Frame Composition Question

J Jones said:

I'm a fairly large guy - 6'4"; 205 lbs - and am currently riding a 2004 62cm
Specialized Allez Pro (aluminum frame w/carbon fork). When I bear down on
the drive train (i.e., out of the saddle on a climb), I can look down at the
bottom bracket and see the frame 'giving' side-to-side with each down
stroke. Is this common? I'm having lots of integrated headset problems at
the moment, but am concerned that my height/weight may spell doom for my
drive train and/or frame as well.

I'm curious as to what frame composition is considered best for a big guy:
steel, aluminum, carbon, Ti? I'm not a racer, but ride about 3000+ miles /
year.

Thanks to all for any info/feedback.

I would say steel(Waterford) or titanium(Moots).
Carbon would be our last choice for a big rider.

Qui si parla Campagnolo said:

I would say steel(Waterford) or titanium(Moots).
Carbon would be our last choice for a big rider.

Could you please elaborate a bit on your answer? I am another "big guy"
(6'4", 200 lbs), and what little info I've been able to find says that
aluminum is generally stiffest in the bottom bracket and the head tube,
and carbon is close in the bottom bracket but not as stiff in the head
tube. Steel seems to be slightly stiffer than titanium, in general, but
not as stiff as either aluminum or carbon. (These are just raw
measurements I've found on the Web. Making generalizations based upon
material isn't really appropriate, because so much depends upon
geometry.)

BTW, I ride a Waterford Paramount OS.

Thanks,
Greg

Greg Berchin said:

Qui si parla Campagnolo said:

I would say steel(Waterford) or titanium(Moots).
Carbon would be our last choice for a big rider.

Could you please elaborate a bit on your answer? I am another "big guy"
(6'4", 200 lbs), and what little info I've been able to find says that
aluminum is generally stiffest in the bottom bracket and the head tube,
and carbon is close in the bottom bracket but not as stiff in the head
tube.

Not to speak for Peter, but it isn't just a question of stiffness.
Durability is an issue as well, and aluminum is less durable than steel or
titanium, as is, probably, carbon.

--

David L. Johnson

__o | "What am I on? I'm on my bike, six hours a day, busting my ass.
_`\(,_ | What are you on?" --Lance Armstrong
(_)/ (_) |

J Jones said:

I'm a fairly large guy - 6'4"; 205 lbs - and am currently riding a 2004 62cm
Specialized Allez Pro (aluminum frame w/carbon fork). When I bear down on
the drive train (i.e., out of the saddle on a climb), I can look down at the
bottom bracket and see the frame 'giving' side-to-side with each down
stroke. Is this common? I'm having lots of integrated headset problems at
the moment, but am concerned that my height/weight may spell doom for my
drive train and/or frame as well.

I'm curious as to what frame composition is considered best for a big guy:
steel, aluminum, carbon, Ti? I'm not a racer, but ride about 3000+ miles /
year.

I'm 6'10"/235. I prefer stiff frames. Stiff frames have less shimmy,
feel more stable at high speeds and don't ghost-shift or rub when you
stand and ride hard.

Stiffness is mostly a function of tube diameter (3rd power, I believe),
so bigger is better, particularly for large size frames (I ride 68 cm
frames). Aluminum frames offer the largest tube diameters and stiffest
frames.

No frame material makes a frame invulnerable to fatigue cracking. It's
really a matter of how far the designer pushed the material. I've
cracked a couple of frames, both were lugged steel, I haven't cracked an
aluminum frame (yet).

Frames aren't the only bike part to fail from fatigue. Cranks, stems,
handlebars, pedals and seatposts fail also, and those failures are
usually more dangerous.

I wouldn't worry about that little bit of flexing too much; some are
stiffer than others, but they all do that. Your oversized aluminum
frame is probably stiffer than most.

Any of the materials *can* be used to make a strong & stiff frame...
and any can be used to make frames that wouldn't last you a year. I'd
rank the materials in the following order for their *potential* for
producing a strong but fairly light frame, based on strength and
density and current technology: 1)carbon 2)aluminum 3)titanium and
4)steel

My personal experience with aluminum... I had a Klein Quantum
(oversized aluminum) frame for 4 years in the early 90s that I used for
hundreds of races (mostly crits), and about 40,000 miles. I had at
least 10 hard crashes as well, trashing the wheels and fork on
occasion, but the frame held up beautifully (except for the der.
hanger). The previous Olmo with SL tubing only lasted me a year... When
I test rode the Klein I was amazed at how stiff it was in a sprint
compared to the steel SL frame I had previously. I don't weigh 200 lbs,
but I'm pretty hard on equipment. In those days the Kleins weighed
around 3.5 lbs (57cm)... now that they are lighter, they wouldn't be as
stiff and probably not as durable.

