Road Bike frame size



I'm in the market for a new road bike this year. Until now I've only really had second hand and hand me downs.

What size frame should I be looking for ? I'm 6ft. It is manufacturer specific (is Trek different from Kona etc.)

Not just frame size but also frame design. best thing to do is pop down to your local bike shop and try a few bike out then head onto the internet and grab a bargin. If your 6 foot you may need a 18 0r 19 inch frame.


War Hero
A lot of good cycle shops have a system called 'bikefitting' which is a device that takes a number of measurements of the skeleton and even takes into account things such as the pedals you use, thickness of the soles of your cycling shoes etc to get a very accurate measurement. The computer will then give a printout of the correct frame size you need for each make of bike because they do differ.


Copied the following from here:

Fit should be the main consideration when buying a new bike. After all, even the most expensive bike won't seem that great if it's too big or too small.


STEP 1: Measure your inseam. This is best done barefoot. Stand against the wall and put a book between you legs so it pressed right up against your pelvic bone. Make a mark with a pencil on the wall along the top of the book. Measure the distance from the floor to the mark in centimeters.

STEP 2: Use your inseam measurement to get a rough idea of your road bike size. Multiply your inseam by .65. This will give you a good estimate of you road bike size for bikes measured center to center. Thus if your inseam is 86 cm, you will fit a 56cm road bike (86 x .65 = 55.9). Note that many road bikes are measured center to top. To determine how to fit these bikes, multiply your inseam by .67.

STEP 3: Subtract an additional 10cm and convert this measurement to inches to get your mountain bike frame size, roughly. Thus, if you fit a 56cm road bike (c-c), you will fit a 46cm - or an 18" - mountain bike.

STEP 4: Consider top tube length. In many ways, this is the most important aspect of sizing a bike. Two 18" mountain bikes may have different length top tubes. Or a 54cm and an 56cm road bike may have the same length top tube. Given the same top tube length, the bigger bike may be more comfortable in that it will allow you to get the bars up a bit higher.

STEP 5: Know that women have longer legs and shorter top tubes than men. Unfortunately, most bikes are designed for men, and women often have a hard time finding a bike that will fit them well. Luckily, some manufacturers have begun to make women-specific models.

STEP 6: Test ride some bikes once you have gotten a rough idea of what will fit you. This will help you determine what is most comfortable for you.

Best option, go to a good quality bike shop and get measured/advice from a expert (not some spotty geek in Halfords who only works on Saturday).

At the end of the day, you could make a reasonable gestimate yourself, however, if you looking to spend your hard earned reddies on a good quality bike, it pays to get an expert to measure you and give you the correct advice.


Interceptor said:
Have a look at Evans Cycle website.

Yes. Each manufacturer is different. I would make sure that you ride the bike before you buy it. That doesn't help with Mail Order firms (eg Wiggle).

Cheers All

My nearest bike shop is 'Halfords' and I wasn't convinced they were that clued up.

How long should I test ride before I get an idea of wether the bike is for me or not? My current bike hurts my lower back after about 2-3 hours on it.


War Hero
It's unlikely they'll let you test ride it for that long (I am open to be corrected) but it's that sort of info that you need to tell them in the shop as the frame size might be right but other factors to do with the set-up of the bike may be causing the back problem. Also, try and find a shop where the shop assistants actually use road bikes themselves. Most young cycle shop staff today tend to be mountain bikers which is a totally different barrel of monkeys.
Be careful if you by on line, one of the larger sites appears to have a security problem when it comes to credit card details.

If you want a cheap bike check out as they sell off old stock for knock down prices!!!
If you're still in Brizzle get along to Bike in Queens Avenue (opposite Habitat). They offer excellent advice, new bike delivery was a tad slow (mine came from the factory in Spain) but I found them excellent VFM (compared with interweb sites etc) and they give a lifetime's guarantee and free servicing.
I think a 56cm would be about right, try some and see. If you go to a good shop that will spend the time with you and get the correct position you will be ok. Don't buy mail order unless you have tried that bike in a shop.
If the pain is in the bottom of your back on your current bike the saddle is probably at the wrong angle - probably nose down, It should be more or less level.


War Hero
Interceptor said:
Have a look at Evans Cycle website.

Yes. Each manufacturer is different. I would make sure that you ride the bike before you buy it. That doesn't help with Mail Order firms (eg Wiggle).

I agree with the last part, but don't touch Evan's with a frikkin barge pole. They are the bike equivalent of PC World or whatever - basically a supermarket with clueless casual labour stacking the shelves.

At 6 foot you'll either be a 56 or a 58 (standard road geometry). One thing to bare in mind is that this figure refers to the up tube which can be adjusted by rasing or lowering the saddle. More important, since it can't be easily adjusted, is the top tube ('crossbar'). This can be a factor particularly if you have a long back and/ or shorter legs for your hight.

As has been said, goto a decent bike shop, get sized up and test ride.


Cheers all,

my current bike is a 58cm frame which I suspect might be a little large for me.

The saddle is level, but the geometry is more of a touring bike rather than a pure road bike.



i used to road race for nottingham team, and i have found out that the best size frames to have are the smallest ones, i had a giant with a 19inch frame and a trek at 18inch, for your size get a 20-21 inch frame, if it feels small thats how u want it, trya and get a sloping frame aswell, hope this helps u

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