Fifty Plus (50+) - toe overlap

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Do any of you have toe overlap and if so, how annoying is it. Do you think it could cause a problem when turning. I was wondering why they couldn't rake the forks or something, to give you more clearance. I would think there is a reason for it.
cccorlew
08-19-07, 01:07 PM
Lean, don't turn the handlebars. And pay attention. I have some overlap and it's never bothered me.
More rake messes up the handling
stapfam
08-19-07, 01:23 PM
The Giant and I don't have any so it came as a shock on the Boreas when The foot touched the wheel on turinng the bars. Hasn't affected the riding at all- except for the sudden realisation that the corner must be tighter than I thought it was.
Jet Travis
08-19-07, 01:30 PM
I don't think it should happen except at the very slowest speeds.
Trsnrtr
08-19-07, 01:51 PM
I'm 5'7" and have always had 52-53 cm road bikes, probably 25 or so, and all, that's every one, has had toe overlap. Considering that i also wear a 7.5 to 8 size shoe, that tells me that it must be darn hard to build bikes that size and smaller without the overlap. I quit worrying about it in about 1982 or so.
Road Fan
08-19-07, 01:59 PM
Do any of you have toe overlap and if so, how annoying is it. Do you think it could cause a problem when turning. I was wondering why they couldn't rake the forks or something, to give you more clearance. I would think there is a reason for it.
Toe overlap is one of the tradeoffs in frame design. It can be avoided by long top tubes, or laid back head angle, or added fork rake. But these all have consequences in bike fit and handling, not all positive ones! I don't know what you ride, but often a frame will be designed with overlap to afford the rider some other capability, usually good handling, targeting a short-torso body shape. A custom frame designer will often make this choice when the customer is skilled and has been consulted.
I don't find it a problem. I only encounter foot-wheel contact at very low speeds, and I've become good at reverse-pedaling to move my foot to a clear position.
Road Fan
Road Fan
08-19-07, 02:01 PM
I'm 5'7" and have always had 52-53 cm road bikes, probably 25 or so, and all, that's every one, has had toe overlap. Considering that i also wear a 7.5 to 8 size shoe, that tells me that it must be darn hard to build bikes that size and smaller without the overlap. I quit worrying about it in about 1982 or so.
I use smaller frames, too, and I find overlap with my steel Trek and my Masi, and much less with my Woodrup. The Mondonico has no overlap, and shows great handling. All are 52-53. I think you get used to it, like bifocals, or at least just stop complaining eventually (also like bifocals!).
Monoborracho
08-19-07, 02:05 PM
More rake messes up the handling
Its a matter of opinon. A raked fork increases the wheelbase and changes the angle at which the tire is pointed when in a turn. It smoothes the ride and changes the handling, but also increases the turning radius. A straight fork shortens the wheelbase and the turning radius. Lack of rake makes a bike "quick" handling to some while being "twitchy" to others, but nearly all have some rake to them, usually built in by putting the steer tube and fork at an angle to one another.
For the first 90 years of biking all bikes had some rake to them. But forks have to be strong enough (i.e., steel) in order to accept an offset loading on narrowing fork tines. The onset of aluminum and then carbon caused fork designs to change, of necessity. In exchange for a lighter bike you get little or no offset, or else you get this thick, massive front fork rather than the smooth taper of the classic bike.
In any event, toe lap should only be a problem at very low speeds when either cornering or starting off.
lhbernhardt
08-20-07, 01:38 AM
Lack of rake makes a bike "quick" handling to some while being "twitchy" to others,
I've read somewhere - and it's been my experience - that just the opposite happens. A short bike is equipped with a small rake in order to make it more stable. A longer bike is equipped with more rake in order to help it turn quicker. Thus, criterium bikes have little rake so that they are easier to control during hard cornering (they will be more stable in a turn, and not as "twitchy," as they would be with more rake). Tandems have lots of rake because they tend to want to go straight. More rake makes them easier to steer.
As I recall, back in the 70's, some university did a study using different rakes. It's been years, but I remember that bikes with negative rake were very difficult - if not impossible - to steer. Which is odd, because the old "demi-fonde" bikes, the ones used for motorpaced racing behind the big motorcycles, always had their forks mounted backwards (they stopped doing this at the Worlds years ago, but you still see it at some European 6-days). This was primarily to get the rider closer to the roller behind the motor (and thus closer to the windshelter of the pacer), but I would imagine that it would have made the bike extremely stable, as it would have to be, spinning along at 60-80 kmh on the 250 or 333 meter velodrome.
As usual, I could be wrong, but I'd be curious to hear from those more knowledgeable than I.
- L.
