roadmaster bb issues is this common?

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heartlandcruisers

heartlandcruisers

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i have a roadmaster mount fury bicycle i use around town
the issue i seem to be having is the bottom bracket bearings going out
i have replaced them twice and even these ones come loose on me i have checked the grease their greased good
im not sure if its an issue with the bearings or just the simple fact its a pos wal mart bike
im gearing a lil from column a lil from column b
any ideas how to solve this?
thanks
Sean
 
I have a Magna Fix'd(Duracraft) from Target that the bottom bracket keeps coming loose. It does it in under half mile after tightening. I put a sealed BB in it just to have it also come loose. I have inspected the bike and can't seem to find anything wrong. Its not cracked or damaged in anyway. I had a more experienced guy look at it and he also couldn't figure out why it comes loose. I am glad I got it on sale for $35 and not the $120 it was new.
 
Did you change your races, or just the actual ball bearings? if not, that could be the source of your troubles. If you have a 1-pc crank, they should be very slightly loose before tightening the lock nut. When you tighten the lock nut, it actually pushes the inner race closer to the bearing. If it's loosening, you aren't tightening it enough.

On a three piece tightening the lock ring would move it further away, but the thread tolerances are usually tighter. Either way, the trick to crank bearings is to find that tiny little spot where they have as near zero play as possible, but aren't yet pressurized, after all threaded parts are locked down very tight

The drive (chain) side race, whether the sprocket-holding "cone" on a 1-pc, or the threaded "cup" on a 3-pc needs to be as tight as you can possibly get it without damaging it.
 
good thought deorman
i never considered the race
it is a single piece crank stock roadmaster crankset
i gonna check the races and see if their good
thanks for the advice
sean
 
so i found the cluprit to this problem
the bearings are actually shrinking
i did a load test by hooking the front sprockets to a small motor to mimmick pedaling
after getting up to about 55 cadence speed i noticed it was coming loose again
so i stopped and checked
the bearings actually shrunk very very mildly!!!
this is entirely new to me but im beginning to think these roadmasters have some major design issues and im gonna avoid getting them
replaced the bearings with a set i scavenged form an old huffy and did the test again
no issues at all the bike has never pedaled easier
after running it up to 90 cadence it is still together and not loose
so the lesson i earned here old huffys make excellent donors for a neww junk bike
lol
thanks for posting
sean
 
Cool hopefully you figured it out. I think the metal tube is expanding/contorting on mine. I can't keep it from coming loose even trying different style bottom brackets.
 
yeah that's possible the bottom bracket tube is expanding
im sure ill find more issues with it
the sad part is i always get these roadmasters in people drop them off and leave them
i don't wanna spit in a gift horses face but i think its time to stop accepting these roadmasters or anything from wal mart lol
thanks for posting
Sean
 
deorman said:
Strip any straight wheels, grips, bars, or what have you and scrap the cadavers.
Click to expand...
Sounds like one of you has a bike the bottom bracket is not true to the other side of it, the shrinking bearings.......uhhhhhhhhh, well maybe the bearings are! Never ran into that, but on the cheap non-radiused races, they wear at an extreme rate.
I would, 1) get some way to accurately measure the B.B. shell acrossed at 3 places, it should be really close to the same.
2) replace any cheapy stock bearing/race/cup with good stuff, tioga.....
3) Or do the above
 
mikeeebikey said:
deorman said:
Strip any straight wheels, grips, bars, or what have you and scrap the cadavers.
Click to expand...
Sounds like one of you has a bike the bottom bracket is not true to the other side of it, the shrinking bearings.......uhhhhhhhhh, well maybe the bearings are! Never ran into that, but on the cheap non-radiused races, they wear at an extreme rate.
I would, 1) get some way to accurately measure the B.B. shell acrossed at 3 places, it should be really close to the same.
2) replace any cheapy stock bearing/race/cup with good stuff, tioga.....
3) Or do the above
Click to expand...
heya mikeeeebaby
neither have i but i did find metals flakes in the gease so maybe not shrinking literallly but wearing excessively
i also think you are right about it being off true
i seem to have resolved he problem with new used bearings and componenrts and a complete cleanup and repack with fresh grease
so for the time it seems to be fixed but im sure ill be at them again soon
thanks for posting
san
 
ok it came loose again!!!
ive quit on this pos time to test out my cutting wheel and make this curse dissapear
im gonna swap the entire bb casing and all
if the patient survives ill let you know how it turns out
thanks
Sean
 
Man I had the same problem on a Roadmaster. Replaced the bearings 2 times then figured out the one piece crank was bent slightly in the middle and was causing the failure. Possibly, someone dropped it and bent the outside arm straight... but the center was bent. Changed crank, cups and bearings from a donor. That fixed it!
 
yeah i hear that i cant be bothered with a roadmaster i have a yeti and 2 giants in my shop as well as my rats one tire on the yeti is worth more then the entire roadmaster
im gonna cannibalize it and use the parts on other rats
id say rust in peace but im so ticked with the time i wasted on it i cant just let it rest i gotta finish it off right
lol
thanks for posting and i swear im not crazy yet lol
Sean
 
h nothing like the site of youre sworn enemy being chopped up with a cutting wheel
i mean the bike of course
id never turnon a human being or living creature out of anger lol
i finally cut the sob up and its in the scrapheap
dd get ots of useable parts for my other builds m working on
so now that this monstrosity is gone time to focus on my builds
sean
 

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