Hello,

I've got a 52 cm Cannondale Six13 which has a 53cm top tube and a barely sloped top tube with a 13cm head tube. It's also got a 74 degree seat tube angle. I personally am 5'7" tall with a 79cm inseam, and when using the "divide total height by inseam" measurement, (174 / 79) I get 2.2. This tells me I have short legs and a longer torso I guess?

I've always felt like my top tube is long enough with a 110 or 120 stem, but when setting my seat to the correct height my seatpost doesn't have much raise and so my saddle to bar drop, even with all the spacers taken out and stem flipped, is just 5 cm. I'm wondering if there are any frame manufacturers y'all can recommend that have a geometry that might give me more drop but a longer tube. Hopefully someone else has similar dimensions or a similar situation and can provide some advice. I'm pretty good at fitting myself to bikes, but I admit overall geometry is still somewhat tricky for me to figure out. I guess I need a longer top tube, but a shorter head tube to get what I need?

Thanks in advance!

paging cdr.

I hear tsunami will build you a nice bike.

+1

Since reading CDRs report I have been in contact and will be ordering a custom Tsunami this week. They do a great job explaining the entire process in detail and answering questions about build.

I went to bed early last night. Still tired from the race

I'm 5'7". I think my inseam is significantly shorter than yours (I want to say 73 cm but I don't remember). I also rode a 52 Cannondale last (SystemSix) with a Thomson post low enough that I couldn't clamp it in a normal Park stand (not the new skinny clamp ones). In fact I could barely put a seat bag on (small one) above a blinkie. I also had a 13 cm stem, 73 deg (horizontal), no spacers at all.

Shot of me last summer on Cannondale. Yes, I raced heavy lol.


This is on the Tsunami.

Picture is a rough by Navone Studios.

I'd originally requested a 76 degree seat tube angle, 57 top tube (effective), "shortest possible head tube" which ends up being around 9-10 cm. The builder convinced me that 75.5 would be better, 56.5 TT, both based on his own personal experience. He said the head tube would be 9.5 cm, whatever they could get it down to.

With the top tube and seat tube angle changes, I got about 5-6 cm more length. Figure 4-5 cm because I went to a 12 cm stem (I'm already thinking of putting the 13 on later). I went from seeing my brake pad bolts in front of my stem (while on the drops) to seeing just the whole front hub.

I have more stuff in my blog, but I haven't posted anything with the bike as it is now - with rocket ship wheels. It's a really, really fast bike

Bike:
https://sprinterdellacasa.blogspot.co...rst-rides.html

Based on the weights here:
https://sprinterdellacasa.blogspot.co...val-build.html

and the fact that I weighed my bike with its rocket ship wheels at 16.8 lbs, the bike is about 1.3 lbs heavier than the SystemSix with the DV46 tubulars. I put on a lighter saddle, much heavier fork, heavier front derailleur (not really that much heavier but technically true), and I think slightly lighter wheels. Everything else is the same, literally, since I pulled them off the Cannondale. Different headset but it's probably same weight.

I also lost weight. From the summer picture, about 25 lbs. From last year's Bethel Spring Series, 30 lbs. So do I notice the +1.3 lbs? Heh. Do I notice the -30 lbs? Heh.

Video of me in action, sort of, here:
https://www.youtube.com/watch?v=BBBg19UnDF8

At the start I rocket up the left side. Nervous I guess. At 3:20 or so my teammate and I are sitting together. At 5:20 I roll pass the camera guy. You can see how short I am on the bike

cdr

*edit* the seat tube, center of BB to top of top tube, is 40 cm. This mimics a size S Giant TCR aluminum (the carbon TCR I have is 44 c-t, the alum one 40). I like the 40 cm seat tube so requested it.

Thanks for the ideas about a custom build, but I really don't want to go that route unless I have to. Perhaps according to my dimensions, this really is necessary? Also I'm not a crit guy - I like to go fast and for long rides with alot of hills. But when the wind hits I find it hard to get low (even though I have excellent flexibility). I've read that a 73 degree angle might set me back further and balance me out better on the bike with my longer torso, but I still see most frames with a long enough top tube for me as having too high of an effective top tube for the saddle to bar drop I need.

I, too, like going fast on training rides. Although I go up hills around here because I have to (I need to do about 500-600 watts just to get to the street from my house - steep frickin hill), I try and do Palomar when I make my annual trip to SoCal. I love, love, love descending, and I will climb for 120 minutes to get 25 minutes of descending. So although I do crits, my riding style sounds exactly like yours.

Incidentally, the only thing spec'ed out on the frame for "crits" specifically is a request for BB stiffness. This works for climbing too but I wanted a stiff frame for sprints. Mind you, my frame is probably not any stiffer than any of the carbon frames out there.

