i am looking for a non-custom bike (cost is an issue) to fit my strangely-proportioned body. i went for a fitting at the LBS recently, and the guys at the shop said that they just cannot get it perfect with my current frame. i have a very long torso and somewhat long arms, as well as somewhat short femurs in relation to my tibias. i am 5'11" and weigh 138-146 pounds, depending on time of year. (people say i'm built like some guy named hampsten?) anyway, after about two hours of entertaining themselves by measuring and tweaking me, the guys at the shop informed me that i need a frame with a long top-tube length and a steep seat-tube angle. the numbers that they said would be perfect for me are as follows: ST angle-74deg, TT length-58cm, ST length(c-c)-56cm

i am thinking that a Trek (as common as they are) might be good for me, because of the long top-tube length and steep seat-tube angle. i am pretty flexible, so i don't think that i would need to add tons of spacers and a riser stem to make a Trek's low handlebar-height comfortable, as many people need to. i have a 7800 group on my current ride, as well as K-Elite wheels, so i am wondering if Trek sells framesets, or if you need to buy the complete bike.

what does everybody think about my fit dilemma and/or the Trek complete bike/just frameset issue? all responses are appreciated. thanks.

Treks do tend to have longer top tubes than other common brands like Giant or Specialized. They are certainly worth a try. Personally, I don't care if a bike is "common" or not as long as it fits and performs well.

ST angle-74deg, TT length-58cm, ST length(c-c)-56cm

A 56cm c-c frame would have tall standover height of about 83cm. To have a minimal 2-3cm of standover clerance, you would have an 85.86cm inseam, whihc would not decribe a long-torso rider.

Do you have a fairly accurate saddle height?

When looking at Treks, note that they (and Fuji) have an oddball measuring system, where the entire ST length is called the frame size. The distance from the center of the bottom bracket to the intersection of the top tube and seat tube centerlines (the correct definition of c-c) is about 2.5cm less than the stated frame size. Trek's do have about 1cm longer TTs than many other brands, but they don't have a steep STA to go with it, in the size that you need. If you have enough inseam to accomodate a "58cm" Trek's 80.7cm standover, then you would get a 57.1cm TT, but after correcting for the difference in the STA, the reach would be 2cm less than the recommended combination of 74 degree STA and 58cm TT.

You don't mention the stem length used with these recommended dimensions. If it was only a 110mm for instance, merely changing to a 130mm would produce the same reach.

c-40, i am in awe of your knowledge of bicycles.

i don't care what length stem i am using, i just want a bike that fits me right. as far as STA goes, i think the guys at the shop said that the reason i need a steep STA is because of my short femurs- a steep STA would position in me over the pedals in such a way as to be more efficient when pedaling. do you have any ideas about frames for me, other than Treks? or would a Trek be my best non-custom option?

You received inadequate info from the fitting. The TT length isn't real meaningful without the stem length.

Go to the website below and check out the fit info. At least get an accurate inseam measurement. That will tell if you really have a long torso. The short femur thing may not be a big deal. Most fitters will use the neutral knee position as a starting point, but it's not a guarantee of the most effective position. My knee is at least 2cm further back. Just 1cm back will change the recommended STA from a steep 74 to a common 73.

www.coloradocyclist.com/bikefit

C-40 is giving you good advice on fit. I'll not try to chime in on that, because he's better at it than I am.

However, if you truly do determine that what you need is a bike with a longer top tube, take a look at Airborne. They run even a bit longer in the TT than Treks, and make some really sweet frames. They make both Ti and Al frames. You say cost is an issue, but don't specify what that means. The Blackbird Al frame is terribly inexpensive. There's a thread going on now from kona_man who just go his, and loves it. Beautiful bike. Their Ti frames start at $999 for the Valkyrie, $1199 for the Zeppelin and go up to $2500 for the Torch. A few of us have mentioned that the Zeppelin was the sweetest-riding frame in our fleets. (Or at least it was - I just got a Torch.) Airbornes can also often be found very reasonably priced on eBay.

