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Discussion Starter · #1 · (Edited)
I went to the bike shop today and sat on a 54 it seems a little big, I sat on a 52 and it seemed like a good fit. The sales person said that the seat would need to be raised really high for the 52 to fit.

Is there anybody with my dimensions that rides a 52 ? :confused:

On the Specialized web site it says: TT is measured horizontally from center of HT to center of ST, does that mean the top size shows is the virtual or actual length?

thanks
 

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krzyray said:
I went to the bike shop today and sat on a 54 it seems a little big, I sat on a 52 and it seemed like a good fit. The sales person said that the seat would need to be raised really high for the 52 to fit.

Is there anybody with my dimensions that rides a 52 ? :confused:

On the Specialized web site it says: TT is measured horizontally from center of HT to center of ST, does that mean the top size shows is the virtual or actual length?

thanks
The sales person is right. I'm 5' 6" and a 52 cm fits perfect. What confuses me is that you have the same inseam as I do, so where's the additional 2.5 inches of height? Unless you're providing a pants inseam and not cycling inseam.

I think the reason you think the 54 is too big isn't because of seat height, but rather, reach. With a shorter stem and/ or higher angle the 54 should be more comfortable. I say should because there's an outside chance that your proportions (short torso?) are such that you may require custom geo.

The Spec geo charts provide virtual (or effective) TT lengths.
 

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Discussion Starter · #3 ·
The inseam I measured is with a book under me, standing against the wall, and measured from top of book to the ground.

Maybe I am not like the average person, where my inseam does not match my height?

My first bike was a 1999 Specialized Allez 54cm standard frame, this bike felt fine.

A Tarmac 52, virtual top tube is 537mm (53.7cm), wouldn't this be equivalent to having a 54 standard frame?
 

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krzyray said:
The inseam I measured is with a book under me, standing against the wall, and measured from top of book to the ground.

Maybe I am not like the average person, where my inseam does not match my height?

My first bike was a 1999 Specialized Allez 54cm standard frame, this bike felt fine.

A Tarmac 52, virtual top tube is 537mm (53.7cm), wouldn't this be equivalent to having a 54 standard frame?
In general, how you've described measuring cycling inseam is correct, but the one big variable is what people perceive as 'saddle pressure' when holding the book. To double check, measure three times and keep the equivalent of saddle pressure on the book when measuring. IME, it's much easier if you have some assistance.

Here's a guide:
http://www.coloradocyclist.com/bikefit#inseam

The reason I'm skeptical that that is your correct inseam is because you feel like the reach on a 54 is too long. At your height and considering your inseam, your torso would have to be slightly longer than the norm, otherwise where's the height coming from? Make sense?

I looked at the archives for the Allez and they only go back to '02. The best way to compare the geo (specifically TT lengths) of the bikes is to measure your Allez. See the chart below and use the orange line for reference.

View attachment 158943

To answer your question regarding a traditional (horizontal TT) frame versus compact (sloping TT), all else being equal, no there is no difference. A virtual/ effective TT of 537 mm's is the same as a horizontal TT of the same length. I think what you might be experiencing is a more aggressive riding position on the Tarmac due to a shorter HT and/ or lower stem angle.

All this may be irrelevant, though because how you feel on a bike obviously matters. So, if you're more comfortable on the 52, have your LBS set it up for you before you test ride it. If the max insertion line on the post shows, you're outta luck, because it's not safe to ride that way. If, OTOH the max line doesn't show, go for a test ride. It might just be the right size for you.
 

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I'm no expert, but I am 5'8.5" w/ a 30.5" inseam and ride a 52cm Tarmac.

I was lucky because a fit calculator worked for me, so when I rode the 52, it didn't take long to get myself set. I was checked out by a fitter and didn't need adjustments.

There's been a lot of discussion about height and inseam, but I think there's a lot more to consider. PJ mentioned reach - what's the measurement from hips to shoulders, shoulders to elbows, elbows to palms? How well can you bend at the waist? We have the same inseam, but my saddle position is way forward because my upper legs are relatively short while my lower legs are long.

