bigdaddy10028

So i'm a newbie cyclist and have the bug. I was hoping someone could help me out. Ideally I want a bike that is built more for speed (20 mile rides and less) but comfortable enough to still do 35 miles + in relative comfort. Which of the below geometries seem best? FWIW, I'm 6'3 235 lbs but fit. I know there are a lot of other details required but i'm just looking for a basic direction in which to start looking at this point.

Bike 1

Seat tube Ctr to top top tube length chainstay head tube angle wheelbase standover
59cm 57cm 43.5cm 72 1020 32.5"

Bike 2

Seat tube Ctr to top top tube length chainstay head tube angle wheelbase standover
58.5cm 61.5cm 42.5cm 72.5 1053 33.5

Bike 3
Seat tube Ctr to top top tube length chainstay head tube angle wheelbase standover
58.5cm 59.5cm 42 cm 72.5 1028 33.5

Additional info, I presently own 2 of these bikes. the other one seems to be the direction a retailer would have me go. Ultimately, I'm trying to figure out if tweaking one of the 2 that I own already is going to get me what I want. Purchasing a new bike is NOT in my budget, though if I can get a proper frameset in the right sizing, swapping parts can make this happen.

DaveSSS 

You left out two of the most critical dimensions, the head tube length and the seat tube angle. You can't define the reach without the STA and the head tube length is what best defines the frame's vertical size. The headset stack height must also be considered, if one frame has an integrated headset and the other a conventional threadless. The standover is usually only relevant for the short legged rider.

Without posting some fit dimensions, like actual saddle height, it would be tough to comment.

If you have a specific fit problem that you're trying to fix, post that info.

HMF

hurts my brain to think about all those measurements, especially when adding different angles.

If you haven't read all this, read all of this: https://www.sheldonbrown.com/frame-sizing.html


Basically, top tube + stem length is most important because seat tubes are adjustable these days. Ask yourself how hunched over you want to be, now and in the future, then pick the appropriate head tube height. But even that can be adjusted with stems.

MDfive21

posting the year/make/model of each bike and/or the full geometry table for each would be helpful.

bigdaddy10028

Ultimately, I'm trying to limit bias towards certain products by being vague, hope you can bear with me. I didn't realize the importance of head tube length, not sure why, I'll look into it

Bike 1
Head tube length 15cm seat angle 72

Bike 2
Head tube length 22.5cm seat angle72.5

Bike 3
Head tube length 22.5 seat angle 72

My saddle height with me on my tip toes is just about 41 inches. My total height is 75" (6'3") again, I do realize that so much more goes into it, just trying to get an idea if any of these frames look majorly illsuited to me. One thing that i can say about bikes 2 and 3 is that those are the largest sized frames they make. Every other manf seems to have a 61 or even a 63" frame but these guys don't. I'm concerned that they are too small, though i own one of them and it's not too small at all.

I don't care about being hunched over on the bike. I'm in the fitness business, I have strong core and know how to properly strength train to avoid issues with hunching over on teh bike. My biggest concerns are not destroying my wrists from numbing and safety, I don't want to build something that is unsafe to ride because i frankensteined it too much.

LowCel 

Keep in mind that seat tube angle is going to come into play as well. More straight up and you will be closer to the bars, angled more towards the rear of the bike and you are going to be further from the bars. That also gives you a different position related to the crankset which comes into play.

merlinextraligh

The reason headtube height is important is, ceterus peribus, it's going to determine the drop from the seat to the bars, which will be the biggest factor in how aero your position is, and will be the biggest determinent of whether the bike is "built for speed"

The bike with 7.5 cm less head tube is going to give you much more drop, again everything else being equal.

The other significant factor regarding whether the bike is "built for speed" as oppossed to stability or comfort is the amount of Fork Rake, and Trail.

bigdaddy10028

okay, this is helping so far. so now here is the other thing, the bike with less headtube is also a vintage bike, the other 2 bikes are modern compact frames, so I think now i seewhat is going on with the seat tube measurements. these new compact frames tend to distort frame size correct? so the vintage bikes frame is actually quite smaller than the other two bikes? this would also explain the much shorter top tube length on the vintage bike correct?

Less rake is more speed correct?