You may note I'm a little fond of them. :) My fleet stands at seven bikes right now (and shrinking! - "yes, honey, I am selling some!"), but the Airbornes get by far the most play.

again, thanks for all the replies. i am currently riding an '04 Specialized Allez Pro, which has a sloping TT. i bought it before i knew anything about bike-fitting, and basically just liked it because it was a DA-10 bike for under $3k. the guy at the shop where i bought it had me sit on it and try to look at the front hub while my hands were in the drops. when i said that i couldn't see the hub, he said that the bike fit me perfectly. apparently, there are things other than the hub-test that can help to evaluate fit, because i just cannot get comfortable on my bike. my back is always slightly rounded when i am riding, and the guys at my LBS who did my fitting said that this was a result of a too-short TT. i believe i am currently using a 110mm stem.

my back is always slightly rounded when i am riding, and the guys at my LBS who did my fitting said that this was a result of a too-short TT. i believe i am currently using a 110mm stem.

Have you tried just bending over more at the waist to flatten out your back? You should be able to do that even with a shorter top tube, though you may have to bend your elbows more. Some people just don't like the flat back riding posture. Lance Armstrong does OK with his rounded back riding style.

I haven't visited the airborne site in quite awhile. There's some variation in the geometry, depending on the model, but you have to be real careful comparing these frames with other brands. The head tube length is actually on the tall side, so this rider may not need over a 56, using airborne's sizing definition. The 56 Valkkyrie has a 56.5cm TT and 73 degree STA, that's just a bit shorter than a Trek, but certainly in the ballpark.

http://www.airborne.net/eready/janette/store/vkbike.asp

Forget about Fuji, I was working from memory (bad idea at my age) the Fuji geometry has a tall BB height, not a long TT.

If you only have a 110mm stem on yore current bike, then you can't compalin about a too short TT causing a fit problem. Try a 120, first, then a 130, if you think you can handle it.

What size are you riding, a 54 or 56? A 54 is probably too small, but the longer stem may be the answer.

My two cents worth; there is more BS talked about bikefit than just about anything else. The human body will adapt remarkably given sufficient time, and to attempt to measure a person and then say you need this size tube in cms is just plain daft.

Seat posts are infinitly adjustable, so get a frame size that suits your height then tinker with the seatpost height until it is ok. Then sort out a stem length; you can go out to quite some length, and always put your seat back a bit more, or get a post with extra layback.

Don't sweat the centimeter measurements, just get a frame that is about right and then experiment with different stem sizes. Take all bike shop fitting advice with a pinch of salt; go to 3 or 4 different shops and you will get 3 or 4 different answers; there is no one correct answer.

Ol

Forget about Fuji, I was working from memory (bad idea at my age) the Fuji geometry has a tall BB height, not a long TT.

If you only have a 110mm stem on yore current bike, then you can't compalin about a too short TT causing a fit problem. Try a 120, first, then a 130, if you think you can handle it.

What size are you riding, a 54 or 56? A 54 is probably too small, but the longer stem may be the answer.

i remember from a prevous post he's on a 54. 5'11 on a 54, it's simple they sold you the wrong size bike.

as for treks having long top tubes. if you go by the listed size (and not measured the way we want to cc or ct) they are actually a little short for example a 54 specialized has a 548mm top tube with a 73.5 seat angle the listed size 54 trek has a 546mm top tube with a 74 seat angle. so by listed size they trek is a shorter bike. i would actually have to go up a size to ride a trek.

wow i was just looking at the carbon frames the aluminum treks are even shorter given a 54 with a 546mm and 74.5 sta.

Going by the listed size makes no sense. The "size" is nothing but the total length of the seat tube and tells you nothing about the important dimesnions of the bike. The only thing that matters is the REAL size, that is the REAL standover height and the REAL head tube length. Once you get those dimension properly compared, then the TTs are long.

If the poster is riding a 54cm, then yes, it's undoubtedly on the small side, but the fit can be made the same as the larger 56cm just by using a longer stem with more rise and/or more spacers under the stem. Not the most desirable approach, but many racers would choose this smaller frame over the larger one.

Going by the listed size makes no sense. The "size" is nothing but the total length of the seat tube and tells you nothing about the important dimesnions of the bike. The only thing that matters is the REAL size, that is the REAL standover height and the REAL head tube length. Once you get those dimension properly compared, then the TTs are long.
How many consumers actually go into a shop and measure the bike for their self? Or study in detail of the charts on geometry? Especially first time customers. They look at the listed size and think I ride a 54 in this brand or have been told they are a 54 at another shop so I should be a 54 in a trek and depending on what brand they currently ride it might be too small. If you forget the actual measures numbers on frame size and go by stated size the treks and their wacked out sizing are very short. honestly saying otherwise makes things more confusing, making people believe they need to go down a size instead of up. People hear 54 or what ever and most consumers don?t realize a trek 54 measures more like a 52 in a lot of brands.

