How is it possible for my rear disk to have buckled

[Parko75]

Hey

I went for a ride yesterday, dropped off the rock n rolla which is about 6 foot on my norco sasquatch. About 30 seconds later my tyre went flat. I couldnt find any slits in the tyres as their was shale rock everywhere. As i was pushing my bike back to the carpark my rear disk started squealing and to my surprise it was reasonably buckled. I have no idea how this could have happened, it was perfectly straight until my tyre blew. Can anyone explain to me how this could have happened?

Cheers

Steve

 

[macca21]

The flat will be because you pinched your tube when you landed. Look at your tube, most likely you'll find two small slits next to each other like a snake-bite.
The axle might be bent, (assuming it's QR), which will make it look like you disc is bent.

 

[driftking]

Is there anyway you hit the disc when landing? this would deffinatly do it, discs can also warp if they are installed incorrectly over time they can warp, some cheaper disc that dont disperse heat very well can have this problem it happened on one of my older bikes.
Is there anyway you might not have noticed it until now and it might just be a coincidence with the flat tyre.
or as said above it could easily be a axle problem

 

[Parko75]

Yea, the tube was pinched. I bought a new disk rotor $69 later :s and its all good now. Do you know what sort of tyre pressure would be recommended for a hardtail which i use for DH? Im assuming it was to low hence the pinched tube?

 

[Parko75]

Is there anyway you hit the disc when landing? this would deffinatly do it, discs can also warp if they are installed incorrectly over time they can warp, some cheaper disc that dont disperse heat very well can have this problem it happened on one of my older bikes.
Is there anyway you might not have noticed it until now and it might just be a coincidence with the flat tyre.
or as said above it could easily be a axle problem

Yea, the tube was pinched. I bought a new disk rotor $69 later :s and its all good now. Do you know what sort of tyre pressure would be recommended for a hardtail which i use for DH? Im assuming it was to low hence the pinched tube? Maby i should just not DH on a hardtail?

 

[driftking]

Yea, the tube was pinched. I bought a new disk rotor $69 later :s and its all good now. Do you know what sort of tyre pressure would be recommended for a hardtail which i use for DH? Im assuming it was to low hence the pinched tube? Maby i should just not DH on a hardtail?

if you want to go tubeless you wont get pinch flats although bit pricey and i know on a hardtail it might be a bit risky. Im not too sure about hardtail tyre pressures, i used to run mine quite high, but i never did too much dh on it so not really sure hopefully someone else can help with pressures. the type of track will also effect what pressures you will run.

 

[macca21]

tyre pressure will depend on tyre(double or single ply), tube(std, fr or dh) and rider weight.
the heavier duty your tyres and tubes the lower the pressures that you can run.
just experiment until you find the best balance of durability and performance.
as a rough idea. for me (about 90kg), i'd run about 30-35psi even with dual-ply and fr/dh tubes.
good luck

 

[Parko75]

Is there anyway you hit the disc when landing? this would deffinatly do it, discs can also warp if they are installed incorrectly over time they can warp, some cheaper disc that dont disperse heat very well can have this problem it happened on one of my older bikes.
Is there anyway you might not have noticed it until now and it might just be a coincidence with the flat tyre.
or as said above it could easily be a axle problem

No chance i hit the disk when i landed, clear track for about 50m. Im running avid juicy 3's so the rotors that came with it when new si what i have. Im positive it was perfectly straight before i went for the ride as it wasnt rubbing on the pads like it was after the tube shat itself. Its near new bike so that axel shouldnt be the axle :/

 

[Parko75]

tyre pressure will depend on tyre(double or single ply), tube(std, fr or dh) and rider weight.
the heavier duty your tyres and tubes the lower the pressures that you can run.
just experiment until you find the best balance of durability and performance.
as a rough idea. for me (about 90kg), i'd run about 30-35psi even with dual-ply and fr/dh tubes.
good luck

Its a standard factory tyre and standard tube, im about 70kg. I guess i should expect alot more flats until i get decent tyres n dh tubes?

 

[koper72]

mate i recommend that you buy a set of downhill tubes and some downhill tyres. and id be running around 30psi i'm guessing. i run 20psi as my main tyre pressure. so 30psi on a hardtail should be fine..

 

[Parko75]

mate i recommend that you buy a set of downhill tubes and some downhill tyres. and id be running around 30psi i'm guessing. i run 20psi as my main tyre pressure. so 30psi on a hardtail should be fine..

What sort of tyres do you reckon would be suitable, not really looking at spending to much.

 

[macca21]

get a pair of either maxxis highrollers or minion dhf tyres. minion front / highroller rear works well. either that or a pair of either.
should find a good deal at tbsm.com.au, under 100 for a pair which is cheap, especially in oz.

 

[harmonix1234]

You may have bent the chainstay? Or your dropout could be impacted and the groove made a little deeper on one side?
If a chainstay is bent even a few mms, the rotor will rub. I'd do a quick check of the frame. Even if just for the process of elimination.

 

[chris95]

What sort of tyres do you reckon would be suitable, not really looking at spending to much.

Hey man, I have a mate who does Dh hardtail on his 2009 norco sasquatch, he goes pretty well and just won the QLD State championships in hardtail junior.
Definetly buy some duel ply tyres and dh tubes, Im not totally sure but he said he runs between 25-30psi in his tyres, and has never flatted with this setup(except when he swaped bikes with another mate he flatted the bike within the first 100m of trail)
,also he is around 80kg