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Discussion Starter · #1 ·
Hi,

I am presently doing research to prep for a new bike purchase. I calculated my frame size using the Wrench Science fit system.

Question … does this sound right?

Wrench Science came up with a frame size of 54cc and 55ct. I am 5 foot 11 and 3/4 inches tall. Does this sound “ball park” correct?

It just “seems” kind of small. I have not tested any frames yet. I have seen some 54 inch Trek, Specialized bikes and they look very small :) Should I try out 56ct frames also?

Funny … or not so funny, my current ride is … ahem, a mid 80’s 62 cm ct Cannondale touring bike. I bought this new at a local bike shop as my first bike. I now refer to it as my tank. It is definitely too large for me by several frame sizes. The vendor should never have sold me this bike.

I simply want to make sure I get the right frame size this time and would like to be armed with what “ball-park” size I should be looking at so I don’t get burned again.

For the record I am looking at the Specialized Roubiax Expert, Jamis Xenith Pro, Look 566 etc. Suggestions of other similar frames I might look at would be appreciated.
 

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Go test ride, then you'll know. 54 or 55 for the TT might be right, depending on the size of your torso and the stem.

Years ago bikes were sized by standover height. My wife's bikes from then had a 54cm TT. The one she rides now has a 50. She's much more comfortable on the current bike. The 54's are even too big for me and I'm 3 inches taller with a longer torso.
 

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There is no real way to tell...however, there are lots of ways to fit bikes and be quite comfortable on them.

I'm in the 5'10.5" - 5'11" range when it comes to height. I have strange dimensions with shorter legs and shorter femurs and should be riding a short but long bike. With that said my current race bike, which is plenty comfortable is a 53cm (seat tube) with a 55cm Top Tube. Everybody else on my team (it's a team sponsored bike) that is of similar height...some shorter...ride a 56 and some are on 58's.

If you are flexible you can make up length on a bike with a longer stem and by dropping the bars (more saddle to bar drop). My current set up has approximately 11cm of drop from the saddle to the top of the bars and I still spend a lot of time in the drops. However our team director calls me "Gumby" as I'm extremely flexible (I can get my elbows about 6" off the ground when bending over with straight legs...palming the floor is nothing :)

Now...would I like an extra 1.5cm in top tube length? Sure, then I could bring the stem back a bit, however for the most part the overall fit wouldn't change for me. The bike would handle a bit different, but most people get pretty used to how their bike handles and make adjustments once it's fit correctly.

For you...if you have a shorter torso length then you are going to want a bit shorter top tube length. This might mean you have more seat post exposed and you might want to look at bikes with longer head tubes so you don't have a lot of spacers under the stem or are not using stems with + rise.

Basically...it might be right, it might be wrong...the only way to know for sure is to get out and ride bikes, find some that feel pretty good, find the one that feels best, then get a fitting if possible to dial everything in.
 

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I find the online calculators to be fairly useless. I think they often come out with a too small size. At your height, you'll probably fit best on a 56-57, maybe even a 58 (depending on other factors other than seat tube size). Go to your local shops and try a few out.

62 was almost certainly too big. But you don't want to go too small, either.
 

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Discussion Starter · #5 ·
Jwiffle said:
I find the online calculators to be fairly useless. I think they often come out with a too small size. At your height, you'll probably fit best on a 56-57, maybe even a 58 (depending on other factors other than seat tube size). Go to your local shops and try a few out.

62 was almost certainly too big. But you don't want to go too small, either.
I must apologize the 62cm is the seat tube length ... still much too big. The top tube is 53. I will have to go out and test ride as much as possible, unfortunately a couple of the bikes I have my eye on are not available where I live.

Basically, I just want to make sure I don't let a sales person talk me into something that is actually not right for me. I am so used to an ill fitting bike that almost any new ride is probably going to feel great to me.

I am pretty evenly proportioned with a 32.5 inch inseam weighing in at 175lb in riding form. My arms are proportioned with my body etc. I am no gumby though :) hands flat on the floor is about all I can muster.

If I was more flexible I would go for some of the racing frames ... perhaps will still try a few. I do ride in the drops almost 100% of the time, but I do keep the top of my bars almost even my seat, so I don't think I am that low overall.

I do not like riding up like is recommended at 45 degrees. The wind resistance kills my speed and me ... especially on my 26 pound bike ha ha.

