Mountain bike ramp.

[hayleyearth]

Is that what she crashed on?

The bridge looks perfect. If you could do something like that for your event it would be great.

If that is where she crashed im guessing she went in too fast like Ratboy and landed to flat.

 

Of course it was that one, why would I post it and say that?

OTB vs land to flat = broken neck vs broken foot

 

Is there any evidence to suggest that the design of the bridge had anything to do with the tragic loss of Annefleur Kalvenhaar's life?

 

Not at all. All I was trying to say with it is that even a simple design, which I would also think is more than acceptable could cause accidents and serious injuries (and these rides where way more advanced than most riders that will ride this race in question). I know she was also not the only one that went down on that bridge. I saw it with my own eyes.

 

Most of the posts here were talking about the angle going up to the bridge but I think from a rider's technical ability the angle coming off is more crucial, especially if the bikes that will be used dont have 'forgiving' suspension. OTB's will happen if the angle between the off ramp and ground is too small. (So try and keep that as flat as possible too)

 

Also if you were to use wood, make sure there is enough grip on it. In most cases chicken-mesh (think that is what it is called) is used, but I have seen people that run tubes getting punctures on it if it has points standing up.

 

I like the point that was made that it should be wide enough for people to also be able to get off their bikes and push. There might be at that same time another rider riding past.

[Sniffie]

Mmmm, that pic is sad...The reason for my question regarding the technicality was to ascertain whether I would be able to ride it on my rigid SS or need some gears and suspension. I would not contemplate taking a rigid SS to Eden Classic as I don't think I will enjoy it much and spend more time than I would like pushing.

 

My skill level has definitely improved since first riding Eden in 2009 and I rode 95% this year. Yes, it is quite tough and some sections are steep and loose. I don't mind a short 'hike-a-bike' every now and again due to the technicality of the terrain or lack of skill on my side.

 

Your event also had a reputation for being VERY technical previously, sometimes comparing certain sections to Eden. I understand that you need to grow your event but isn't this a bit extreme and scarring nature / taking away from what sets mtb apart from road?

Ok, I know it's sad to see concrete on a MTB trail but we have a very valid reason. The area on the koppie were we started to cut the single track some 6 years ago is very rocky with loose sandy soil in between. Whenever we used to cut a new piece of single track the cattle starts to use our paths because it is easier for them to get from their water trough to the other side of the koppie were the grazing is. Their hooves work all the soil loose between the rocks and it becomes unrideable even by the most skilled riders. The heavy summer thunderstorms, that Bothaville are renowned for, causes further erosion. We used to fill he soil back in every year, but it is a huge task hauling wheelbarrows up 30% gradients every time. Don't be fooled by the fact that it is concrete, it remains a challenge because of the winding of the track, the steepness as well as the fact that the concrete strips is less than 400 mm wide.

 

Unfortunately I don't have any SS experience so not sure what is doable and what not. But if you were able to ride 95% of Eden, I think you would ride 99% of Two River Challenge. We don't have any long technical climbs, but their are some steep parts. The longest I would guess is about 45 m. Most of the steep bits on the river banks is quite easy if you carry enough momentum. Momentum really is your friend in this race. What I am trying to say you will never have to hike a bike further than 45 m at the most.

 

We are still suffering the stigma that the severe technicality of our first two events have tainted us with, but like I said in a previous post the 65 km would be 99.5% rideable by any fit mountain biker of only average skill level.

 

Our observation over the past 7 years have been that the fitness and skill levels of the average mountain biker has been constantly improving, so that an obstacle that was a major challenge 7 years ago is now doable by the majority of the field.

[Sniffie]

Of course it was that one, why would I post it and say that?

OTB vs land to flat = broken neck vs broken foot

 

 

 

Not at all. All I was trying to say with it is that even a simple design, which I would also think is more than acceptable could cause accidents and serious injuries (and these rides where way more advanced than most riders that will ride this race in question). I know she was also not the only one that went down on that bridge. I saw it with my own eyes.

 

Most of the posts here were talking about the angle going up to the bridge but I think from a rider's technical ability the angle coming off is more crucial, especially if the bikes that will be used dont have 'forgiving' suspension. OTB's will happen if the angle between the off ramp and ground is too small. (So try and keep that as flat as possible too)

 

Also if you were to use wood, make sure there is enough grip on it. In most cases chicken-mesh (think that is what it is called) is used, but I have seen people that run tubes getting punctures on it if it has points standing up.

 

I like the point that was made that it should be wide enough for people to also be able to get off their bikes and push. There might be at that same time another rider riding past.

Thanks for your and every one else's input, some very valid points being raised.

[SCD]

The point with the solid balustrade was mentioned for a reason. If you come off the bike at speed the uprights of a normal open balustrade system become very dangerous for your limbs and neck. The Sani2C bridge is a good bad example. So apply some horizontal boarding between the posts to make it solid with gaps of 80mm or less.

 

With regards to risks of the steep descent to flat transition. If there is enough space making it a flat off-ramp would be the easiest. But if there is not enough space you also can form a radial transition at the bottom. A formwork carpenter could help you with this (or any qualified farmer. They can build everything... ;-))

[hboli4]

Ok, I know it's sad to see concrete on a MTB trail but we have a very valid reason. The area on the koppie were we started to cut the single track some 6 years ago is very rocky with loose sandy soil in between. Whenever we used to cut a new piece of single track the cattle starts to use our paths because it is easier for them to get from their water trough to the other side of the koppie were the grazing is. Their hooves work all the soil loose between the rocks and it becomes unrideable even by the most skilled riders. The heavy summer thunderstorms, that Bothaville are renowned for, causes further erosion. We used to fill he soil back in every year, but it is a huge task hauling wheelbarrows up 30% gradients every time. Don't be fooled by the fact that it is concrete, it remains a challenge because of the winding of the track, the steepness as well as the fact that the concrete strips is less than 400 mm wide.

