hi folks,

last night i was riding home and the car in front of me broke suddenly and came to a stop. i hit the brakes to slow down and the rear wheel started sliding back and forth, left and right, like i was driving on ice or something.

what causes this? did i press the rear brake too hard? or some wrong combo or rear and front braking?? or is my alignment messed up? (i recently changed my chain and sprockets myself for the first time and had some issues w/ the alignment bolt, when i look down the chain it lookss straight to me but may not be perfect, i plan to do the string test this wkend).

btw, i have a 2004 cbr 600rr

 

You may have locked up the rear tire. Did you check the tire for flat spots or to see if there's any chunks of rubber missing? I did this about a month ago while following my friend down a not so good back road. About 2 weeks later the rear tire started showing threads in the spot where it slid.

 

^^^ Yeah it sounds like a typical rear wheel lock up. Rear tyre has trouble going forward cos you got the brakes locked on, so starts moving left to right. Drivers that tow trailers can relate to this sort of thing happening for the same reason. Its a fine line between applying good brake pressure & lock up. Also the type of road & weather (more likely to lock up in the wet for instance) Most likely to happen in emergency situations & followed by a severe case of sphincter pucker. Happens to all of us unfortunately.

 

Did you only align the rear wheel by looking at the chain? If so, you are going to want to adjust your rear wheel correctly.

It may have just been you locked up the rear, but a messed up alignment can cause all sorts of issues.

 

hmm, thanks for the advice.

@pacemaker, haha yes i think i did have a case of the sphincter pucker. nothing like having a care slamming the brakes in front of you and no room to avoid.

@kevwa- i just checked the tires and i do seem uneven wear (see pics). the bike was sitting for about 2-3 years and wasn't moved at all. i should've prob kept on both front and rear lifts but i didn't. anyway, looks like some portions of the center (i do mostly freeway riding to commute) are worn more than other. time for a replacement or you think i can get a few more months in, haha!?

@justasquid- yeah, i just eyeballed the chain but i know it must be pretty bad. when i replaced the chain/sprocket i thought i was suppose to completely loosen the alignment bolt so i was turning and turning and turning when i figured i was doing something wrong. what's the correct way to align? it's not the string method??

 

The string method is the way to go. There are variations on a theme when doing it, but the result is the same, a properly aligned rear wheel. Do it as soon as you can so you don't put undue stress on the new chain and sprockets you've just installed.

For the string method, take a little extra time to understand the principals that it's trying to get across to you and why it works. Once you understand what's going on, it becomes really easy to do anytime you want.

 

thanks idodirt. yeah, i figured its not good for the bike and unsafe as well. just haven't had a chance to get around to it.

what do you folks think of the tire? do you guys usu replace as soon as it reaches the wear indicator?

 

I look to replace tires as soon as I hit the wear indicators, just like on a car tire. Personally I wouldn't be riding on that back tire. That tire has what I affectionately call "May-Pops", because that tire "May Pop" anytime now. I would not want to be mid corner when it lets go.

 

I used to mark one flat of each adusting nut on the same flat, with tippex or white paint that way you can see how much each nut is turning and by turning them both one flat at a time to the same position, you will keep your wheels in line. All this is done once you have the wheels aligned properly from the beginning of course. It may be worth dropping into your local MOT station and have them check your wheel alignment for you then use the above method when adjusting your chain. As to you having to stop so suddenly and not wanting to patronise you, ALWAYS leave plenty of distance between you and any vehicle in front of you at all times! You can't afford not to on a bike and it's only when you find you have to stop that you realise just how close you are and it can be lethal. Sorry if it sounds as I'm having a go. I'm not. I just don't want you to be another hospital casualty.

 

thanks highwaypatrol, appreciate the lookout. yeah, think i'm starting to slack on "defensive" driving as i become complacent riding the same route to commute.

idodirt, got it. just one more trip to school and back tonight then will replace this wkend. wish me luck!!! buahahaha!!