Conor the basher. Posted March 17, 2008 Report Share Posted March 17, 2008 Right so i was thinking today that if we have reverse maggie mounts why dont we try reverse disc mounts, so insted of the mount being on the back of the fork why not on the front.... im not to sure if there would be any gain but isit worth a try ? Quote Link to comment Share on other sites More sharing options...
MadManMike Posted March 17, 2008 Report Share Posted March 17, 2008 I would guess the disc would put strain on the mounts more or something? ie, easier to break the mounts? Quote Link to comment Share on other sites More sharing options...
NVWOCI WVS Posted March 17, 2008 Report Share Posted March 17, 2008 It's been done. Iolo did it, and i was thinking about it on some pashley forks, because i got to the left. Quote Link to comment Share on other sites More sharing options...
walker Posted March 17, 2008 Report Share Posted March 17, 2008 trials motorbikes are like that. Just seems a better, more compact place to have it behind the fork leg... Quote Link to comment Share on other sites More sharing options...
grant wildman Posted March 17, 2008 Report Share Posted March 17, 2008 pace did it years ago , rc 32 or 35 forks??couldnt you get adapters for P-Bone forks for disc's , like in tricks and stunts? they were front mounted calipers?think hope made the adapter , you had to use a hope hub with it though as you used a shorter axle......that histroy lesson didnt help much did it?? Quote Link to comment Share on other sites More sharing options...
basher Posted March 17, 2008 Report Share Posted March 17, 2008 Think why reverse maggie mounts are like that and then youll relise it would be worse off to have reverse disk.Reverse maggie mounts are like that so when the brake is applied the forces are directed in towards the forks where as normally they would be directed away from the forks. So in theory its stiffer and so on reverse.If you had a reverse disk mount the forces will be directed away from the fork leg putting more forces on the dab and i should think the break won't be as good. Quote Link to comment Share on other sites More sharing options...
Conor the basher. Posted March 17, 2008 Author Report Share Posted March 17, 2008 Think why reverse maggie mounts are like that and then youll relise it would be worse off to have reverse disk.Reverse maggie mounts are like that so when the brake is applied the forces are directed in towards the forks where as normally they would be directed away from the forks. So in theory its stiffer and so on reverse.If you had a reverse disk mount the forces will be directed away from the fork leg putting more forces on the dab and i should think the break won't be as good.yeah i geuss i was just thinking out loud lol Quote Link to comment Share on other sites More sharing options...
psycholist Posted March 18, 2008 Report Share Posted March 18, 2008 There is a good reason to put the disk mount on the front of the fork. It stops braking forces from pulling the front wheel out of the fork dropouts... There have been some nasty XC and DH accidents linked to this... Quote Link to comment Share on other sites More sharing options...
Haz Posted March 23, 2008 Report Share Posted March 23, 2008 Think why reverse maggie mounts are like that and then youll relise it would be worse off to have reverse disk.Reverse maggie mounts are like that so when the brake is applied the forces are directed in towards the forks where as normally they would be directed away from the forks. So in theory its stiffer and so on reverse.If you had a reverse disk mount the forces will be directed away from the fork leg putting more forces on the dab and i should think the break won't be as good. I came here to post this, the less shear force you can generate the better. If you have a joint, under tension, in most cases, it won't be as strong as a weld under compression. There is a good reason to put the disk mount on the front of the fork. It stops braking forces from pulling the front wheel out of the fork dropouts... There have been some nasty XC and DH accidents linked to this...Would only be a problem when there is a lot of momentum im te wheel, and in trials, there's not really.Would be cool to see an integrated caliper, would keep it safe and out of the way, like on the old Leesons, but on forks... Quote Link to comment Share on other sites More sharing options...
cai Posted March 24, 2008 Report Share Posted March 24, 2008 Don't vee's actually work better being mounted on the front of forks? as the arms and pads move slightly forwards with the rim (if your bolts are loose, the ones that go into canti-mounts) and this in turn offers greater bite, along with a greater noise.But this therory wouldn't work for a disc braek Quote Link to comment Share on other sites More sharing options...
Dan6061 Posted March 24, 2008 Report Share Posted March 24, 2008 When the mounts are on the back, the force from the braking goes into the forks.If they were on the outside, the force will be going against the forks, so it'll flex outwards.Same with the Magura mounts really... Quote Link to comment Share on other sites More sharing options...