Are the bikes I mentioned all more relaxed frames? I think that is what is should look for as my rides are 60 - 100km and try to go as fast as I can.
 

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Based on the overall height you provided, I'd suggest a 56-58cm C-C frame, leaning toward a 56-57cm seat tube. But of course, you would be better off choosing more based on top tube length.

What you need is another fit system to compare the Wrench Science numbers with. Comparing the two will give you a better sense of whether you can trust the Wrench Science numbers or perhaps if you split the difference of the two systems, you'll be much closer than if you based your fit solely on one method. Here I offer another method from well respected retired framebuilder Dave Moulton. This chart is very accurate for my frame/body. Follow the directions.

<a href=http://www.prodigalchild.net/Bicycle6.htm#FrameChart>Dave Moulton's Frame Sizing Chart</a>
 

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Discussion Starter · #7 ·
Peter P. said:
Based on the overall height you provided, I'd suggest a 56-58cm C-C frame, leaning toward a 56-57cm seat tube. But of course, you would be better off choosing more based on top tube length.

What you need is another fit system to compare the Wrench Science numbers with. Comparing the two will give you a better sense of whether you can trust the Wrench Science numbers or perhaps if you split the difference of the two systems, you'll be much closer than if you based your fit solely on one method. Here I offer another method from well respected retired framebuilder Dave Moulton. This chart is very accurate for my frame/body. Follow the directions.

<a href=http://www.prodigalchild.net/Bicycle6.htm#FrameChart>Dave Moulton's Frame Sizing Chart</a>
Thanks ... that's a good idea. I will do that and I think I will also make a point of crossing the border and visiting a couple shops in Michigan also ... more variety.
 

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Discussion Starter · #8 · (Edited)
Wow ... from Dave Moulton's chart I am not as proportioned as I thought. :)

I have the lower body of someone who is about 5 "9 and 1/2 ... who knew???

But, I am actually just a hair off 6 feet tall. So that puts me at 56cc - 58ct (6 feet) or 53cc - 55ct (lower body) so somewhere in between would be 55cc - 56-7ish ct.

Wrench Science was 54cc - 55ct. So pretty close. That's great! ... sounds like a good starting point. I must say Dave Moulton's chart seems logical.
 

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stringer said:
Wow ... from Dave Moulton's chart I am not as proportioned as I thought. :)

I have the lower body of someone who is about 5 "9 and 1/2 ... who knew???

But, I am actually just a hair off 6 feet tall. So that puts me at 56cc - 58ct (6 feet) or 53cc - 55ct (lower body) so somewhere in between would be 55cc - 56-7ish ct.

Wrench Science was 54cc - 55ct. So pretty close. That's great! ... sounds like a good starting point. I must say Dave Moulton's chart seems logical.

Your proportions are not much dissimilar to mine, and if you can palm the floor you are more flexible than 95% of the riders out there...so looking at racing frames/geometry should be just fine as a lower bar height shouldn't effect you much...and it sounds like you want a lower bar anyway.

I would say to look at bikes in the 55cm - 57cm range depending on the manufacturer since they all size differently.

With the shorter legs you might want to look at frames that have steeper seat tube angles and sloping top tube frames, which will also make a difference when it comes to top tube length.
 

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Discussion Starter · #10 ·
I have to look into this ....

I've noticed that the selection and pricing of race bikes is somewhat better. Plus, I really like the look of the new Cervelo Soloist S1 (less money than others too) but assumed it was too aggressive for me and probably was too harsh for longer rides in farm country. Now I will take a look at it and some others ...

Thanks, this information gives me renewed hope and greater options.
 

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Discussion Starter · #12 · (Edited)
I am just now realizing significance of the length of the top tube in relation to one's own body geometry.

I've also learned how to measure my current bike more accurately ... ha ha. I was measuring the seat tube length from center of the crank to the top of the seat tube = a whopping 62 cm. If I measure from the crank to where the top tube meets the seat tube (in the middle) it is 57cm ... big difference.

So I guess my current bike is more like a 57 with a 53 inch top tube.

Factoring in top tube length and the numbers that seem right for me thanks to everybody's help here, I can say that it will help me ball park the right frame but even more will help me eliminate frames that do not have a geometry for me.

