Does my rear brake look like its dragging? (Video Inside)

[The^^Rock]

Hey all,

I have just thrown some new pads on my CR250 and I can't help but they are dragging a little when I spin the wheel.  It looks to me that the brake's are dragging a little.   To explain the situation best I can, I filmed thw wheel being spinned, so hopefully someone might be able to have a squiz and tell me what they think :laugh:           Link is :

http://www.fmxaustralia.com/~hardcore_cr/brake.mpg

Is this something to be worried about?

Thanks

Jim :)

 

[Rcannon]

I think your ok. If the pads are brand spanking new they have not yet mated to the rotor. I would imagine they will loosen up after a ride or two.

Just comparing it to my bike. No video, but mine is "dragging" about the same amount.

 

[MrLuckey]

Is your axle nice and clean with a thin layer of grease? I think I'd pull the chain off and give the wheel a spin, then pull the brake pads out (with the chain still off) and give it another spin just for comparisons sake. I doubt the pads are dragging as much as you might think.

 

[Camstyn]

Is that an o-ring chain, maybe needs a shot of lube?
Use a screwdriver and spread the pads apart in the caliper so that they do not contact the rotor. This can be done with the rear wheel in place. See if that makes any difference.. I'm doubting that your brakes are causing any/much drag here.

 

[georgieboy]

cld be wheelbearings. Like said disconnect chain and spin wheel.
One of mine wheelbearings was shot, caused drag.

 

[cr25096er]

did you put break fluid in when it had the old pads? if so you may need to drain some out, i did on my cr when i added new pads.

 

[The^^Rock]

Originally posted by Camstyn
Is that an o-ring chain, maybe needs a shot of lube? Use a screwdriver and spread the pads apart in the caliper so that they do not contact the rotor. This can be done with the rear wheel in place. See if that makes any difference.. I'm doubting that your brakes are causing any/much drag here.

Haha nah its just the stocker, she definetly will need to be lubed before next ride.   Ill give the screwdriver a shot tonight, hopefuly itll be a goer.

Thanks all for your reply's.  Yes the axle does have a nice layer of greese on it :)

ill have a nang tonight and see how it goes.  How hot should my disc be getting.  

 Last night when I came back it was just about too hot to touch, and I was doing alot of hard cornering.  Tonight I won't use the back brake for a few mins when I start and see if the disc gets hot again.  Im assuming it shouldn't?

If its still getting hot, ill check out the berings and fluid

Thanks

Jim

 

[chrishorton]

It seems like your rotar is bent. My front rotar is bent on my YZ125 and i have the same problem.

 

[motometal]

a rotor which is too hot to touch is very normal! I have seen a rider either do a lot of hard braking on a tight track and/or drag the rear brake and actually get it 500-600 F, enough to discolor it! Make sure there isn't any oil or grease on that screwdriver you use to spread the pads. Also make sure your rear brake pedal adjustment is right...this could cause dragging if set improperly.

 

[john stu]

the axle being greased is very importent if you ever want to able to take your axle out again but it has nothing to do with your wheel spinning because the bearing races do not actuly spin on the axle (unless the bearings are frozen or seized)when you tighten your axle the axle spacers clamp down on the small inside bearing races and prevent them from spinning on your axle if they spun on your axle you would wear a grove in the axle.you could try greasing your brake pads lol.... seriously though it looks fine to me but i have an o-ring chain.

 

[kawi35]

what you might want to check is the pins that the caliber slides on. are they lubed? i know when i put on new brakes mine rubbed too but i greased those pins it rides on it it made the brakes work alot better. let us know how its doin

 

[The^^Rock]

Turns out it was rubbing a little still.  Went for a quick 5 min ride without touching the rear brake once, and when I came back, the rear disc was nearly too hot to touch.   I then proceeded to greese up those pins like kawi35 said, and that has seemed to work :).  The wheel seems to be spinning alot more freely now, and dosn't seem to get as hot (unless im using it alot that is :D )

Thanks all, comments are all very much appreciated :thumb:

Thanks agian

Jim :laugh:

 

[MikeT]

Originally posted by TTRGuy
Is your axle nice and clean with a thin layer of grease?

The wheel doesn't spin on the axle. It spins on the bearings on the axle. As stated above an O-ring will slow it down. Brand new unseated pads will slow it down. I'm not sure, but I think if you over tighten the axle, it might have some adverse effects on the wheel bearings.

 

[motometal]

if you don't want to overtighten the axle nuts, (if you have a Honda) don't follow the torque specs in the book! Same with the linkage bolts...theyll break or strip before you ever reach the spec. Common sense and a good "feel" for it is better than a torque wrench many times.

 

[The^^Rock]

Originally posted by motometal
if you don't want to overtighten the axle nuts, (if you have a Honda) don't follow the torque specs in the book! Same with the linkage bolts...theyll break or strip before you ever reach the spec. Common sense and a good "feel" for it is better than a torque wrench many times.

 

Hrrm, you might have a point there.  I have always torqued my axle nut to 96 ft/pounds as that is what the manual calls for, but have always thaught it was to tight, but then thaught "what the manual says must be right".

Anyone got any comments on that? 

 

[john stu]

i tighten mine to factory spec as always but it does seem i a little tight after hearing what you just said maybe i won't anymore!

 

[Camstyn]

The manual rating is for dry threads. When you get any grease/oil in the threads you will overtighten them if you follow the torque wrench's reading.

 

[motometal]

the front axle nut it the biggest mystery of them all...the spec is like 85 foot pounds, but actually once you have the axle set in place you could throw away the nut and have no major problems, since the pinch bolts hold eveything in place anyway (plus the nut is self-locking so it shouldn't come loose)

 

[sweden_345]

Man. Your resolution on that clip is just awesome. What kind of camera did you use

 

[Camstyn]

Originally posted by motometal
the front axle nut it the biggest mystery of them all...the spec is like 85 foot pounds, but actually once you have the axle set in place you could throw away the nut and have no major problems, since the pinch bolts hold eveything in place anyway (plus the nut is self-locking so it shouldn't come loose)

I dunno, with the beating the front wheel takes, I wouldn't want to throw away the axle nut! There's probably a good reason for it.. If you grease your axles like I do you're bound to get some in the threads.. Instead of torquing to 85, ballpark range (with grease) should be around 50-60. Unless the threads are bone dry, I just go by feel.

 

[The^^Rock]

Originally posted by sweden_345
Man. Your resolution on that clip is just awesome. What kind of camera did you use

A JVC DVL320 Digital to be exact :laugh:

Its one of the cheaper one's, but seems to do the job of whatever I need very very well.  Cost me $1200 Australian.

 

[motometal]

I wasn't suggesting we should all literally throw away our front axle nuts, actually the nut is probably useful for the purpose of putting the proper compression on the inner races of the wheel bearings and spacer. Just making the point that getting this fastener super tight is not a safely issue, since the clamps are capable of holding the adle on by themselves.