BluesDawg
08-20-07, 04:22 AM
Isn't overlap more often associated with small frame sizes? I don't expect that George will be experiencing this.
maddmaxx
08-20-07, 04:51 AM
Overlap can also be a function of Crankarm size. Smaller Frames should come with smaller crankarms but sometimes don't. This can be a factor for some of us in 50+ as there is a tendancy to go with the smaller frame size for a more upright seating position. Consequently your body may be slightly tall for the frame and you may (if there is a choice) opt for a crank that fits your body. In most cases this will be a set of 175mm crankarms in a frame too small for them. In these cases a 170mm crank may be called for. That extra 2.5mm may be the difference between overlap and not.
Another factor is from moving the cleats on clipless pedal shoes too far aft. Now the toes will stick out further.
rodrigaj
08-20-07, 05:33 AM
You have to be aware of overlap at stops when you are just taking off. It should never be a problem in normal riding. The awareness becomes quite automatic after a few stops.
Bike design and fit is all about compromise, given the riders preferences and physical attributes.
Beverly
08-20-07, 05:44 AM
Overlap can also be a function of Crankarm size. Smaller Frames should come with smaller crankarms but sometimes don't. This can be a factor for some of us in 50+ as there is a tendancy to go with the smaller frame size for a more upright seating position. Consequently your body may be slightly tall for the frame and you may (if there is a choice) opt for a crank that fits your body. In most cases this will be a set of 175mm crankarms in a frame too small for them. In these cases a 170mm crank may be called for. That extra 2.5mm may be the difference between overlap and not.
Another factor is from moving the cleats on clipless pedal shoes too far aft. Now the toes will stick out further.
The Madone (51cm) came equipped with 170mm cranks and after a few hundred miles I opted to exchange them for 175mm cranks. The LBS warned me I might experience overlap problems. I've only had this problem a couple times and both were at very low speeds on extremely tight corners. In my case, the large crank was worth the small annoyance.
BSLeVan
08-20-07, 06:46 AM
Toe overlap can also occur when you put fenders on a bike. I have a Cannondale 800T with is a nice stretched out touring frame. No over lap, until I put fenders on it. Now I have just the slightest overlap. The only time I notice it is when I've stopped riding, have one foot planted on the ground while the other is still clipped in, and I'm reading a map or some other such thing. Typically, the front end (bars, forks, wheels, etc.) turn to one side or another, depending on the slope of the ground. This is the only time I notice the toe overlap. I think with proper turning technique, crank arm length, etc. it's pretty much not a problem on the other road bikes I have with tighter geometry.
Monoborracho
08-20-07, 07:45 AM
.......I'd be curious to hear from those more knowledgeable than I.
- L.
+1 Me too.
I can't see how a shorter wheelbase makes a bike more stable.
I think they become more stable at a higher speed due to gyroscopic effects of the wheel rotation (up until something like a harmonic vibration negates the gyro effects). Consider the difficulty of taking both hands off the bars at low speed.
Its an interesting subject, and I'd like to know more. Some info is posted below:
From Sheldon Brown glossary (my emphasis)
Rake
The "rake" or "offset" of a fork is the distance between the wheel axle and the extension of the steering axis. This may be accomplished by bending the fork blades, or by attaching the fork ends to the front of the blades, or by tilting the blades where they attach to the crown.
Rake is one of the three factors that affect the trail of the bicycle, which has a considerable influence on the handling qualities.
Trail
Trail is the distance from the contact point of the front wheel with the riding surface to the intersection of the steering axis (head tube) with the surface. The trail is a function of the head angle, the fork rake, and the tire diameter. Trail has a major effect on the handling of a bicycle. More trail increases the bicycle's tendency to steer straight ahead. A bicycle with a largish trail dimension will be very stable, and easy to ride "no hands". A bicycle with a smaller trail dimension will be more manuverable and responsive.Joshua Putnam has a good discussion of trail and Bicycle Steering Geometry in general on his Web site.
Here is link to the Putnam article http://www.phred.org/~josh/bike/trail.html
BlazingPedals
08-20-07, 08:14 AM
By my understanding, trail is the thing that makes a bike handle 'quick' or not, with less trail being more twitchy. Trail, as most of you know, is the distance between the contact patch and the imaginary line extended down the steering axis to the ground. The contact patch "trails" the imaginary point. Forward rake decreases trail and should therefore cause twitchier handling. A steeper steerer tube will do the same thing. If you get too far outside the normally-accepted geometries, then other stuff like head tube lift starts affecting steering, too; but that's for the homebuilders and non-comformists to worry about - nothing you're likely to see at a bike shop will come close to being outside the envelope.
The subject of 'gyroscopic effect' has been beaten to death; and it's generally accepted that although it exists, the effect is not large enough to have any practical effect on balance.