I see headtube height being important, I guess i don't understand how headtube length affects the actual tube height but I'll look at some pics and kind of figure it out.

Okay so i'll let the cat out of the bag, the 2 bikes i own are bikes 1 and 2 An 83 Nishiki Century and a 2010 Giant Rapid. Bike #3 is the Giant Defy which is the drop bar version of my rapid.

The nishiki is MUCH faster than my rapid. The nishiki has been updated to a threadless headset with nashbar carbon fiber fork, alloy wheels, truvativ elita triple crank, 7speed freewheel. It weighs in at 24.5 lbs which is basically exactly the same as the rapid. I have much more than the traditional "fistful of seatpost" showing on this vintage bike and while it's fast and rides smooth, I am definately having some issues with my wrists getting a bit numb.

The real question is are the geometries on the rapid and the defy similar enough for me to convert the rapid to a drop bar bike? for a tall guy I don't think of myself as havnig incredibly long legs so I think the longer top tube of the rapid may be a good thing. But is the worst case scenario that I would simply use a shorter stem?

merlinextraligh

^ It's going to be difficult to directly compare "vintage" i.e. non sloping geometry to compact frames. Manufacturers will give you "virtual" lengths for seat tubes to try to do this.

With compact geometry, seat tube length is just about irrelevant to bike fitting, and it's more important to concentrate on the Top tube length in fitting a compact frame, whereas back in the day we always thought of frame sizes by theire seat tube length.

jayp410

It sounds like you like the Nishiki but it's just causing some wrist pain. Are your bars too low relative to your seat? A couple options might be to get a different stem to raise the bars up, or a shorter stem so you're not reaching as far.

FWIW - I'm also 6'3", and have been riding a 58cm Fuji Cross Pro w/ 57 cm top tube. Saddle height 41", top of bar height 36", center of seat clamp to center of bars 28.5". For me, that frame felt a bit undersized so just ordered a 59 cm top tube frame...haven't had a chance to try it yet. However the 5" seat-to-bar drop didn't cause me any wrist issues...of course everyone is different but those numbers might be of interest to you.

bigdaddy10028

great info, I kinda like the nishiki, but it's an old vintage hi ten frame so it's heavy. I have it down to 24lbs as is which surprisingly is a shade lighter than my rapid so i have to figure out what the hell is so heavy on the rapid. perhaps it's the flat bar brifters either that or the brakes. the vintage diacompes on the nishiki are actually quite light. lastly the crank is prob a shade heavy but i'm prob gonna pull the crank that is in there and put it on a bike I build for my gf. There really isn't any way for me to economically get this bike lighter, its already got a carbon fork in it.

your numbers are interesting, I have 37.5 top of bar height and and 27.5 for center seat clap to center of bars so i don't have quite as much drop as you hve going. I am definately heavy in the upper body and while i've had the bike together for a few weeks, it wasn't until the other day that I took it on a long ride so perhaps i just need to give my body time to adapt. Certainly on the shorter rides I do it feels quick and pretty comfortable.

I'm leaning towards converting the rapid to a drop bar setup using some of the parts from the nishiki. The rest of the nishiki's parts along with other parts off the rapid would go into bldg my gf a bike. I guess i just feel like if I transfer the similar setup over to the aluminum frame rapid it should get a lot lighter.

I really would be happy with just finding a larger vintage frame, thought I found one last week and it turned out to be bent, just a nice 61cm chrome moly vintage would be good.

jayp410

Try weighing the wheels. It's easy to do and will give you a sense of whether it's something attached to the frame that's heavy or whether the wheels are the culprit.

