bondy Posted September 9, 2012 Report Share Posted September 9, 2012 hello guys i need addvice. i did ask this a wile back and i was told it was normal anyway ive noticed if i pull the front brake leaver when the the front wheel is off the ground it stopps the wheel ok but theres movment back. and forth i didnt notices but when ive had a good look its the disc that moves is this normal???? Quote Link to comment Share on other sites More sharing options...
lee99780 Posted September 9, 2012 Report Share Posted September 9, 2012 Hi, Yeah this is normal, you have 'floating discs on it, there is some bushes you can get to replace depending on the amount of movement Quote Link to comment Share on other sites More sharing options...
bondy Posted September 9, 2012 Author Report Share Posted September 9, 2012 cheers mate its only aittel bit off movment. i thought the bearings needed replacing i need to take the wheel off anyway to fit some fork sleeves. just fitted new swing arm decals. as they lookt abit tatty i bought the full 210 kit but the rest of the decals or ok yet. Quote Link to comment Share on other sites More sharing options...
sting32 Posted September 10, 2012 Report Share Posted September 10, 2012 check the bearings by doing side to side movement of the tires... if you are holding the brake and that is rotating movement, then that is the "floating" brake rotor, it should be pretty small bolts can get worn too, allowing the wheel to move back and forth in the direction of normal wheel travel you know. IT is side to side that is a problem with bearings... I grab the wheel and try pulling the top of the wheel directly at or towards left or right fork, checking for play, there should be NONE. while off the ground is easiest. if you have slop then bearings are worn or bad. BTW, when you install the new bearings, be sure to remove on side's seal (very carefully) I use a stick pin and get under the lip on the outer race, so you dont mess up the seal at the inner race, THEN push some grease in there with your FINGERS, then replace the seal. it will last longer, the MFG I got my bearings from, one bearing had "SOME" but very little grease, the other had NONE at all! BTW, I use waterproof grease, when I do this, if it matters. more grease the better IMHO. Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 14, 2012 Report Share Posted September 14, 2012 I had the same problem on mine and didn't worry about it because I thought a little 'float' was fine it's something I've encountered on various road and off road bikes over the years... However upon closer inspection, now I'm not sure the exact setup of yours, but on mine (2001 txt) the 8mm bolts are sat inside a cup, the cup then seats in the disk hole and bolts securely to the wheel. When I looked closer at mine because I was changing the bearings I noticed that the cups weren't seated in the properly in the disk and gave just enough movement to create the feel of 'float'. Once I'd reseated them all properly and re tightened the bolts the disk was the held securely to the wheel with no 'float' at all. So it may be worth having a closer look just in case. Quote Link to comment Share on other sites More sharing options...
sting32 Posted September 17, 2012 Report Share Posted September 17, 2012 (edited) I had the same problem on mine and didn't worry about it because I thought a little 'float' was fine it's something I've encountered on various road and off road bikes over the years... However upon closer inspection, now I'm not sure the exact setup of yours, but on mine (2001 txt) the 8mm bolts are sat inside a cup, the cup then seats in the disk hole and bolts securely to the wheel. When I looked closer at mine because I was changing the bearings I noticed that the cups weren't seated in the properly in the disk and gave just enough movement to create the feel of 'float'. Once I'd reseated them all properly and re tightened the bolts the disk was the held securely to the wheel with no 'float' at all. So it may be worth having a closer look just in case. Tazz, that is Weird, the front brake rotor should NOT be tight to the hub, because loading of the front suspension can cause the brakes to drag (sometimes drastically) on the rotor (which is like applying the brakes for you) and that is why they went to floating brake rotors, least that is what I keep being told. I know my 99 321 had floating front disc. I Happen to have picked up a 1994, 250 Gas Gas, that I'll check when it gets back from my mechanic, but I thought it had floating front disc already, even back then.... Edited September 17, 2012 by sting32 Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 17, 2012 Report Share Posted September 17, 2012 Hmmmm...... Ok thank you I'm gonna look into that one! Out of interest how can loading the forks cause the brake to drag? Surely because the caliper is fixed to the lower leg and the wheel is also fixed to the lower leg nothing can move as long as its all bolted together properly no?? Forgive me I'm in no way saying your wrong, dont get me wrong, I just can't work that one out in my head lol Quote Link to comment Share on other sites More sharing options...
