Advice on Road bike size

horner2222

Looking to start biking, i'm 6'6/7 and inside leg of 38' seems according to the charts that i'll need a 66cm frame however these are hard to find and expensive as well, would getting a 63/62cm frame make that much of a difference?

t4tomo

It's certainly easier to make a smaller big bigger than vice versa. You will end up with having more seat tube showing so a bigger drop from seat to handlebars , but you can add a couple of spacers under the stem to lift the bars a bit. Also you can fit a longer stem to give you a bit more reach.

So inn theory yes you can probably get a reasonable fit on a 62 63 cm but for gods sake try it in the flesh before ordering, don't just click and order else it could be an expensive mistake. At least in decent bike shop they can help with trying longer stem and stacking some spacers etc.

horner2222

ok thanks for the reply, would you recommend any decent brands at a reasonable price? dont really want to be spending more than 300 at the moment in case i dont keep it up then in the future if im still going will spend more. would you recommend a specialist bike shop to try them out rather than a place like halfords for example?

Jules Winnfield

I'm just wondering if the charts you consulted take your height or inseam into consideration. I have an inseam of 78.5 cm and my height is 5' 8.5". According to some of these "mythical" charts I need a 54 cm frame, I've even been quoted a 56 at one point. Yet I have sat on a Specialized Allez 54cm bike but the whole thing felt too big. I barely had a centimetre standover height yet when I told the supposedly expert LBS this, he tried to make out that the head stem was perfect for me because of the reach and the bigger frame would be better for me because it would be more stable.

What does he think I am? 5 years of age and just had my stabilisers removed?

I'm going on Ribbles frame size estimate here which has stood me in great stead in the past. They say for a sportive, more relaxed bike with a sloping top tube you need to times your inseam by 0.64 to get your frame size. So in your case :- 96.52 cm x 0.64 gives you a maximum frame size of 61.77 cm.

For a more aggressive geometry bike with a horizontal top tube you times your inseam by 0.69. So once again :- 96.52 cm x 0.69 gives you a maximum frame size of 66.59 cm.

I used the above measurement to find out my perfect frame size when I bought my bike from Ribble. So, 78.5 cm (my inseam) x 0.64 gave me a frame measurement of 50.52 cm. So I opted for a 49 cm frame because the next size frame up was 52 cm which would be too big. Apart from me needing to change the head stem from 100 mm to 130 mm in length to get my bike fit bang on, the frame size is perfect for me. I can throw it around the corners and it feels like I'm in control of the bike, not the bike in control of me.

It seems to me that most LBS just take the top tube measurement and whatever head stem is on the bike from the factory and fit you like that, regardless of what standover height or how the actual bike feels underneath the rider. Whereas the top tube measurement is important, there is no problem in buying a bike smaller and fitting another, longer stem to get bike fit correct.

Jules Winnfield

t4tomo wrote:

At least in a decent bike shop they can help with trying longer stem and stacking some spacers etc.

How can you stack more spacers (if needed) on an fork that has already been cut and stacked out from the factory? :?

horner2222

Jules Winnfield wrote:

I'm just wondering if the charts you consulted take your height or inseam into consideration.
I'm going on Ribbles frame size estimate here which has stood me in great stead in the past. They say for a sportive, more relaxed bike with a sloping top tube you need to times your inseam by 0.64 to get your frame size. So in your case :- 96.52 cm x 0.64 gives you a maximum frame size of 61.77 cm.

For a more aggressive geometry bike with a horizontal top tube you times your inseam by 0.69. So once again :- 96.52 cm x 0.69 gives you a maximum frame size of 66.59 cm.

I used the above measurement to find out my perfect frame size when I bought my bike from Ribble. So, 78.5 cm (my inseam) x 0.64 gave me a frame measurement of 50.52 cm. So I opted for a 49 cm frame because the next size frame up was 52 cm which would be too big. Apart from me needing to change the head stem from 100 mm to 130 mm in length to get my bike fit bang on, the frame size is perfect for me. I can throw it around the corners and it feels like I'm in control of the bike, not the bike in control of me.


The chart i used was both height and frame size, just had a look on the Ribble site and what youre saying is right it does suggest a smaller frame ie 61 cm, but how can this be so different to the suggestions of other people/charts? On the bike builder they go up to a 64cm thinking maybe thats more suited? but its £530 for one which isnt much to people who ride constantly but i just wanted to see if i keep to it and only really wanted to spend about 300 to start with. I'm guessing local shops arent going to have a custom 64cm Ribble for me to try either!

Jules Winnfield

Use the calculations I referenced as a guide to all frames mate, not just Ribbles own. Yes all frame geometry will differ from manufacturer to manufacturer but I don't think you will be far out. Like I said before, it seems some LBS treat customers like idiots and tell them they need a frame far to big for them when in truth a smaller size but a longer head stem would be more suited. I've lost count the amount of times I've seen cyclists on bikes that are clearly far too big for them. They look like a child riding on top of an elephant

If I was buying a brand new bike today from a totally different manufacturer, even online, I would have no worries about using Ribbles sizing guide in choosing the frame size. What's the worst that could happen? You may have a couple more centimetres of seat post showing and you may need to purchase a longer head stem to get the bike fit right but that's it.

Jules Winnfield

horner2222 wrote:

On the bike builder they go up to a 64cm thinking maybe thats more suited? but its £530 for one which isnt much to people who ride constantly but i just wanted to see if i keep to it and only really wanted to spend about 300 to start with.

Merlin Cycles have got their new PR7 in stock for £299. The only thing is the biggest frame size is 59 cm but with it being a sloping top tube you 'might' get away with just a longer head stem, at worst a more set back seat post but then that's going to bring the bike in over budget

http://www.merlincycles.com/merlin-performance-road-pr7-bike-73113.html

Even Halfords don't do large bikes for £300 so maybe going second hand is your best option.

drlodge

Setting the seat post back to compensate fora small frame won't work - the seat post setback position is dictated principally by leg lengths

Jules Winnfield

Yes of course drlodge, that does make sense.

kajjal

To give a comparison , I am the same height but about an inch shorter in the leg. I ride a 62cm Trek 1.5 road bike with the stem flipped to the upright position. There is just over an inch of drop from the saddle to the bars as I prefer a more upright riding position. The only upgrades to the bike are swapping out the appalling tektro brakes it comes with for 105's and I also got a wider better fitting saddle.

Just make sure you get a bike that fits you well as bike shops can try to get tall riders on bikes that are too small for them.

Jules Winnfield

Kajjal wrote:

Just make sure you get a bike that fits you well as bike shops can try to get tall riders on bikes that are too small for them.

I think they just try and sell whatever excess stock they have, in any particular size, to anyone who walks through the door as long as the customer can just get their leg over the top tube

blackhands

drlodge wrote:

Setting the seat post back to compensate fora small frame won't work - the seat post setback position is dictated principally by leg lengths

Please explain why

kajjal

Jules Winnfield wrote:

Kajjal wrote:

Just make sure you get a bike that fits you well as bike shops can try to get tall riders on bikes that are too small for them.

I think they just try and sell whatever excess stock they have, in any particular size, to anyone who walks through the door as long as the customer can just get their leg over the top tube

Your not wrong there