Power Kite Forum

Building a Bigfoot Buggy

treblehook - 17-6-2010 at 08:16 PM

After attending Cinco this year on the Texas Coast.
It was plain to see (after taking many runs in Joe's Big foot
buggy..again thanks Joe ) that in the soft sands of summer,
Big foots are a must. Have read several posts on big foot conversions , store bought and home brews. With welding skills
and access to scrap pipe,,have decided to go the home brew route. figured tires would be the starting place , so I ordered the 21x12x8 Nanco slicks (3). next rims. I have read that the standard
4" x 8" rims will work with these tires . question: could anyone
point me in the direction of a supplier that sells the rims, bearings,
spacer, and valve stem ? also what psi is close to the norm for these tires? going to try to have the buggy ready for DBBB in Nov.
thanks,,, Herb

cheezycheese - 17-6-2010 at 09:06 PM

Try jellis or windofchange. They can hook u up.

DAKITEZ - 17-6-2010 at 10:33 PM

usually around 5 psi works with the big balloons. You will also need to determine what size bearing you need 20mm or 12mm.

rando - 18-6-2010 at 12:27 AM

"You will also need to determine what size bearing you need 20mm or 12mm"


What would be the performance difference between the two bearing sizes?

WIllardTheGrey - 18-6-2010 at 12:37 AM

The size of the axle, 20mm is thicker and stronger, 12mm is cheaper and lighter.

treblehook - 18-6-2010 at 06:20 AM

I am sure it will be 20mm in the rear. 15mm in the front.

Chook - 18-6-2010 at 07:04 AM

Yes build your own. It's a great project and very rewarding.

With 8" x 8" rims these tyres are 49mm wider, than when fitted to 4" x 8" rims. (I have a 4" rim on the front).
I have just made up forks, swan neck and rear axle to change from barrows to Big Foots.
Yet to try mine out as there isn't any wind.

Cheers Chook

awindofchange - 18-6-2010 at 11:45 AM

I would recommend putting 20mm on front and rear, that way you only have to carry minimal amounts of spare parts and it makes the purchasing easier. If you have any issues with any one of your tires, just swap it out instead of having to get one set of bearings for this tire and one set of bearings and wheel for those tires...

Just my opinion.

flexiblade - 18-6-2010 at 11:41 PM

When it comes to the larger race buggies the tires become the single most frustrating thing to deal with.

I. TIRES

1. Brands

- Nankang/Nanco bigfoots work but are not the best quality - the tire can be unbalanced and deformed causing elliptical wobbling - they are also 2 ply which is fine for beaches and grass - but use them on any hard surface and they will disappear pretty fast. Dimensions are 12x21x8 (12" wide - depending on the size of the rim - 21" tall and fit 8" rims. These are about $40 - $50 each.

- Carlisle "smooth operators" are a bit beefier with 4 ply and they come pre-grooved - which is commented on in another post about factory "casted" grooving versus "hand cut". I didn't see a price but would speculate them to be around $40 each. These seem to be the best bet for the money - but I have no experience with them.

- Eurotrax and Cadkats - I lump these two together based solely on their cost - around $150 - $180 each (I don't know what the shipping would be from Europe or if they are even available from a US distributor) with plastic rim included. These are most likely the best quality you could get but only if you can get over the sticker shock - $450+shipping for a set of 3 tires.

II. Rims

1. Bearings

- When building your buggy you always have to keep the size of the bearing as your guiding principle, it always comes back to this - ID and OD. Your ID (inner diameter) determines your axle end sizes (the part that goes through the bearings) - in this case it sounds like 20mm (good call - I run 3/4" and 20mm comes in a little bit bigger than that) - you have to then sleeve that 20mm into another pipe and then another pipe to get an axle that is beefy enough to handle the torque and pressure you will be hammering it with. The OD (outer diameter) determines what rims the bearings will work with. I don't know how metric rims work - but if its anything like standards they can be a pain in the but when dealing with larger ID's.

2. Rim Sizes

- There are rims that come in both 4x8 or 8x8 configurations (4x8 8" tall with a 4" distance between rim lip to lip - the 8x8's are 8" from lip to lip). I found that crushing a large tire onto a small 4x8 rim tends to compress the side walls into ripples and will create a very unbalanced tire. I would say always go with a big rim for a big tire.

3. Golf Cart Rims

- Golf cart rims are nice in that they are cheap - $20 each or free if you have a hookup at a golf course. Golf cart rims are not nice in that they are set with a four hole mounting assembly that has to be overcome with a 4 lug adapter with a a center bore for bearings (I have no idea if they come with 20mm bores for these things - they can cost around $40 a piece and be very crappy as far as being aligned properly.



I'm sure that you'll find what you need to make it happen - just letting you know some of the pitfalls before you stray to close.

Happy building to you.

Krohn1999 - 19-6-2010 at 12:39 AM

Don't forget Duro tires.
They are just like the Nankang only the Quality is way better. I have a set here that run just as smooth as my Eurotrax.

