bent axle

[hotroddal]

i now have 2 bent axles i think. is the stock axles on the 84 250r and the 83 200x weak or sumthing and do they bent easily because now both my 83 200x and my 84 250r kinda jump up and down just a little bit when i ride them on tar, i can only notice it on tar not on dirt, so im asking are the stock axles weak and how do you check to see if the axle is bent and not an out of round tire or bent hub? both of these machines i have been jumping them on umps almost every day for the past coupe weeks now.

[freewheel3]

Jack the back end up on blocks, remove the wheels, fire it up, put it in gear & look at the axle. This will tell you if the axle is bent or not. Make sure it is blocked securely though.

[thedeatons]

After checking my 185S rear axle for hardness (Rockwell Hardness test), it came up as a 20 on the C scale, which the shop said was very soft. I would suggest buying a Dura Blue that is specifically made for punishment... good luck... Oh, and the test method listed above should work great... James

[chris200x]

Someone posted a picture of a broken axle on the forums not long ago. I was amazed to see that it was hollow!

[thedeatons]

I've heard and read that hollow axles (in the bicycle world) have more strength, due to there beign more surface area... Maybe some engineers could clear this up....

[toyvette81]

to check to see if its bent and how bad and where. you need to jack the bike up on the frame and support it well so it will not shake or move at all, then put a jack stand infront or behind the axle and clamp a pick of some sort or a sharp nail would be great, clamp it with the point right up against the axle and slowly spin the hub by hand. if it scrapes the axle all the way around... the axle is not bent (at least in that spot,) so you can move the jack stand around to a few diff locations among the axle, if the nail or w/e you use comes off the axle momentairly and then touches again it is bent and just a little gap is a serious bend. my 350x axle was bent so little it was not visible just by turning it but it was almost impossible to ride on pavement (depending on where its bent makes a difference on how severe the wobble is), mine was right at the hub on the thinnest part of the axle) most of them bend within 4 or 5 inches from the hub.... and lol firing it up and watching the axle spin will only let you see the axle wobble if it is bent like a S (you already know its bent, if you can see it wobbeling doing it that way, and you are just doing it to see the huge wobble), theres too many vibrations/moving in the running bike to look at a small wobble. like i said mine was bent and no one could see the bend just by spinning the hub you need something stationary (the nail clamped to stand). that method also tells you where its bent at Exactly and thats how we have straightened axles in the past, using the torch, get it cherry red and beat lol if you do it right you will get it 100% straight again, he11 of alot cheaper than a durablue... there a rip off in my opinion you dont even get a free one when you bend yours, the next is like half off with alot of restrictions on the warrenty so you probbly wont get that.
let me know if you have any q's and if you need to see what im talking about ill go out there, set it up and take a pic, it takes 1 min

[hotroddal]

the more and more i think about this, i have come to another question i am running around 15-20 pounds of air in all 3 tires, i like the tires to be full of air so i can slide around corners and fishtail better, could i have broken some of cords in the tire making one part bulge out more than the other? causing it to wobble?

[freewheel3]

the more and more i think about this, i have come to another question i am running around 15-20 pounds of air in all 3 tires, i like the tires to be full of air so i can slide around corners and fishtail better, could i have broken some of cords in the tire making one part bulge out more than the other? causing it to wobble?

15 - 20 PSI is way too much air pressure, 5 PSI is lots.
Same thing, jack the back end up on blocks, fire it up, put it in first & watch your tires rotate. See any bulges or abnormalities?

[Howdy]

[QUOTE=hotroddal]the more and more i think about this, i have come to another question i am running around 15-20 pounds of air in all 3 tires, i like the tires to be full of air so i can slide around corners and fishtail better, could i have broken some of cords in the tire making one part bulge out more than the other? causing it to wobble?[/QUOTE]

Heck yes it can, the tires also absorb some of the jumping, so running too much air in your tires can cause more stress on the axle. Too much stress = bending.

FYI, you can get different tires to make it fishtail and slide. Tires are a heck of a lot cheaper than axles and such.
Howdy

[toyvette81]

just get some holeshot style tires (square). they will slide better than your pumped up tires

[TeamGeek6]

I've heard and read that hollow axles (in the bicycle world) have more strength, due to there beign more surface area... Maybe some engineers could clear this up....

Close. Filling in a hollow axle adds very little strength, but adds a lot of weight. Thats why piston pins are hollow. "Moment of inertia" is the term. Ive done calcs on titanium piston pins and making them solid only adds a little strength for the weight.
Hollow eliminates chances of having "voids" in the metal (hollow spots) that can cause breakage.

Ive beat my stock axles to death and never bent one. Cracked the swingarm and Geek7 broke his badly, but never bent an axle. The axle might have been hit on a rock which is real easy to do.

[slothminx]

Why would you look into making stronger piston pins. The place where the piston pin goes through the piston will fail well before a standard hollow pin will. You will bend an axle if you catch it on a tree at 30mph


Will

[toyvette81]

if your bike rools down a hill it'l bend a axle, mabye not on sand. but here the ground is hard and trees everywhere, itl catch a few of them on the way down too lol

[hotroddal]

ill de-air the tires and put the correct amont of air in them, and see if that helps at all, thanks for your help.

[freewheel3]

ill de-air the tires and put the correct amont of air in them, and see if that helps at all, thanks for your help.

If the tires started to seperate due to overinflation, they will probably still give you trouble even if you deflate them to the correct pressure. But try it out & see what happens, you might get lucky & problem solved.