Correct size frame, an age old question, but again..

[midliferider]

I am sure we have talked about how to select the correct frame size many times in these pages. But I want to ask your view about it again.

I want to buy B'Twin Triban 520 flat bar bike. According to their website I should select size small, I am just 165 cm tall. I have Triban 300 road bike and I must say that it is my best bike. It fits me so well. It is Medium size. I measured all its dimensions as it is the perfect fit for me. Then I looked at the Triban 520 geometry and it actually corresponds to the size Medium in 520 flat bar bike with regard to top tube, seat tube and head tube. I did not measure the angles.

I went to their store and tried it on the shop floor. I feel comfortable on Medium. But the shop assistant tells me that I should get the Small as that is what their guide says. I came home and thought I will ask from my trusted source of advice!

 

[Jenkins]

Stuff the guides - get what's comfortable for you.

 

[biggs682]

Stuff the guides - get what's comfortable for you.

Gets my vote every time

 

[Deleted member 1258]

Gets my vote every time

And mine.

 

[Grant Fondo]

And mine

 

[Gravity Aided]

And mine.
Because fit is not just about frame size and geometry, but also about components and stance on the bike.
Stuff no guide can take into account.
You are your own guide.

 

[Banjo]

Guides are only guides.

But I dont think you can decide if a bike fits you just by sitting on it in the shop.

I would try both sizes and go for a ride of at least a few miles.

Evans are pretty good at allowing test rides and if you still think you have wrong size will change it up to 30 days.

There is nothing worse than a wrong size bike frame .you can change stems seatposts etc but your just making the best of a bad job it will never be quite right.

 

[Smokin Joe]

If it rides ok, don't worry about what the guide says.

 

[iluvmybike]

Get a proper bike fit to be sure before you part with your hard-earned money

 

[brucers]

Height of seatpost and handlebars/stem can, in effect, change the frame size.

 

[Banjo]

Of course you can alter the dimensions with stems etc but if altering big amounts then bike is wong size.

Back to the OP I find a small to medium hybrid works ok for me but on a road bike I am somewhere between medim and Large so if possible try both sizes for a ride.

 

[youngoldbloke]

I'm 165cm too. I think I would opt for small myself, but then I have quite short legs too, and I like to have a fair bit of seatpost showing too. I do tend to prefer a longer stem on smaller frames with shorter top tubes though. However I haven't tried the bike. I was thinking of getting one after my hip replacement to give me a more upright position but the small 520 was never in stock in when I was in Decathlon (or online). Be interesting to see a photo of your position on your current bike maybe?

 

[midliferider]

Thanks for all your replies.
I am going to get a medium one and will let you know how I get on.

 

[vickster]

Get a proper bike fit to be sure before you part with your hard-earned money

Except you generally need a bike to be fitted on. Doesn’t sound like Decathlon offer the service in store pre purchase

 

[iluvmybike]

Except you generally need a bike to be fitted on. Doesn’t sound like Decathlon offer the service in store pre purchase

You don't - a good bike fitter will take all your measurements using a jig & computer software to work out what is required for you. Then you can look at the all frame measurements of the bike you would like