Road Bike Size Advice

[iancrt]

hello,

I am a short-arsed male looking at buying a general purpose road bike for a bit of riding variety, however I am a little confused with some of the sizing so some expert advice would be welcome. I normally ride a MTB with 16" frame, and its pretty comfortable with the saddle 6-7 inches above the toptube.

I have calculated I need a road bike around 44cm (27*0.65*2.54), however looking at bikes available in this size they seem to have smaller wheels- 650 (or 24" on some bikes).

My Questions are:
Have I calculated my frame size correctly for an inside leg of 27"?
how critical is this? could I get away with +4cm or +6cm as these seem more common.
Should I be looking at smaller wheel bikes? - I would assume these may have a shorter top tube that may cause issues as well as the smaller diameter throwing my frame calculation out.
Any suggestions on suitable bikes?

Any guidence is most appreaciated.

Thanks

Ian

[stewartpratt]

If I were you I'd go to a shop, jump on their smallest 700c road bike and work from there. At the extremes of sizing (I'm at the other extreme) you often find that normal guidelines break down, so trying stuff out is important.

Ending up on smaller wheels will limit your choice and availability of componentry (assuming by 'road bike' you mean a racing-type bike rather than a tourer - in which case consider 26" stuff).

[Flinders]

I'd agree, go to a shop- and one that really cares about getting you a bike the right size. I'm a very short (5') female with a long back and short legs. I've just got my first new bike for about 25 years, and my choice was very limited by my leg length. My LBS took time to really understood my needs, and built a bike on an XXS Ridley frame and a longish stem for me, and I now realise that it's the first bike I've ever had that's really been the right size- even though it's predecessors were all hand-built for me elsewhere. It does have 700cm wheels, but with a sloping top-tube and the saddle nearly as low as it will go, it fits me exactly. (The main reason I abandoned my old bike is that its 26 1/4 wheels and many of its other odd components are now darn near impossible to replace.) In my case, there were few frames that would do at all, but I bet some places would have sold me any old thing.

I'd go for a frame that:
a)fitted exactly (I can't believe the difference this has made), and
b) used the most standard parts possible, to give a good range of tyres, etc.

[Phil_Lee]

I'd agree, go to a shop- and one that really cares about getting you a bike the right size. I'm a very short (5') female with a long back and short legs. I've just got my first new bike for about 25 years, and my choice was very limited by my leg length. My LBS took time to really understood my needs, and built a bike on an XXS Ridley frame and a longish stem for me, and I now realise that it's the first bike I've ever had that's really been the right size- even though it's predecessors were all hand-built for me elsewhere. It does have 700cm wheels, but with a sloping top-tube and the saddle nearly as low as it will go, it fits me exactly. (The main reason I abandoned my old bike is that its 26 1/4 wheels and many of its other odd components are now darn near impossible to replace.) In my case, there were few frames that would do at all, but I bet some places would have sold me any old thing.

I'd go for a frame that:
a)fitted exactly (I can't believe the difference this has made), and
b) used the most standard parts possible, to give a good range of tyres, etc.

[Flinders]

Sorry- typo!
(I do wish I had longer legs, but not that long !)

[loafer]

alwats best to get fitted i used to ride 21 frame as inside leg was 30.. then i splashed out on a made to measure from a local builder.. seems 19 1/2 fits me great fits like a glove worth every pound spent.. for help try this

http://www.coloradocyclist.com/BikeFit/ ... rframesize

[ANTONISH]

Are you sure its 27"? . Inside leg length for cycling purposes is crotch to ground-longer than inside trouser length. The received wisdom is 10"less than this. As for 650 wheels there is a 650 wheel enthusiasts association in France ( not all diminutives like myself). I believe that building a small frame for 650 wheels enables a longer head tube which may have advantages preventing headset movement-does this still apply with aheadsets?

[Mister W]

How tall are you? If you've got a long torso then you may be able to get away with a larger frame as you'll have the reach to manage the longer top tube. If you're of average proportions then you really need to look at small frames. Try Planet-X. They do some very small frames with 650 wheels. If you e-mail them they'll also help with sizing.

There's nothing wrong with riding a bike with 650 wheels except you'll have less choice when it comes to picking your wheels. On the positive side though, 650 wheels go really cheaply on eBay because so few people use them so you could pick up a pair of really good wheels for not a lot of money.

[lowrider]

I am of similar size to yourself I also have been considering a new 700c bike I currently have a Dawes Horizon 43cm with 700c wheels. I was considering getting a light weight tourer as an upgrade however the kind of difficulties you are experiencing have put me off so Im just going to get thinner tires for the Horizon for now.

The frame design for a 43 or 44 cm frame for 700c tires is extreme it looks more like an MTB frame than a tourer. The top tube slopes at a very steep angle and you dont get the clearance you might expect from such a small frame. I am not aware of anything that small on the market at the moment 46 cm seems to the smallest at the moment but not common.

I got this because I was advised on size at the bike shop in reality the next size up as I have found out later would have been better(46). The reason for this was if I get a good fit for clearance the bike is usually too short to be comfortable, what I should have done is get the longest bike I could find that I could just get some clearance at the expense of the conventional guidelines. In short if you can stand over it and lift the front wheel off the ground say an inch that’s enough. Even doing this you still might have to get a stem extension to get a fit.

Forget frame size all together you should instead be interested in the stand over height, but even if you find a bike on the web with enough clearance you are still not in the clear though. You have to make an assessment on the length this could be done from comparing virtual top tube dimensions( +stem length + saddle adjustment ). This will only work if you can work out the length you need and if like me you cant you have to go to the shop and try the bike before you can even put it on the list.

The choice is going to be very limited

The idea of 650c wheels is Ok but the frame is probably proportionally shortend to suit so although you can stand over it you still have to try it for length.

There are not many bikes 700c wheel I could find as small as 43 or even 46 and these tend to be Hybrids when you do. All the road bikes I have seen do not come small enough they seem to start at around 50cm so stand over height is likely to be the problem.

One bike you might be able to stand over I found on the web would be a Thorn audax Mk3 from St johns Street Cycles. These come in small sizes quoting stand over heights from 701mm (27.6ins) but I still would not buy one of these unless you can try the length. If the shop is to far away for you they do have a sizing chart on the order form on the web, this might help and you could give them a call for some advice if you were interested.

There are also some tourers around that might fit but unlike the thorn they slower and much heavier than a road bike. The Claud butler Dalesman and the Edinburgh Traveller come in 46cm if you can find one near you they maybe worth a try.

If you still don’t have your new bike good luck

[Jonny]

Check out http://www.bikefitting.com/English/Frame.aspx and perhaps visit your local dealer who has this software.