HELP! Launch ramp curve measurements?

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HELP! Launch ramp curve measurements?
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flag Dannyhxward
Posted: Apr 1, 2016 at 11:08 Quote
Hey guys im planning on building a 3ft tall ramp just to mess around with in the garden,
It was going to be 1.5ft wide x 3ft tall x 5ft long, i dont really know what im doing as far as measurements go so this was all guess work, i understand you get different amounts of curve to the ramp but i dont know how much curve id want and i also dont know how id mark it out on the wood, all help is apreciated Smile
flag Joegrant
Posted: Apr 1, 2016 at 19:13 Quote
I don't really have any suggestions per se, but if I was doing it, I would want to make an accurate plan of what I was going to build first.
Have you ever heard of Google SketchUp?
http://www.sketchup.com
It Is a free 3d modeling program that is very easy to use. Just download it from the website.
You should be able to get all your measurements using this program.
Hope I am helpful.
flag KingsgateDirtJumper
Posted: Apr 4, 2016 at 12:26 Quote
Width:
2 feet wide is better than 1.5, as a rule of thumb, shoulder width has a nice feel to it. Wider depending on speed.

Height:
3 feet tall? You prob don't want to waste time cutting any curve for that, just make it an easy-to-build flat ramp and feather in the curve with dirt. In fact, it would take less time to pile up 3 feet of dirt than to build it out of wood.

Read these:
https://www.pinkbike.com/forum/listcomments/?threadid=29852

https://www.pinkbike.com/forum/listcomments/?threadid=178880

Also post up photos of your before / during / after so we can get stoked and learn from your experience
flag cmc4130
Posted: Apr 7, 2016 at 12:03 Quote
The key with shorter ramps is they need to be mellower than you think. If a short ramp has the same steepness (i.e. degrees of arc) as a tall ramp, it will feel stupidly abrupt when your bike hits it.

Bijou Bike Park, Lake Tahoe
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For a 3 foot tall ramp, you probably should stick between 30 to 45 degrees of arc. A height that is half the radius length puts at around 60 degrees of arc. In other words 3 foot tall 6 foot radius would be 60 degrees of arc. But, that's still to abrupt for a short ramp (it's okay for a bigger ramp). So, I would do more like 11-14 foot radius and 3 feet tall. If it was a 5+ foot tall ramp, you could do 60-ish.

photo

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https://www.pinkbike.com/forum/listcomments/?threadid=29852&pagenum=87#commentid5031336
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Note that you can still do serious tricks even when a ramp does not go up to 70-ish degrees of arc. This one is probably only around 55.

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Greg Tait, Austin TX, photo by Octavio:
flag lyophilization
Posted: Apr 28, 2016 at 14:53 Quote
what CMC said. some terrain park builders use a rope tied loosely between posts to keep the right arc.
flag cmc4130
Posted: Feb 23, 2020 at 13:09 Quote
Flatter jumps tend to be better for full suspension bikes sending for distance.
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flag milesd2407
Posted: Feb 24, 2020 at 8:06 Quote
I have a 2 foot tall booter in my back yard and it has a 3.5-foot radius. I would say that is one of the best transitions for tricks. I got the plans from a 6 foot tall ramp with a 10.5 foot radius but I scaled it down. I have it a bit angled so the front is higher than the rear by about 3 inches.
flag cmc4130
Posted: Feb 24, 2020 at 10:08 Quote
milesd2407 wrote:
I have a 2 foot tall booter in my back yard and it has a 3.5-foot radius. I would say that is one of the best transitions for tricks. I got the plans from a 6 foot tall ramp with a 10.5 foot radius but I scaled it down. I have it a bit angled so the front is higher than the rear by about 3 inches.

Got any pics of it?

This one looks roughly 18" - 24" feet tall:

photo
flag IdahomeMTB
O+
Posted: Apr 18, 2020 at 14:01 Quote
Reviving this thread. It's got great info and I'd like to see it keep going.
One rule of thumb I typically try to follow is that most small to medium jumps should never be more than 1-3 ratio rise over run (ie slope). I see a very common mistake that beginning builders do is build small jumps at a 1-2 ratio which means a foot high jump is 2 feet long- basically an annoying speed bump for fast/skilled riders and a small but mighty OTB-kicker for the less skilled. Yes, you can have a jump at a 1-1 ratio (basically a quarter pipe) but that would be a very large and high skilled build. Most people should stick between the 1-3 and 1-4 with jumps under a 15' radius. Between the two, 1-3 well typically be a little boostier, more max height, typically better for tricks, and the 1-4 will be a lil sendier distance-wise and smoother. I should note that everything I'm talking about above is for trail bikes and DH bikes, not DJs.
flag Ilovedirtjumpingnotherstuff
Posted: Jul 14, 2020 at 22:56 Quote
I recommend using xtremeskaters website as the ramp calculator is very helpful, it allows you to see the radius and height before actually building the ramp.
flag cmc4130
Posted: Jul 15, 2020 at 6:31 Quote
Ilovedirtjumpingnotherstuff wrote:
I recommend using xtremeskaters website as the ramp calculator is very helpful, it allows you to see the radius and height before actually building the ramp.

That is pretty cool.

https://www.xtremeskater.com/ramp-plans/ramp-tool/
flag Stinkyriderjon
Posted: Jul 20, 2020 at 19:12 Quote
I did a 3' tall lift with a 10' radius, it works great, i made the same ramp as a landing it sends you pretty high and far. It took a couple run ups to send it because man it looks steep.
flag cmc4130
Posted: Jul 21, 2020 at 3:39 Quote
Stinkyriderjon wrote:
I did a 3' tall lift with a 10' radius, it works great, i made the same ramp as a landing it sends you pretty high and far. It took a couple run ups to send it because man it looks steep.

Got pics?
flag Stinkyriderjon
Posted: Jul 21, 2020 at 17:46 Quote
Not at the moment, but next time i go use it ill take some pics and post them. the ramp definatly sends you up more than out. If i did it again id keep it at about 45° and abot 2 feet tall. I think that would be better for up and out. I think i read somewhere that after 45° you start loosing distance and gaining height.in fact, i think i will do it again and update on this post
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