Wheel spacer question. Anyone running spacers?

[Lemming Train]

To keep things simple, if you are changing your wheels to a set with a higher offset by 6mm, should you fit 6mm spacers to maintain the centreline position of the wheel on the road to prevent any handling/driving feel issues?

The longer version is that I'm changing from ET39 4.5J wheels with 155/65/14 to ET45 5.5J wheels with 175/50/15, keeping the standard suspension. Because the wheels are an inch wider plus also an additional 6mm further into the arch due to the higher offset they come rather close to fouling on the strut and calipers so 3mm spacers are recommended by those that run the same wheels. But while this sorts out any fouling issues it means that the centreline of the wheel is still 3mm less than what it was, or an overall reduction in wheel track by 6mm across the car. Would this cause the car to drive and handle like a dog?

Am I missing something or shouldn't the spacers match the reduction in offset, not just be enough to clear the strut/calipers? In my case the wheels and tyres would still be contained within the arches with 6mm spacers, but handling/driving feel wise what difference should I expect between running 3mm and 6mm spacers?

Anyone experimented with this on your own car and if so what were your findings please?

[HustleRussell]

3mm is going to make zero perceptible difference. If you choose to fit 6mm spacers, ensure your bolts are still long enough- you want a minimum of 1.5D worth of thread engagement in the hub.

[designforlife]

I fitted 3mm spacers to the rear of my car just to bring the wheels flush with the arches, and it handles no differently whatsoever.

[Lemming Train]

HustleRussell said:

3mm is going to make zero perceptible difference. If you choose to fit 6mm spacers, ensure your bolts are still long enough- you want a minimum of 1.5D worth of thread engagement in the hub.

Thanks, yes I'm aware of the bolt length and they require different ones anyway as they need to be domed rather than tapered like the current ones. Also they require a hub centric spigot ring to bring the size down. But is there a reason why you'd only fit the minimum spacing to clear the strut/caliper/prevent any fouling rather than just get spacers that equal the distance in the offset reduction? What am I missing?

[AceOfHearts]

Lemming Train said:

HustleRussell said:

3mm is going to make zero perceptible difference. If you choose to fit 6mm spacers, ensure your bolts are still long enough- you want a minimum of 1.5D worth of thread engagement in the hub.

Thanks, yes I'm aware of the bolt length and they require different ones anyway as they need to be domed rather than tapered like the current ones. Also they require a hub centric spigot ring to bring the size down. But is there a reason why you'd only fit the minimum spacing to clear the strut/caliper/prevent any fouling rather than just get spacers that equal the distance in the offset reduction? What am I missing?

So the new wheels are an inch wider so 13mm either side of the centreline. 6mm offset difference means that the outside of the wheel will still be sticking out 7mm more than standard, and with a 3mm spacer this will be back up to 10mm more 'poke out' than the original wheels.

Maybe nobody fits bigger than 3mm spacers as the outside of the wheel is getting close to the outside of the arch?

Anyways 3mm is not enough to make any difference to the feel of the car so just do what makes you happy

[Scrump]

The new wheels will stick out by 7mm more but will also be 19mm closer to the suspension on the inside face.
If you really want to keep the centre of the wheel in the same line then you would need a 6 or 7mm spacer.
I wouldn’t bother unless you are going to have clearance issues on the inside face.
“Tire size calculator “ is a useful app (on Android) for this sort of thing.

[Lemming Train]

Yes, I have looked at the tyre size calculator sites already but none of them mention anything about spacers, offset and different driving characteristics if you don't get them right, hence asking for actual experiences from those who have experimented with them. The power steering assistance is already quite high and 'floaty' on these, probably not helped by the skinny 155/65 tyres. In my opinion they're so light they don't even need power steering. Part of the reason for fitting bigger wheels aside from the aesthetics is the wider and lower profile tyre apparently improves the steering feel considerably according to those who have done it, but I don't want to go wider than 175s because I've had previous experience with wide tyres on light cars and they can become a bit of a handful in heavy rain with aquaplaning if you're doing some speed. 175/50/15s are supposed to be the 'sweet spot' on these .

