Topic: Wheel questions...

We are building an E12-based BMW 633 and are having trouble finding wheels. The criteria for our decisions are:

  • Wheels that will fit affordable tires (16" and 17" tires are most affordable)

  • Appropriate width for 225's (7 - 8" wide)

  • 5x120, 20mm offset, 72.5 center bore bolts right up but we can machine something to make a larger center bore wheel hub-centric

  • Not break the bank buying wheels

  • No spacers (wider spacers seem too sketchy)

That's leads us to three wheel sizes: 16x7.5, 16x8, and 17x8. There are a few BMW wheels that work coming from late 90's 7-Series. Obviously there are also (expensive) aftermarket options. Another option is to run a 20mm wheel spacer and use 3-series wheels with a 40mm offset, but we are concerned that puts too much leverage (?) on the hub/bearing.

Lastly, there are tons of 15" wheels that fit but tire options are limited to 205's, which we think are too narrow for a heavier car. I autocrossed the car on 205's, and it felt like we needed more grip. Admittedly, we have not set up the suspension yet.

Am I missing something? Any thoughts or suggestions?

Thanks,
bb

Re: Wheel questions...

Skip 15s they’re basically a dead size now.

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Re: Wheel questions...

Guildenstern wrote:

Skip 15s they’re basically a dead size now.

That's an important consideration. We don't want to buy additional wheels (we already have five 15" wheels) and not be able to buy affordable tires. That makes me wonder if 16's are on their way out, too. Should we shoot for 17's?

The problem we keep running into with bigger wheels is offset. Newer BMW's have 40mm-ish offset.

bb

Re: Wheel questions...

17X8 ET20 will have just as much leverage on the bearing as a 17x8 et40 with a 20MM spacer unless it has a convex face to it.  But check FB marketplace often  ive gotten 16 and 17s that fit your criteria for under 200$ and they both weigh less than 17lbs because aftermarket.

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Re: Wheel questions...

Guildenstern wrote:

Skip 15s they’re basically a dead size now.

That is news to me.  There are plenty of good tires in 15" sizes.  We run Hankook RS4s, but you can also get BFG Rivals, Dunlop Direzzas, Falken Azenis, and Maxxis.

Captain
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Re: Wheel questions...

VKZ24 wrote:
Guildenstern wrote:

Skip 15s they’re basically a dead size now.

That is news to me.  There are plenty of good tires in 15" sizes.  We run Hankook RS4s, but you can also get BFG Rivals, Dunlop Direzzas, Falken Azenis, and Maxxis.

As long as people race Miatas there will be 15 inch race tires.

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Re: Wheel questions...

VKZ24 wrote:
Guildenstern wrote:

Skip 15s they’re basically a dead size now.

That is news to me.  There are plenty of good tires in 15" sizes.  We run Hankook RS4s, but you can also get BFG Rivals, Dunlop Direzzas, Falken Azenis, and Maxxis.

agreed, i have 3 race cars on 15"s and I have 0 issue getting Hoosiers, Nitto's, RS4's for the Lemon, etc.....

Re: Wheel questions...

Guildenstern wrote:

Skip 15s they’re basically a dead size now.

On what planet?  SE30, SM, etc are all 15".  Theres plenty of options.

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Re: Wheel questions...

15's are pretty much only good for 205/50/15 if you want a lot of options, although you can get the 225/45/15 for some stuff like the RS4's.

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Re: Wheel questions...

I'm not going to claim to be an expert, but the wheel spacer was a concern of mine as well. The more research I did, the more it appeared that a properly mounted wheel spacer should not have any adverse affects on the hubs/bearings. The excessive hub/bearing wear information may be from people running massive spacers, but at the 25mm size I'm going to run I'm not worried. It's an '02 Crown Vic that will be on 17x9 et35 wheels with 255/40 17s.

Jeremy
Bourbon & Bad Choices Racing - 2002 Crown Vic

Re: Wheel questions...

We run 245-40/15’s... there are somewhat fat tires available on 15” wheels

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Re: Wheel questions...

VanillaHaze wrote:

15's are pretty much only good for 205/50/15 if you want a lot of options, although you can get the 225/45/15 for some stuff like the RS4's.

Basically this. You want a Spec Miata tire you're good, but try finding a middle of the road 15. I had 2 whole not super high performance summer tire options for my NA and both were crappy off brand tires. And then there were the old used set of 15's I had to buy on Craigslist for rollers for the T-bird before I got 16's then later 17's. It's either race or junk.

Mistake By The Lake Racing (MBTL)
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Re: Wheel questions...

billy bee wrote:

Another option is to run a 20mm wheel spacer and use 3-series wheels with a 40mm offset, but we are concerned that puts too much leverage (?) on the hub/bearing.

This is a popular misconception but if you think it through, you are not changing the stresses on the bearings or hub if the net offset difference is 0.  That said, finding quality bolt on spacers in 20mm is slightly harder than 25mm.

Now lets think outside the box.  if you are going bolt-on spacers, why not change to one of the most common bolt circles around and ditch the early BMW lug bolts, odd center bore size and less common bolt circle.  I would vote 5 x 4.5" but others will have other opinions.  This process costs a lot more in the converters (25mm adapters instead of spacers) as an upfront cost but WILL save heartache and likely money long term.

Re: Wheel questions...

OnkelUdo wrote:
billy bee wrote:

Another option is to run a 20mm wheel spacer and use 3-series wheels with a 40mm offset, but we are concerned that puts too much leverage (?) on the hub/bearing.

This is a popular misconception but if you think it through, you are not changing the stresses on the bearings or hub if the net offset difference is 0.  That said, finding quality bolt on spacers in 20mm is slightly harder than 25mm.

Now lets think outside the box.  if you are going bolt-on spacers, why not change to one of the most common bolt circles around and ditch the early BMW lug bolts, odd center bore size and less common bolt circle.  I would vote 5 x 4.5" but others will have other opinions.  This process costs a lot more in the converters (25mm adapters instead of spacers) as an upfront cost but WILL save heartache and likely money long term.


Not entirely true. While you can have a wheel that sits in the same spot edge of barrel wise, you do change the bearing stress anytime you add a spacer. When you draw out the force diagram on the hub/bearing, you have the weight of the car pushing down, the reactive force from the wheel supporting it, but you also have a torque because those two are not directly in line with each other. Torque in the direction of camber adjustment for lack of a better way to describe it.

As you move the mounting surface of the wheel outward, that torque load rises, even if the barrel edge of the wheel doesn't move. Think about it with an extremely unrealistic example, if you have a wheel that has an extremely convex face, something that moves the mounting surface out past the lip of the wheel. Then you add spacers to keep the barrel of the wheel in the same place it was before. There is now a very large upward torque on the hub. The normal force hasn't changed, there is still the same amount of weight sitting there, but because you've moved that mounting face, the torque has grown quite a lot.

Now, is it something to worry about with something like a 25mm spacer? probably not. But any spacer does increase that bearing wear by some amount.

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Re: Wheel questions...

http://www.bmwstylewheels.com/

weights, offsets, and specs all inclusive.      I'd just look for some E34 wheels  16x8 et 20 and if you find some lighter weight Kosei or blah blah blah you live in Cali land of cheap rust free BMW's.   Try being a BMW guy in the rust belt it sucks.