For reference I'm running Mavic Open Pro (32 spoke) with Ultegra hubs, Conti GP4000 tires (25mm), and Forte lightweight tubes. These aren't the lightest wheels but they're fairly light, not terribly expensive, and durable. They are a LOT (2-3 lbs) lighter than the original cyclocross wheelset that came with my bike, and probably 1 lb lighter than the stock wheels on my wife's road bike. Rear wheel w/ skewer and Dura Ace 7800 12-27 cassette weighs 1585g (3.49 lb), front weighs 1160g (2.56 lb). I've ridden these when I weighed 225 lb - down to 200 now.

bigdaddy10028

actually, I have weighed the wheels as i was building everything up. Mine definately are a bit heavier than yours 1470 up front and 1960grams in the rear, about a pound and a half difference. But considering i paid $30 each for my wheels new, paying $300 to lose a lb really isn't economical right now. The way I see it, a hi ten frame at 24.5lbs, I can't complain. I'm a little stumped as to why my rapid weighs as much as it does with it's aluminum frame. I suspect the brakes are heavy and the flat bar brifters must be heavier than I realize. It also has chromoly fork vs carbon on the nishiki but it's still a threadless setup so it's probably not too much heavier.

I need to take some parts off the Rapid and weigh them and see what I can do. The rapid stock is a great bike, a big part of me wants to just leave it alone. I use it to travel to all of my clients and I paid $550 for it brand new. It's spawned a new passion for cycling and the money i save vs taking cabs has paid for this bike multiple times over in just 6 months. It just sucks that business is slow for me right now because otherwise I'd just reward myself with a nice ultegra Bikes direct bike and call it a day.

I dunno, I got so many options to consider, ultimately, I just wanted to understand frame geometry better. If someone told me something like "that is a touring style frame built for abc/xyz, don't change it" that would be one thing. But i gather that the geometry changes on my rapid are subtle enough vs other drop bar bikes that I can easily make the conversion and only need to worry about possibly tweaking things like stem size to get a decent fit.

DaveSSS 

Forget the old bike, it's too small. The bike made for flat bars has a lot more TT length and reach since you don't have all the extra reach that drop bars and brake/shifters add. Whether it can be converted to a drop bar depends on how short the stem need to be in order to produce the same reach. The each difference is about 25mm when you include the effect of the differing STA.

I don't think anyone mentioned anything about how to cure problems with too much weight on your hands. Too much saddle to bar drop is a contributor, but so is having the saddle positioned too far forward.

Edit: Ignore my previous respons on saddle height. My brain must have been asleep this morning. The saddle height that you posted of 41 inches does not make sense. I see that you've listed it as 77cm. That would still be on the short side for someone who is 6'-3" or 190cm tall. That would certainly make those 22.5cm head tubes plenty tall. Compared to my setup, you have only 4cm more saddle height, but 10cm more head tube length.

FWIW, most people think that a 10cm drop from the saddle to the bars is a lot, but for larger riders, it may not be. I'm a lot shorter and use 9-11cm.

bigdaddy10028

keep the good info rolling guys, this is incredibly helpful thus far.

the saddle height from the center of the crank on my rapid is 77cm, not 87cm. This has me a little bit puzzled as you say 87 would be on the short side for someone 6'3" tall unless of course this goes back to my thought that for someone as tall as I am, I don't have incredibly long legs, i'm more evenly built. In fact, I have a female client who is 5'4 and has very long legs, her waistline comes within about 2 inches of mine. She has excessively long legs and short torso and I'm the other way around.

The stem on the nishiki is 120mm. The stem that is on the flatbar rapid is 115mm. One of the biggest differences is definately in the wheelbase. The wheelbase on the rapid is 105.3

merlinextraligh

Less rake equals more trail. All else equal more trail equals more stability (i.e. more of tendency to want to go in a straight line, and corrct back to a straight line)

More rake equals less trail. Less trail tends to be "quicker" handling, i.e. more of a tendency to want to change directions.

bigdaddy10028

okay so another question to you roadies, how much saddle to bar drop to you guys have to the hoods and then how much to the drops? I decided as an intermediate step I'm going to flip my stem. Before my bar height was dead even with my seat height at 41". By flipping the 10* stem it's now 39.75 inch bar height. so then my only other option to get the bars lower on this bike would be to cut the steerer down some? presently I've got about 4" of steerer tube protruding above the headtube.

DaveSSS 

My brain was not in full working mode earlier this morning, so I revised my post about the saddle height. 77cm is still short for someone of your height. I'm 5'-6.5" tall with a 73cm saddle height (obviously at the opposite extreme).

The 22.5cm head tubes are extremely tall. Those who sized you obviously went by torso length and not saddle height. Those large frames would be OK for a rider wanting a recreational position, but the head tubes are so tall, you could never get the bars low enough for a very agressive position. It would have been better to go with the next smaller size, unless a 130mm stem did not provide enough reach.

