PCD Wheel Bolt On Spacer - solution

[AJSGSE1990]

For those wanting to fit a lower ET value wheel can I recommend bolt on spacer rather than normal spacers. I use these on my older cars including a 1988 race car (Lancia).

The spacer has 8 holes, four bolts fit the spacer to the hub, the other 4 the wheel to the spacer. I have used this site, and they have most in stock:

https://www.pcdparts.co.uk/products/whe ... cer-silver

However, I would highly recommend buying a set of 5/10/20mm normal spacers to test and get the lowest offset to fit your chosen wheel. The PCD spacers come at 30mm minimum, so for an ET60 your wheel should be ET30 max.

[Tuga2112]

just to clarify

is the idea to allow a broader range of wheels to the car while keeping the same geometry ? or something else?

[AJSGSE1990]

is the idea to allow a broader range of wheels to the car while keeping the same geometry ? or something else?

It's a better solution than a simple spacer, when you add a normal spacer the thread is unsupported for the length of the spacer and the bolt ends up being really long. Wheels with a PCD of 35 and below are plentiful, ET60 is a rarity according to what i have found up to now.

By the way, PCD 56.1 or 57.1 I see references to both!?!

Thanks.

[chrism]

Like Tuga, needing a bit of head-setting around both of your posts...

My '90 SE has 15 x 61/2J / PCD 4 x 100 / 56.6mm centre bore / offset ET +60 / 205 50 R15 tyres (I think you wanted to confirm this data, but I'm not aware of 14" m100 wheels )

Adding 'ET+' means pushing out the wheels, I think (ET- values are pulling them in...) so if I wanted to fit (say) ET45 MINI Rocket wheels to my m100, then I'd need a set of 15cm wheel spacers to bring the MINI tyres further out to the m100 ET+60 position. Then the wheel centres would be 15mm further out, but the tyres would be in the same position as before, hence I could keep the original 205 tyres? (but 195s would be a better bet?)

Just 'mulling' a bit

ps I've seen a third centre bore number of 56.6mm - others have mentioned 'dremmeling' the centre bores...
pps I now see your preference for that make of spacer, but on first inspection they're 30mm size. Do they do your 5mm/10mm/20mm options? The PCD spacers come at 30mm minimum - ah, sorry...

[AJSGSE1990]

ps a third centre bore number of 56.6mm - others have mentioned 'dremmeling' the centre bores...
pps I now see your preference for that make of spacer, but on first inspection they're 30mm size. Do they do your 5mm/10mm/20mm options?

Its getting more interesting by the minute! Three bore sizes now! I have a bag of spacers I just use to fit and test for clearance tyre -> suspension and caliper. I have ordered 26mm from another firm but they are custom and about 3 times the price. Cannot really go thinner than 26mm as the bolt heads need to fit. The point is that it much better than just sticking a 30mm spacer and a 30mm longer bolt. Also some wheel might have the same ET number but the required bolt length varies. Example:

Lancia Delta Integrale 8V 4 bolt
original design wheels ET30 require a 120mm bolt for a 26mm spacer (120mm don't normally exist)
Fiat 500 Abarth (same design more or less) also ET30 can use a 20mm spacer but only need an 86mm bolt

The Fiat bolt area is dished inwards, vs a flat design for the 80's original.

[dapinky]

Spacers will tend to make the offset worse not better.....

.... adding a 20mm spacer with a 48mm offset will result in a 28mm offset, taking the track an extra 40mm wider.

It needs to be further inboard, and thus removal of material from the hub, not adding to it (and that would weaken the hub or wheel too much if you took 20mm off it).

[AJSGSE1990]

Spacers will tend to make the offset worse not better.....

I'm confused, which is why I have a bag of spacers!

[AJSGSE1990]

Spacers will tend to make the offset worse not better.....

Have play with this:

https://www.willtheyfit.com/

[dapinky]

It doesn't matter which way you cut it, decreasing the offset will put the wheel rim further outwards, and adding a spacer will exacerbate the effect....

....from the site you reference, I have entered the OE Lotus wheels (orange) to compare with the {blue) Corsa alloys I mentioned previously (45 offset) and fitted with 205/40 tyres.

You can see that the OE wheel is further inboard than the Vauxhall wheel, and if you add a spacer it will sit even further out. The biggest drawback on doing it will be the chance of the tyre and the wheelarch rim coming into contact, which could cause anything from a bit of a paint scrape, to a blow-out.

The wheel without a spacer certainly looks better, and fills the arches nicely, but I can't see any advantage in fitting a spacer, and there are far more negatives than positives involved in doing so.

wheel offset.png

[AJSGSE1990]

IThe wheel without a spacer certainly looks better, and fills the arches nicely, but I can't see any advantage in fitting a spacer, and there are far more negatives than positives involved in doing so.

wheel offset.png

No no, you are right, I got it the wrong way round. The reason I posted that site is to see if a ET45 can be used, even found an ET48. Both about 2cm more protrusion.

[dapinky]

As I said, I used the +44/45 Vauxhall 17 7J wheels for a while, without any problem at all (it needed some plastic spigot rings to sit nicely on the hub), and didn't notice any problems on full suspension travel with 205/40 tyres...... not sure if 195 would be better, worse, or indifferent, same with 215....... but I wouldn't go wider or there is a chance of rubbing the wheelarch liner if braking and heavy cornering.

One thing to consider, is ensuring that the flexible brake hose is secured away from where any tyre may rub - possibly more thinking to do with a change, but it shouldn't be a problem.

I know many Elans which either run, or have run in the past, on 17" x 7J wheels of various offsets - the ones from the MINI are the closest offset to the Lotus, but the centre bore does need to be machined out just a tad to clear the hub.

[chrism]

So I tried the "Will they fit?" calculator using a hypothetical replacement of a 15" ET 60 m100 wheel with a 15" ET 45 MINI Rocket wheel and the app told me that it'd fit, but that the wheel + tyre would move 15mm towards the outside of the car - AJSGSE1990's protrusion - shown by the blue outline and agreeing with dapinky:-



So, no added spacers needed...perhaps a bit of bore dremmeling tho'.

[AJSGSE1990]

So, no added spacers needed...perhaps a bit of bore dremmeling tho'.

So what is the actual bore of the M100? This site has a reasonable database of car models:

https://www.wheel-size.com/

[chrism]

I agree that all the other info on that w/site is stuff that I've seen before - and confident to be 'correct' - so why wouldn't their bore size of 56.6mm be correct?:-



Incidentally, I now see where your 14" m100 rim size has come from. That's the first time I've seen a reference to 14" m100 rims and tyres for winter use!

(I'm assuming it's correct since all the other stuff seems to be...can anyone confirm?)

[AJSGSE1990]

(I'm assuming it's correct since all the other stuff seems to be...can anyone confirm?)

I've seen 57.1 and 56.1 quoted so just want to check. Need to make some decisions on the front brakes and wheels are a determinant.

Cheers,

Andrew.