Size advice

Dick Scruttock

Just been on the competitive cyclist site and done a fit guide. Now i have been looking into bike sizing etc and found what i believe to be the correct size for me and wanted some advice. Everything is within size guild lines off the site fine but the following measurement:

Seat tube range c-c : 51.2-51.7 or 52.4-52.9

The frame actually measures 50.2 but the next size up has far to longer toptube and it throws the c-t measurement out as well. That would go from a advised range of 53.9-54.4 to a 56.0 on the next bike up.

What would other people do?

Dick Scruttock

Anyone able to provide any help?

ugo.santalucia

The tendence now is to go for sloping frames and very limites sizing options, sometimes they come in S-M-L-XL sizes.
In sloping frames as long as you don't go too much out of your size range, things can easily be adjusted with seatpost length and stem length. I've seen 6 foot 4 blokes riding a 56 sloping frame and being happy.

If you go for a traditional frame, with little or no slope, then the size options should be greater, normally sizes with a 2 cm increment are offered. In this case you should find your match easily.

Ultimately, if you want the perfect fit, you should go for a custom made frame, which involves turning to the dark side (steel that is).
If you are serious about your cycling, you will never regret a custom made steel frame, but you might regret having bought a ludicrously small sized Giant frame (that isn't to say that Giant frames are bad)

chriskempton

RD, I'm confused by your post. I've used the fit calculator before (I think it's pretty good), but I'm not sure what you're saying with the seat tube measurements. I think the best approach normally is to pick the frame size with the best top tube measurement to get the right saddle-bars length with a sensible stem length (10-13cm). Once you've done that, you need to check that the seat tube length (plus seat pin and saddle height) will get you the desired BB-saddle distance as per the calculator. Given that you can compensate for a wide range of seat tube length by lowering/raising the seatport (within the seatpost limit), the seat tube measurement is less critical than the top tube.

Sorry that's a bit of a mouthful isn't it. I'll have another go if that's unclear....

Dick Scruttock

Sorry for any confusion. On the fit calculator it advised me i needed a seat tube range of between 51.2-52.9.

Here is what they said about the range:
Seat Tube Range C-C
Your new bike's seat tube height should fall within this range. "Center-to-Center" signifies the length of the seat tube as measured from the center of the bottom bracket spindle to the midpoint of where the seat tube intersects the top tube. The seat tube height is most important as it relates to your head tube. If your seat tube is too short, your head tube will almost certainly be too short. This results in too low of a handlebar position placing an inordinate amount of stress on your neck and back. For this very reason, if you feel as though you could go with either of two sizes, going with the bigger frame is normally advisable. Please keep in mind that many frames come with a sloping or "compact" frame geometry in which the C-C seat tube measurement is artificially short. In the case of compact frames, you should primarily focus on the top tube measurement.

Now should i not bother so much about this and get one with a top tube that is the correct length or go for a larger one with a top tube thats 2cm longer than advised?

The bike in question is a Felt F4.

ride_whenever

have you tried something really radical, like say swinging a leg over the bikes?

It mostly comes down to personal preference. You realistically cannot modify stem lengths and post setback without radically changing the feel of the bike, so get on them and see which (with the correct saddle height and fore-aft) feels best.

chriskempton

RW's right if you can get to a dealer, but if you can't then yes I'd give priority to the top tube length. If you have a top tube that's too long, you'd have to hve a silly short stem that would meake your steering twitchy, or you'd have a position that's overstretched.

Having a seat tube that's 1-1.5cm shorter than advised just means putting your post up a bit which doesn't create any problems as long as you don't exceed the post limit.

BTW, the geometry for the F4 is pretty racy, with a shorter than average head tube, so will you be happy with a low front position for the bars? Another good reason to follow RW's advice...