The head tube angle is identical to the Cannondale, rake also, and that's because the Cannondale is great in crits. Basically a normal road bike works fine in crits - you just have to be able to corner normally.

Custom build isn't that painful. To wit:

Cost:
$600 + shipping (approx $50 for shipping). Add $50 for BB30. He's supposed to be raising his prices but not sure when that will happen. This doesn't include a fork, but he can sell you one, ditto headset, build kit, etc. Or you can buy a bike from, say, Neuvation and sell off the frame.

I paid more because I felt he was undercharging me. This wasn't anything except a gift to the builder. I didn't get any faster service, faster shipping, nothing. I just felt he deserved more than $650 + shipping for a full custom frame.

Time:
8 weeks. Normal time period.

Color:
Your choice. I let him pick the color, although I had to okay it.

My bike's use and therefore requests to the builder:
crits
group rides up to 2-3 hours long
solo rides up to 6-7 hours long
New England roads (rough, with sharp climbs and descents)
comfort comparable to SystemSix, which I think is comfy

I got into a "discussion" with someone at sweep day last Saturday about seat tube angle. It has very little or nothing to do with comfort, nor balance, etc. It has to do with your quad length. I have short quads so I want a steep seat tube angle. I automatically slide forward on my saddle anyway but I'd do so more if I were on a slacker ST angle. Plus my saddle would be slammed forward.

The guy wanted to argue with me that the BB/saddle/bar triangle can be rotated around a circle and it'd fit no matter where you ended up with the saddle (i.e rotating the circle so the saddle moves back). That's not necessarily true - have you ever ridden an Electra cruiser? Do you think that it's as efficient or comfortable (or insert your adjective here) as your road bike? Electra marketed their cruiser position as a rotated version of a normal road position (they had a funny diagram of a "racer" trying to hold a latte type drink on a "racing bike" versus a cool casual dude on his Electra cruiser who wasn't spilling a drop). If that was the case, recumbents would be similar to road bikes (they're rotated more than a cruiser). That's not true either.

Electra cruiser site. Click on "technical".
https://www.electrabike.com/home.php

This is because your bar position relative to the BB is important when you stand up. And that length is determined by a combination of quad, torso, and arm length. If the bars are too close to the saddle, you feel cramped, you can't pull up very hard, and you lose power. Even if you're not racing, that's not ideal, else you'd be riding a cruiser around instead of a road bike.

You mention flexibility. I'm not flexible, but in the past I couldn't get low enough because, frankly, I was too fat. But now I can get much lower. On the trainer I experimented with how low I could go. After pedaling for about 5 minutes with my face literally about a cm above the bars and my elbows well below the drops, I knew I could go as low as I wanted. I'm not flexible but I like getting low. In fact I find it more comfortable at the end of a long ride (4+ hours) to be in the drops than anywhere else.

So, when I went to figure out what I wanted, using the Cannondale as a base, I knew I wanted a particular BB-saddle relationship.

Everything was based on that.

I put it in bold italics because that's the key to the frame, the key to a properly fitting bike. You have to have the right saddle/BB relationship. You never, ever compromise it to make up for a deficiency elsewhere.

Once I decided the saddle position relative to the BB (i.e. how it is on my Cannondale), I started on the frame fit and geometry. First I left the saddle where I wanted it. Then I figured out everything else.

Seat tube angle. Got a straight edge, put it along the line from the BB to center of saddle rails. This draws the line of the optimal seat tube angle. It offers the most adjustment fore/aft for future play (on the Cannondale I could only move the saddle back). I use a zero-setback post so if I wanted to really move the saddle back I could with a different post. But since I have short quads, I left the zero setback post in place.

The angle, using a crude protractor, was about 76 degrees.

Then, once the optimal seat tube angle got "drawn", I checked top tube length from the optimal seat tube location. In my case that seat tube centerline was 2 cm forward of the current seat tube. To replicate my position on the Cannondale, I'd have to get a 2 cm shorter top tube.

However, I wanted to get a longer frame. I played with position on the trainer and knew that 5 cm longer would be pretty conservative (I would ride with my hands 5-7 cm in front of the bars). I figured 6 cm would be sort of aggressive. So I figured on +6 cm top tube, or +4 when you take into account the seat tube will be steeper. This is what made me request a 57 cm top tube.

I was talked out of it by the builder as he'd built a bike almost exactly what I was describing and it didn't handle well.

So I settled on a 56.5 cm top tube. This would be 5 cm longer effectively - 3 cm longer in actual tube length, 2 cm longer due to the steeper seat tube angle.

The reality is that is was slightly shorter since I also eased up on the seat tube angle. So take off another 5 mm.

Remember that I was fitting with a 13 cm stem. I knew I could go 14 if I had to, and I didn't want to go below 12 cm (under 12 doesn't feel stable at speed).