I was up late last night bopping around on-line looking at various frames etc. the one thing I was really able to do was notice the frames that would not fit me. I also noticed how confusing some of the sizing diagrams can be .... Look, Colnago etc. ... my eyes were bugging :)
 

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Find out who the best fit person is on your area, and go get fitted before you buy. Nothing worse than having to buy another bike because it doesn't fit. FWIW, I'm 5ft11' and ride a 58 which is too big for me. So now I'm working on getting a 56cm.
 

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Discussion Starter · #14 ·
1stmh said:
Find out who the best fit person is on your area, and go get fitted before you buy. Nothing worse than having to buy another bike because it doesn't fit. FWIW, I'm 5ft11' and ride a 58 which is too big for me. So now I'm working on getting a 56cm.
That is good advice. I have found at least one shop that has a good fit system. I have also done some searching regarding shops/manufactures and know I will likely be limited to trying the bigger name manufactures, Giant, Specialized, Trek, Cervelo etc. Which is too bad because I would also like to try others like Felt and Jamis. Regardless, I am sure I will find something that will be a huge improvement.
 

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stringer said:
That is good advice. I have found at least one shop that has a good fit system. I have also done some searching regarding shops/manufactures and know I will likely be limited to trying the bigger name manufactures, Giant, Specialized, Trek, Cervelo etc. Which is too bad because I would also like to try others like Felt and Jamis. Regardless, I am sure I will find something that will be a huge improvement.
What you want to do is find someone who is not affiliated with a store, that way they just want to fit you to a bike, not sell you one (from their store).
 

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Discussion Starter · #16 ·
Not sure I would be able to find someone that knowledgeable. But, Dukes in Dearborn MI have the Specialized system ... I believe you pay for that? I read in another thread that this system was a good starting point.
 

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stringer said:
Not sure I would be able to find someone that knowledgeable. But, Dukes in Dearborn MI have the Specialized system ... I believe you pay for that? I read in another thread that this system was a good starting point.
If you want a fitting done and don't want to be "Sold" a bike to get it done...try local coaches in the area. Many of them run total fitness programs and have fit bikes that they can set you up on and find out the correct measurements you need....however some will only be able to fit you to the bike you own.

Also, many bike shops have their own "Fit" bikes that they use to find out measurements for custom orders. You can get a fitting done by them and just use those measurements for the purchase of a bike.

However, for a good custom fitting like these, expect to pay around $300.00 to have it done.
 

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Discussion Starter · #18 ·
$300 ... ouch!!!

Getting fitted on my own bike would not be worth while as it is simply the wrong size.

Maybe I just need to go into shops armed with the sizing I've got from this thread and try out a handful of bikes. Hopefully, shops will make adequate adjustments so I can get a good enough feel to make a purchase decision then fine tune afterward.

I have not done and exhaustive search, but I did notice that based on my sizing from this thread, I've noticed that Specialized and Cervelo both have geometries that seem suitable. I think if I find two or three more and can try them out then I should be okay ... I hope :)
 

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Discussion Starter · #19 ·
Found the catalog for my current Cannondale "Tank". The frame is 58cm at 24 pounds = much too big for me.

I did the Wrench Science fitting again = 3rd time. I had an assistant this time and followed the directions to a "T". I am 56 ct and 55.5 -56 tt. I was not measuring my inseam accurately as I had it a 32.5 before and it is actually 33.5. This pretty much coincides with Dave Moulton's chart.

I've went into two stores and sat on a couple bikes. Owners said I could demo the bikes ... a Trek Madone 5.2, Cannondale Synapse C4 and Cannondale Six carbon 5.

Sitting on them did not tell me much ... felt a little stretched out on the Trek for some reason. Thought it was funny how sales people seemed to slag competition a bit ... especially Giant and Orbea.
 

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info..

If your cycling inseam is 85cm, a normal saddle height from the center of the BB to the top of the saddle, measured along the center line of the seat tube, would be about 75cm. That is really what determines the proper vertical frame size. Your legs are not very long for your height.

Frame size number mean very little these days. What you want to look at is the head tube length, including the headset, to figure the true vertical size of the frame.

Comparing TT lengths can also be confusing since because the reach of a frame is not determined only by the TT length. The seat tube angle also affects reach. Steeper angles add about 1cm per degree to the reach.

When it comes to the LOOK 566, you would need a 53cm or medium size. The 566 is suited to those who need a bit taller head tube, to raise the handlebars higher than any of their racing oriented frames.
 
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