Monoborracho
08-20-07, 08:26 AM
Following a little research on my part, I agree with Blazing Pedals about the gyroscope effect.
I'm 5'7" and have always had 52-53 cm road bikes, probably 25 or so, and all, that's every one, has had toe overlap. Considering that i also wear a 7.5 to 8 size shoe, that tells me that it must be darn hard to build bikes that size and smaller without the overlap. I quit worrying about it in about 1982 or so.
Hi,
+1
I'm 5' 7" when I stand up straight and I wear a size 10 shoe. :eek: I've owned about 15 road bikes and I can't think of one that didn't have toe overlap. I know that every once in a long while I hit my front whel with my foot but I can't think of one time where it caused me to fall. :)
OK here's the deal, the dealer is getting a Cannondale T800 and I know I'm going to have overlap and I can test ride the bike, by the end of the week. I have to order the LHT by the end of the week if I want to get it around the end of Sept. I can test ride the Cannondale, but not the LHT, should I gamble??
BSLeVan
08-20-07, 09:30 AM
OK here's the deal, the dealer is getting a Cannondale T800 and I know I'm going to have overlap and I can test ride the bike, by the end of the week. I have to order the LHT by the end of the week if I want to get it around the end of Sept. I can test ride the Cannondale, but not the LHT, should I gamble??
I like my Cannondale T800 a great deal, but should you gamble? Wow, do you promise to do just what I suggest? (Obviously, I'm not being serious.) Generally, I don't like to buy things sight unseen unless I can get full refunds and have it in writing. But that's just me.
Road Fan
08-20-07, 10:46 AM
OK here's the deal, the dealer is getting a Cannondale T800 and I know I'm going to have overlap and I can test ride the bike, by the end of the week. I have to order the LHT by the end of the week if I want to get it around the end of Sept. I can test ride the Cannondale, but not the LHT, should I gamble??
If you haven't sat on the bike, how do you know you'll have overlap?
Have you ever experienced overlap? Is it really a big problem for you?
Can you get your feet down quickly at all times, or do you fall fairly easily?
Road Fan
I'm not understanding the physics of this. Granted, I have small feet and have never experienced toe overlap, but I'm understanding it to be that you toe touches the tire while turning at a slow speed.
Now, what exactly* does speed have to do with it? Your toe and the tire are always in the same spots...
stapfam
08-20-07, 11:14 AM
OK here's the deal, the dealer is getting a Cannondale T800 and I know I'm going to have overlap and I can test ride the bike, by the end of the week. I have to order the LHT by the end of the week if I want to get it around the end of Sept. I can test ride the Cannondale, but not the LHT, should I gamble??
No. The LHT may have some good reviews but the only test you want is to ride it. May seem very hard but Give the Dale a chance- Test it and if it is good enough- It will tell you. Then If you are still convinced about the LHT- Sight unseen and Unridden- Whats another weeks wait?
Try the Dale- It may shock you.
stapfam
08-20-07, 11:37 AM
I'm not understanding the physics of this. Granted, I have small feet and have never experienced toe overlap, but I'm understanding it to be that you toe touches the tire while turning at a slow speed.
Now, what exactly* does speed have to do with it? Your toe and the tire are always in the same spots...
At speed- you do not turn the bars to steer- You lean the bike.
Couple of pics to show you- The same shoe in the same position relative to the pedal, (Clipped in) and the cranks horizontal on both bikes and the same length cranks.
The Giant (Red Tyres) is a relaxed geometry Sports bike and there is clearance between the shoe and the tyre- Even though this is a small bike.
The Boreas is a race geometry bike with a shorter wheelbase and tighter clearances. As you can see-I touch the tyre if I turn the bars.
Now the chance of me touching the tyre is remote. Only at slow speed when I am turning the bars to steer and the foot has to be in that position to touch the tyre. Normally I am not pedalling when negotiating obstacles at slow speed and has only occured twice since I have had the bike.
The Weak Link
08-20-07, 11:47 AM
Yep. Toe overlap would be very unwanted in a mountain bike, where very slow speed turns are required.
On a road bike I don't think it's that big a deal.
Here's something I just found.
There was a discussion recently on Classic Rendezvous Bike list; the tread titled “Toe overlap even on good bikes,” implied that toe overlap was a design flaw and one should not expect to see this on quality bikes. Toe overlap is a result of other critical design factors and cannot always be avoided especially on smaller frames.
When a framebuilder designs and builds a racing frame, his main criteria are to: (1.) Place the rider in a position where he can pedal with maximum efficiency, and (2.) Design the frame so the finished bike will handle at speed in the best way possible. If the result of the design is toe overlap then the builder can do little because to achieve toe clearance other aspects of the frame’s design would have to be altered.