With seat tube length, angle, and top tube length (and head tube height - "shortest possible"), my three contact points have a min/max range.

I let the builder choose the chainstay length to keep the weight distribution normal, but I think my next one will have shorter stays. I lift the front wheel even with the longer frame so I should be okay with the wheel an extra 5-10 mm closer to the BB.

I also requested the stiffest possible frame that wouldn't beat me up over 6 hours. Since the rear triangle is similar to the SystemSix, and the fork is a carbon fork, it worked.

Everything came out fine, and it was much less than even a SystemSix frameset.

cdr

Thanks for all the info, you know quite a bit more about geometry than I do. Yeah I get your point about the rotation around the BB but wasn't aware the angle was really based on femur length. How would you determine whether your femur is short vs. long? I've measured mine but don't know what an average vs. short/long ratio is.

Not too hot about getting a custom aluminum frame. If I was going custom would rather do steel which is pretty pricey I think.

Any particular (rationale) reason?

I have a bee in my bonnet about the fit of bicycles for shorter riders and while your not really short, an inseam of 79cm is shorter than what mass produced bicycles are designed for.

Firstly when it comes to fitting a bicycle well I have a mental concept where the bicycle is cut in half at the Bottom Bracket (infront of/behind the BB). You fit yourself to the rear of the bicycle FIRST depending on what suits your legs and then once that is sorted you fit yourself to the front of the bicycle to suit your arms but without making any more adjustments to your saddle (only adjusting the reach and height of the handlebars).

Now I'm also a proponent for proportional length cranks. Based on an inseam of 79cm I think you should be using cranks no longer than 165mm. Try some 160mm cranks if you can come by then but they are VERY rare. Once you have the right cranks selected start with the saddle positioned for KOPS (knee over pedal spindle). KOPS generates plenty of controversy but I recommend its the place to start but not an iron clad rule. Anyway fitting 165mm cranks (I'm guessing you currently have 170mm or 172.5mm cranks) and positioning for KOPS is likely to move your saddle up and rearward and this will extend your reach. This may well be what you want so do this first before adjusting the bars.

Anthony

AnthonyG - thanks, I do have 170 cranks and am surprised you recommend 165s. That would put me higher on the saddle by 5mm but my bigger concern would be the loss of leverage on hills.

kudude - I guess the reason I'd prefer steel over alum if I was going custom is durability (in case of a crash) and ride quality/compliance. I wanted a carbon frame when I first started riding a few years ago but since then the thought of one failing on me freaks me out.

Your legs are not extremely short. I'm only .5 inch shorter and my cycling inseam is 83cm (saddle height 73cm). You don't find legs much longer at my height, so I'm at the opposite extreme.

You just need a sloping TT frame and either the smallest frame offered in most brands or the the next size up. I ride a 51cm LOOK 585. A 49cm would fit your legs better, but it depends on your preferred saddle to bar drop. The 49cm just requires one size longer stem.

There are swings and roundabouts when it comes to leverage from long cranks. While you may gain a fraction in leverage with slightly longer cranks you lose out when you come to top dead centre because its harder to get your leg through that position. Shorter cranks means your in a stronger position to start the stroke so you gain there. I've got really SHORT legs and I use custom 125mm cranks. I was pleasantly surprised myself when I first climbed a hill using them in that I wasn't slower at all. I liked climbing with the short cranks. Raising the saddle will also counter and desire to lower the handlebars.

Anthony

I think your reasons for desiring custom steel are a little off, but to each his own. FWIW I've crashed my carbon bike HARD twice and gone down on it 2 other times. It's fine. Ride quality is far and away not only a function of frame material.

The 160/165 crank idea makes sense, weird that Shimano, SRAM, and Campy don't make smaller than 170s?

As for the frame size, that Look is a hot frame - wish it had BB30 though.

Okay, 179cm inseam is not short for someone 5'7". 179cm is roughly 31".

I'm 5'9" and have a 76.5cm inseam, which is just over 30". I consider myself one of those short-legs-long-torso guys. I ride a bike with a 51cm 76º ST, 51.5cm TT, and 74º HT (track frame, I'm not a roadie like you guys). I also run 160mm cranks, which are comfortable but having come from 170mm cranks on the retired road bike (frame was too big for me anyway), there is a slight but noticeable loss of torque, but it's not a big deal. I like having a bike that fits.

Also, I feel like you'd have to be quite strangely proportioned to require a custom frame for fit reasons alone. Most frames, as long as the geometry is roughly within what you need, can be adjusted to fit you.

Just a question - is STA really important? Isn't the crucial measurement saddle setback from the BB? For example, a steeper st would need more setback in the post whereas a lacker st would need less setback in the post. Or am I missing something here?

