Touring - Frame sizing / toe overlap

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View Full Version : Frame sizing / toe overlap


modbiker
03-22-06, 02:17 AM
I've been researching touring bikes here on this forum for weeks now -- what a treasure-trove of information! So much to learn... I don't have a specific big trip in mind yet, but I've always wanted to. I'm planning to do some short trips this summer with my girlfriend, and plan a few years ahead for a longer trip (multi-month hopefully). I imagine mostly pavement, some dirt road touring, unsupported.

Most of the biking I've done in recent years has been urban commuting on mountain bike frames. So I don't know what feels good on a road/touring bike yet. I've been experimenting with my riding position on used bikes, friends' bikes, and on longer rides than my usual 10-15 mile per day commute. I've also test ridden a few touring bikes recently.

I'm finding that I like a shorter cockpit than most bikes in my size (56-58cm, I'm 5'10.5", 34" pbh) have. I don't know if my measurements are unusual, or if I'm just accustomed to a more upright riding position. And maybe I should try to get used to a slightly more stretched out position. I like what I've read about the LHT, especially the price, but the 58cm just felt too long. It had a fist of seatpost showing, and a little standover clearance, so I thought the size would be right. I could "make" it work with a very short stem and short reach bars, and a zero offset seatpost, but that doesn't seem ideal. Haven't found a 56cm LHT to test ride yet, but maybe it would work better. Does it make sense to down-size to get a shorter top tube length?

A LBS has a 57cm Co-motion Americano at a 20% discount, so I took it for a test ride this past weekend. Very nice! Their sizing seems to have a proportionally shorter top tube, which felt more comfortable to me. I'd still want a slightly shorter stem than was stock, or at least shorter reach bars, but it was a much closer fit than the 58cm LHT. Still a big chunk of change at over $2400 though. It's do-able, I can keep stretching the "don't have a car" rationale, but I'd only want to spend that much if I knew it was the only way I'd be comfortable on the bike.

Anyway, I noticed that my toes hit the tire when turning the wheel sharply, at very slow speed or stopped. No fenders on the bike yet. Should I be concerned about this overlap when shopping for a tourer, or is it pretty much irrelevant?

Thanks!


onbike 1939
03-22-06, 04:14 AM
I've been researching touring bikes here on this forum for weeks now -- what a treasure-trove of information! So much to learn... I don't have a specific big trip in mind yet, but I've always wanted to. I'm planning to do some short trips this summer with my girlfriend, and plan a few years ahead for a longer trip (multi-month hopefully). I imagine mostly pavement, some dirt road touring, unsupported.

Most of the biking I've done in recent years has been urban commuting on mountain bike frames. So I don't know what feels good on a road/touring bike yet. I've been experimenting with my riding position on used bikes, friends' bikes, and on longer rides than my usual 10-15 mile per day commute. I've also test ridden a few touring bikes recently.

I'm finding that I like a shorter cockpit than most bikes in my size (56-58cm, I'm 5'10.5", 34" pbh) have. I don't know if my measurements are unusual, or if I'm just accustomed to a more upright riding position. And maybe I should try to get used to a slightly more stretched out position. I like what I've read about the LHT, especially the price, but the 58cm just felt too long. It had a fist of seatpost showing, and a little standover clearance, so I thought the size would be right. I could "make" it work with a very short stem and short reach bars, and a zero offset seatpost, but that doesn't seem ideal. Haven't found a 56cm LHT to test ride yet, but maybe it would work better. Does it make sense to down-size to get a shorter top tube length?

A LBS has a 57cm Co-motion Americano at a 20% discount, so I took it for a test ride this past weekend. Very nice! Their sizing seems to have a proportionally shorter top tube, which felt more comfortable to me. I'd still want a slightly shorter stem than was stock, or at least shorter reach bars, but it was a much closer fit than the 58cm LHT. Still a big chunk of change at over $2400 though. It's do-able, I can keep stretching the "don't have a car" rationale, but I'd only want to spend that much if I knew it was the only way I'd be comfortable on the bike.

Anyway, I noticed that my toes hit the tire when turning the wheel sharply, at very slow speed or stopped. No fenders on the bike yet. Should I be concerned about this overlap when shopping for a tourer, or is it pretty much irrelevant?

Thanks!