sting32 Posted September 17, 2012 Report Share Posted September 17, 2012 Hmmmm...... Ok thank you I'm gonna look into that one! Out of interest how can loading the forks cause the brake to drag? Surely because the caliper is fixed to the lower leg and the wheel is also fixed to the lower leg nothing can move as long as its all bolted together properly no?? Forgive me I'm in no way saying your wrong, dont get me wrong, I just can't work that one out in my head lol I am just regurgitating what I have seen/read/heard. I hope others on the forum will chime in, since before my 99 321, I had drum brakes. so I havent had 1st hand experience for why they went to the floating design, that is still in place today. Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 17, 2012 Report Share Posted September 17, 2012 I am just regurgitating what I have seen/read/heard. I hope others on the forum will chime in, since before my 99 321, I had drum brakes. so I havent had 1st hand experience for why they went to the floating design, that is still in place today. Generally the idea behind floating disks is to simply allow for expansion when they get hot. On road bikes it's kinda essential given the stresses they're put under in heavy braking. But I don't see a massive "need" for it in a trials bike.... Someone else pipe up and shed some light here please do trials have float for the same reason? Quote Link to comment Share on other sites More sharing options...
jse Posted September 18, 2012 Report Share Posted September 18, 2012 Generally the idea behind floating disks is to simply allow for expansion when they get hot. On road bikes it's kinda essential given the stresses they're put under in heavy braking. But I don't see a massive "need" for it in a trials bike.... Someone else pipe up and shed some light here please do trials have float for the same reason? Heat is not usually a considertion as to a floating disk. It allows the disk to self-center in between the pads. Some systems "float" the caliper (common on dirt bikes in general) and use a rigid disk. There are stress forces that misalign the forks slightly and if the system were rigid, there would be a gap between pad surfaces and the disk and you would have to take up the slack, resulting in a spongy, long travel lever. The back brake, being a more rigid system and smaller disk, usually has a non-floating disk. Jon Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 18, 2012 Report Share Posted September 18, 2012 Heat is not usually a considertion as to a floating disk. It allows the disk to self-center in between the pads. Some systems "float" the caliper (common on dirt bikes in general) and use a rigid disk. There are stress forces that misalign the forks slightly and if the system were rigid, there would be a gap between pad surfaces and the disk and you would have to take up the slack, resulting in a spongy, long travel lever. The back brake, being a more rigid system and smaller disk, usually has a non-floating disk. Jon Jon if that's the case then I hold my hands up and stand corrected mate. I've always understood that it was for heat expansion to stop the disk's from fracture. However your explanation also makes perfect sense too. Which now confuses the crap outta me cos my calipers certainly dont float and neither do my disks and low and behold I have a slightly spongey lever......... (Big sigh) Here we go with another problem to solve. Why don't my disks float?? Lol Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 26, 2012 Report Share Posted September 26, 2012 Ok my disks DO float!! I went on a mission and took the wheel off for a closer look. I unbolted the disk and laid it on a piece of glass and noticed straight away that the metal surrounding two of the bolt holes was ever so slightly bent, as a result holding the disk tight to the wheel! After a little "persuasion" with a hammer and the flat surface on the back of my vice the disk mount is now perfectly straight as is the disk. Everything perfectly straight and floating and working pretty damn well, and also less sponge on the lever Please note I'm not recommending anyone take a hammer to a bent disk I did it in full knowledge that it wasn't the best idea and may have ended up having to buy a new one. On this occasion I think Lady Luck may have been looking over my shoulder! Quote Link to comment Share on other sites More sharing options...
jse Posted September 26, 2012 Report Share Posted September 26, 2012 Ok my disks DO float!! I went on a mission and took the wheel off for a closer look. I unbolted the disk and laid it on a piece of glass and noticed straight away that the metal surrounding two of the bolt holes was ever so slightly bent, as a result holding the disk tight to the wheel! After a little "persuasion" with a hammer and the flat surface on the back of my vice the disk mount is now perfectly straight as is the disk. Everything perfectly straight and floating and working pretty damn well, and also less sponge on the lever Please note I'm not recommending anyone take a hammer to a bent disk I did it in full knowledge that it wasn't the best idea and may have ended up having to buy a new one. On this occasion I think Lady Luck may have been looking over my shoulder! tazz, even on non-floating disks you will get a small amount of movement with the brake on as the pads move slightly forward/backward in the caliper housing, so under any circumstances there will be a little movement. Jon Quote Link to comment Share on other sites More sharing options...
tazz229 Posted September 26, 2012 Report Share Posted September 26, 2012 Yeah I understand that completely I've got a lot more movement now though which isn't a bad thing for two reasons.. 1. My brake seems to be more responsive and sharper. 2. The "creaking" noise I could hear when compressing the forks whilst holding the font brake has gone. It turns out the creaking was the disk trying to move on the hub! Quote Link to comment Share on other sites More sharing options...
sting32 Posted September 27, 2012 Report Share Posted September 27, 2012 (edited) Naw, I think the creaking you heard was pads slipping until they completely aligned to the rotors and got a grip usually. BTW, the brakes, you probably could guess, are just big enough for the job, (weight considerations you know) and when they work "right" they work better than anything we've had in the past trials bikes (well in stock form, you know...) But when they have an issue, they suck as bad as old drum brakes, until you sort it out, lol. Edited September 27, 2012 by sting32 Quote Link to comment Share on other sites More sharing options...
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