont worry about my safety, thanks anyway.

    Slam on front brake on motorbike…I’ve see you’ve been framed, over the bars they go, slam on rear brake and its a graceful skid!!

    SiB
    Free Member

    M1llhouse….not trolling at all, I’m just not scientifically minded so still scratching my head over these rear and front brakes…..surely a front wheel skid is more dangerous than back wheel skid regardless of where weight, centre of gravity is etc. I wuold rather my back wheel slip sideways than my front sliding out when braking.

    Pierre
    Full Member

    Bit confused on one point though….if I had to pull on one powerful brake as hard as possible to come to a stop I would alwaysd chose the back one, done it with front one once and ended up OTB flat on my back! Would have much rather used the back and skidded to a halt!

    If you can _control_ your front brake (i.e. not just on / off), you have much more stopping power. Move your weight back (stick your arse off the back of the saddle) and you can do a very strong stop using only your front brake, without risking going over the bars.

    Granted, people may go on about riding more smoothly when not using the front brake, but that’s more because they’re not using the brakes at all then…

    M1llh0use
    Free Member

    seriously???

    ok, i’ll bite.
    why would you EVER “slam on” that’s just poor technique!?!?

    SiB
    Free Member

    Was riding behind someone not so long ago who didnt know the way, they stopped, I saw him too late (admittedly you could only put a rizla between his back and my font wheel) and slammed on…wrong I know but it does happen. Didnt have time to move weight over nback of saddle to prevent OTB.

    So what you’re saying than if its not an ’emergency’ and skidding isnt involved its best to use front as more effective……..but if you’ve got to slam on use the rear??

    M1llh0use
    Free Member

    not at all. What i am saying is that progressive use of brakes is far more effective than locking wheels.

    sounds like you need to go out and practice on some wet grass with just a front brake (PLEASE DO NOT TRY THIS AT HOME, WITHOUT THE CONSENT OF YOUR PARENTS, WHILE RUNNING WITH SCISSORS, IN THE CORRIDOR OR WITHOUT FULL BODY ARMOUR)

    firstly just grabbing a handful of front brake and falling off.

    then getting on the brake more progressively (to transfer some weight to the front tyre) and braking a bit harder.

    see which one you can stop with quicker. 🙂

    trail_rat
    Free Member

    Motorbike back wheel locked a graceful skid…. Not quite. My dads engine siezed and there was no graceful skid . There was just a graceful thump as it spat him over the bars.

    The only reasoning i can see is that on a rigid your front wheel will flutter around less if not being asked to brake over bumps.

    That still doesnt mean its good practice not to use it.

    Sounds like someone needs to go see jedi or a.n.other skills day

    trail_rat
    Free Member

    Once your rear wheel locks on a slippy surface like mud btw your no longer slowing down.

    ir_bandito
    Free Member

    how about this:

    glupton1976
    Free Member

    Jesus wept.

    SiB
    Free Member

    Yes, I realise that progessive braking is more effective than locking up and thats why I do it, dont need to line anyones pocket to teach me that. BUT if you have to slam on, say ractor coming out of gateway that hasn’t seen you (OK I should be ready for that as would be able to see and hear and be prepared), dog/cat running out infront of you (yes, I know this deserves them to be run over), mate slamming on infront of you………ie not enough room for progressive stopping I would prefer to slam on the rear and hopefully strill be on bike than front and OTB.

    br
    Free Member

    Slam on front brake on motorbike…I’ve see you’ve been framed, over the bars they go, slam on rear brake and its a graceful skid!!

    You’ve never ridden a m/c have you?

    johnellison
    Free Member

    surely a front wheel skid is more dangerous than back wheel skid regardless of where weight, centre of gravity is etc. I wuold rather my back wheel slip sideways than my front sliding out when braking.

    In a way you are correct – unless you’re an absolute genius, a front wheel slide is way more difficult/impossible to control/recover from.

    Think about it this way – most modern cars (bear with me) have the brake bias about 60/40 front/rear. Assuming that you are travelling at a constant speed and press the brake pedal, the weight of the car continues to travel forward (momentum) even as the car slows. This compresses the front suspension and presses the nose of the car down, increasing traction through the front tyres.

    As long as you brake progressively then the wheels won’t lock and break traction, which is when the trouble starts, because a locked wheel is neither slowing you down, nor can it be steered. If this happens, the correct remedy is to release and reapply the brakes, “pumping” the brake pedal (cadence braking). This is essentially waht ABS does for you, it pumps the brakes very rapidly to prevent the wheels locking completely and allowing you to steer under hard braking.

    Now look at a motorbike – a motorbike (with a few exceptions) has independent brakes. You operate the front with your right hand and the back with your right foot. You can stop a motorbike safely and quickly on a dry, non-slip surface by applying the front brake only, even if you really anchor on. Look at a modern sport/racing motorcycle – the front brakes are huge in comparison to the rear, often twin four- or six-pot calipers hauling on discs which are approaching 300mm diameter whilst the rear might be half that size with a measly single-pot caliper. All good motorcyclists know that all the braking is done on the front, in a straight line and bolt upright.

    HOWEVER…If you are on a loose or slippery surface you need to adjust your braking technique accordingly. You need to give yourself longer to stop; and you need to adjust your bias accordingly (with a few exceptions you can’t adjust the brake bias in a production car, which is why you need to leave longer and longer to stop as road conditions deteriorate).

    For motorcycles, the police “Roadcraft” driving manual recommends 80/20 bias on a dry road; 60/40 in damp conditions; and 50/50 in wet or icy conditions, increasing braking distances accordingly.

