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z31maniac
z31maniac MegaDork
7/19/18 6:41 a.m.
81cpcamaro said:
z31maniac said:
Stefan said:

In reply to z31maniac :

BTW, Ford uses 5x108 on a lot of their cars (like my Focus), I suspect Jag used the same pattern when they were under Ford's umbrella.

Yeah, and I think Chevy still does 5x120.65, and Subaru has/had some 5x100 cars like my old BRZ.

Chevy has two patterns now, 5 x 120.65 for the Corvette and 5 x 120 mm for the Camaro (5th gen & up), G8, SS and GTO.

That's interesting and seems, ahem, unneccesary.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/19/18 9:14 a.m.

Most engineers are not as smart as most non-engineers have been led to believe.

Most OE engineers are not as stupid as non-engineers seem to believe.

TheRX7Project
TheRX7Project Reader
7/19/18 10:54 a.m.

I just want to go back in time and beat up whoever made the decision to make the 1st-gen RX7 have a 4x110 bolt pattern. Talk about limited wheel options.

If they ever create a real Holodeck, I'll be there beating a hologram of this guy up.

java230
java230 UltraDork
7/19/18 11:21 a.m.

Try a 10x225. Yeah you get Brodozer rims (and only two actual ones that fit....), Full custom or OE. I feel your pain.

purplepeopleeater
purplepeopleeater Reader
7/19/18 11:45 a.m.

In reply to frenchyd :

The aftermarket makes a lot of hub adaptors cheaply. Most cars are wheel centric so the wheel is centered on the hub. This is an issue for wheel manufacturers because it's much more cost effective to make wheels with only 2 variables (bolt pattern & offset) than to make smaller batches of wheels to match 3 variables. There's no profit in them but talk to a knowledgable aftermarket wheel salesperson.

 

Driven5
Driven5 SuperDork
7/19/18 1:33 p.m.
Keith Tanner said:

Most engineers are not as smart as most non-engineers have been led to believe.

Most OE engineers are not as stupid as non-engineers seem to believe.

In my professional (engineering) experience, the industry has little to do with it.

nderwater
nderwater UltimaDork
7/19/18 3:19 p.m.
Stefan said:

In reply to z31maniac :

BTW, Ford uses 5x108 on a lot of their cars (like my Focus), I suspect Jag used the same pattern when they were under Ford's umbrella.

Online sources say my 2010 Jaguar XK wheels are 5x108, 63.4 bore, offset 27, on 12x1.5 lugs
Online sources say the 2017 Focus RS wheels are 5x108, 63.4 bore, offset 50, on 12x1.5 lugs

Tirerack shows 7 wheels available for my XK and 238 available for the Focus RS.  What am I missing? Anything that 25mm spacers can't solve?

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/19/18 3:29 p.m.

The offset. +50 is a typical FWD offset, and there are a lot more FWD cars out there. You can probably solve the problem with spacers, but Tire Rack isn't going to suggest that.

Driven - I see a lot of automotive enthusiasts deriding how stupid the OE engineers are because they left horsepower on the table or didn't put in the bigger engine or made the rear spark plugs inaccessible. But knowing what they have to do, it's the enthusiasts who are missing the actual details. There are a lot of constraints put on the OE designers that we ignore in the aftermarket. I specified the automotive industry because that's the one I have the most experience with, I'm sure the same thing applies in the alarm clock enthusiast groups.

Knurled.
Knurled. GRM+ Memberand MegaDork
7/19/18 7:46 p.m.
TheRX7Project said:

I just want to go back in time and beat up whoever made the decision to make the 1st-gen RX7 have a 4x110 bolt pattern. Talk about limited wheel options.

If they ever create a real Holodeck, I'll be there beating a hologram of this guy up.

 

It's only the same bolt pattern that they used since the 1960s, what's the problem?

 

What is annoying is that RX-7 cross wheels do not fit over RX-3 brakes.  Somehow the calipers (clamping solid rotors) that look exactly like the ones on a '91-03 Escort stick out too far and hit the spokes.  This ruins my ability to run waffles.

 

 

Knurled.
Knurled. GRM+ Memberand MegaDork
7/19/18 7:56 p.m.
Keith Tanner said:

Because an engineer said "you know, we could make it better if we changed this one parameter".

More like, an engineer threw a dart at a dimension 60 years ago, and industrial inertia is a helluva strong force.

 

The Chevy LT5 engine (the DOHC engine in the ZR-1) was hamstrung for power because Chevy insisted, INSISTED, that it have the same bore spacing as the three-man team of engineers knocked together in a few weeks in 1954.  Because.... reasons, i guess.  It's not like it was being built on the same machining lines as the small-block, or shared any parts anywhere at all.   Lotus originally penned it with a wider bore spacing, Chevy execs said no.

 

How many Ford engines have the same bore spacing?  The Y-block, Windsor, Cleveland, and two different series of inline sixes all have the same bore spacing.  IIRC the 3.8/4.2 V6 shared it as well.  Why?  It was pre-existing.

 

How many VWAG engines share the 88mm bore spacing of the four cylinder engine from the very first Rabbit (or was it the Dasher)?  ALL OF THEM.  Fours, fives, V6s, V8s, V10s.  All on 88mm bore spacing, except for the 4.2V8, which had 92mm bore spacing... but 88mm bore spaced heads, because then they could keep using the old tooling.  Only the VR style engines are different... and all of THOSE are the same, be it VR5 or VR6 or W8 or W12...

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