Sizing nightmare.

stoveman

Set my sights on a BMC SLR02 and have finally saved the hard earned cash.
spoke to a recommended bike fitter and told him my planned purchase and his first comment was concern at the size based on the BMC website figures.
On his recommendation visited LBS,which I already have a good relationship with, and have been offered £800 off on a Colnago CX zero 2015 with Ultegra,but to be honest just doesn't grab me like the BMC does.the colnago is a 52 cm I think,where as the BMC would be a 51cm.what causes the issue is BMC jumps from 51 to 54 cm.
I am 170 cm tall with a 79 cm inseam.
Is 1 cm really that critical in sizing?
Sorry for the long post but dropping £2K on my first higher end bike so need to know I am getting it right.

Phil.

nicklong

What do BMC recommend for your height? I doubt 1cm is going to make a huge amount of difference. If you listen to all the bike fitting advice it's a miracle that anyone ever learns to ride a bike. Worst case, a £30 100mm/110mm stem will fix it for you.

I'm roughly the same height and dimensions and have 2 bikes, both 54cm frames with apparently identical geometry (with regards to seat and head tube). They have different length stems, different handlebar reach and different stack heights, and I feel comfortable on both.

Evans always seem to stock a lot of BMCs and I think they do a no-quibble return, so I'd suggest trying a couple there for size.

There is nothing worse than ending up with a compromise because someone else thought it was a better idea for you - of you've fallen for the SLR02 then go for it.

Fat-Boy-Roubaix

Can you not get to an Evans store and grab a test ride?

Or Compare geometry of both of them.

BMC Geo http://images.evanscycles.com/product_document/file/cac/f3f/9e0/2877/bmc-2015-slr-geometry-chart.pdf

CX zero 2015 http://colnago.com/geometry-cx-zero-2/?lang=am

keezx

Size and seat tube are the least interesting sizes of any bike.
Top tube horizontal and headtube determine the usable size of a bike frame.

kajjal

Reach and stack are useful to compare bikes just be careful to allow for actual stem reach / height and bar reach. As long as the bike is not too big making it fit is easy enough. 1 cm in frame size doesn't matter, check the geometry figures for a better idea and arrange to test ride both sizes if needed.

Fat-Boy-Roubaix

I would also be a bit skeptical of advice sending me somewhere they know doesn't sell my dream bike..

On that basis I reckon the BMC would be a good fit, you are right on the edge of two sizes on BMC website, but I am just someone off the internet.

stoveman

Understand what your saying Fat-Boy and the more I think about it the more I think stick with the original choice of the BMC.
The whole idea of sizing with bikes is a nightmare and using common sense I am sure one person shouldn't have to rule out a certain bike because of a cm or two.

Thanks for the input,appreciate it.

Phil.

Fat-Boy-Roubaix

Evans are the exclusive UK distributor for BMC.

They have a 30 Day guarantee on bikes. "Right Bike Guarantee" http://www.evanscycles.com/help/right-bike-guarantee

Really don't see any risk get the size you think is right, and if it is too big\small exchange it for another size.

northcliff66

At £2k for the bike I would try to find a couple of hundred more for a Guru fit first. You will then know which measurements work best for you, and therefore take away the frame size dilemma.

Most differences from one frame size to another (the next size) can be accommodated for in bike setup. The trick is to find the combination of setup dimensions that suit you. Just trying two frames doesn't really work as too many variables change at the same time. The Guru process eliminates this problem by systematically working through only one variable at a time. It will then show you what setup parameters you need to dial in on a particular fame to suit your own ideal position.

kajjal

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19768727#p19768727]northcliff66[/url] wrote:

At £2k for the bike I would try to find a couple of hundred more for a Guru fit first. You will then know which measurements work best for you, and therefore take away the frame size dilemma.

Most differences from one frame size to another (the next size) can be accommodated for in bike setup. The trick is to find the combination of setup dimensions that suit you. Just trying two frames doesn't really work as too many variables change at the same time. The Guru process eliminates this problem by systematically working through only one variable at a time. It will then show you what setup parameters you need to dial in on a particular fame to suit your own ideal position.

The guru fit can also quickly help you decide between 2 bike sizes as it will simulate both frame, stem, bar and saddle setups. They will likely do this part for free if you are sure which bike but unsure on frame size etc.

stoveman

After mulling things over decided to drop into another local bike shop today and get their take on the situation regarding sizing.
What was refreshing was that the owner took the time to explain the mechanics of fitting a bike and the theory behind the different measurements.this was refreshing as at no time was a hard sell evident in any way.
After I mentioned that I had a brand and size in mind he addressed this and demonstrated the issue with a bike of similar size.
Following this I asked about what bikes they had that would be a potential fit and he then called the bike fit guy out and went through at least 5 bikes to satisfy himself that I had the correct fitting bike should I wish to make a purchase,this even resulted in offering to order in a specific size to try.
After spending at least an hour and a half with me the customer service was impressive to say the least,the bike I am now doing the deal on is a 2015 Bianchi Oltre XR1 105,complete with a Garmin 520,HR/cadence pack for £2200, they are going to swap the rear cassete for a 32, and swap the stem to shorten ever so slightly at no extra charge,these were their suggestion as Cornwall has its share of hills,and the slightly shorter stem makes the fit spot on.
One lesson I have learned is that a knowledgeable LBS really is the best place to go when unsure.
Well chuffed to be getting my first best bike to go with my old school Bianchi from the 90's.

Thanks for all the help everyone,very much appreciated.

Roberto di Velo

Glad to hear that the OP has found a bike he is happy with. As it happens I'm a bit taller than him and ride a 51cm BMC slr02, which I love. I tried both the 51 and 54 at Evans, as well as a few other bikes. 51cm sounds like a small frame, but there's only 5mm difference in top-tube length to my 54cm Canondale. Lesson being that every manufacturer has a slightly different sizing metric.

stoveman

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19769512#p19769512]Roberto di Velo[/url] wrote:

Glad to hear that the OP has found a bike he is happy with. As it happens I'm a bit taller than him and ride a 51cm BMC slr02, which I love. I tried both the 51 and 54 at Evans, as well as a few other bikes. 51cm sounds like a small frame, but there's only 5mm difference in top-tube length to my 54cm Canondale. Lesson being that every manufacturer has a slightly different sizing metric.

Glad you posted that Roberto,after I paid a deosit for the Bianchi in a local shop,they called me a few days later to say they had found an issue with the frame and were not able to complete the sale.Apparently they found a hole in one of the tubes they suspect happened when it was unmoulded.
Anyhow have now booked a test ride with Evans on a BMC SLR02 51 cm in the morning,as I had ruled this out purely on the say so of people far more experienced in bike fitting than me.
Yes I have a 4 hour round trip to test the bike but I will be much better informed because of it.
the Bianchi was a 55cm,so when you mentioned the Cannondale at 54 I thought give it a go.

Thanks again.

Phil.