I think you are right to say that you need a bike with a shorter top tube. You appear to have reasonably long legs and a relatively shorter trunk so you would be right in that. A shorter stem can help but it does change the feel of the bike as it sets your weight further back causing the bike to be lighter in the steering. Better to find the correct length of top tube.
A touring frame has a longer wheel-base than the bikes you are accustomed to and that ensure a more stable ride with no twitchiness when loaded. The longer chain-stays also allows more room for rear panniers which may otherwise foul your heels when riding.
Toe clearance is essential and if you do not have it then look for another bike with the correct angles. The rake of the forks are a factor in this also. Th traditional touring bike frame should work fine for you but problems may arise in those frames that compromise between this and a fast/audax frame.

MichaelW
03-22-06, 04:41 AM
Toe clip overlap may be acceptable on a race bike but when you are winding yourself up an 18% slope with a load at 5mph you need to flip the bars pretty hard.
One way to avoid TCO on smaller bikes is to use 26" wheels. The Surley LHT is one of the few affordable bikes to do this.
There is a lot of debate of 700c vs 26". In practice you will not be using a race wheel so the comparison is between a 700c 32mm tyre or a 26"x1.5". The differences are marginal and the availability of 26" tubes and tyres can swing the argument in their favour.

Also, check the crank length; from the sound of things you need 170mm or smaller. Avoid anything larger.


CdCf
03-22-06, 08:33 AM
I'm 5'10.5", with 33 or 33.5" legs. I ride a 54 cm Surly LHT (largest model with 26" wheels). Short stem and low bars. Very comfortable!

modbiker
03-22-06, 09:04 AM
Also, check the crank length; from the sound of things you need 170mm or smaller. Avoid anything larger.

The cranks on the Americano I tried were 175mm. One of my bikes that I've had for 5 years has 170mm, which have always been pretty comfortable to me. A used bike that I bought a couple months ago (a Bridgestone MB4) has 175mm. The 175's do feel like a much bigger circle to pedal. Is there a formula to suggest crank length, or is it just something to develop a personal preference for?

modbiker
03-22-06, 09:08 AM
I'm 5'10.5", with 33 or 33.5" legs. I ride a 54 cm Surly LHT (largest model with 26" wheels). Short stem and low bars. Very comfortable!

Do you have the handlebars much lower than the saddle? Doesn't this put more weight on your hands?

ken cummings
03-22-06, 09:28 AM
For $2,400.00 you can start talking to small-lot and cumtom builders about a near-custom frame. Have Exactly what you need. Eisentraut and Gordon come to mind. There are several others.

halfspeed
03-22-06, 07:31 PM
Does it make sense to down-size to get a shorter top tube length?


Not necessarily. Riding a smaller frame means the bars will be lower compared to the saddle which increases the effective reach. Net result may be worse rather than better. It all depends on the frame and exactly what the differences are. I'll never ride a little frame again.



Should I be concerned about this overlap when shopping for a tourer, or is it pretty much irrelevant?

If it's only on sharp turns at low speed, it's probably no concern.

moki
03-23-06, 12:54 PM
For $2,400.00 you can start talking to small-lot and cumtom builders about a near-custom frame. Have Exactly what you need. Eisentraut and Gordon come to mind. There are several others.

+0.5 (an eisentraut or bruce gordon would be near that amount for the frameset alone)

A friend had a cross bike built by Mike Truelove (http://members.shaw.ca/mtmetal/mtmabout.html) out of Squamish BC for a ridiculously low price. Check him out.

also check out frameforums.net if you're going custom. $2400... I can only dream.

MichaelW
03-24-06, 04:45 AM
There are various formula for crank size but most of them will come down to the same thing. For a guy your size (5'10" with short legs) you want a 170mm max. This will fit your legs and it will fit a frame without toe-clip overlap.

When sizing a modern frame, maintain adaquate standover but the critical dimension is reach. If you are between sizes, smaller is usually better than larger. Stems are easy to switch for different height/reach.

Check out
www.peterwhitecycles.com/fitting.htm

For an rough-stuff touring bike, check out the Bruce Gordon BLT-X (http://www.bgcycles.com/blt.html). It comes ready to tour with no modifications required and you get change from $2k.

acantor
03-26-06, 08:19 PM
Anyway, I noticed that my toes hit the tire when turning the wheel sharply, at very slow speed or stopped. No fenders on the bike yet. Should I be concerned about this overlap when shopping for a tourer, or is it pretty much irrelevant?



One of my touring bikes has toe overlap, and wish it did not.

The truth is that toe overlap has not caused significant problems for me so far. This bike has taken me up mountains, so I have done a lot of very low speed riding.I have never lost control because of toe overlap, but I have come close a few times. Overall, though, the bike is a pleasure to ride, so I have learned to live with this wrinkle.

If I were looking for a new bicycle, I would look for a model with no toe overlap.

I have the impression that toe overlap bothers some people more than others.