Trek Domane SL6 - 52 vs 54?

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jm-black
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Trek Domane SL6 - 52 vs 54?

Post by jm-black »

Having just gotten into cycling and having bought a hybrid in the summer, i am now looking to get a "proper" roadbike (rather than trying to convert the flat to a drop handelbar...)

However the question of right fit is really puzzling me at the moment, as I was given mixed messaged by two separate bike fitters
My measurements
Height 5.8 (173m)
Inseam around 80-82cm

Based on the trek website, i should be a 54cm
Bike fitter #1 also confirms based on my measurements, in person consultation etc, i am a 54 (although only has a 52cm in stock)
Bike fitter #2 insists i am a 52 size (they have both 52 and 54 in stock). They say based on my inseam, and the relatively high seat tube of the domane, i should go 52 else my seat post would be too low (on the website pictures, it does look like the domane seattube doesnt allow for a lot of seatpost, fair point!)

So far i went with the 52, expected delivery by the end of the month.

However i keep going back and forth, i guess a bit of buyers remorse, should i cancel and get 54cm? My hybrid is a trek fx 4 in size M, and i quite like the size/fit, however i was told by bike fitter #2 that i can't compare the two bikes, completely different geometry...

Or am I overthinking this and at the end of the day as long as the bike is properly fitted, it doesnt matter?

Appreciate any help or guidance, many thanks! :)
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TrevA
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Re: Trek Domane SL6 - 52 vs 54?

Post by TrevA »

A bike shop owner once said to me - you can always make a small bike bigger, but you can’t make a big bike smaller.

I’m 6 ft 2 and normally ride a 58cm frame - my last bike was a Trek Domane in that size, but since breaking the frame I’ve been riding around on my son in law’s 54cm Cannondale Caad8. I’ve had to flip the stem to give me a bit more height at the front, but other than that it’s been fine.

However, coming from a hybrid you may find the position on a road bike takes some getting used to. The hybrid will almost certainly have a more upright position than the road bike.
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Debs
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Re: Trek Domane SL6 - 52 vs 54?

Post by Debs »

I'm 172 cm tall and by far prefer the 52 cm frame size.

My inseam is about 82 cm

Also the 52cm size frames come with 40 cm handlebar width, and 170mm crank length, both which i by far prefer to the 54 cm frame sizes that come equipped with 42 cm bar width and 172.5 crank length.

However i needed to fit a 1 cm longer stem, and i use the longer version seat pin.
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Paulatic
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Re: Trek Domane SL6 - 52 vs 54?

Post by Paulatic »

I’m six foot with an inseam not much more than yours and ride a 56cm Domane which I find to be excellent. I did need to flip and fit a shorter stem.
True on the Trek site you are in the 54 zone for your height. If I was to follow the Trek site they say I should be on a 58. which was too big when I tried one.
Whilst either size is going to fit I think a lot depends on how you like your bike to be. As Debs points out your crank length and handlebar width is also to be considered between the two sizes.
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jm-black
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Re: Trek Domane SL6 - 52 vs 54?

Post by jm-black »

Thanks a lot, appreciate your feedback and comments

So it feels to me like I should be fine on the 52cm, and yes the shorter handlebar will also be a better fit for me. Cranks, not sure, my hybrid currently has 175 cranks, think i would have preferred 172.5, but let's see. Stem will have to figure out whether the 52cm will work for me or whether i need to replace longer.

I don't really have any experience in road bikes, it's all still a feeling out process for me, was just thrown off by how both fitters insisted they were right on the different sizes...
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531colin
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Re: Trek Domane SL6 - 52 vs 54?

Post by 531colin »

Geometry chart is here https://www.trekbikes.com/gb/en_GB/bikes/road-bikes/performance-road-bikes/domane/domane-sl/domane-sl-6/p/28313/
Theres very little difference between the 2 sizes you are contemplating.
On balance I'd go for the bigger bike if it was me; the bigger bike gives you 1.5cm taller head tube (ie you can get the bars higher) for only 3mm longer reach. You can tune out much more than 3mm reach with a shorter stem (stems generally come in 1cm increments) Ability to raise the bars might well be in short supply; yeah you can flip the stem, but if you want more than that its high rise stems, which provide a rather coarse adjustment.
2.5cm on the seat tube....doesn't matter, either will do
Smaller bike is half a degree steeper seat tube angle; thats not enough to matter; both are far too steep for me, as it happens
head tube 1.5cm taller on the bigger bike.
effective top tube is longer on the bigger bike; you must assume they got the maths right, but ETT looks more different than the reach/seat angle would suggest, to me at least. (half a degree on the seat tube will give 5mm on ETT at most)
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jm-black
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Re: Trek Domane SL6 - 52 vs 54?

Post by jm-black »

Thanks a lot Colin, very helpful!

The Trek geometry chart indeed also points towards the 54cm bike, based on my height and inseam, which has been casting doubt on my decision.

I have spoken to the shop today, i think since we have ordered the 52cm i will stick to that and then test fit in person. If I get to the stage where I need to change stems etc which would have not been the case with the 54cm, i think they would be ok to swap it for the 54cm.

As a new cyclist, I must admit that bicycles are a lot more complicated than I thought, but at the same time i am really enjoying learning about it and getting into the technical details, and this forum has been absolutely superb so far stimulating my desire for more (bike) knowledge!
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The utility cyclist
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Re: Trek Domane SL6 - 52 vs 54?

