y2kh8r

I posted this in the triathlon area, as the question is about a triathlon bike, they sent me here.

I'm selling a triathlon bike, and I have a prospective buyer who is very heavy, and has broken some bicycles in the past. I don't know just how big this guy is just yet, but, the question is:

Do you think that my bike frame, with Reynolds 853 tubing, is stronger than a normal cro-moly/aluminum frame, or just lighter?

Bike is a 1999 schwinn circuit

You should be able to click the image to enlarge it (click it again in the new page and it will enlarge again)

chasm54

Reynolds tubing data.

As you'll see, 853 is pretty impressive stuff as far as its strength and stiffnesss are concerned.

StephenH

The strength of a frame would depend on the thickness, size, and connection details of the material, and without going through a lot of analysis, there's no real way to say whether a light high-end frame is stronger than a heavy low-end frame. I would be inclined to think the heavy low-end frame is stronger, myself, as it's made with less attention to weight-reduction and with wider range of riders in mind.

Generally, I've heard of wheels being the weak points in frames, and if someone says they're breaking frames, I would be disinclined to sell to them with any promise of suitability. They might be REAL heavy. Or they might be jumping the thing off curbs, etc. You for sure don't want them to go bust it and then expect you to make it up for them.

dcrowell

I would say the wheels are the weak point, but they can be replaced. It's really hard to break a quality frame.

Homeyba

An 853 frame is good stuff. I have a Peugot frame made of the stuff. It's a little noodly under my weight but it's plenty strong. He's more apt to break the drive train and wheels than the frame. I'm in the 230-250 range.

CliftonGK1

From any damaged frames of high caliber tubing that I've seen, the damage isn't from rider weight, but it's always been some sort of crinkle/crumple/dent damage. Thinner walled tubing is easier to damage in a front-end impact with crinkle damage to the downtube, or dent damage from a hard laydown if the tube impacts something (I've seen a 953 frame dented from tipping over into a picnic bench when the wind caught it just wrong from where it was leaned. Flip-side; I've dropped my '88 Trek 400 on a parking block and barely done anything beyond scratching the paint. Could be coincedental or bad luck/good luck, though.)

Askel

I doubt he'll kill it, but he might not like it. The last (and only) 853 frame I rode was very flexy. Might be a desirable quality in touring, but if you're throwing down in a race sprint, could be annoying.

But that could be construction more than frame material...

y2kh8r

He's commuting, so hopefully sprinting is out of the picture!

The guy bought the bike. He was HUGE! at least 6'6" (maybe closer to 7') and husky, but not fat. Turns out that the bike he was currently riding had been converted to a one speed, and because of the high gearing, he put so much torque on it that the frame would bow and the chain would slip.

I ended up swapping out the pedals for him- the original ones required special shoes. I used the sturdiest looking platforms I could find, turns out they were a respectable brand (at least he liked it).. he said it was the go-to pedal brand in BMX circles back in his time. It was an all-metal pedal, the type that allows you to service the bearings.

I'd like to thank all who replied for your input, it's been very informative!