Why did this Fail ?

[splat]

My latest break. Now can some one tell me why this failed like this ? This is a Bontrager rim. I was inflating the tire this morning before my ride and herd a Clunk and I look and see the on side wall is coming way out, deflate remove tire and this is what i saw.

[AA]

Rims are made by extruding aluminum then rolling the extrusion in a circle and welding the seam. It looks to me like there was a groove in the center of the rim and the rim failed along the seam. My guess is that either the batch of extrusion that your rim was made of was thin in that area or that Trek (the makers of all the Bontranger stuff) skimped in that area of the rim to save weight. Take it to the shop where you bought it and see if they have seen this before.

[NEMBA_bkr-dude]

HOLY CRAP!!! what pressure were you inflating your tires to?!?!?! I bet you beat the **** out of your rims and the pressure of the air in the tube cracked the seam. Call up bontrager and see what they say.

Whats the big deal? Don't they make rim tape to fix stuff like that?

[NEMBA_bkr-dude]

The big deal is that his rim is on a path to split in half which would instantly pop his tube and rip through his tire and he could have a possibly life threatening crash and/or get a spoke impaled in his leg.

[AA]

I think that Bill is pulling your leg ;)

[splat]

Iwas only at 80 PSI, on a pair of Specilized Fat boy's, anmd I probably would have ridden it if it wasn't for the fact the actually rim sidwall was popping out and hitting my brake pads. As for taking it back, I don't think so, this wheel has seen a lot of miles/rocks had been demoted to the backup set of wheels, could barley get the wheel true, But I will save the XT hub.

[Zog]

You over pressurized the RIM. Rims have a max inflation pressure just like a tire does. I don't know what the max is for that particular rim is but I bet it is around 60 psi. The mavic and I think the Sun rims websites have max pressure listed for their rims.

[splat]

I don't buy that I over persurized it. The fat boy it self say 60 -90 PSI 80 PSI split a rim , no way , then every rim would fail when riding. what do you think hapends when your full weight is on the bike ? the pressure in crease to as the weight of the rider does, I don't have any Numbers to how much this changes , But it does.

[Zog]

The RIM has a maximum inflation pressure as does the TIRE. You over pressurized the RIM not the Tire. Check out the rim mfr. websites, particularly Mavic and you will see. I found this out the hard way too a few years ago. Just because the rim is metal does not mean its really strong. Light, Strong, or Cheap; pick any two for mountan biking!

[splat]

Well , I went to Bontrager's web site , and no where do they mention a Max pressure for the rim. So I emailed them a Question ( with a Link to this discussion) and lets see what they say.

[splat]

Very intersting Botrager got back to me.
this is what they have to say.



Thank you for your email.

Interesting, I viewed the photo on the NEMBA site and would like the opportunity to see it first hand.
Ask your retailer to contact me personally for a return authorization. Without seeing it it's hard to say what happened.


Thank you in advance for your time,


Jeff Grotjahn


It will be interesting to hear what they have to say after I send it back, But will be unable to do that till Early next week.

[Zog]

Any word yet from Bonty?

[splat]

Good point ! I need to email them , I sent the rim back a while ago and have herd nothing.

[splat]

I have emailed them two more times and got no response , today Landry's Not relizing I wasn't expecting the wheel back called me , and told me they have been unable to any info from them either ( they were going through open tickets and had this down as one ) so I'm unsure why they are not getting back to me.