GRRR
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| posted on 26/9/24 at 08:28 PM |
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Choices - Driveshaft, hubs and PCDs for a middy
Hi all,
Many moons ago I started designing my scratch built mid engined sport car. 20 years later Im starting to make some progress on the details, such is
life. Hoping to build up some momentum now and I'll post progress here as this site has been a regular go to for most of that time. LCB also
seems to have an unusually high number of clever and resourceful people on it, and I hope you can impart some of that with this issue.
Engine and transmission is Alfa V6.
My brake size calculations need roughly 280mm vented front, 280 solid rear.
I'm resigned to custom alloy wheels (like Image Wheels) as I want 16" in 7" width front, 8" rear and there's not really off
the shelf options I like. Therefore PCD choice shouldn't be a major issue but should match front to rear.
Minimising custom machining is preferable. I will design custom uprights to get the geometry I want so bolt on hubs is something that makes life
easier. Hubs with matching brake discs in the right size is also preferable.
Option 1, use alfa driveshafts, alfa hubs, which means having to work out the dimensions of the rear Alfa 156/166 knuckle/spindle to get new spindles
machined to mount on a custom front hub, using the rear alfa bearing on the front, and front alfa bearing on the driven rear.
Option 2, BMW Mini bolt on rear hub on the front, front hub on the rear and have custom driveshafts with Alfa one end, Mini on the other. Correct size
discs are available. A bit of googling suggests that after market Mini CVs are terrible quality though, and genuine are expensive.
Option 3, BMW mini bolt on rear hub on the front, Fiesta/Puma front hub on the rear, custom driveshaft, ST170 rear disc on the rear, hubcentric spacer
to convert Ford 4x108 to 4x100 to match the mini front. Cheap parts, but spacers are a bit of a bodge if everything is being designed with no
constraints (within reason)
Option 4 Mini rear on the front, Alfa front bolt on hub on the rear, with a custom hub machined to suit the alfa driveshaft but with a 4x100 PCD and
flange to suit a mini 280mm disc.
There's probably other options too but does anything jump out as being far more sensible than the others?
Thanks and sorry for the essay!
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gremlin1234
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| posted on 27/9/24 at 07:54 AM |
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I am surprised MX5 is not on the list
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GRRR
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| posted on 27/9/24 at 09:04 AM |
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I think i had discounted MX5 as most of the matching centre-bore rear discs are pretty small, but have just noticed there's 276mm discs available
which is probably close enough. On the MX5 fronts I'd need to machine a spindle for my uprights, and again off the shelf discs are available
little smaller than i wanted at 276 being the largest. The NC mx5 has 280mm rear discs but the rear hub and bearing don't seem to be a convenient
bolt on type.
I'll look and see if there's other mazda model discs in a good size with matching pcd and centre bore.
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nick205
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| posted on 27/9/24 at 09:26 AM |
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Nothing in the Audi stable worth a look?
No doubt parts might be more costly, but they might have the sizes you're are without having to machine them.
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JimSpencer
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| posted on 27/9/24 at 11:20 AM |
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Hi
Option 2, all day..
Not heard of the BMW Mini CV joint quality issue (original mini yes..) but a quick Google suggest that OE ones aren't 'that' expensive
to be worth spending a shed load of cash on custom components to avoid, I'd suggest a quick chat with somebody like Lohen would confirm one way
or another?
Hence, on option 2, the driveshafts being the only custom component make that the no-brainer for me as they're easily available from several
sources for not a lot of £'s.
HTH
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GRRR
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| posted on 27/9/24 at 12:09 PM |
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Thanks for the replies, Audi is a great suggestion as there's bolt on hubs front and rear and plenty of disc sizes, and parts prices are low.
Good to hear a vote for option 2 as well, I appreciate the input.
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