Too Tall's Tubes

[Tmogul]

Hello,

I remember a discussion about how Too Tall's bike was the epitomy of stiffness at the BB. I was curious as to what size tubes and thicknesses were used to obtain such stiffness. Too Tall if you are around could you maybe comment on your bike versus others you've been on? Any other info on tubes from big guys on legends? I just wanted to run some numbers to quantitate versus aluminum. Thanks

[Too Tall]

Ouch. My Ti Legend uses a massive downtube however other than looking like it belongs on a tandem do not have a spec. at hand. I can go look at the build sheet this weekend if you like. As for stiffness at the BB it is without an equal. The bike is a rock and combine that with typical Serotta stable Geo. it is a fantastic bike to train on. I've got a steel Clark Kent that has very short chainstays and a tout build....said it before...if you were to blindfold me and chuck me on the drops of either bike and tell me to hammer away I'd be hard pressed to tell the diff. It really is impressive what Serotta can do with Ti.

I've owned several other steel bikes....all garbage and have one other Ti bike that is for track...it is very different than the Legend. No comparison.

What else can I tell you?

[Sandy]

Sandy can beat you in a race??


Me

[Brian Smith]

I've got a steel Clark Kent that has very short chainstays and a tout build....said it before...if you were to blindfold me and chuck me on the drops of either bike and tell me to hammer away I'd be hard pressed to tell the diff. It really is impressive what Serotta can do with Ti.

I've owned several other steel bikes....all garbage and have one other Ti bike that is for track...it is very different than the Legend. No comparison.


Every Ti bike remotely my size that I ever rode felt completely noodly to me until I rode a Serotta Ti bike. The swaged tubesets, both steel and ti, are one of the largest reasons I ever considered trying to become employed here.

[Sandy]

I think BigMac, a former NFL player, has a Legend with a zillion miles on it.

Sandy

[Ahneida Ride]

Ask William if my 64 Legend is a Noodle ...
William weighs 240 just in his legs !

[Tmogul]

Too Tall,

You have a ti track bike? Is it stiff enough? I ride a cannodale integrated with their bigger BB and I have never ridden a ti bike that came close to its stiffness. I tried moots, vortex, ultimate (but without cycling shoes so can't say), and friends 90's legend. However I love the way ti soaks up vibrations. I personally think a ti bike built as stiff as aluminum will ride smoother. Also some people say their overbuilt legends still flex too much compared to cannondale. So I was just curious as to what tube sizes and gauges they used to acheive your BB stiffness. I figure you're bike would allow me to know what the limits are of ti. How is your ti track bike compared to your legend? I would think unridable for road? Or just different geometry? Huge tubes or just really thick gauges?

I realize everybody's idea of stiff is different so that is why I was curious about your tube numbers....especially the down tube.

Also does anyone know if there is such a thing as round straight gauge tapered ti tubes or are all tapered tubes swaged? Don't know how tubes are made. Thanks again.

[Ahneida Ride]

I'll take a stab at this.

My tubes are not of the caliber of TT's. I belive TT's downtube resembles
Ruths's Bat, and yet my bike is plenty stiff. This really oversized tube set is
available on special order.

I believe Serotta is quite capable is building a Legend to your specifications.

[dirtdigger88]

Tmogal-

My 60 cm Legend's Down Tube: 3.55 cm at the head tube to 4.20 cm at the BB

I think it is stiff like viagra

Jason

[dirtdigger88]

TT is 3.49 to 2.92cm

ST is 3.18 to 3.49cm

jason

[Too Tall]

Brah, wife is scrounging for the build sheet but I know Smiley has a copy so hang tight. You are right the Ti track bike is way different. I ordered it with a super stiff drivetrain and designed to be vertically compliant and it is all that? Not really sure how to describe it. The bike certainly is compliant but not spongy. No life to it. Very comfortable all day bike. I did tell the builder it was for road training so I pretty much got exactly what I asked for.

[Tmogul]

Hey thanks guys for posting some diameters.

Too Tall,

Thanks for even bothering to post your tube numbers. I appreciate it. I was just curious if your downtube was as big as 2 inches (5.08cm) with 0.037 inch gauge or so. I assume your chainstays are probably ovalized and probably thick too? (0.0045 or 0.0065?)