Post by The utility cyclist »

Agree with Colin, get the 54, depending on your desired position it wouldn't surprise me if a 56 would also be fine, I ride everything from a 54 to a 62 at 5ft 11 and 32.5" inside leg, slightly longer arms than normal.
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531colin
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Re: Trek Domane SL6 - 52 vs 54?

Post by 531colin »

Never looked at 56
The important numbers are
head tube 14.5/ 16 /17.5....the 56 gets your bars 30mm higher....17.5mm head tube is what this old man has on the Spa Elan.

Image_DSC0829 by 531colin, on Flickr

Reach 37.1 / 37.4 / 37.7 ...the 56 is only 6mm longer than the 52!
seat tube angle is a whole degree shallower on the 56 than the 52 (still too steep, for me)
jm-black wrote:.........
Or am I overthinking this and at the end of the day as long as the bike is properly fitted, it doesnt matter?......

Yes, indeed, the fit is the crux of the matter. It doesn't matter a hang if the frame label says 52, 54, or 56....you only need the contact points in the right places.
Its easy to see if you can get the saddle height right, even though this particular bike seems to have 2 different lengths seatpost available. (Thats kinda complex, but I guess at this price the bike is aimed at riders with enough experience to know pretty much what they want?)
The "special" seatpost is a bit of a worry; I would want the saddle further back that it allows, and presumably an aftermarket long layback seatpost won't fit?
After saddle height, the next big thing is handlebar height. A regular handlebar stem will go either way up; in the publicity photos they are always shown more or less horizontal; turn it the other way up and it slopes up quite noticeably. For somebody new to drop bars, a good place to start is with the bars and saddle level ( like they aren't shown in the publicity photos) and if you can get bars and saddle level with the stem in the "pointy-up" position, then thats a win; you can always return it to the more usual almost level position when used to a new bike. Stems of different lengths are cheap enough; most cyclists end up with a boxful of the things.
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The utility cyclist
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Re: Trek Domane SL6 - 52 vs 54?

Post by The utility cyclist »

I always think a larger frame offers better options for non racing types, it's easier to get the bars in a more comfortable/relaxed position without having to have the upturned stem/huge number of steerer spacers, but you can reduce the bar height if need be. of course if you like having the bar to saddle height - a lot then maybe the fit that a shop says you should have is more in line with what's best.
This is my '59' ex conti team, despite the bars been a fair bit lower than saddle the overall height of the bars isn't that low down and the bike is very comfortable in any case but I can get the bars up higher if need be.
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Re: Trek Domane SL6 - 52 vs 54?

Post by Paul Smith SRCC »

jm-black wrote:...was just thrown off by how both fitters insisted they were right on the different sizes...

How detailed was their data, did they give you the contact points, saddle height and setback then reach and drop to bars? When you have those and significantly if you are confident that they are correct then it should be easier to work out which one of those two sizes is the most suitable. The Domane by design has quite a conservative bike fit, these are not long and low race bikes, so potentially both could be well be a viable option, it's not uncommon that more than one size in a model range can be a valid choice.

2021 Trek Domane SL 52cm.jpg
52cm
2021 Trek Domane SL 54cm.jpg
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Morph Domane 52 to 54.gif
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keyboardmonkey
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Re: Trek Domane SL6 - 52 vs 54?

Post by keyboardmonkey »

I didn’t end up buying a Domane, but I tried a 54 - too big - tried a 52 - spot on. I’m 173cm.
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531colin
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Re: Trek Domane SL6 - 52 vs 54?

Post by 531colin »

keyboardmonkey wrote:I didn’t end up buying a Domane, but I tried a 54 - too big - tried a 52 - spot on. I’m 173cm.

Just out of curiosity, in what way was the 54 "too big"?
If I'm reading the geo. chart right, the 54 (FRAME) reach is only 3mm longer (they may use a longer stem as well)
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Re: Trek Domane SL6 - 52 vs 54?

Post by keyboardmonkey »

To be perfectly honest it was a few years back so although I’m absolutely certain I would have chosen the 52 might it be possible that the geometry has been tweaked a little since?

From memory I’m around the upper limit for the 52 and the lower boundary for the 54, but also if memory serves I felt a bit too high up. Does that make sense? My steel bikes from the 80s were always the smallest in the range but, by modern standards (fashion?) are too big and for one bike I had to fit a shorter stem.

531
531


In any case I got a Giant TCR in a small, but in a headwind it felt like I was riding a chopper, so I put the headset spacers above the (longer, replacement) stem to make it a virtually identical fit to my Kinesis T2 (51cm).

Any road up, as someone mentioned earlier you can make a small bike bigger etc, but admittedly with the OP coming from a hybrid his preferences may not be the same as mine.

T2
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Hey ho. I’d be interested to see how the OP gets on. (As an aside I’ve been looking at the Ti Spa Audax frameset - I’d thought about the 52 in that...)
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Re: Trek Domane SL6 - 52 vs 54?

Post by 531colin »

Its readily possible the geo. has changed.
I like the way the Spa Audax rides, but I don't these days ride any tyres less than 32mm, so the Audax with dual pivot sidepulls is no good to me.
At the time I designed the Spa Audax, we could only get carbon forks in 45mm offset. If I ever get the chance to re-design it (that'll be based on sales; currently disc brakes are what the customer wants) then I will use 52mm offset carbon forks on at least the 50 and 52cm. Currently only the 50 uses a long-offset fork (which had to be steel originally); the upshot of all this is that (in order to get toe clearance) the 52 is just a few millimetres shorter than the 54. Of course this isn't a problem if it suits you!
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