From what I've read, these calculators don't work for everyone, but if you're interested in seeing what measurements they consider important, here's the one I used:
http://www.competitivecyclist.com/za/CCY?PAGE=FIT_CALCULATOR_INTRO

My suggestion would be to take both for lengthy test rides to find out. Good luck!
 

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Im 5'8.5 here as well with a 29"inseam and I ride a 52, the reach on the 54 is whats giving you the issue, its too long for you. Depends how streched out you want to be
I could have gone with the 54 and gotten a shorter stem but I liked the idea of a smaller frame fit and get the stem to give me the stretch I needed. I have WAY MORE control on the 52 than I did on a 54 I used to ride.

the salesman told me I needed a 52 and I thought he was nuts!!!!!!! since Ive always ridden a 54 on a trek. the way I have it setup the measurements form the front of me seat to the center of the bars is the SAME on both bikes and the seat height is the same.
The Tarmac has a longer stem but thats it. I like the 52 better though. hte carbon fram doenst hurt my pref either

I have a long torso BTW and short legs.
 

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Ditto on the measurements here. I ride a 52cm Tarmac as well. I like the feel of the 52cm when I am racing. I feel like I have more control of the bike but I did have to make some changes to dial in the fit.

The 54cm just felt a little too big when I did a test ride. I knew that with whaterver bike I got I would need to replace the stem because the 54 was too long and the 52 was too short based on the TT length.

I got a 1cm longer stem for the 52cm and now the handlebars put me at the perfect reach for the hoods. My bike came with the SRAM Rival so you may not need to make an adjustment with Shimano since they are bit longer.

As for the seat post yeah, I have a lot showing but well within the safe area of the post. I replaced the Specialized with an Easton zero offset.
 

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I'm 5'8" and I bought a 54 and it fits fine. Only 20mm of spacers undae stem and using a 110 stem go for the 54
 

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I think you are in between sizes and will likely get by on either one with the appropriate adjustments to stem length, rise and stack. I am 5/8 with a 31 in inseam. My current ride has a 54.5 top tube and I use a 120mm stem.

Keep in mind that the smaller bike has a shorter wheel base and will likely be more responsive and possibly twitchy than the 54. But that may be what you want.

Also of note is that according to the Specialized website the (S-Works SL2) 52 is spec'd with 170mm cranks, the 54 comes with 172.5 cranks.

I am concerned that switching out the 170's for 172.5 cranks on the 52 frame will result in bad toe overlap. Not the end of the world but annoying, and possibly unavoidable on smaller frames.

I am leaning towards the 54 with a 110 stem like the last post but still not sure. Have you decided?
 

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52

I'm 5' 5.5" with a 30 in. inseam and i ride a 52 as well.
I just use a zero setback post for a better fit.


What size mountain bike do all of you ride, if you ride one?
I've been going with a M Specialized Epic with Zero setback post and a slightly shorter stem. 80 mm rather then 90mm. Seems to work for me but I was curious to what others in this size catagory ride.
 

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jack_okole said:
I think you are in between sizes and will likely get by on either one with the appropriate adjustments to stem length, rise and stack. I am 5/8 with a 31 in inseam. My current ride has a 54.5 top tube and I use a 120mm stem.

Keep in mind that the smaller bike has a shorter wheel base and will likely be more responsive and possibly twitchy than the 54. But that may be what you want.

Also of note is that according to the Specialized website the (S-Works SL2) 52 is spec'd with 170mm cranks, the 54 comes with 172.5 cranks.

I am concerned that switching out the 170's for 172.5 cranks on the 52 frame will result in bad toe overlap. Not the end of the world but annoying, and possibly unavoidable on smaller frames.

I am leaning towards the 54 with a 110 stem like the last post but still not sure. Have you decided?
Sorry, but a couple of these statements are (at best) questionable. For example:
I think you are in between sizes and will likely get by on either one with the appropriate adjustments to stem length, rise and stack.
I understand that adjustments can be made to stem length and if by rise, you mean angle, ok. But stack? Frame stack is what it is for a given frame size and cannot be changed.

