I know it’s not as easy as MTB sizing (well, average MTB user sizing anyway) but I’m looking at a cheapish commuter/winter training hack and found one at the right price. Manufacturer has a size guide that says I fit the one they have available but the shop says (and I quote) “That’s frickin huge for someone your height”. Who do I believe (shop is too far away to size it and it’s a 2010)?

You could always give us some ideas as to what it is that you’re buying, what the size of it and you are too.
Shops tend to know what they’re talking about though, so it might be worth listening to them.

Yeah, I got quoted a range of sizes depending on the company. Many road bikes have a more compact geometry now.

Depends on the geometry etc. I ride a 52cm road bike with a 120mm stem and I’m 5’10, MTB in Medium/18″. I had a 53cm one as well, and fitted me fine as well. However I had a 56cm Trek and it fitted me as well although I had a 100mm stem as it was a bit longer. If it’s a hybrid I would probably go similar to a MTB size rather than a road sizing something like a 19″ frame.

I’m 5’9″ and ride a 54cm Specialized with 100mm stem and a 56 Bianchi with and 80mm stem. Both fit me perfectly.
Mountain Bikes are 17.5″ and 18″ both with 585mm top tube.
HTH 🙂

Ribble have got a sizing guide, which might help.

Ribble always size up large in my – and mates – experience.

Only way to tell with a road bike is to sit on one – I have a 54cm Spesh, had a 52cm “traditional” Ribble and a 48cm “compact Ribble – all fit(ted) fine!

I size bikes using the horizontal top tube length, and seat tube length, measure your bike and use as a starting point, road bike will have a longer seat tube, ideally you want 4 to 6 inches of seat post showing, this is for a starting point not an exact fit.

Looking at a Felt F85. I’m 6’1 and Felt reckon I’d be fine on either the 58 or the 60.

You need to sit on a few bikes, bear in mind geometry is different from brand to brand and dependant on what style of road bike. Say a 56cm in a Spesh will measure up longer than say a Cube. Inch to two inch standover height on the top tube is a good start point, then run a line from the front of your knee when your crank is forward and paralell to the ground to the front of the crank will give you your correct saddle height.

Well I am 6’1 and ride a 58.5. So yeah You probably don’t want any smaller.

Felt tend to come a touch on the large size IMO, My ex boss is 6’1 & he had a 58cm F55, I’m a mere 5’8, tried a 56 & it was massive on me, so could only ride a 54 in Felt.