Bike size

[reuben]

:help:

Back in the late 80s/early 90s I used to do triathlons, and a lot of riding with regular drop (non-aero) handlebars. Then I stopped riding until this year.

I'm 5'10, and have "normal" proportions. I don't have long or short legs, long or short femurs, long or short torso, etc. I have pretty average dimensions for my height.

My old bike was steel, classic horizontal top tube, 56cm c-c top tube.

About 3 years ago I went to an LBS and bought a bike for knocking around town. I ended up with an aluminum frame with carbon fork, sloping top tube. Nothing fancy, as it was just for knocking around town. It's a Specialized Diverge Sport A1, if that matters. They put me in a 54cm.

https://www.specialized.com/us/en/diverge-sport-a1/p/106496?color=197281-106496&searchText=95416-6149

As I've been riding more this year I've noticed that it feels small. So I've been looking up some online fit formulas and comparing the new and old bikes.

Not only is the new bike smaller overall, but the stem is shorter, the cranks are shorter (170 v 172.5), the handlebars have less reach and drop, etc. I'm considering getting rid of it at some point and buying a 56cm c-c top tube more like my old bike. Sure, I could change a bunch of components to make a small frame feel larger, but I suspect that I should really be on a 56.

It's fine riding on the hoods, but when I get into the drops I'm definitely cramped. I tried to move the saddle back this morning to a position similar to the old bike (and per some online fit guides) and ran out of room. I'd probably have to get a longer stem as well, and maybe new bars. And that's just the horizontal part of the fit.

I'm not ready to pull the trigger yet, but before I do - has there been a change in size/fit philosophy that I missed during my multi-decade hiatus? Or am I really riding a bike that's too small?

I realize that that's a difficult question to answer over the internet, but I'm sure plenty of you will try. :D

Thanks in advance.

[Dave]

A geometry chart would help.

https://geometrygeeks.bike/bike/specialized-diverge-comp-2019/

These days, bikes are fit based on stack and reach, making it easier to get the right fit.

A diverge has a tall head tube and short reach, but needing to use a longer stem is no reason to get rid of a bike.

[Toeclips]

You can use a measuring tape to measure the distance from front of seat post to back of stem, then you will know how much of reach you may need to compensate for if you buy a longer stem
Angle the stem up if you need to
If you buy bars then make sure you get the depth you need but measure your shoulder width as well for getting the width of bars correct
Try a seat post with a set back if it already doesn't have a set back
A longer seat post may help to compensate for the crankset

All this you might be able to determine through a good bike shop that can size bikes properly

Buy used until you find your fit

Hope this helps

[Davist]

Lance Armstrong is 5'10" and rode/rides 58s. They do tend to size you down now for sure vs previous. I'm 5'11" and ride 56 cannondale, M in Canyon, L in Carbonda gravel bike. Charts alone don't tell the whole story.

[Peter P.]

Of course it's too small.

You had a history of riding 56cm frames and it's obvious you remember sizing numbers and what seemed to fit you. It's not like you're new to the sport and don't know what fits.

If you can remember what the TOP TUBE length of your old, familiar bike was, I would suggest you seek out a bike based on a similar top tube length. I'm guessing it's closer to 56cm than the 54.9cm of the bike you have.

In the case of the Specialized Diverge you have now, merely buying a longer stem will not recreate the fit you are comfortable and familiar with. Also, I notice the 56cm Diverge comes with the same stem length as the 54cm. Even if you were to just up-size to the 56, you may need a longer stem as well. That's common.

The shop you purchased the bike from may take trade-ins and while it may be a bit of a loss on the trade-in, if they do it will be worth it to size up on the Diverge. I did that once and it was worth the money.

[ultraman6970]

I was looking at the geometry tables and those front tubes in the tables are really small... are those right?

[Dave]

All I see is TT lengths that are maybe 1cm shorter than normal. It's a bike with an upright fit for beginners. 1cm more stem length would fix that. A 120mm stem wouldn't be a crime.

[reuben]

Thanks everyone. Looks like the bottom line is that measurements and sizing have changed, apparently for the better.

I found this drawing at this page (https://www.bikeradar.com/features/your-top-tube-length-is-irrelevant/), and took measurements of the old 80s Bianchi (which I need to dust off and ride), and the newer Diverge. Hopefully you'll agree that these are the measurements to be taken.

https://forums.thepaceline.net/picture.php?albumid=146&pictureid=668http://

Bianchi Diverge
BBX 29 29.5
BBY 10.875 10.75
BarX 48.75 47.5
BarY 36.25 36.25
FrameX 45 45
FrameY 33.25 33.25

Thus:
Handlebar reach is 19.75 (Bianchi) and 18 (Diverge)
Handlebar stack is 25.375 (Bianchi) and 25.5 (Diverge)
Frame reach is 16 (Bianchi) and 15.5 (Diverge)
Frame stack is 22.375 (Bianchi) and 22.5 (Diverge)

So it looks like the big difference is the handlebar reach, which agrees with my feeling of being cramped when I get down in the drops. Note that the bars on the Diverge are smaller as well - they have both less reach and less drop. The old stem is 125 (pretty long, IIRC).

Saddle position is a whole 'nuther kettle o' fish, which I'm slowly working on. I raised it at least an inch this morning, and my knee and pedal spindle seem to be OK (back of kneecap more or less above spindle). I tried to set it back more but ran out of room, so I just positioned it about as far back as the manufacturer recommends. I'll get in a test ride tomorrow.

Toeclips - yeah, I'm aware of the bar stuff, but I want to get the stem right first, or at least in the ballpark. The stem seems to be the bigger issue at this point, and I might just live with the bars until I buy something else. If I'm reading the old bars right they're classic Cinelli 66-42.

Peter - the Bianchi top tube is 56cm c-c.

Ultraman - tables for the Diverge?

I'm pretty sure that the same shop would be willing to fit it better, but I'm not sure that I trust them at this point. They should have fitted it when I bought it or I should have asked them to do so, so that's at least partially my fault. IIRC all they did was have me stand over a level and take a measurement. So basically they measured my inseam and that was it.

It's no great shakes as a bike, and I'm using it for more than just the riding around town that I originally envisioned, so I wasn't worried about really dialing in the fit when I bought it. Now I'm starting to want to get down in the drops on the sweeping downhills and the flats that sometimes come next, which is where I feel really cramped.

I was at the LBS where I bought the Diverge about a week ago, and they didn't actually let people in the store except in rare cases, which is understandable. Not sure what their policy on fitting is now, or if I trust them on it at this point. There are a couple of other shops I could try, but I may just dial it in myself and be content until I upgrade.

[Toeclips]

Cool Reuben,
Sounds like you're on your way
Love the cinelli bars

[reuben]

Cool Reuben,
Sounds like you're on your way
Love the cinelli bars

They look pretty sweet in a Cinelli XA srem. :)

[Toeclips]

I agree
Good choice

[djdj]

I find this tool very helpful for comparing geometries: bikegeocalc.com

A lot of older bike geometries can be found on the net with a lot of searching. Where the stack and reach are not listed, you can use that tool to calculate those metrics and others.

[colker]

Buy a larger frame and move every part. You can even use the same cables. Frames should fit.