ToniH. 

Hello,

I have been riding for a quite long time but just recently started to obsess about the fit and the geometry of the bikes. I'm quite short so normally I have just tried to find the smallest possible bike and the shortest possible stem and that has been quite good so far...

But now I have my eyes on a Alex Singer that is a bit bigger than what I'm riding now.

Different online charts and tools normally suggest that a proper frame size for me would be from 51 to 47 depending on the source. I now have been riding a Miyata 600GT with a following geometry, 60mm stem and a short reach handlebars and I quite like it. There is a quite a bit of the seatpost showing so I think theres room there to rise the seat tube to more "french" dimensions. And also as the front tube would be much longer in the alex singer, if I understand correctly it would balance the bit more longer top tube of the Singer versus Miyata.



Geometry






Here are some more measurments that I tied to take by myself:



Dimensions and a picture of the Singer itself to give you better idea of that kind of geometry it has.

Here are the dimensions:

Seat tube 51.5
Top Tube 52
Stand over lenght 77




Would it seem possible that I could ride the bike comfortable or should I look for an other example? Thank you in advance if someone has time to look into it.


ps. Also I know that some people wouldn't like it but I was thinking this could be a nice candidate to make a 650b conversion. If I would go from 700c, 32 tires to 650b, 38 it would lower the stand over height 2cm if I calculated correctly. Ofcourse I would keep the original parts if I would want to restore it someday.

All the best,
Toni

unterhausen

you should be able to make that fit. Finding a stem that short is possible, but might take a while.

ToniH. 

Hi,

Thanks for your opinion. Yea I have a feeling that it might work... What stem do you mean? Like the one Singer has in the picture? Or even a shorter one?

ThermionicScott 

I don't think a short stem is a goal in French fit, just something that can happen. Ideally the top tube should scale to the rider. With a long top tube and short stem, your hands end up further behind the front axle than otherwise (assuming the same overall geometry), and that isn't to everyone's liking.

unterhausen

my most recent frame build, I intentionally made the top tube longer so my front bag would be close to the steerer. No problem with that from a handling perspective. Some people say that the chain stays should be proportionally longer to compensate. I don't think that's a bad idea. I'm not a big fan of the way short stems look though. I think most of the french fit bikes do have shorter stems for the same reason that mine does.

Seat height and reach need to be the same (within reason) whatever stem you need to make that happen is the one you should use. You will be happiest if stack is the same as well.

ToniH. 

Maybe my post was a bit of a mess. I try to make my question more clear and shorter:

Would this (ST 51.5 TT 52) bike be a good fit for me as a 5' 3 tall rider?

All the best,
Toni

ThermionicScott 

Interesting -- does your stem (or decaleur) get in the way of moving the handlebar bag back?

I'm getting a front rack made precisely because I didn't like how high up and out the KlickFix mount put the old one. I want to get my bag closer to the steerer, too...

I've read (I think from Dave Moulton's blog) that getting the rider's hands over the front axle was an epiphany in handling back in the day -- is that less of a priority for good handling with low trail?

Wildwood

The answer to your question is = It Depends.
1. TT grows by 2cm = Can you stretch to bars ~1inch further forward???
Saddle set back on current ride? Also, some saddles/rails may position rider differently.
2. Standover of Singer = 77, your chart shows cycling inseam = 75. So you can't standover the bike flatfooted barefoot - acceptable???
3. Wheel sizes the same on both bikes?

IMHO, if you need changes to make this bike fit, it's not the right bike for you.
OTOH, if it works for you, snap it up!

ToniH. 

Thanks for taking time to look into this. I measured my curren't bikes, also the miyata, and they all have 52 top tubes. Seems that the singer would just have more box like geometry. Its definitely bit too high for me at least in modern standards. But then again I would like to get the stem bit more higher on my other bikes and this would solve the issue of using really high stems... Its annoyingly close to what would be optimal. When I look pictures of vintage Herses and like, they all seem to show just a bit of seat post, not even the fistful but even less, and that's how this bike would be if set up for my dimensions.

Wildwood

I'm one of those people who believes there is no 'one perfect position' for riding a bike.
I own and ride bikes from 58 - 63cm, with top tubes ranging from less than 57 to more than 59cm. And yes, saddle setback and stem lengths vary.

IMHO, primary determinates of the range of sizes one can ride are flexibility (back and upper body) and core strength (can you support a forward leaning position without pressure on hands/wrists).

But all long-time riders have their personal preferences (more than hard requirements) for how we like our cockpit set-up. Even tho' i'm 6'1" with a 'wing span' of 6'3", my preference is for narrow handlebars - 38cm preferably and not over 40 (charts say i should use 44cm bars).

Fit is a finicky subject.

Chr0m0ly 

I'm 5'10" (almost) and I have a biking inseam of 88.25cm. The overall height measurement puts me on a 56/58cm frame, but with more of my height in my legs, I ended up raising the saddle. I needed a longer seat post for my 57cm Miyata 710 to get the proper leg extension.
Once I did that, my seat to bar drop was too much, maybe 2.5 or 3 inches or so and that's at the steering stems minimal insertion mark.