Your comments got me a bit confused. Were you talking about your track bike the whole time or your legend. So its super stiff but compliant yet no life to it yet used for road training. (how do you guys post quotes from previous posts? copy/paste) What you're saying sounds too good to be true. Super Stiff but all day comfortable? Also why buy a track bike for road training? I must of missed something here.

Anyways take your time with the numbers and get some good riding in this weekend.

[Too Tall]

Tmogul , sorry I was typing fast and not clear. Recap: Ti Legend is very stiff bike and super training machine. Not terribly compliant vertically and ride very similar like my wonderful steel Clark Kent. Ti Legend is super stable. Eat lunch on it in a crosswind downhill with a bee sting in my left eye? No problem ;) The Ti Track bike has a stiff BB / drivetrain and soft vertically....that bike has no life man it just does it's job.

I got coffee this morning and got out the calipers. This is pretty accurate not perfect measures..hey it's a cheap plastic mic. and I only had 1/2 a cup of coffee!

DT vert.@ BB = 45
DT vert.@ HT = 50
DT horiz.@HT = 42
CS vert.@chainring = 32

[dirtdigger88]

TT- am I reading that right- is the DT on your Legend larger at the HT than at the BB? That is interesting if that is the case- mine and most others I have seen are larger at the BB- aren't they?

jason

[Tmogul]

Thanks too tall,

I too am curious about what dirtdigger88 said below about DT at head tube. So from your comments are you suggesting that for big guys you can build up ti super stiff like your legend and still enjoy the ride for hours and hours? Do you wish it was a bit more compliant or are you completely happy with your setup?

Hey thanks again for all the info. I appreciate it.

[Too Tall]

Correct. The DT is bigger vertically at the HT than at the BB. I would not change one stinkin thing about this bike it is wonderful. No, if I wanted a really comfortable bike I'd have asked for it and not had any expectations for a very stiff BB / back end. I dunno, just because the bike is built stout does not mean you'd be uncomfortable riding it long. I would not think twice about riding it across the USA or for PBP. I'd just put appropriate tires on it.

[Ti Designs]

I realize everybody's idea of stiff is different so that is why I was curious about your tube numbers....especially the down tube.


And it's not just every rider, but every builder as well. Serotta takes the weight of the rider, the size of the bike and the requests of the rider/fitter and picks a tubeset. Seven has a number scale from 1 to 10 for bottom bracket stiffness. I've owned one of each, I've fitted and designed dozens of bikes for customers, I still can't tell you how the two companies relate in bottom bracket stiffness.

It shouldn't be that hard to come up with some form of comparison chart, but no frame maker seems willing to do the work because they all work to their own standards. The problem comes in when selling a bike and asking how stiff they want the bottom bracket. How stiff is a Cannondale CAAD7 compaired to say a Seven with a BB stiffness of 8, both in 56cm??? Is a Serotta Legend Ti stiffer than an old Merlin Extralight? It seems wrong that the only way to tell is to spend a few grand to get something built.

Here's my idea (feel free to tell me just how stupid it sounds...). Build a testing rig that consists of a flat table with T slots, holders for the head tube and a holder for the rear dropouts. Build a set of test cranks that get mounted in the bottom bracket, the lower set gets fixed to the table, the upper set gets a force applied to it (induction of torsion from offset). Use an air cylinder to apply force to the crank, use a gauge to read deflection, take force readings for even amounts of lateral deflection.

Once the test rig is built, test the same size bikes and post a few results. There will be clear differences between materials which will also show up in the test if there are multiple readings per test subject - say every 1mm of deflection. In the end I'll be able to tell my customers what the numbers mean, that has to be a good thing.

[zap]

Ti design. Subscribe to Tour. They do test bb stiffness on all bikes tested on a custom built jig. HT stiffness is tested as well.

Here are some measurements from '95 models.

Serotta CSI 59c-c 87.7 Nm/degree
Merlin Extralite 60c-c 81.2 Nm/degree
Trek 5500 60c-c 79.9 Nm/degree

Sorry, no c-dale in this issue.

