Gravity Racing

[Shaggy WGtech]

not sure if this should go here, but i cant think of anywhere else to put it.. it is made up from alot of bike parts so it probably fits well here.. but mods move it whereevr you feel its best suited.

i am a student at a motorsport engineering college, and one of our projects is to build and run a gravity racer. now this is no wooden soapbox that you make in your garage, we have aquired over £500 in sponsorship (a long way off the £20,000 lotus were romoured to have spent on their GR when they won a goodwood) but we are using the skills that we learnt in our lessons and the facilities we have available in our college to really push this thing forward...

this is the chassis that we were given to start the project off.
http://www.forum.the5thplace.com/forums/uploads/ph...

we have since had our chassis powdercoated (for free, sponsorship deal)
we also aquired some aerotube steel wishbones from a formular palmer audi, which we cut down and shaped into our own design..
http://www.forum.the5thplace.com/forums/uploads/ph...
i also designed & machined the wishbones myself from alluminium bar

at this moment in time (this morning) we have completed our steering arms and track rods. so the front end is almost complete (bar finding our best setup)

i have also designed our rear eprights and am waiting to machine them out. but am a bit busy fabricating parts to fit our rear wheels to the rear axle.

if you want i can keep you updated with pics and stuff.. sorry if i bored you. i just wanted to share it.

[groomi]

Looks like an interesting project. I've often fancied having a crack at somethign like this myself, but there doesn't seem to be much of a competition scene beyond Goodwood (invitation only) and the Red Bull stuff.

Keep us posted with pics and details.

Edited by groomi on Thursday 24th January 15:40

[Shaggy WGtech]

umm well there isnt so much of a league, but there are one off races. but i would take a guess towards them all being aimed at students and uni's

there doesnt seem to be much stuff on the internet for this either, not since goodwood got rid of it..

heres a few website:

http://www.engineeringyourfuture.com/grav_racer.ht...
http://www.formulagravity.co.uk/index.htm

[nervous]

drop me a line, I can almost certainly help you out.

[snotrag]

Looks great.

Hint - you wheels look like they weigh a fecking tonne.
And of course, we know that rotational weight is much worse than weight elsewhere. What size are they? Hard to tell from the angle of the photo.

But I'm pretty sure you could get a lighter wheel set up on there.

[Shaggy WGtech]

they are 23" i think on the front, and we got them slick tredded because we need them to be get alot of grip through the corners (we have got to go through a chicane flat out on not brilliant road surface) and the rears are bigger like mountain bike wheels that we have yet again slicked tires... although yes we could get lighter thinner wheels, but our budget wasnt large and we really needed big thick axles to take the loads on..

[snotrag]

Shaggy WGtech said:

but our budget wasnt large and we really needed big thick axles to take the loads on..

You might be interested to look up the Cannondale 'lefty' fork - the hub may be of use to you.

I wasnt sure whether grip was really going to be an issue.

[groomi]

snotrag said:

I wasnt sure whether grip was really going to be an issue.

On a smooth track grip shouldn't be an issue at all - narrow road bike tyres woudl be ideal. However, if the surface is crap (as the OP suggested) then a deeper section tyre like the slick mountain bike tyres fitted here, would help to absorb the bumps and keep better grip. Unless ofcourse you have very well controlled suspension...

[Shaggy WGtech]

i know that the track is a concrete slope that runs down a hill with a long right turn then followed by a chicane. and the track will have a lot of gravel and crap on it.. and very bumpy.. so not too good to be honest..

[groomi]

Hmmm... if there's loose gravel then you may be better with narrow tyres as the wide ones will just sit on top of the gravel which will then act as ballbearings and you'll have virtually no grip.

Ofcourse, this is all relative to how fast you'll be going in relation to the tightness of the bend and chicane.