Another questiion :will the changes put the steering and suspension geometry out, requiring a fresh set-up? I don't want to find out in a few thousand miles that my tyres are wearing unevenly.

[anonymous-user]

I have 20mm spacers all round on my megane, it is used mainly as a track car. No adverse affects in the last 2years of thrashing it round tracks and tyre wear is wuite even.

[Robmarriott]

My Clio 182 left the factory with 7x16 ET45 wheels, I’m running 7x15 ET38 with a 10mm spacer (!) on the front and it doesn’t do anything weird at all.

[HustleRussell]

Lemming Train said:

Thanks, yes I'm aware of the bolt length and they require different ones anyway as they need to be domed rather than tapered like the current ones. Also they require a hub centric spigot ring to bring the size down. But is there a reason why you'd only fit the minimum spacing to clear the strut/caliper/prevent any fouling rather than just get spacers that equal the distance in the offset reduction? What am I missing?

I guess people probably fit the minimum they can get away with for strut clearance. If the wheel rim is noticeably proud of the wheel arch it may draw the attention of the MOT examiner who may fail it.

Lemming Train said:

Another questiion :will the changes put the steering and suspension geometry out, requiring a fresh set-up? I don't want to find out in a few thousand miles that my tyres are wearing unevenly.

Nah, geometry will remain unchanged and no adjustment from spec will be necessary.

[SlimJim16v]

It's to do with scrub radius, either + or - and whether you're increasing or decreasing it.
Reducing it reduces weight/feel and increasing it improves weight/feel.

That small amount will be negligible, but it depends on how your steering feels now and if you're happy with it.

Tyre protrusion is a C&U issue, but not an MOT issue.

[eloelcamerom]

Can anyone help me out?

Just fitted a set of staggered mv2s on my bmw with an offset of 47 on the front and 50 on the rear.

The previous factory set I had on had an offset of 31 all round so am I right in saying I need 15mm spacers on the front and 20mm on the rear?

[Scrump]

What are the rim widths of the original and new wheels?
What are you hoping to achieve with spacers: keep the centreline of the tyre in the same place, maintain the same clearance to the strut or maintain the same position of the outer face?

[eloelcamerom]

Factory rim size: 7
New rim size: 8 front/8.5 rear
And to answer your other questions, I'm just trying to match the new wheels with the old alloys to get the same offset so I guess I'm trying to get the same centreline. All this offset stuff confuses the crap out of me lol

[PositronicRay]

Scrump said:

What are the rim widths of the original and new wheels?
What are you hoping to achieve with spacers: keep the centreline of the tyre in the same place, maintain the same clearance to the strut or maintain the same position of the outer face?

https://www.willtheyfit.com/

[eloelcamerom]

I've gone onto the website and filled out my details but I'm not really sure what I should be looking at. Still not entirely sure what spacers I need 🤷‍♂️

[Scrump]

Fronts will need a spacer of 16mm to keep the centreline the same (in practice this means a 15mm spacer which is normal size). With a 15 or 16mm spacer the inside of the wheel will be 12.5mm closer to the strut and the outside edge will be 12.5mm nearer the arch. (12.5mm is half of an inch, so an inch wider in total).

Rears will need a 19mm spacer to keep the centreline the same (in practice this means a 20mm spacer). With this spacer the inside of the wheel will be 19mm closer to the strut and the outside edge will be 19mm closer to the arch. (19mm x 2 is 38mm which is 1.5 inches)

You may need larger spacers than this in order to stop contact with the strut, you also need to check clearance to the arch.

Looks like you got your spacer calcs correct.

[eloelcamerom]

Okay so pretty much that's what I want to achieve? Have the new alloys the same centreline as the old ones? Thanks for the help by the way