Get a 17 degree stem and point it down, if you don't have one already. That will lower your bars quite a bit compared to a standard 6 degree stem. You can also look into a shorter stack headset for even lower bars. My height to inseam ratio is exactly the same as yours and I don't have any fit issues on stock frames. If I want lower bars, I size down and use a longer stem. If I want them higher, I go up a size and use a shorter stem.

Gotta comment on CDR and his Tsunami. I've been thinking about the geometry since seeing the bike on Sunday. With CDR draped over it, stretched out long and low, and it fitting him like a glove, he and the bike look like a missile or torpedo (or a Ducati). It is crazy (I mean that in a good way).

I included it because the STA of my frame is actually pretty extreme, so I figured I'd point it out. Also, since I was just listing the specs of the main triangle of my frame, it was kind of automatic. But you're right, effective STA can always be adjusted, as with most things on a bicycle (my point).

Ok, I was just wondering, especially because CDR talked alot about needed a steeper STA to fit his body. My bike has a 76 STA, but I have my seatpost setback 25+mm, so for my next bike I'm looking for an STA that is <76.

Okay I just through CDR's posts, as I hadn't read them earlier because they were tl;dr. Interesting read, though the nice thing is that much of what he mentioned (seems like his proportions are similar to mine) came to me intuitively. As in, I would ride the bike for a while, make some adjustments, ride more, adjust, etc. I came to the conclusion that I, like CDR, have short legs (which I already knew) and short femurs (which I didn't know). I noticed I had to move my saddle pretty far forward, in addition to the 76º ST, just to get KOPS. This also allowed me to get lower without sending my knees into my chest. I do run a shorter, higher stem than CDR though because I don't actually race and ride less aggressively.

Anyway I guess all I'm trying to say is that, reflecting upon CDR's posts, when you get down to the nitty gritty regarding bike fit and odd body proportions, I can see how things like STA can make a difference.

Does anyone make a 165mm BB30 crank? I was looking at the pedal force frames and the 50cm seems like it would fit me.

Why are you convinced that you need 165mm cranks? Your legs are not short. They are basically the same length as mine and I use 172.5mm cranks on my two road bikes. I've also logged a lot of miles using 175mm cranks but the 172.5's are a bit more comfortable after a lot of miles. 165's are super short. I don't see the point in searching out such short cranks unless your knees are not happy with 170's or whatever you currently use.

im in a similar boat. im 6'1" with a 79 inseam. while this adds nothing to the ops question, i just ride 56cm frames with long stems and make due the best i can. since no one is paying me to ride, its good enough for my simple needs.

i think people make too big an issue of crank length. 5mm isnt a big deal, then again, some people are finicky.

re: STA - you can adjust around a non-ideal STA but it would be better to be in the middle of the range. So instead of slamming a saddle all the way forward on the rails on a zero setback post, get a steeper STA. Or, if you're tall, instead of jamming the saddle back on a huge setback post, get a more slack STA. For saddles it can reduce stress on the saddle (they don't seem optimized to be clamped at one end or the other), post (having a saddle hang way forward or backward doesn't seem good for the clamp), or even increase comfort (pushing the saddle back allows it to flex more).

In another "stay in the middle of the range" example. I use the 4.5 degree Keo cleats. I try and have the cleats set up so I have about the same amount of float in each direction. I could easily ride with just, say, 1 deg one way and 3.5 the other, but it doesn't allow the same amount of float each direction. I've been meaning to adjust my left foot ever since I unclipped while pedaling seated, but I haven't. I should do it before this weekend's race.

Re: cranks. I use 175s. I'm away from my tape measure but I think my inseam is 73 cm. It's really short. I find the 175s work really well for overall riding - long rides, hills of all flavors, etc. The only place it loses out is in top speed, but my top speed is down at least 10-15% (on equal length cranks) so I've given up on top speed. Now I want to finish races/rides with the group, and long cranks really help me with that.

I think I'll be switching to 170s for the summer (because I have 170s on the track bike - but the track I go to just got weirded out - NE Velodrome). If I don't race track I'll keep the 175s on.

If I go to 170s for the summer, I'll raise my saddle 5 mm. I'll let the raising bit move it back too, so maybe a net gain of moving it forward 1-2 mm. I'll leave my bars as is.

When judging what I use/do, try to keep in mind that "racing" is just riding. Fine, I race, but that doesn't automatically discount what I use for normal riding. My racing is no harder than a group ride, and in fact I get dropped from the local shop's ride all the time (and there's one, maybe two racers, Cat 4 and Cat 5, that do the rides regularly - the rest are explicitly non-racers).

Although long cranks "help" me race, I put them on because they help me go up normal hills better (less than 10% grade). If they didn't help me go up hills easier, they wouldn't help me race.

cdr