Sandmobile Idea

sparkwizard

sparkwizard

#1
#1
Think about a snowmobile...Remove the skis and put tires on it. That has been done already.
Now, imagine two drive tires under the seat instead of the track system. Low pressure, waffle tread tires, maybe 145/70-6.
Now take that vision and put a mini bike seat mounted low , above both tires, engine in front of the seat, below the handlebars.
Maybe we could use a go kart front end because we really don't need all of that suspension. After all, we can see the obstacles before we hit them.(NO snow)
It should have running boards, fairly wide, and wide handlebars because the rider will need to use lots of body English to control the thing.
I have been thinking about building something like this for a long time. I am talking with my design team (Will is a gifted 10 year old) about some important things we will need like brakes and a siren. Paint color is also important to him. Red, White and Blue are very important to him.
If you can think of any design suggestions, please share. Any of you folks who have any actual snowmobile experience, please tell me this is stupid and unsafe before I get started.
Thank you. Dave
 
Ginz61

Ginz61

#2
#2
I think it all depends on what your drive train consists of. Snowmobiles accelerate violently and with no front suspension travel your steering tires would only be on the ground under braking and deceleration.Snowmobiles have roughly 12-18” of travel on the front suspension and “english “ steering works pretty good on snow. I don’t know if it would work as well on hard ground. Just my thoughts and I don’t think it’s stupid but maybe unsafe especially on the test runs.
 
sparkwizard

sparkwizard

#3
#3
We do not have access to 40 horse 2 stroke snowmobile engines, so violent acceleration is not a factor.
I am thinking maybe a governed 5 horse Briggs flathead with a torque converter. Top speed somewhere near 20 MPH for testing purposes.
Probably will never be able to get it to fishtail or get "loose" on the sand, so it will probably lift a front tire in turns. Should be great whole body exercise.
 
Augiedoggie

Augiedoggie

Well-Known Member
#4
#4
Recent posting here of a track bike reminded me of a build I saw years ago. A fellow cut the tread from a huge tractor tire and used it as a track and drove it from inside with modified steel rims with spikes welded to rim edges. Looked like a crude snowmobile track. Reckon it was a low speed machine as well. Perhaps 2 small truck or tractor tires could serve as tracks? The tread can be removed from nylon belted tires with careful use of razor knife
 
sparkwizard

sparkwizard

#5
#5
I think two low pressure tires would be less maintenance and a better ride when riding on sand. I prefer to get a good idea of the finished project before we start collecting parts. Now that we have a tubing bender, little Will thinks we need 10 projects going at the same time.
 
sparkwizard

sparkwizard

#6
#6
Both rear tires do not need to be mounted at the same height.
The front could be slightly lower, giving a shorter wheelbase when not sinking into the terrain.
OR, the rear could be lower, giving a longer wheelbase for less twitchy steering.
They could be mounted on a trunnion bearing so they are both equally in contact. ( Absolutely not my choice!)
But the trunnion could be selectable by the operator, which is an interesting idea.
It could be a short wheelbase, long wheelbase, or maybe floating both drive tires on the ground.
 
M

MJL

Active Member
#7
#7
Waiting on build pics! I’ve been thinking of a compact, lightweight (100ish pounds) 196cc powered snow capable kart for quite some time. The idea being it could go on a roof rack for a roadtrip to snowy climes. Best I have come up with so far would look similar to a drift trike but have some larger waffle tread tires for floatation and traction (studs would be cool, but probably dangerous). Maybe a bicycle front end...wonder how the concept would work in sand?
 
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Augiedoggie

Augiedoggie

Well-Known Member
#8
#8
I wonder if tandem axles with knobbies from snowthrower would work as well as a track. My Honda track snowthrower slips like a tire in low traction conditions. A track has more footprint on surface but won't dig down in sand like a grippy tire
 
sparkwizard

sparkwizard

#10
#10
Augiedoggie said:
I wonder if tandem axles with knobbies from snowthrower would work as well as a track. My Honda track snowthrower slips like a tire in low traction conditions. A track has more footprint on surface but won't dig down in sand like a grippy tire
Click to expand...
Sand would clog it, eat the track, and the track would not slide or skid. Just my thoughts.
 
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