For example the picture above shows my own bike. It has a small 52 cm. (C to T) frame and has about an inch of toe overlap. If I were to make the front end of the bike one inch longer to avoid toe overlap, I would have to do one of the four following things or a combination of all four.
(1.) I could make the seat angle steeper, or (2.) the top tube longer. (3.) I could make the head angle shallower, or (4.) the fork rake (offset) longer. The first two would effect my riding position; the last two would affect the handling of the bike.
Toe overlap is not a problem because riding and cornering at normal speed the front wheel never turns far enough for the toe to hit the front wheel. The only time it becomes an issue is when turning sharply at a very slow speed; doing a U-turn on a very narrow road for example.
Caution and common sense are all that is required when executing a tight U-turn. If you are turning left then your right pedal will be down for maximum ground clearance as you coast into the turn. By the time you need to start pedaling again you are already half way through the turn, and the right crank has to complete ¾ of a turn before the toe is opposite the front wheel.
By that time, you should be all the way around and the front wheel is straight ahead again. If you are not the coast again, or ratchet the crank back again on the freewheel.
Doing the same maneuver with a fixed gear is a little trickier; but it is a matter of timing. Go very slow and start to turn as the toe passes the front wheel; that way the crank has a whole revolution to go before it makes contact again. If the front wheel is still turned the next time round; straighten the front wheel so the toe clears, then turn sharply after it has passed.
Fixed gear and fenders (Mudguards.) is going to make this move a little difficult, but not impossible. With clipless pedals, you could unclip the outside foot and move your toe back to give more clearance. I sometimes get out of the saddle and simply point my toe downwards to give more clearance.
What you need to avoid is a situation where you get your toe on the wrong side of the wheel in a turn; if you do, try not to panic. Ratchet the crank back if you have a freewheel, or if you are riding fixed gear, keep going and let the toe pass the front wheel so you can straighten up again.
Lastly, I would like to point out that a racing motorcycle with narrow swept down handlebars; turning is restricted because the handlebars touch the fuel tank. Here is a machine that will go 200 mph plus, and restricted turning seems not to be a problem. Therefore, I maintain the opinion that toe overlap on a bicycle is neither a design fault nor a problem.
cyclezen
08-20-07, 03:58 PM
Here's something I just found.
There was a discussion recently on Classic Rendezvous Bike list; the tread titled “Toe overlap even on good bikes,” implied that toe overlap was a design flaw and one should not expect to see this on quality bikes. Toe overlap is a result of other critical design factors and cannot always be avoided especially on smaller frames.
....SNIP... Lengthy justifications
By that time, you should be all the way around and the front wheel is straight ahead again. If you are not the coast again, or ratchet the crank back again on the freewheel.
Doing the same maneuver with a fixed gear is a little trickier; but it is a matter of timing. Go very slow and start to turn as the toe passes the front wheel; that way the crank has a whole revolution to go before it makes contact again. If the front wheel is still turned the next time round; straighten the front wheel so the toe clears, then turn sharply after it has passed.
Fixed gear and fenders (Mudguards.) is going to make this move a little difficult, but not impossible. With clipless pedals, you could unclip the outside foot and move your toe back to give more clearance. I sometimes get out of the saddle and simply point my toe downwards to give more clearance.
What you need to avoid is a situation where you get your toe on the wrong side of the wheel in a turn; if you do, try not to panic. Ratchet the crank back if you have a freewheel, or if you are riding fixed gear, keep going and let the toe pass the front wheel so you can straighten up again.
... SNIP - non appilicable moto stuff...
The guy that wrote this is certainly much more multi-tasking that I am on a bike. I can barely ride and chew gum (ergo I don;t chew gum anymoe...)
I will admit to having, on a number of occassions, made tight U-ies on my Limongi and DID jam my shoe toe so hard down on the Tahr, that I wuz locked in. All culminating in a very ungraceful end.
...I don't care to admit how often I have done that. Nor will I absolve myself from the possibility of doin it again... :o
so, I no longer buy bikes which can't give me, a 5'10"+ (and growin !!!) dumm guy, toe clearance.
Butt dats just me.
coincidentally, I bought my daughter a very nice Tommaso a little while back, a 48 compact frame, full 700c wheels. And with size 7 women's shoes she clears the wheel (167.5 cranks). If they can do it, anyone can.
...very nice bike...
BTW - re trail nee rake and angle, there is some generally accepted old-time logic which says that trail of 54 to 58 mm generally gives the best compromise of handling for most road machines. Ask some framebuilders with some history. Same kinda thing can also be said for BB drop...
as for buyin sight unseen
I do it quite often meself... with the full understandin that I might end up turning it around almost immediately.
...anyone shoppin for a nice digital camera??? :o
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