[Tmogul]

Ti designs,
You're right. That is the big unknown with custom frames. You just don't know exactly what you're going to get. It makes things bit uneasy when you need to pay out all that cash for a possible mistake. Actually I think at this level all the bikes will ride beautifully but maybe just not perfectly and frankly when you pay that much money it should be spot on. Actually you might want to take a look at damon rinard's numbers. It on sheldonbrown's site and he compares flex in many different frames. They're older models though.

Zap,
Anymore numbers on say moots or litespeed ultimate vortex etc. Ti bikes. I saw the number for my bike on weight weenies and it was like 98 or so. Actually my caad6 is a bit stiffer than the newer models. Yeah too bad they don't publish something like tour here in the u.s. Of course I hear their numbers could be baised possible due to advertiser's dollars but generally good.

Too Tall,
I'm glad to hear you feel stout is still comfy enough. Maybe its your steel frame back ground or do you ride aluminum also? I've been talking numbers with a builder about stiffness levels and tube selection wall thickness etc. Its just hard to know how stiff I should ask for. That is why I was very interested in your frame design. Most people go to ti for comfort. I want ti for durability and dampening qualities. So my requirements would be much different where weight is not the issue but "bombproofness" and a solid stiff ride. Since ti isn't usually built as stiff as aluminum a builder might think you're nuts for asking for the biggest tubes and thicker gauges. So I was curious as to how stiff ti could get and if it would still be ridable and well in your case it seems that both are possible. I was afraid of asking for too stiff and ending up with a ti bike that feels like super stiff aluminum....that jarring hard ride (should of saved money and bought another aluminum) but if you don't push the stiffness level then you're stuck with too soft a ride. Does stiffness make you faster? I guess you could argue that but the point is some people like myself like that solid feeling of stiffness even if arguable it doens't make you faster. Isn't that the reason why people prefer the material they ride? Its for the feel. Steal is real; ti is fly; carbon is Fahrvergnuegen (german for driving pleasure??? old VW commercials) (your'e right what rhymes with carbon?)

Anyways anyone have the answer to my previous question of how they make tapered ti tubes? Can they be made straight gauge or do they just start with one size and open up the other end leading to differing wall thicknesses?

[Ti Designs]

In selling high end bikes I often have the customer who comes in, stands on the side of the bike, brings the crank to the bottom and pushes against it sideways to tell how stiff the bike is. The test is invalid unless you plan on pushing on it sideways instead of riding it. The idea behind testing is to simulate the stresses of a good pedal stroke - and I do stress the good pedal stroke bit because it makes a huge difference. Looking at the Rinhard test procedure it assumes the bottom bracket remains fixed and force is applied to the ends of the frame. In this model there is no factoring in where the power at the pedals is applied. In fact, no part of the pedal stroke is taken into account, it's a simple number based on a fixed amount of force at the head tube or dropouts. While I know nothing of the data from Tour, the single number format is of limited use. The test tells me the amount of force per degree it takes to deflect the frame (somewhere), but how could that be a linear function? Does this imply that twice that force would yeild twice the deflection - I don't think so.

Getting back to the test, there are a few assumptions that can be made about a bike being ridden. First, the tires are on the ground and have enough friction to stay that way. Second, the forces at the bottom bracket are due to pressure at the pedal, the crank arm, the offset to the pedal and the q-factor. There is no twisting induced by the cranks themselves (assuming your bottom bracket is working), If there were no resistance to the movement of the chain there would be no forces on the frame (again, assuming good pedal stroke). So, the ideal test rig would hold the frame much like the wheels hold the frame (point of pivot at the contact patch) with the satpost and top of head tube having variable restoring forces. The deflection of the frame should be measured at a number of different forces to create a deflection curve, and this data should be collected at various points within the pedal stroke.

This is probably way more data than any consumer cares to see, but it's valid. It would show the "spring return feel" of a steel bike, the more linear resistance to deflection of the oversized alumnium frames and the progressive resistance of carbon tubes. It would make for a fair comparison between bikes, which is what I'm after from a selling point of view. Just a single number does none of that.