From your earlier post:

"as for treks having long top tubes. if you go by the listed size (and not measured the way we want to cc or ct) they are actually a little short for example a 54 specialized has a 548mm top tube with a 73.5 seat angle the listed size 54 trek has a 546mm top tube with a 74 seat angle. so by listed size they trek is a shorter bike. i would actually have to go up a size to ride a trek"

You need a lesson in how to calculate the REACH of a frame, which determines the stem length required. Reach is the TT length minus the frame's setback. Setback is the STA times the c-c frame size. In the example above, you should subtract about 6mm from the TT length of the Specialized frame to compensate for the less steep STA. This would make the comparable TT length of the Specialized about 4mm shorter than the Trek, not 2mm longer. I'm sure this went over your head, since you seem to think that steeper STAs make the frame horizontally shorter, when in fact, it's just the opposite. A frame with a steeper STA will have a longer front-center and a longer reach (requiring a shorter stem), once the saddle is moved back to the same positon relative to the BB. Any comparison between different frames should always be made with the saddle in the same position relative to the BB.

With most stems only available in 10mm increments, 2-3mm differences are pretty trivial.

From your earlier post:

"as for treks having long top tubes. if you go by the listed size (and not measured the way we want to cc or ct) they are actually a little short for example a 54 specialized has a 548mm top tube with a 73.5 seat angle the listed size 54 trek has a 546mm top tube with a 74 seat angle. so by listed size they trek is a shorter bike. i would actually have to go up a size to ride a trek"

You need a lesson in how to calculate the REACH of a frame, which determines the stem length required. Reach is the TT length minus the frame's setback. Setback is the STA times the c-c frame size. In the example above, you should subtract about 6mm from the TT length of the Specialized frame to compensate for the less steep STA. This would make the comparable TT length of the Specialized about 4mm shorter than the Trek, not 2mm longer. I'm sure this went over your head, since you seem to think that steeper STAs make the frame horizontally shorter, when in fact, it's just the opposite. A frame with a steeper STA will have a longer front-center and a longer reach (requiring a shorter stem), once the saddle is moved back to the same positon relative to the BB. Any comparison between different frames should always be made with the saddle in the same position relative to the BB.

With most stems only available in 10mm increments, 2-3mm differences are pretty trivial.

if i'm following you and taking an extreme example to make a point given a bike with the same top tube lenght a 90 sta would have a greater reach that a bike with a 75 sta? i don't buy that anyone who took any trig or geometry would by that the 90 was longer unless you had major offset on the seatpost and saddle rails to get you the position relative to the bottom bracket the same. i've got where your coming from but there's something else you have to consider. if you're thinking the two bikes with the same seat position relative to the bottom bracket you're right but there's more to it than that. i know given the same seat hight on a slacker bike compared to a steeper bike and don't miss this point the same seat postition on the rails the cockpit of the bike is longer on the slacker bike, and would get longer as seat hight increased. it's a given you can get the same position over the bottom bracket with less offset of the seatpost or saddle rails on the slacker bike, i know you would just move the seat back on the steeper bike and then you would be right in saying it's longer but given the fact we are limited in the lenght of saddle rails and seatpost offset that's not allways an option for someone. i know in my case a .5 degree change in sta (74.5 to 74) meant sliding the seat a bit about 8mm or so forward to get the same position. honest C-40 i think both our takes on this are valid just different.

There is only one proper way to caluculate how a bike will fit compared to another, with the rider in any given position relative to the BB. Calculate the reach as the TT length - [c-c frame size x the cosine of the STA]. This is a very simple equation that tells you exactly difference in the reach of the bike. Furthermore, if you want to figure out the difference in the seat post offest, just multiply the saddle rail height times the difference in the cosine of the two STAs.

For example, on my two 51cm c-c frames, one has a 74.5 STA with a 52.5cm TT and the other has a 72.5 STA with a 54cm TT. This is about as extreme difference as you'll find, but it's quite simple to find seatposts to produce a nearly centered saddle on each bike, so you argument about seatpost and saddle rail constraints does not hold water.