Have fun building
Chris
P.S. go with 20mm axles all the way around.

popeyethewelder - 19-6-2010 at 04:34 AM

20mm all round for bigfoots is best

Kenda Beach racers also, pregrooved..

treblehook - 19-6-2010 at 08:07 AM

so far have the (3) 21x12x8 Nanco slicks ordered
$101.94 shipped.
(3) 4x8 plastic rims w/ 15mm bearings & spacers.$80.00 shipped.
one mistake so far,,I did not order axle bolts for I thought I could
buy them locally. looks like that is not the case. found that 15mm is not a shelf item. saw a 15mm x10" motorcycle AXLE for $12.95 online ,but feel sure that will have to be
more like 12 to 14 inches for the front axle and 6" bolts on the rear..don't like the idea of sleeving 9/16.
so might need some direction there. Understanding the many ways to go about Buggy building (appreciate all input) but being a poorboy with a kite buggy addiction on a budget has its limit's.
I feel safe to say that with all the resources here in the forum,
and a few skills on my behalf , I will meet the November goal.
On Popey's home brew site(http://pic7.piczo.com/Popeyethewelder/?g=41859403&cr=7 ,buggy 349 is my current ride (home brew by Ted Dougherty) inspiration and vision for the new buggy 205,267,280,301 and 399.
any input on the 15mm bolts ??? Thanks .........Herb:singing:

flexiblade - 19-6-2010 at 08:51 AM

At least you got things moving - starting can be the hardest part. Now you have to deal with the problem of living in the states: most hardware stores (the most convenient place to pick up parts) deals mainly with standard sizing - it does have some metric, but not the selection that standard offers. Mixing the two (standard and metric) will leave your bug with clinks and clanks here and there (a little duct tape in the right place as a spacer in between spacers can help that) but getting things to be smooth and well fitting is just nice. Do you have any plans drawn up?

P.S. regarding your question earlier about tire pressure - I have found this to be very true - it all depends on the consistency of the sand you are going to be running on. Soft dry sand = low tire pressure 5-8 psi for the nankangs. Hard wet sand = stiff tire pressure 12 to 18psi (I have inflated these tires to about 35psi for mounting)- a few times I ran low tire pressure on hard wet sand and found that when I was trying to break traction around corners the tire would stick and momentum would throw the buggy up on 2 wheels - cool trick unless your trying to turn at 25mph.

treblehook - 19-6-2010 at 09:20 AM

Have a rough sketch of axle width ,and stretch ft to back.side rail
width and hight..Waiting on tires then will make a cardboard template.. Herb

cheezycheese - 19-6-2010 at 09:37 AM

I was able to find steel rod in metric size from Mccarr/Master. Call them they have 15mm should be less than 15bucks. Just be VERY specific that it is for an axle and that you need a rod with .000 tolerance. The first rod I ordered did not fit because ofthis oversight. Then
thread them yourself of get a machinist to do it...

treblehook - 19-6-2010 at 10:21 AM

that was what i was thinking....believe i can get the 6" bolts
front axle ..custom Herb

cheezycheese - 19-6-2010 at 11:59 AM

McCarr/master should have the bolts also. Check 'em out online, they have everything.

treblehook - 4-7-2010 at 12:33 PM

tires and rims arrived ....got um mounted
bearings size changed at the 11th hour to 20mm all around
Thanks Angus. I will pick up all the 20mm hardware on Tuesday.
Been thinking about either a standard fabric seat or a store bought lawn tractor type seat ( like flexiblade's Lay-Z-Boy bug)
The lawn tractor seat would be an easy install . but my thoughts go to::: black vinyl , hot in summer sun:: steel bottom and back ,,
salt water and rust...
pros or cons ?
progressively moving along
toward soft sand bugging :singing: Herb

rocfighter - 4-7-2010 at 12:40 PM

Willard what have you been reading now??? And do you have your towel? you never know. :dunno: D.A. we miss you.
(end of hyjack)

WIllardTheGrey - 4-7-2010 at 02:02 PM

Just got done reading "So long and thanks for all the fish" for the um-tenth time.:rolleyes:

RIP Douglas.


Sand-Yeti - 7-7-2010 at 02:42 AM

My preference is 20 mm rear & 15mm front axle.
My rear wheels are assymetrics and I use a BF light on the front. The the rim on the front has bearings with an I/D of 20 mm but use a couple of top hats so that the 15mm dia front wheel axles fits well.

I carry two spare BF lights with 20mm I/Dia. bearings in my buggy trailer. In the event I get a puncture, the BF light fits on both the rear and front .
My latest Buggy the Sand Shocker is built like this.




Note that the rear axle looks massive but is extremely light as it is a carbon composite construction .

cheezycheese - 7-7-2010 at 02:51 AM

Herb, how is your build coming...? Any pics..?