 

Unfortunately I don't have any SS experience so not sure what is doable and what not. But if you were able to ride 95% of Eden, I think you would ride 99% of Two River Challenge. We don't have any long technical climbs, but their are some steep parts. The longest I would guess is about 45 m. Most of the steep bits on the river banks is quite easy if you carry enough momentum. Momentum really is your friend in this race. What I am trying to say you will never have to hike a bike further than 45 m at the most.

 

We are still suffering the stigma that the severe technicality of our first two events have tainted us with, but like I said in a previous post the 65 km would be 99.5% rideable by any fit mountain biker of only average skill level.

 

Our observation over the past 7 years have been that the fitness and skill levels of the average mountain biker has been constantly improving, so that an obstacle that was a major challenge 7 years ago is now doable by the majority of the field.

 

Thanks for your reply!!!

 

Getting back to your original question (apologies for the derail), what are your other options or what did you do previously? Safety is paramount and I think it is a bit risky with less than 2 weeks to go to the event.

[Sniffie]

Thanks for your reply!!!

 

Getting back to your original question (apologies for the derail), what are your other options or what did you do previously? Safety is paramount and I think it is a bit risky with less than 2 weeks to go to the event.

Our race forms part of the 2 River festival. http://www.2riverfestival.co.za/ We are expecting thousands of people at the festival as their is a freestyle MX demonstration as well as a Breakfast run and lots of other entertainment. We managed to re-route the cycling through the school grounds, where the event starts and finishes, in a way that no motor traffic will be encountered. The only remaining problem is the crossing of the pedestrian walkway in the first photo. The only other alternative would be a couple of marshals controlling the pedestrian traffic. We expect very heavy traffic at this particular crossing, so marshaling presents its own dangers and difficulties. We have seen similar structures like the one we are planning, being fruitfully used at other events.

[Peach.]

Of course it was that one, why would I post it and say that?

OTB vs land to flat = broken neck vs broken foot

 

 

Because you thought it was a bad design for some reason?

or she did an OTB and land to flat head first!!!

freak accidents can happen anywhere and on the simplest stuff, believe me, I know.

[Sniffie]

The point with the solid balustrade was mentioned for a reason. If you come off the bike at speed the uprights of a normal open balustrade system become very dangerous for your limbs and neck. The Sani2C bridge is a good bad example. So apply some horizontal boarding between the posts to make it solid with gaps of 80mm or less.

 

With regards to risks of the steep descent to flat transition. If there is enough space making it a flat off-ramp would be the easiest. But if there is not enough space you also can form a radial transition at the bottom. A formwork carpenter could help you with this (or any qualified farmer. They can build everything... ;-))

Thanks! We are all farmers involved in this event! Better skilled at welding than carpentry though.

[Hairy]

Because you thought it was a bad design for some reason?

or she did an OTB and land to flat head first!!!

freak accidents can happen anywhere and on the simplest stuff, believe me, I know.

one of my hardest falls was coming off a pavement at slow speed

[Sniffie]

Paris has got the Tour de France and the Arc de Triomphe. Bothaville has the 2 River Challenge and the Arc de Two River:

[Odinson]

Paris has got the Tour de France and the Arc de Triomphe. Bothaville has the 2 River Challenge and the Arc de Two River:

 

I'm no bridge builder, but I'd add some reinforcement to that bad boy, to prevent any flexing.

[Hairy]

I'm no bridge builder, but I'd add some reinforcement to that bad boy, to prevent any flexing.

I agree with this and maybe some lateral support too .... looking closer at the pic it looks like the structure is bolted together?

 

The bracing would help prevent those legs, that appear to only be free standing on the paving, from kicking out under load.

 

I am no engineer, but more in the architectural game and selecting finishes ...... so my comments above could be off the mark.

 

Any engineers in the house that would not mind giving a comment?

[hayleyearth]

I agree with this and maybe some lateral support too .... looking closer at the pic it looks like the structure is bolted together?

 

The bracing would help prevent those legs, that appear to only be free standing on the paving, from kicking out under load.

 

I am no engineer, but more in the architectural game and selecting finishes ...... so my comments above could be off the mark.

 

Any engineers in the house that would not mind giving a comment?

 

I am also concerned about the fact that there is not 'foot' under the square tubing which stands on the pavement. That thing is going to move!

[Gen]

Paris has got the Tour de France and the Arc de Triomphe. Bothaville has the 2 River Challenge and the Arc de Two River:

Ooi.. hey the bridge at the end of the crater cruise broke the weekend.. Fortunately I was not on it when it went south.. and I am thinking of doing that 2 river challenge the weekend...[emoji15]

[Nibali]

I would suggest adding bracing in at least 2 bays, i.e. leaving one open for people to walk through. I also agree with Hairy with regards to lateral support, it will help the structure to not buckle as people cycle over it. Top and bottom lateral supports should be sufficient. The bracing plus the lateral support will then in essence stiffen the bridge in all directions. Hope this helps

[Cassie]

Weld some braces! And put a couple of haybales around...it always feels reassuring...