Finally, which of the two frames above has the longer reach? 54- (51 x cos72.5) = 38.66cm and 52.5 - (51 x cos 74.5) = 38.87. Thus, the frame with the 52.5cm TT length is 2mm LONGER than the frame with the 54cm TT. A great reason NOT to just look at the TT length without considering the STA. These frames fit the same wihin 2mm, with the same length of stem, certainly not what you might think at first glance.

The difference in seat post offset for my 71cm saddle height, is approximately 68 x (cos72.5-cos74.5) = 2.3cm. Finding two post to produce a nearly centered saddle on each bike was not difficult as all.

As for the total difference in the seat post offsets available, a Thomson straight up post has the front of the clamp 2cm in front of the seat post centerline and the post like the Easton EC-70 and FSA K-force are 1.5 to 2cm behind the seatpost centerline. This range, plus the 3-4cm of saddle rail travel covers a 7-8cm range that can compensate for up about 7 degrees of STA.

There is only one correct way to calculate the difference in the fit of two bikes with the saddle in any given position (but the same) relative to the BB. The frame's reach is the TT length minus the setback. The setback is the c-c frame size times the cosine of the STA.

Consider my two 51cm c-c frames. One has a 52.5cm TT with a 74.5 STA and the other ahs a 54cm TT with a 72.5 degree STA. Run through the calculations and you’ll find that the frame with the 52.5cm TT actually has a 2mm LONGER reach. I use the same length stem and have the same saddle position on both bikes, producing a reach that’s within 2mm of the same.

The difference in the seat post offset, for my 71cm saddle height is 68 x (cos72.5-cos74.50 = 2.3cm. It was simple to find two posts with the necessary difference in offset, to produce nearly perfect centering of the saddle on both bikes.

Seat posts can be found with the clamp positioned anywhere from 2cm in front of the post centerline to 2cm behind the centerline, for a total of a 4cm difference. Add another 3-4cm for saddle rail travel and you can easily compensate for up to 6-7 degrees in STA. Your contention about the limitations of saddle positioning is not correct.

There is only one correct way to calculate the difference in the fit of two bikes with the saddle in any given position (but the same) relative to the BB. The frame's reach is the TT length minus the setback. The setback is the c-c frame size times the cosine of the STA.

Consider my two 51cm c-c frames. One has a 52.5cm TT with a 74.5 STA and the other ahs a 54cm TT with a 72.5 degree STA. Run through the calculations and you’ll find that the frame with the 52.5cm TT actually has a 2mm LONGER reach. I use the same length stem and have the same saddle position on both bikes, producing a reach that’s within 2mm of the same.

The difference in the seat post offset, for my 71cm saddle height is 68 x (cos72.5-cos74.50 = 2.3cm. It was simple to find two posts with the necessary difference in offset, to produce nearly perfect centering of the saddle on both bikes.

Seat posts can be found with the clamp positioned anywhere from 2cm in front of the post centerline to 2cm behind the centerline, for a total of a 4cm difference. Add another 3-4cm for saddle rail travel and you can easily compensate for up to 6-7 degrees in STA. Your contention about the limitations of saddle positioning is not correct.

you know what C-40 we are both right on some points, i knew what you're saying i got it the first time didn't need a techincal explaination but given the same seat post and seat which last i checked most bikes came with similar offsets for the factor a bike with a slacker sta has has the potiental of having a longer cockpit or further rearward position. plain and simple even if the difference is slight.

What you're saying is finally correct, but it's not a comparison made for a specific rider who knows how much setback he wants. Sure, on my frame with a 72.5 degree STA, the post sits further back and I could put a post on it with a lot of setback to create a longer reach, but the riding position would not be the same relative to the BB, nor would the weight balance. The idea is to compare frames with the rider in the same position on all frames being considered.

This is probably the most common mistake made when comparing frames. Only the TT length is considered, when many times a TT that seems longer is actually shorter.

Regardless of what the average consumer does, the smart way to compare frames is to compare the critical dimensions of TT length, STA, head tube length and stadover height (if the frame has a horizontal TT). Comparing hese dimensions and ignoring what the manufacturer calls the "frame size" will result is a properly fitting bike.