Rims / Tires for Spider Arachnid

[chaznaster]

Hi All. I am pulling together parts for an Arachnid build with my son. I’ve managed to figure out most of the parts but have a question regarding rims … I am hoping someone out there has built one of these and might shed some light …

For tires we are planning on 18x9.5-8’s based on the BMIKarts parts package. It seems they should be put on 8 (diameter) x 7 (wide), 4 on 4 rims. My question is whether the rim should be centered (3.5x3.5) or offset (3:4 or 2:5). Was planning on centered ones but do not want to get it all together and find the tires are rubbing.

Thanks for your insight!

 

[Denny]

Use what ever offset fits the kart the best. Or modify the kart to suit. Those plans are concidered fluid.

 

[chaznaster]

Thanks. We do plan for a roll cage and a few other customizations but still interested in what has been successful for others for rims.

 

[Denny]

Some use golf kart wheels with ATV tires. And some use ATV hubs, wheels and tires. I’ve even some with narrow tall trailer tires. Like I said your choice.

 

[ONE-EYE]

What's your axle size? Length? Rear frame width measurement? What style of brakes are you using? All this will come into play. You basically want to leave space for the tire to move freely without hitting anything else. Do you have any pics of the rear of your kart? Have you decided to go with tires on the axle or switch to the 4 on 4 lugs? I'd like to see the rear axle if you can.

 

[chaznaster]

Thanks One-eye. I am not building yet - just collecting parts.
So far:
Axle: 1 1/4” aluminum keyed 45in (need to double check the length - I am not near the parts just now)
Brakes: Disk
Wheel mounts: front and back 4 on 4
Rear Frame: (will be) 22.5”
Tires (planned): 18x9.5-8 (8x7 rim)

I realize I may be getting ahead of myself and should wait until I have the basic structure welded up …

 

[Denny]

That aluminum axle will not last. That is meant for a low to the ground pavement racing kart. Instead use a steel 1” fully keyed, solid axle. It will last way longer and be stronger.

 

[ONE-EYE]

Thanks One-eye. I am not building yet - just collecting parts.
So far:
Axle: 1 1/4” aluminum keyed 45in (need to double check the length - I am not near the parts just now)
Brakes: Disk
Wheel mounts: front and back 4 on 4
Rear Frame: (will be) 22.5”
Tires (planned): 18x9.5-8 (8x7 rim)

I realize I may be getting ahead of myself and should wait until I have the basic structure welded up …

Based on those measurements, you should be able to use whichever you like. The rear of my frame is 24"and I have a 40" steel axle. My rear tires are 20x10-8 with the 4 on 4 and drum brake (that mounts on the outside of the frame). With a disk brake (that you can move it if you have to toward the center verses the outside) you should have more than enough room I'd think.

 

[madprofessor]

use a steel 1” fully keyed, solid axle. It will last way longer and be stronger.

Ditto on the solid steel for strength. Ditto on fully keyed, being forced to locate parts wherever there happens to be some keyway is wrong on many levels. Ditto on it being 1", there's unlimited options for 1" sprocket carriers, brake discs, sprockets, etc., not so true for 1 1/4" flat track racing axles that bend on the first big hole or hump at speed.

 

[chaznaster]

This is all great info - thank you. Problem is I already bought the 1 1/4 and related kit. My inclination is to either run with it until it breaks or source a fully-keyed 1 1/4 steel axle. That way I can use all my parts. Does such a thing exist?

 

[Denny]

I have never seen that big of a steel axle. That does not mean they don’t exist, just I never seen or heard of them.