Another example:
Keep in mind that the smaller bike has a shorter wheel base and will likely be more responsive and possibly twitchy than the 54.
This simply is not true. Geo for a given frame size changes proportionately so that the rider is positioned (more or less) in the same position relative to front-center. Of course wheelbase varies, because (one example) TT length varies by framesize. Manufacturers go to great lengths to retain the handling (and even ride qualities) across the range of frame sizes. One caveat: this assumes a rider is on the correct sized frame. Too small/ too large and handling will become 'unpredictable'.

RE: toe overlap. It's a fact of life and yes, generally speaking is more pronounced on smaller sized frames - unless compromises are made which adversely affect handling. If you're interested, Cervelo has a decent write up covering this topic on their website. Bottom line, though. It isn't a hiccup in the life of someone with even a moderate amount of experience.

Lastly, not sure why you're on the fence between the 52 and 54. Given your inseam and TT/ stem length of your current ride (assuming the fit is right), IMO you're clearly better off with the 54.
 

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the salesman told me I needed a 52 and I thought he was nuts!!!!!!! since Ive always ridden a 54 on a trek. the way I have it setup the measurements form the front of me seat to the center of the bars is the SAME on both bikes and the seat height is the same
In my (limited) experience, sizing across brands is a tough call. Not knowing the specific bikes you're referring to, going from a 54 by Trek to a 52 isn't surprising to me at all. I'm 5' 8.5", 30.5" cycling inseam, and ride a 54 Tarmac, which fits well. My BMC is set up with the same set-back, drop, reach, etc. as my Tarmac, and it's a 52. I'm looking into a BMC ProMachine, and if I go that route, will probably end up on a 51.
 

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Your fit will be determined by what you want out of the bike. With your sizing, assuming the measurements are properly taken and accurate, you could fit on either. However, I'll side with the post that says you have shorter legs and a longer torso. This means you could go with a 54 and have less seatpost showing, or go with a 52 and have more seatpost showing (the difference would be 2cm). However the headtube sizing between the 52 and 54 would give you a vastly different riding experience. If you need the lower, "euro" style body angle for hard racing, the 52 would give you a greater saddle to bar drop. If not, the 54 will give you a more relaxed body angle with the potential for much less drop. Keep in mind that Specialized permit a maximum of 40mm of steerer extension above the top of the headset to the bottom of the stem. So if you want the racing experience, go 52, if you are more into JRA, go 54.
 

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krzyray said:
I went to the bike shop today and sat on a 54 it seems a little big, I sat on a 52 and it seemed like a good fit.
I'd get the 52 unless I was coming off a bike w/ an upright riding position - if so, I'd have to think about whether I would develop enough flexibability to prefer the 54 after some time on the new road bike.
 

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I'm 5'7" and ride a 52 because seat post should be up a little the frame has a sloping top tube and longer reach than some others out there. It is easier to add 10-20 mm to the stem than take it away to get the correct fit. Because to short of a stem effects the handling, makes it easier to over steer where a little longer just slows it down a small bit and make steering more predictable.
 

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what is your saddle height?

do you have long arms?
are you flexible?


many people here are forgetting saddle to bar drop!

yes you can set up the 52cm and the 54cm to be very close, but and i mean but

frame stack will be very different and wheelbase should also be different.

all these people who ride with 3cm+ of spacers and and a rise stem of 2cm+ are ignoring proper weight distribution and handling on a short wheelbased bike, with short chainstays.

figure out your saddle height, setback and reach and you are 3/4 there..

jmlo
 

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I have similar dimensions to you.

Im on my second 52 cm Tarmac. It works well for me. Ive got 2cm of spacers on my current Saxo Team SL2 and 1.5cm on my previous Expert Team (8r). Both stock bars set up -8.

I debated about the 54 on the second bike but in the end went with what I knew worked for me.
 

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5'8.5" here. 29" Inseam. Im riding a 52cm here with a longer stem. Works real well. SHop guys told me 54 was too big for me and I thought he was nuts as Ive always ridden a 54 here. The 54cm had me too stretch and I feel like I have more control of the 52 verses the 54. Im more on top of the bike if that makes sense. FWIW, the 52 with the 100mm stem has the SAME measurements throughout as my Trek 1200 54cm
 
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