What are your thoughts?

[Tangoup51]

So, I've known this guy for a few years, first met when I did a short stint of work at a local LBS, he's somewhere between an author and a bike mechanic, he also does some metal work.

He's creating this Book on the ways to prolong your frame life, in the chapters dedicated to the alloy frames (I think 7005 and 6065?)

me and him were debating something he was weighing up adding in his book, it was about

On the rear disc brake mount bosses, does increasing your rotor size by 20mm (i,e 160 rotor to 180) shorten the life of your frame by flexing your seat/chainstay more than it was designed to be?

I argued that it wouldn't do any damage because the rear brake is only as strong as your rear tires traction.

Then he said if you use an adaptor to get that +20mm increase, you cause more leverage on the bolt mounts as the caliper is moved further away from the frame.

He also added that if you have a bike that is designed to operate in areas with less traction (like cyclocross) then your frame isn't designed to take the braking power from using it on the road with say, grippy tires.



What are your thoughts?

 

[Lozz360]

Is this a serious question? Does he / you have evidence or knowledge of frames breaking due to the larger diameter of disk rotors?

 

[Yellow Saddle]

Sounds like a best-seller to me.

 

[S-Express]

"Ways to prolong your frame life".

 

[davidphilips]

My thoughts are that any bike frame will last a lot longer than your friends books but good luck to him hope he does not spend to much money hoping for a best seller.

 

[Drago]

I'm a heavy, fat blancmange and I don't feel the need to go oversize on any rear disc brake. If a heavy lump like me doesn't need to, why would a more regular sized rider?

 

[si_c]

I'm a heavy, fat blancmange and I don't feel the need to go oversize on any rear disc brake. If a heavy lump like me doesn't need to, why would a more regular sized rider?

Same, I regularly lock up my back wheel with just a 140mm rotor. It's fun. Doesn't help with braking though.

 

[numbnuts]

Having a 180 rotor IMO would put more strain on the spokes if anything

 

[Cycleops]

Not so sure on your friends theory but reading that would a perfect cure for insomnia.

 

[Will Spin]

I think my bicycle frames will live longer than I will.

 

[Smokin Joe]

I hope it is a thick, heavy book. I need something to sit on the inner tube patch while the adhesive dries.

 

[Tangoup51]

I hope it is a thick, heavy book. I need something to sit on the inner tube patch while the adhesive dries.

My favorite comment i've seen on this website to date.

In all honesty, he did say his book was about tackling certain Myths about frame life and "fears" people have had. You know, things like not using exposed alloy/steel/carbon in a humid environment together for corrosion reasons

and some other things he spoke to me about that I droned out of listening too, but this disc brake one was interesting to me because i've never heard of it.

As @numbnuts said, its more likely to strain your hub/wheel than your frame.

I do think it is true however, that it does strain your frame more but reality is you're going to replace/destroy your frame before those times come anyway.

Not sure who the book is aimed for. I'm assuming it might be for people with old touring bikes?