-Ron Ruff

David L. Johnson said:

Greg Berchin said:

Qui si parla Campagnolo said:

I would say steel(Waterford) or titanium(Moots).
Carbon would be our last choice for a big rider.

Could you please elaborate a bit on your answer? I am another "big guy"
(6'4", 200 lbs), and what little info I've been able to find says that
aluminum is generally stiffest in the bottom bracket and the head tube,
and carbon is close in the bottom bracket but not as stiff in the head
tube.

Not to speak for Peter, but it isn't just a question of stiffness.
Durability is an issue as well, and aluminum is less durable than steel or
titanium, as is, probably, carbon.

Not true. Depends entirely on how the frame is designed.

According to J Jones <[email hidden]>:

Quoted message said:

I'm a fairly large guy - 6'4"; 205 lbs - and am currently riding a 2004 62cm
Specialized Allez Pro (aluminum frame w/carbon fork). When I bear down on
the drive train (i.e., out of the saddle on a climb), I can look down at the
bottom bracket and see the frame 'giving' side-to-side with each down
stroke. Is this common?

Yes. This is normal.

---
Lars Lehtonen

Quoted message said:

As for your frame. AL typically fails through
fatigue.

All frame fail from fatigue.

Quoted message said:

For an AL frame to last it has to be stiff as a board.

Not true, there are plenty of old Vitus frames out there.

Quoted message said:

I think it all goes down to ride quality. What do you want? An
extremely stiff frame inspires confidence in corners, but it also beats
you to death, especially your lower back, and if you are out of the
saddle a lot, your knees. A more limber steel frame will ride better
but may take some getting used to before you can take advantage of its
dynamic qualities in fast riding.

Nonsense. A floppy frame is only good if you like shimmy.

Greg Berchin said:

Qui si parla Campagnolo said:

I would say steel(Waterford) or titanium(Moots).
Carbon would be our last choice for a big rider.

Could you please elaborate a bit on your answer? I am another "big guy"
(6'4", 200 lbs), and what little info I've been able to find says that
aluminum is generally stiffest in the bottom bracket and the head tube,
and carbon is close in the bottom bracket but not as stiff in the head
tube. Steel seems to be slightly stiffer than titanium, in general, but
not as stiff as either aluminum or carbon. (These are just raw
measurements I've found on the Web. Making generalizations based upon
material isn't really appropriate, because so much depends upon
geometry.)

BTW, I ride a Waterford Paramount OS.

Thanks,
Greg

A big guy comes in and asks about a new bike and what would be the best
for him...if all fit and I would say I would recommend steel or
titanium. I think he would be happiest with those two materials. If he
wanted a Calfee or LOOK(altho I'm not sure any are big enough), would
sell it to them if they fit but I think steel and ti are better suited
for big, powerful riders.

Qui si parla Campagnolo said:

A big guy comes in and asks about a new bike and what would be the best
for him...if all fit and I would say I would recommend steel or
titanium. I think he would be happiest with those two materials. If he
wanted a Calfee or LOOK(altho I'm not sure any are big enough), would
sell it to them if they fit but I think steel and ti are better suited
for big, powerful riders.

Not quite the detailed answer I was hoping for. Why would you recommend
steel or titanium? Why are they better suited?

Thanks,
Greg

Greg Berchin said:

Qui si parla Campagnolo said:

A big guy comes in and asks about a new bike and what would be the best
for him...if all fit and I would say I would recommend steel or
titanium. I think he would be happiest with those two materials. If he
wanted a Calfee or LOOK(altho I'm not sure any are big enough), would
sell it to them if they fit but I think steel and ti are better suited
for big, powerful riders.

Not quite the detailed answer I was hoping for. Why would you recommend
steel or titanium? Why are they better suited?

Thanks,
Greg

First, not many carbon frames are made for riders at or above 76
inches. Of the ones that are, riders that are big and powerful seem to
like the ride of well made ti or steel. Durability of great big carbon
may not be in the 'lifetime' range with carbon either.

So as a shop that is n the position to recommend a frame to somebody
that has no material pregerence, we recommend Moots or Waterford.
Carbon provides no advantage over these two for riders well over 6
feet, well over 200 pounds.