    Where am I going with this? Weeellll – personally I’m an advocate of using the front brake sparingly in off-road conditions, and the worse the conditions get, the less you should use it; BUT at the same time, good technique is just as important – grabbing a handful is asking for trouble; firm and progressive is where it’s at and if you lock up, let go.

    bentudder
    Full Member

    OP

    james
    Free Member

    V front, disc rear, I’ve done this before. But only on a real scrap parts bin special for local XC SS. Had a (cracked) disc only frame with V or disc mount fork (bushes had it, replacements n/a), and hadn’t a usable front disc brake. Only a V.
    Worked alright for waht I wanted it for, ie not much. It then got nicked

    TuckerUK
    Free Member

    I was always taught the front brake is for braking, and rear just for adding a touch of directional control as needed. Same on an MX bike, and same in a car really.

    SiB
    Free Member

    Slam on front brake on motorbike…I’ve see you’ve been framed, over the bars they go, slam on rear brake and its a graceful skid!!

    You’ve never ridden a m/c have you?

    last time about 20 years ago on nothing more than 125s off road as a bit of fun, no proper gear, just a bit of fun in school hols kind of thing…….and i have seen lots of you been framed clips of motorbikes doing front end skids that result in laughter!!

    br……i guess I’m just stupid, please accept my apologies

    As I was saying

    Yes, I realise that progessive braking is more effective than locking up and thats why I do it, …. BUT if you have to slam on……ie not enough room for progressive stopping I would prefer to slam on the rear and hopefully strill be on bike than front and OTB.

    johnneillson

    In a way you are correct – unless you’re an absolute genius, a front wheel slide is way more difficult/impossible to control/recover from.

    Thanks john, and thanks for your lengthy laymans term explanation

    I am aware progressive braking always best, yes, more on the front BUT as i keep saying (and its now a long way from my opening q but i’m glad we’ve come this far) when you have to slam on, say like when a badger suddenly appears and stops in your path 12 inches in front of you whilst you’re doing doing 15mph plus (i couldn’t in that situation you see, well done if you can, jumping over it best bet I reckon?)or a walker suddenly appears infront of you, or……..theres a lot of examples where instinctively you slam on, well I do anyway, when split second to think…..would you rather skid with no control on back or front wheel? Remember the important point….no time to stop progressively.

    londonerinoz
    Free Member

    There was a recent thread that mentioned that downhillers might be encouraged to stay off the front brake on steep or technical sections to prevent crashes and injury.

    In a panic stop situation though surely you would use both brakes? The influence of bias mix and body position for that terrain should mean you’re unlikely to go OTB, so the progression and bias mix is really just determining how far you travel before you stop. You may or not stop in time.

    If you were trying to avoid a serious enough collision, and realised you didn’t have enough distance to stop in control, like heading into a car or over a cliff, you may even intentionally go OTB, drop the bike into a slide, or leap off because crashing may bring you to a faster stop.

    The only stopping advantages I can think of might be a high end v brake compared to a poor disc brake that may have better modulation and even power. That being the case it would probably be better to have 2 high end v brakes. There are other advantages to v brakes such as the lack of drag, reliability and serviceability especially when travelling, and possibly weight. If I ever did want to build a rigid SS I probably would be tempted to put my old XTR v’s on. It’s clean and simple much like a canti equipped cross bike.

    joao3v16
    Free Member

    So overall it actually won’t matter in the slightest if you have v-brake on the front and disc on the rear.

    You’ll just adapt to the differences and you’ll soon be braking normally/correctly without even thinking about it.

    Talk about making a mountain out of a mole-hill 😀

    chiefgrooveguru
    Full Member

    I am aware progressive braking always best, yes, more on the front BUT as i keep saying (and its now a long way from my opening q but i’m glad we’ve come this far) when you have to slam on, say like when a badger suddenly appears and stops in your path 12 inches in front of you whilst you’re doing doing 15mph plus (i couldn’t in that situation you see, well done if you can, jumping over it best bet I reckon?)or a walker suddenly appears infront of you, or……..theres a lot of examples where instinctively you slam on, well I do anyway, when split second to think…..would you rather skid with no control on back or front wheel? Remember the important point….no time to stop progressively.

    At the exact same moment as you ‘slam on’ the brakes, you should powerfully push your hips back and down, like this:

    If you get in the habit of braking like this when you’re not panic braking, the probability that you’ll do it instinctively when panic braking will vastly increase, meaning you skid less, stop quicker and are far less likely to go over the bars.

    ndthornton
    Free Member

    I once had a set of bombers that had 2 disc mounts – I only ever mounted one though and never seen any double discs before. Who made the hubs to go with them? Im guessing this only lasted for a year?

    As for going over the bars – I can pull a full a front wheel skid on tarmac without even lifting the back wheel – just a question of getting your weight back. Haven’t been over the bars from over braking since I was 6 years old. People that do this can’t have been taught properly by their Dads – this is lesson 1!

    tmb467
    Free Member

    you can always progressively brake – it just takes time and practice

    if you don’t practice it you’ll get into bad habits and will end up going over the bars

    front brake will stop you much quicker than using the back…skids are for kids

    monkeytrousers
    Free Member

    I would consider a V on the front / disc on the rear, for the simple reason that I am uncomfortable with the braking forces being lower down towards the end of the fork with a disc, rather than higher up at the wheel rim… The rear disc brake, to me, seems subject to less force since the rider weight is in front of it, rather than behind it, and the seat / chainstay junction seems stronger than a near vertical length with a brake at the tip, acting like a lever. Just a theory I have based on logic.

    julianwilson
    Free Member

    Did this on a parts bin singlespeed for a mate (Fritz Von Rundle of this parish), just beacaue the fork had no disc mount and the frame had no canti bosses. It worked. Bike looked a delightful state, also had 26″ wheels, singlespeed, 1″ slick on rear, 1.8″ slick on front, and drop bars 😆

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