[Tmogul]

Ti designs,

Well put. I wish those numbers did exist. That is a very good point about the deflection curve for each type of material which would be great if measured for a given size frame and geometry. I still think there would be twisting forces (torsional stress) during an all out sprint where say the left leg pushes down while the opposite arm pulls up. I guess this would depend on how vertical or not the bike was at the time. Again the technique like you pointed out. But you seem to be in the business and I'm just an inquisitive rider and no expert. But again you would think some magazine out there would publish such numbers. It would only help the customer but I guess they like just hyping things up with silly names like geometrically enhanced tubes.

[Ti Designs]

But again you would think some magazine out there would publish such numbers. It would only help the customer but I guess they like just hyping things up with silly names like geometrically enhanced tubes.

You would think, but the magazines are in business to sell magazines (and advertising space), it's the bike companies which are in the business of selling bikes. More to the point, it's the ones that make custom their main business. I can show someone how stiff a Cannondale CAAD7 is by sending them out on a test ride, but how do I explain the difference between a 6 and an 8 on Seven's 1 to 10 scale? All the custom makers THINK they have a handle on this stiffness issue, but I've had three different custom bikes, all with the same geometry with significant differences in stiffness. They all got the geometry right - they had numbers to go by...

I guess the saving grace with selling a custom bike without any true knowledge of the stiffness of the frame is that the customer will probably adapt to the feel of the bike - most do. I read in a catalog from one of the custom builders of titanium frames that they had some huge number of satisfied customers. How do they know this? (the answer is probably that it's the same number of frames they sold) How many people who own their frames have tried something else and liked it more? How many of their customers thought frame stiffness was the key number and asked for the maximum, only to find the bike isn't as comfortable as it should be?

So this whole issue brings up one big concern. Knowing relative numbers puts a larger burden on both the shop and salesperson selling the custom frame as well as the customer who has to ride a number of bikes and sort out the numbers. Is it worth it and will it happen? Walk into a bike shop and order a custom frame, do they send you out on a few test rides to get feedback and establish some level of understanding or do they just do a fitting, take your money and fax in the numbers. From the rider's point of view, the better educated they are they closer the custom bike comes out the way they want it. From a business point of view, doing a fitting and taking money is way better than all that wasted time - oops, did I say that???

[zap]

The Tour issue I'm refering too has over 100 pages devoted to materials, construction methods, workmanship (paint hardness test too), defects, forces, ride quality and testing protocol.

In this issue, they did test one frame extensively using different force levels. The result as Ti-design suspected, was not linear.

They also test one model from two manufacturers in sizes ranging from 50-62c-c and measured deflection for each size. AL Tubing dims were the same for each. Just longer. Deflection increased from the smallest frame to the largest by 10%.

Tour bb deflection data is based on 1000N with pedals at 45 degrees.

Tmogul, I have data on other frames but most were not available in the US market. I do have one additional number for a '95 Klein Quantum Pro.

Klein Quantum Pro 57.5 c-c 89.3Nm/degree

Tmogul, if I may, I would recommend that you test bikes even if they are smaller than what you require. If it's a Serotta, note what tubing was used and consult with the factory regarding what mods you would like. I wouldn't be surprised if Serotta has a ton of data to help you out.

On another note, in this Tour issue thay also tested tubes of different dia., wall thickness, and materials. Very interesting and quite contrary to what some steel brazers would have you believe.

time to ride :beer:

[Tmogul]

Ti designs,

I really appreciate your thorough explanation of the matter. I'm sure it takes a bit of time to respond at such length and I just wanted to say thanks for sharing your wisdom.

Zap,

I have no doubts that serotta would hook me up with a great frame. However their prices are a bit steep for me right now. There are other builders out there that are a bit more affordable for me anyways. I just wanted to keep throwing out some ideas to all you guys as you have a lot of experience buying top end custom bikes. As for testing, I did test quite a few but its not possible to make sure they all have the same position and the same wheelset and such. I was able to get some idea of things but again there still is that leap of faith in the end. Actually Ti-designs has it right, in the end you just get used to your ride and you enjoy it if the fitting was done right.