Stays flexing??!

[Cyclist33]

Ok this might be a really dumb question but I was tinkering with my mtb the other day and had the back wheel off, and I noted that if I put one hand on each seat stay around the dropout, and pushed inward, the whole seat/chain stay triangle flexed horizontally.

Is this, er, normal? Can't see any fractures on the frame or out,but a bit worried!

Thanks

Stu

 

[festival]

Yes.
What material is the frame made of.

 

[Cyclist33]

6061.

 

[MrJamie]

If you squeeze your rear brake quite hard against the rims you can probably see the stays flex inwardly too, they sell "vbrake boosters" which make the frame more rigid in that area to improve braking.

http://www.chainreactioncycles.com/Models.aspx?ModelID=8215

 

[Cyclist33]

If you squeeze your rear brake quite hard against the rims you can probably see the stays flex inwardly too, they sell "vbrake boosters" which make the frame more rigid in that area to improve braking.

http://www.chainreactioncycles.com/Models.aspx?ModelID=8215

Thanks mate but I've got disk brakes!

 

[cyberknight]

Sounds ok to me, just check for any cracks at the joins just in case

 

[black'n'yellow]

if you take the wheel out and push the stays inwards, of course they will flex. Normally, the presence of a wheel (and specifically the hub which sits in the dropouts) prevents this from happening.

 

[Cyclist33]

if you take the wheel out and push the stays inwards, of course they will flex. Normally, the presence of a wheel (and specifically the hub which sits in the dropouts) prevents this from happening.

Well, I did wonder but had never noticed before. So how come say, a 6061 handlebar doesn't flex in a similar fashion?

 

[jonny jeez]

if you take the wheel out and push the stays inwards, of course they will flex. Normally, the presence of a wheel (and specifically the hub which sits in the dropouts) prevents this from happening.

I took it the OP meant inward , as in towards the seat tube, as opposed to pinching the dropouts together...in which case you are spot on.

 

[Deleted member 20519]

When I had my steel frame, the wheel wouldn't fit so I had to stretch the dropouts and pop the wheel in. Nothing to be worried about.

 

[black'n'yellow]

Well, I did wonder but had never noticed before. So how come say, a 6061 handlebar doesn't flex in a similar fashion?

tube size, wall thickness, leverage. You need to worry about other stuff.....

 

[Cyclist33]

I took it the OP meant inward , as in towards the seat tube, as opposed to pinching the dropouts together...in which case you are spot on.

Thanks you crazy writer in a snowy backwater. I meant pinching the dropouts together.

Stu

 

[ianrauk]

I am amazed at how much carbon seat stays can flex.

 

[MrJamie]

Thanks mate but I've got disk brakes!

Doh! It was more the point that the stays can be quite flexy, mine flex a small amount but visably when i squeeze the brakes hard, they definitely move at the dropout without the wheel in. If i stand over the bike and push hard down on one pedal you can see the whole frame bend a little, scared me at first and made sure my friends bike did the same, its probably less noticable if youre lighter

 

[Deleted member 20519]

I am amazed at how much carbon seat stays can flex.

Carbon shouldn't flex. I think that your bike is very dangerous and if you send it to me, I'll dispose of it properly