Offset vs. Spacers - Scrub radius affected?

[kam]

Track width.

Just thought I'd throw that in there...

[FireStorm999]

You're all saying the same thing.

This ffs. Painful read.

[Mike@TDSW]

This ffs. Painful read.

Innit!
Mitto without trying to be clever or over thinking it can you answer the op question?
Ie will a 9j et10 wheel have the same scrub radius as a 9j et30 wheel with a 20mm spacer?

[Munkul]

You're all saying the same thing.

just some with more words and diagrams than necessary, lol

[jankes]

Innit!
Mitto without trying to be clever or over thinking it can you answer the op question?
Ie will a 9j et10 wheel have the same scrub radius as a 9j et30 wheel with a 20mm spacer?

if its same wheel without different concave style/design then will be same scrub radius

[mitto]

FFS. I give up.

[Mr Bizzle]

Innit!
Mitto without trying to be clever or over thinking it can you answer the op question?
Ie will a 9j et10 wheel have the same scrub radius as a 9j et30 wheel with a 20mm spacer?

As a loose rule no, because the hub offset isn't the same. Most wheel manufacturers alter the wheel's structure to change offset - not just pack the back face of the wheel with more material (what you do when you fit a spacer)

[Mike@TDSW]

Ha come on bizzle, your first reply was yes then you've edited it.
It's obviously not as simple as it seems.
Your answer doesn't really explain why it doesn't equate to the same thing.

Fwiw whilst most wheels structures alter according to offset some do just pack out the mating face of the wheel.
Im fairly certain Rotas are one of them, for example a grid drift from et30 to et12. I've seen it on borbets, mims etc. Ie the wheel design /concavity / everything else remains constant but the back spacing alters.

[Robbs]

As a loose rule no, because the hub offset isn't the same. Most wheel manufacturers alter the wheel's structure to change offset - not just pack the back face of the wheel with more material (what you do when you fit a spacer)

on the same width wheel they do, the structure (spoke design) is normally only different on different width wheels.

[kevinLee]

For this question thread the answer is yes!

It's the same fitment! Et10 is the same as et30 with 20mm spacer. It's obvious. Just a couple people on here trying to be clever and make it complex imo

[Ade B]

I've seen it on borbets, mims etc. Ie the wheel design /concavity / everything else remains constant but the back spacing alters.

Totally agree. In the example in the OP it's exactly the same.

Why do people try and overcomplicate matters?!

[Andy_F]

Yeah... this was made to be way more complicated than my initial post was questioning.

I understand how offset works, obviously. I understand suspension geo also, obviously. I just have gaps in my knowledge when it comes to scrub radius - I knew the logic, but just wanted to double check. If I could increase the track width to achieve my desired result (basically to be able to fit wider wheels for wider tyres, and have clearance room on the rear face from the coilover body) then I would do that, but I'm not simply looking for spacing on my car, I need clearance.

[mitto]

For this question thread the answer is yes!

It's the same fitment! Et10 is the same as et30 with 20mm spacer. It's obvious. Just a couple people on here trying to be clever and make it complex imo

Of course it's the same fitment you plonker, nobody said otherwise... however it does not change the wheels offset, just moves the centreline of the wheel further away from the hub, altering scrub radius, akerman and various other steering and bump related things.

Basically, don't use spacers when you don't absolutley have to, because it's a shit idea

[mitto]

Why do people try and overcomplicate matters?!

because it is actually complicated. cheaper brands tend to use one mould and machine the offset to suit. More expensive brands use different moulds. Then of course you have 3pce wheels.

[Will.]

You have the spacer on the wrong side chumley.

[CIH]

Um, I'm confused. Scrub Radius is established by Camber and SAI. Offsets or spacers would reposition in the SR within the tyre contact patch but wouldn't actually make it larger or smaller. Atleast, that's how I understand it ?

[mitto]

LOL! principal is the same.

[mitto]

Um, I'm confused. Scrub Radius is established by Camber and SAI. Offsets or spacers would reposition in the SR within the tyre contact patch but wouldn't actually make it larger or smaller. Atleast, that's how I understand it ?

when the wheels are all pointing straight yes... now work out what happens on full lock.

[dale_b]

Of course it's the same fitment you plonker, nobody said otherwise... however it does not change the wheels offset, just moves the centreline of the wheel further away from the hub, altering scrub radius, akerman and various other steering and bump related things.

Basically, don't use spacers when you don't absolutley have to, because it's a shit idea

So fitting low offset wheels is a shit idea too? If your saying that running a spacer would make the same fitment as a low offset wheel then your saying that low offset wheels are a shit idea, surely?

[kam]

Spacer on the face of the wheel

An ET10 wheel or an ET30 wheel with a 20mm spacer is exactly the same thing.

The distance from the hub face to the centreline of the wheel will be the same for both.
No of course it doesn't magically change the ET of the wheel, but effectively in terms of geometry its THE SAMEEEE.

JAYSUS.