Asthetics comes in at this point. I can comfortably ride a 57cm frame with taller post and stem, or try a taller bike. I tried a 24" Trek 610. The taller bike has a longer top tube, so I needed a shorter stem. 6.5 cm stems work very well for me on a 24" bike frame.

So both frames "fit" with a bit of parts modification.

I really like the looks of the old French constructour bikes from the '40s. They seem to have about three inches of seatpost showing, and I came to associate that proportion with beautiful bicycles. My 57cm Miyata just looks off to me.

There is also a difference in road feel. With the smaller frame I feel "on" the bike. I can whip it around, and really tick the frame back and fourth for high effort, but I prefer the feel of the taller frame. Instead of up on top of the bike it feels like I'm more "in" the bike. Or instead of perched on top of the rear wheel with my face hanging over the front wheel, I'm tucked in between the wheels.

Instead of cutting turns, it carves turns. When I hit a bump the bike seems to rock back when the front raises, and forward when the rear raises. The smaller frame makes bumps feel like they're transmitted up more.

I also think if a frame fits correctly then your post and stem should have adjustment either up or down. If you have everything at the limit of it's adjustment range, it seems like a different frame might be in order.

This is all my opinion and a lot of it is based on what I think looks and feels right. If you prefer a more aggressive and sporty ride, then a smaller frame might suit you best.

I like the feel of a long frame, and tend to go for bikes with long chainstays, relaxed geometry, and at the higher end of my fit range. Never have I felt like my bikes don't turn in fast enough, or corner tight enough, and I find a stable ride is faster because you aren't constantly correcting your course.

So really this is a loong post about everyone is different and you'd need to try it. But I can't flat foot my 24" bike and it doesn't bother me at all. You don't ride a bike with your feet on the ground.

I come to a stop, move forward off the saddle, put a toe down, and lean the bike a couple degrees to put my heel down. Coming from motorcycles a bicycle feels extremely safe and stable.

I spent years on bikes that were too small and I wouldn't go back.

ToniH. 

I made a quick mockup with my bike on top of the Singer... The only thing that still worries me is the bottom bracket height difference. I asked the seller for some more measurements, but I'm quite close to purchase the bike. '

curbowman

I also have a bike with a classic frame that's a bit bigger that usual. I did that because I wanted to have the handlebars almost as the same height as the saddle and I couldn't find a stem that was high enough for that. So instead of my usual 54 cm this one is 57 cm. To keep my usual fit, the seat post sits deeper in the frame and I use a shorter stem, and I made sure I can stand over the top tube!

Chr0m0ly 

That bike, to my eye, looks "right". Most of my bikes fit me like this set up. Fist of seatpost showing, and a shortish stem. I like 60-75mm or there abouts.

Chr0m0ly 

The singer looks great! You'd need to lower the seat post to match the lower BB. You could also put shorter cranks on it, then you wouldn't have to lower the saddle quite as much. You'd also give yourself less toe clip overlap, and more cornering clearance.

I need to do that on my Miyata...

Road Fan

The lower BB does not concern me. The higher top tube does. If your PBH is 75 and the Singer's standover height is 77, you will be standing with a lot of top tube pressure up into your groin - you can think about how that might feel. I simply could not ride that.

It's remotely possible that with the lower BB you could have more pedal-dragging on turns, but I think that problem is rare. Plus, Herse was among the best designers of road bikes ever, and cyclists ride on paved roads in France, too. I doubt a Rene Herse would have a dangerously low pedal clearance.

A change to 650b 32 wheels would lower the frame by about 1.3 cm (change in teh radius of the wheel) relative to your 700c 28 wheels. The change in diameter is 2.6 cm. I would check your body on the Rene Herse twice before pulling the trigger.

ToniH. 

So I went ahead and purchased the singer. The geometry and size feels... absolutely perfect! I changed the the tires to 650b, 42mm extra legers and with the shoes on I have absolutely no problems with the standover height. Turns out that I don't ride naked that often.

Makes me wonder if the contemprorary bike sizing is more about companies trying to avoid law suits by being over the top careful and less about optimising frame sizes for the best performance.

Road Fan

This time reading this, that guideline seems amazing to me. First, what exactly do you mean by "reach?" and for that matter "seat height" as well. I've been thinking for years that for stem length no such simple formulas exist. This rule seems like the cubit rule or the "handlebar should occlude the QR ends" rules. So please at least state it precisely.

I can certainly see the intricacies of setting up a front end design that satisfies trail, toe interference, weight distribution, room for a bag, room for a decaleur, AND a proper riding position. But I have trouble thinking all that is so simple.

Road Fan

I think you are wondering the right way! I have a 1952 English Clubman-type bike that has a 55 cm seat tube. My good height is usually more like 52 or 53. I was apprehensive at first, but I sat the bike a few times trying to see how it could work, and it feels very well! I have to finish overhauling and re-assembling before I ride it t I have high hopes, like the ram that tried to batter a hole in a big power dam, in an old song that was popular when my bike was built - lol!