Competitive Cyclist Bike Fit Advice

derbygrimpeur

I'm in the market for a new bike and am looking at a Ribble Stealth (or possibly the Sportive Bianco). I guess main use will be summer riding, including some road racing, sportives and hill climbs.

I've used the competitive cyclist bike fit calculator which has thrown out the following results:

Seat tube range c-c 56.4 - 56.9
Seat tube range c-t 58.1 - 58.6
Top tube length 55.5 - 55.9
Stem Length 11.5 - 12.1
BB-Saddle Position 78.3 - 80.3
Saddle-Handlebar 54.7 - 55.3
Saddle Setback 5.8 - 6.2

Based on the above (top tube length), it looks like I am in between Ribble sizes?

The Stealth geometry:


I'm 5'11.5" so am thining the 52.5 frame would be best, but then I wonder what size stem to get. Should I go for 110 (to account for slightly longer top tube than the bike fit calc suggests), or 120

I've not been able to find the geometry for the Sportive Bianco.

Not really sure how to interpret the bike fit calc data so any help much appreciated.

rolf_f

Last time I looked all the geometries are there in the frame section. The Bianco should be shorter than the Stealth and the Gran Fondo shorter than both of them. They are not all the same so you should find a fit as long as you aren't hung up on a particular model.

derbygrimpeur

As I say, the Sportive Bianco geometry isn't there.

I am slightly "hung up" about the frame as I don't want a frame with red on it. Alot of my kit is blue, so would rather have a frame that will "go"

rolf_f

derbygrimpeur wrote:

As I say, the Sportive Bianco geometry isn't there.

I am slightly "hung up" about the frame as I don't want a frame with red on it. Alot of my kit is blue, so would rather have a frame that will "go"

http://www.ribblecycles.co.uk/assets/im ... ometry.jpg

I know exactly what you mean about frame colour. Personally, I find red, white and black incredibly unimaginitive on a bike. Still, the GF, in red, white and black was the best fit bike for me that Ribble listed so I am stuck with it! And to be fair, it does look nice

derbygrimpeur

that's the sportive racing. Is it the same as the bianco, and if so why is there a difference in price?

Red seems to be a very popular colour on bikes, and ordinarily I'd go for that. But as my club kit is blue, and so is alot of my normal kit, I'd rather not have a bike with red on it haha

derbygrimpeur

I gave them a call and you're right bianco = sportive racing geometry (thanks)

So back to my main question, what size should I get...

Would I be best with a 52cm (based on top tube measurement)?
Or, should I get the 54/55 based on seat tube? Ribble's suggestion of 0.64 * inseam (87cm) suggests the larger frame size. But I guess I have longer legs proportionally to my body. So with the larger frame I might be over-stretched, whereas with the smaller frame I can just put the saddle up?

graham_g

derbygrimpeur wrote:

So with the larger frame I might be over-stretched, whereas with the smaller frame I can just put the saddle up?

Far more to it than this. Your saddle position relative to BB is important, and means that two different frames with different seat angles and different TT lengths could have you in an identical position. If you are genuinely longer in the leg then going up a size is probably a better compromise as you can fit a slightly shorter stem (could only be 10mm in it), whereas if you go shorter you risk having a saddle to bar drop that is more akin to a pro's bike and totally unsustainable for your average rider.

derbygrimpeur

Cheers Graham

I definitely am longer in the leg than torso, but a bit nervous about plumping for the 54/55 as the top tube may be too long. The competitive cyclist thing says for compact frame geometry to base decision more on top tube length.

My bike fit data above suggests TT length of 55.5 - 55.9cm
Teh 52.5cm Stealth has TT length of 565.5 and the 54.5cm frame 583cm TT. So using Ribble's calculation, surely I'd be far too over-stretched on the 54.5cm frame. Might be better getting the 52.5cm frame with 110 stem.

As a slight comparison, for a horizontal TT the data would suggest a 58cm frame based on seat tube measurement and 56cm frame for top tube measurement. The bike fit explanation says "if you feel as though you could go with
either of two sizes, going with the bigger frame is normally advisable", so for that I'd probably go for the 58cm

graham_g

Sounds fair enough. What I would advise though, is to phone them after you've placed the order and tell them to leave enough room for about 40mm of spacers on the fork steerer (if it's a full carbon fork then ~30-35mm is the recommended max). It's easy to cut it down afterwards but supremely annoying to have to fit a high-rise stem or other such work-arounds just because the shop cut the fork steerer right down.

I'm 5'10" with a 34" inside leg... I've been burned

derbygrimpeur

thanks for the advice.

JLC

Have you thought about a bike fit? I can throughly Adrian Timmis at Cadence Sport but others are available. He will actually watch you cycle rather than just putting measurements into a computer. You may be lucky and get the correct size frame but it still doesn't mean that it will be set up correctly. Adrian will adjust the hoods and bar rotation etc to maximise fit, along with saddle position, tilt etc etc
Certainly worth it as once you have once bike fitted it will be easy to replicate on any new bikes or winter bikes etc.
Once you have it fitted then you can just go off cycling rather than spending every ride moving things forwards and backwards and always being in doubt whether the position could be better.

derbygrimpeur

Bike Science are based in Derby and I'm considering getting a proper fit once I've got the bike. But was using the calculator to determine the size of bike I should actually buy.

rolf_f

derbygrimpeur wrote:

I gave them a call and you're right bianco = sportive racing geometry (thanks)

I probably should have explained it! Sportive Bianco replaced the identical Sportive Racing frame which was red and black. Probably they just wanted it to be more obviously different to the New Sportive Racing.

Anyway, do consider the Gran Fondo as that is shorter still. Even if you don't get one, looking at its geometry it will probably help you to feel more confident about the fit of the others.