Found the updated ramp calculator really useful, thanks! Will be sharing this.

Thanks for the clarification. I'm a bit smarter than I was two minutes ago.

Johnr - Crossfall is the side slope when a vehicle is travelling on a sloped surface. Most ramps have no crossfall in the direction of travel. However at some sited forklifts are required to travel on slopes where the direction of travel means the forklift is subject to both a slop in the direction of travel and a side slope or crossfall at right angles to the direction of travel

I'm not familar with the term "cross fall" but I am guessing that it is the point of transistion at which a lift would be traveling from a level warehouse floor on to a down ramp. If my guess is correct then on a lift truck this would be referred to as the "break over angle" (at least in the States or at that is what I learned along the way). This angle varies wideley from model to model & make to make due to several key factors - wheelbase ground clearance distancebewteen the wheelbase points (most often this is the frame side members, but I have seen oldr model Toyota's where the transmission actually was below the frame) and some units had metal ring protector welded around a hydraulic or fuel tank drain plug. But what ever is the lowest point is what we need to be concerned with.
The break over angle is formed by two line one starting a point wher the steer tire contactct the ground adn the other where the drive tire contact the ground. Then a line is drawn upwards towards the midpoint of the wheelbase and where the intersect at the lowest point an angle are created - this is the break over angle of the lift truck (and after all these words hopefully the "cross fall" angle). At one time most lift truck companies in the US published this info (I did when I was involved in literature development) but more & more companies now follow the ISO formats on there specification literature. But manufactuers can supply this info w/o much issue - unless they are too busy or sleeping.
One final note, this angle will vary as the tires wear (the lowest point gets closer to the ground) and the steering tires generally wear out twice as fast as the drive. So it is always best to use the data on the conservative side.
If I have totally confused you send me a mailing address & I'll draw you my best stick picture w/ real stick men with a straight edge & a dime (or a 6 pence) and forward it.

i wouldnt try to over-think this too much
safety is your main concern (even over money)
if you have sitdown counterbalance AND standup reach trucks negotiating this ramp the obvious calculation would have to favor the standup reach truck and building the ramp so that these trucks can negotiate this ramp in the safest manner. Reach trucks being the most likely unstable on a ramp situation.
Even basing the ramp angle on what the spec's say the reach trucks can do is tricky because you also need to factor in human interaction (the operator's judgement and ability to operate the lift even if trained) IOW... no 2 drivers are the same so the safer you make the ramp the better off you are.
The lesser the angle the easier it would be to negotiate the ramp safely.
I've had some experience with ramps on reach trucks and it is a very tricky situation when carrying loads and even more so driving empty. Trying to negotiate a ramp on the down angle on a reach truck is tricky especially if the truck has electric brakes. Sure you can use plugging to help slow the truck and control it but the steeper the ramp the harder it is to achieve this in a safe manner.
Not to mention the effect it will have on the battery life of the truck, steeper ramps take more power to pull the truck up the ramp.

Just some of my thoughts on this
Just remember safety for your operators is your main concern period.

good luck

Hi John L (and others) - I recently came across your great comments regarding operational slopes for forklifts - great stuff. Really condenses it down to the basic guidelines from which a decent risk based operational assessment can be made. Any words of wisdom regarding maximum cross fall of unladen counterbalanced forklifts.

JohnL I understand what you say & have no issue with your "on average" analysis. An issue that must be understood that the steeper the incline the greater the risk of having a safety issue. Like I stated before a 1/10 (10%) is a steep grade a 1 in 4 (25%) is very steep (like mountain climping).
I realize operators are taught to negotiate a ramp with a load to travel w/forks up hill. ( I have developed & presented operator training prgrams during my 41 year career). In "the real" world I have personally witnessed many operators just believe this this as just a mere suggestions (kinda' like the Max. Speed Limit signs along the roadside) and travel in the opposite direction with a load. With steeper grades the greater the chance of a "ya ha" should the operator brake on the ramp as the load can be only tilsted back 8 to 10 degrees.
I understand ther are many situations that ramps are much steeper than 10%, in the States. "Most" of these situations arise in the older cities & buildings - like around NYC, Chicago, etc

Hi again John an others
The worst situation with a counterbalanced forklift is when it is very lightly loaded and hence is to be driven up a ramp with the forks facing up the ramp. As the ramp gets steeper more and more weight is transferred off the drive. As an indication for the normal range of counterbalance forklifts, and assuming a low friction factor between the forklift tires of 0.4 (normally will be as high as 0.6) then the limits are:
Empty forklift, forks facing down the ramp - on average can traverse a slope up to 24% and worst weight distribution forklifts would be limited to 18%;
10% loaded forklift, forks facing up the ramp - on average can traverse a slope up to 15% and worst weight distribution forklifts would be limited to 12%;
100% loaded forklift, forks facing up the ramp - on average can traverse a slope up to 28% and worst weight distribution forklifts would be limited to 25%;

I understand what you stat about what manufactuers publish. But these results are demonstrated under ideal conditions with new or near new conditions. 5 years from now how much has the performance been reduced and what type of tires are installed - high or low durometer, smooth or traction treads. A 1 in 10 grade or 10% is quite steep but is the most common ramp grade in the US & Canada.

They are all sit down counterbalance or container handling reach trucks

I take it these are all sit-down counterbalanced (class 4 or 5)

Average gradeability of 208 driven forklifts I have details on is 20%.
Only one's limited to 10% are TCM brand units.
Out of the 177 forklifts I have gradeability data on, 6 TCM units have a limit of 10%, another 13 had limits of 12% - 14.3%, another 11 have limits of 15% - 19%, and all the others have capabilities of 20% or more.

From the what it is worth dept. Most ramps are built on a 10% grade or the vertical height from ground level to the top of the entryway (dock floor) x 10 will give you the horizontal length of the ramp required.
Using the maximum gradeability from a spec sheet can be dangerous, as most of these specs are measured in ideal situation in a testing lab (controlled conditions) - new truck with less than 100 hours, new tires, rough brushed concrete surface, truck travel speed at 1 mph or even at the point of stall (to get a bigger numbers for the buying public); the engine and transmission in perfect running condition (new plugs, etc etc. Also, gradeability #s will vary widely from brand to brand, except Mistubishi - Cat & Yale-Hyster (same units different decals & paint color).
Most truck can achieve a 10% ramp either empty or loaded. Generally speaking the empty gradeability that is published is becasue of drive tire wheel slippage, yes there are a few exceptions.

usually the fork lift manufacture will recommend a maximum ramp angle

Better check the Gradability Specs for the trucks that would be operated on the incline.