Frame size

[Johnno260]

I am a little confused on frame sizes for a road bike.

I am 183cm with an inner leg of 88cm all the size guides are telling me anywhere from size 57-60 frame, but whenever I sit on a bike a 54 seems to be what I feel most comfortable on.

People in the shop said the 54 seemed to fit me best, is it one of those cases where science can be ignored as long as I am comfortable?

 

[T.M.H.N.E.T]

There is little science in a generic sizing guide.

If its comfortable go for it

 

[vickster]

You need to check which bit of the bike the 54cm measurement comes from. The manufacturers don't use the same measurement for their sizes

This is why you need to ride them

 

[CanucksTraveller]

So long as the seat post isn't extended to the max on a 54 you should be fine. On road bikes I tend to find that if you're not going for the full on, all out aero position, then slightly smaller can be better since it's not such a stretch to the hoods. Stretching too far forwards can cause all sorts of issues, from lower back pain to pulled hamstrings and wrist pain.

As you say, sizing guides can only ever be guides, comfort is the really key thing for most riders. If you're comfortable sitting on that frame in the shop, you're really not far off. Try a test ride to confirm, if you can.

 

[simon.r]

I agree with the above, but...54cm does seem a little small for your height / leg. Have you got the saddle at the correct height?

 

[Ajax Bay]

You need to check which bit of the bike the 54cm measurement comes from.

At 183cm with 88cm IL, 54 seems small if measured centre (of BB) to centre (of virtual horizontal top tube/seat tube intersection). At least 56.

 

[Brand X]

I've come to the conclusion that bicycles come in three sizes: Small, medium, large. Everything else is a case of sitting on the bike to see if it actually fits.

 

[Roadrider48]

I hate metric measurements!!

 

[Johnno260]

I sat on the 54 at the shop and took it for a ride, the reach to the hoods etc seemed right.

I will speak to them again and make sure the seat post wasn't maxed as I know that causes issues.

The shop thought a 56 would be better for me but after looking at me seated on the bike etc the 54 seemed the better fit, also the shop seem really solid and have helped me a lot in the past.

My Hybrid is a 54 as well, it's a Boardman and I believe Merida make the frames for them? Not sure if that has a relevance on comparing the frame sizes.

 

[MistaDee]

The shop thought a 56 would be better for me but after looking at me seated on the bike etc the 54 seemed the better fit, also the shop seem really solid and have helped me a lot in the past.

Wonder if the shop had a 56 in stock but not a 54 in the style you wanted

 

[Johnno260]

Wonder if the shop had a 56 in stock but not a 54 in the style you wanted

The one I tried is the 54, but it's the 2016 version of the bike I like and the last in stock.

He knows I am not ready to purchase yet and if I miss this one than I shall raise the cash for the 2017 model, if he was trying to rip me off it would benefit him more to say you need a bigger frame get the 2017 model.

 

[T.M.H.N.E.T]

I agree with the above, but...54cm does seem a little small for your height / leg. Have you got the saddle at the correct height?

What about his torso length, reach and arm length? If you ride a 54cm top tube (I'm 6ft3 and I do) with no discomfort and you aren't maxing out seatpost lengths there's no issue.

I have suffered the effects of incorrectly sized bikes and I can tell you it is not pleasant and it's not cheap to fix, a simple stem swap is often not the answer

 

[ColinJ]

Translating to inches ... at only 6' 0" tall but with 34.5" legs, it does sound like Johnno has long legs and a shorter than usual torso so maybe he is better suited to a smaller frame.

I am 6' 1" but only have 32" legs so I have a longer than usual torso. I have been riding 58 cm bikes for years and have only just discovered that I am more comfortable with a 13 cm stem than the 11 cm I had been riding. It might be that a 60 cm frame and an 11 cm stem would suit me. I also thought that I wanted my bars almost level with the saddle but it seems that I am more comfortable with quite a big drop. I now have it at about 10 cm (4").

I think that shows 2 things - (1) Don't automatically accept that you suit what is average for your height. (2) Even if you feel 'comfortable', maybe you could feel more comfortable with a different setup. It might be that only a long, hard ride really reveals what is comfortable and what isn't. Sitting on a bike in a shop is not the same as doing a long, hard ride!

 

[steveindenmark]

I agree with the above, but...54cm does seem a little small for your height / leg. Have you got the saddle at the correct height?

But then the op may just suit small bikes. If you measure my partner up she is spot on for a 54cm but she hates them but loves 53cm frames. 54cm frames are too long for her and that is something everyone always seem to forget. Its not just about legs, its about arms as well.

The best way to find if a bike fits is to throw your leg over one and grab the handlebars.

 

[robgul]

The only real answer nowadays is to sit on the actual [not even another model or manufacturer] bike that you're interested in (with the classic "heel on the pedal, knee just about bent" assessment)

Bike sizes all went mad when they changed from a horizontal cross-bar (top-tube as it's now called) when measurement was easy - BB axle to top of seat-tube/or seat bolt.

Rob