Tuesday, April 23, 2013

Basic Wheel Offset Solutions


Hey there... Lets look at some wheel solutions for that perfect "Stance".



How can I stuff the biggest/deepest rims under my rc body? the answer is always three fold; Tyre Sidewall/profile, Offset and Camber.

While some people don't like the latter, I am a proven believer that an rc "drift" chassis can run just as well with a lot or a little.  Anyway...




If you don't know the offset, just pad the spacers in the rear until the match the hub.


A 1/10 RC wheel is 52mm diameter and 26mm wide.

in RC

0 offset is actually a hub face of 5mm from the outside edge (usually) but these days it's better to measure 21mm from the back as different lips are being added.

0 offset allows 5mm for the hex nut to be fitted and still remain flush with the wheel rim.


the material around the center hole is usually 2mm thick. so lets check

far right is a Yokomo Drift Package Enkei NT-03  OFFSET +3 which is usually pretty stock on Yokomo.
there is a 16mm spacer to the rim flush +2mm of hub = 18mm .... 21mm-18 = OFFSET +3 or

5mm +3mm = actually 8mm to the hub face.

Track will increase 3mm each side over the Offset 0 wheel.


get your width of spacer again to the inside rim 

this white top line wheel is Offset 12.
there is a 7mm spacer to the rim flush +2mm of hub = 9mm .... 21mm-9 = OFFSET +12

the silver M-type wheel is offset 10 but it has an extra 1mm lip making it 27mm wide.

there is a 9mm spacer to the rim flush +2mm of Hub = 11mm .... 21mm-11mm = Offset+10
If you calculated this from the outside face lip it would be different.


Offset 0
Offset +3 Track will increase 3mm each side over the Offset 0 wheel.
Offset +12 track will increase 12mm over an Offset 0 wheel. 24mm total, this makes things more stable, so Settings need changing as this will also effect spring rates as the pressure on a wider location will change.

If you need more to fill say a 200mm body then add some spacers
or

I love those wheels but they are the wrong offset. ... the simple answer is spacers. The RC square spacer system runs from 4mm to 8mm with thick and thin shims that optionally screw together for strength and they are clamp hubs for good setting on the drive shafts. I thoroughly recommend this. You can go wider easily and adjust within 0.5mm. 

If you want to go narrower. There are a few 3mm spacers on the market from RC926 etc, but sometimes the shaft still only accepts 4mm, so you have to drill the wheel slightly. Also the wheel hub may touch your suspension so be careful. usually 4mm is the standard minimum.

For intermediate level users, increasing track width and scrub radius should start to be considered in setup.

As usual effecting one thing changes many others. so getting that exact look, may change chassis behavior. 


This is an example of my setup for my FC. At full compression the body is sanded to allow a almost zero gap to the tyre. It never rubs even as suspension arc rises. 4mm hub and +9 wheel with RC926 tyre.
This tyre has a round sidewall so I cant get any wider.

If I run Yokomo R2 in this config, there is no way they fit. +6 is about the best I can do as the sidewall is MUCH higher.



So sidewall is important and companies like Street Jam and RC-Art offer 60 degree and 45 degree stretch look tyres. so you can get an extra mm without touch.

These are  Kazama FXR +10 which are 1mm wider than the Top Line +9. Still no touch.


Then recently there are wheels from overdose, M's and topline that give more poke with an exposed rim.


These M's M-type +10 @ 27mm wide give an extra 1mm (only on the outer edge.) for a wider impression.


FXR +10 with Street Jam 45 degree + 7 degree camber


I also run about 7degree of camber on the reargiving about 3mm of extra clearance. (note a crazy 13deg on the front) all these things effect many other components like drive shaft length and turnbuckle lengths etc so changing camber can only go so far with stock components.

note** asphalt tyre wear is flat for full contact patch. On carpet you need to choose the tyre that best matches your camber and castor settings with more scrutiny.


M-type +10 with Street Jam 45 degree + 7 degree camber

There is still a gap for suspension compression.

You could simply buy a wider body, but we all want that perfect look and performance. sometimes they aren't compatible, but we try our best.

You can also look into adjustable suspension arms and knuckles to push wheels out or in to maintain track.
there are lots of products (like Active Hobby) on the market these days.

Russ.

 



2 comments:

  1. Hey! Nice explanation, very usefull! But, where did you got those wheel hubs for adding spacers? It's impossible for me to found them!
    Thx

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  2. I was following you until you didnt describe how physics come into the play, like why it matters to have a wider tire track for example. I can however find that information by other means but was hoping for a simple rc example explained here. Where you really lost me was when you started explaining spacers without explaining why or how or anything really other than inverting the numbers you originally started with in steps which made no sense to me. By default my 200mm shells are what ive always known to be what you go with, whether im running 5mm offset of 9mm offset rims it doesnt really seem to make too much of a difference other than how much it sticks out or out from or stays directly in from where the lexan lines up. I care less about aesthetics and more about how it affects the actual performance and will work aesthetics around that as practicality usually always wins out. I have confusion with why we have wheel hex hubs labeled as 3mm, 5mm, and 7mm offset and then we also find wheels that have other offsets. How do i find my actual offset when im working with 2 different things. When running my usualy chrome brakes as opposed to the screw clamped hexs i have no idea what the offset of those are as it never said what they were when i got them so i just eyeball everything. Anyways, i just wanted to say your article had me confused more so at some parts than others, and at this point im just entirely more confused about offset altogether than i was before lol. I think the problem might have been that you over explained your understanding of offsets in not a linear enough manner to follow, and you didnt start with what most ppl are understanding when they hear the word offset, which is their rims and nothing else. You could have gotten to all the measuring that im not gonna bother with later as i trust the numbers im given on packaging. Either way tho thanks at least for trying and i hope this helps in some way with your future writings and good luck

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