Token Posted March 24, 2008 Report Share Posted March 24, 2008 I'm pretty sure the majority of the force would be pushed against the bolt head and threads, where as having the caliper in the normal position, the force is pushed through the mount an not the bolts because the bolts only hold the caliper in place.But then your not going to get the problem with Hopes only with BB7s. Quote Link to comment Share on other sites More sharing options...
psycholist Posted March 24, 2008 Report Share Posted March 24, 2008 For a correctly designed bolted joint there will be no change in the bolt tension with braking force. This works as follows - the bolt is tightened into the mount causing tension in the bolt and matching compression in the part the bolt is holding. When an extra load appears on the joint the load is absorbed by a change in the compression in the part the bolt is holding until this figure reaches zero in the case of an applied tensile load. At this point the bolt will take the remaining load as a change in tension. This is why bolts don't fatigue crack through the threads all the time as even on cyclically loaded joints the load on the bolt remains constant. Similarly the friction between the parts the bolts are holding together should be greater than the side loads on the joint in order to prevent the bolt from taking a shear load. Depending on the safety requirements of the joint the bolt is often sized big enough to not fail under direct shear just to be sure too... The reason tensile loads are less favoured in structures is because a tensile load is required to initiate a fatigue crack - an all too common cause of catastrophic failure in bike parts, so keeping disk mounts running predominantly in compression is a good thing. Metals are as stiff in tension as they are in compression while loads are below the yield strength of the material. Quote Link to comment Share on other sites More sharing options...
JT! Posted March 24, 2008 Report Share Posted March 24, 2008 Think why reverse maggie mounts are like that and then youll relise it would be worse off to have reverse disk.Reverse maggie mounts are like that so when the brake is applied the forces are directed in towards the forks where as normally they would be directed away from the forks. So in theory its stiffer and so on reverse.If you had a reverse disk mount the forces will be directed away from the fork leg putting more forces on the dab and i should think the break won't be as good.That's the theory, but looking at how tight maguras and disc brakes are held on, they shouldn't flex with the direction of the wheel enough to make even the slightest difference. Non noticeable to a trials rider anyway.There is a good reason to put the disk mount on the front of the fork. It stops braking forces from pulling the front wheel out of the fork dropouts... There have been some nasty XC and DH accidents linked to this...That interesting! Quote Link to comment Share on other sites More sharing options...
Mark W Posted March 24, 2008 Report Share Posted March 24, 2008 I thought that hype about the wheel being ripped out by XC and DH riders blew over a long time ago, and now forks are made with the whole 'Lawyers Lips' setup so that you'd either have to be mentally handicapped or mechnically inept to have your wheel possibly rip out? It only happened to a couple of people too. I'd imagine for the vast, vast majority it'd be nothing to worry about, especially as DH riders now almost exclusively use through-bolt axles which entirely eliminate that problem anyway? Quote Link to comment Share on other sites More sharing options...
Josh Greenan!!!!!!!!!! Posted March 24, 2008 Report Share Posted March 24, 2008 doesnt the xtp or the hydroxx have it on the back? Quote Link to comment Share on other sites More sharing options...
psycholist Posted March 24, 2008 Report Share Posted March 24, 2008 The problem of wheels falling out has been mostly linked to the use of lightweight skewers. There is a European standard for testing bikes (Can't remember the number, but I have a copy of it on my desk at work), which gives a figure of 2300N for the pull out force on a skewer - this was increased from I think 500N a few years after disk brakes came out. The safety lips on fork dropouts get worn away or ripped through in some of the accidents, so not a guarantee the problem is removed. I've never had a QR loosen on me, but I use Shimano QR's, so not a big deal, Hope QR's have been implicated in quite a few of these accidents in the UK. I have a mechanical engineering student measuring the pull out force on QR's for his final year project at the moment, so I'm looking forward to seeing the data from that ... Quote Link to comment Share on other sites More sharing options...
Revolver Posted March 24, 2008 Report Share Posted March 24, 2008 seeing as front wheels are pretty much reversible, why don't they make some forks that have the disc mount on the other side? Then people who are at risk of damaging the disc because of how they do stuff can get the opposide-side forks. Quote Link to comment Share on other sites More sharing options...
psycholist Posted March 25, 2008 Report Share Posted March 25, 2008 That's probably the best reason to change the disk side. If they can go to the trouble of making reverse threaded freewheels and hubs for use on left side drive BMXes it's far less of a deal to stick a disk mount onto both sides of the fork. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.