FWIW, to produce a modest 7cm saddle to bar drop, all you need is a total length of 205mm, including the headset and spacers, with a common 84 (+6) degree stem. The minimum height on your frames is probably 240mm with the headset and no spacers. Using a 73 degree stem would lower the bars about 2cm.

bigdaddy10028

ok, this is good info to know, ultimately it is a flat bar road bike so it is designed to be more of a recreational position. Seems like one size down in the rapid frame would allow me to get more aggressive. you are dead on the money, it's exactly 240mm to the top of the headset. So let me ask you this, is there any danger in cutting the steer down a bit more? i've got about 40mm of spacer in there now, I could cut that in half to about 20? Or are you saying it would simply be easier to get a 73* stem to achieve similar position?

i'm not too upset, ultimately i think i'm going to put the drops on this anyways and at least try it out. I really like building and tinkering so it's fun and fortunately time isn't an issue for me, I have the time to tinker and experiment. It's the best way to learn I guess! I just want to be sure I don't make any type of critical, completely dangerous changes first.

DaveSSS 

I'd probably do both. Take 20mm of spacer out and use a 73 degree stem. To see what the 73mm feels like, you could take all 40mm of spacer out and put it on top of the stem, just temporarily. The only problem with that is it also moves the stem forward by about 12mm, which is more than the next longer stem size.

bigdaddy10028

so I went ahead and bought some microshift 9speed brifters and did the conversion. here is a pic of the bike now. unfortunately, I didn't have anyone to take a pic of me on it which i'm sure would be more of a help. This seat is at 41" and has me on my tip toes, I would probably lower it an 1/2 to an 1". As you can see the bar height is still pretty high up there, though if i get down into the drops I'm a bit lower. I've only done a couple of miles because i've got some tweaking of the drive train to do but my initial thought is that I'm reaching out way too far forward. There was some discomfort inmy wrists again but I can't really tell if it's just residual from the long ride I did the other day. Do you guys think a big part of this is just me getting used to riding a drop bar?

DaveSSS 

I don't get the 41 inches and tiptoes thing. The proper way to set the saddle height is to set it such that your leg has about a 30 degree bend at the knee, at the bottom of the stroke, during normal pedaling. If you have an accurately measured cycling inseam, multiply that by .883 and you'll be close. Initially, I would set the height so the foot is horizontal with the leg fully extended at the bottom of the stroke. During normal pedaling, it requires a 2-3cm rise of the heel to create the 30 degree bend at the knee. If you pedal with little or no rise to the heel, then the saddle would be lower.

Don't expect to be able to touch the ground with your butt on the saddle. That's got nothing to do with proper saddle height.

For me, with an 83cm cycling inseam and a shoe/pedal combination with a very low stack height, the formula just happens to work out. With other shoe and pedal combinations, it would be a little higher.

bigdaddy10028

okay, thanks for your patience with me! I realize to that a big part of proper fit is ultimately just whatever feels comfortable, at the same time, the personal trainer in me knows there are certain things biomechanically that are going to work out better than others. I guess without a goniometer it's going to be hard for me to see the exact angle my leg is at but I should be able to eyeball it somewhat. At the end of the day, my nishiki weighed in about the same as this bike and was flat out faster. Part of it is the fact that this bike is rolling on armadillos but I,m also confident that a big broad chested guy like me has horrible aerodynamics on a flat bar, I just don't want to put drops on this bike and still find myself sitting straight up all the time.

I do notice a ton of people riding on the hoods a lot of the time, do subtle changes make a huge difference in aero dynmaic properties? for example, right now, the handle bar height is slightly lower than before because I flipped the stem and then riding on the hoods has me reaching forward a couple inches more than i would be on the flat bar. is that enough to make a considerable difference?

DaveSSS 

A couple of inches is about 5cm and yes that is huge.

merlinextraligh

A rough test that works out pretty well is placing the heel of your foot on the pedal. Your leg should be fully extended in that position. That pretty much works out to having the right degree of bend when you actually clip in the pedal.

Just a guide, but not a bad place to start from.