Granada uprights
- Thread starter mickky3
- Start date
Mickky3,
For what it is worth ......
After 103 races, not sprints, hillclimbs or trackdays, and mounted with four pot Willwoods, vented disks and bells and knock-on hubs and BRM wheels i have never ever had even a hint of knock back or spindle flex. Front wheel bearings and seals still as good as they were 10 years ago. Believe me my poor old 40 has been pushed hard and to the limit in every race and has several excursions in its time.
Some may damn and curse them but for my part they have been brilliant and so resiliant.
Graham @ GTA Racing with Gulf Oil UK.
For what it is worth ......
After 103 races, not sprints, hillclimbs or trackdays, and mounted with four pot Willwoods, vented disks and bells and knock-on hubs and BRM wheels i have never ever had even a hint of knock back or spindle flex. Front wheel bearings and seals still as good as they were 10 years ago. Believe me my poor old 40 has been pushed hard and to the limit in every race and has several excursions in its time.
Some may damn and curse them but for my part they have been brilliant and so resiliant.
Graham @ GTA Racing with Gulf Oil UK.
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A bit of an old thread I know but wtf.
Has anyone considered other more modern replacements for the Granada Mk2 front hubs?
Such as from other double wishbone RWD cars such as the Honda S2000, Nissan 350Z, Mazda RX-8 or (new) Mazda MX-5 etc?
While I ended up going for buying a chassis which will have Granada MK2 front hubs (or something close) I'd originally looked at using RX-8, from having the two side by side they are a million miles away, the RX-8's are designed for a low (although not GT40 low) good handling sports car with huge 323mm brakes the granada's er aren't.
RX-8's being rotaries tend to blow up by about 50k so there are plenty around and seem to go for about ~£30/side on ebay.
Down side is the RX-8's uprights are huge in comparison, the lower joint is the opposite way round to the granada and the rears don't have separate bearing carriers so can't use them easily. Upside is you might be able to use the upper wishbone as its quite a nice little alloy item.
Anyway as I said, a bit pointless should you already have granada upright designed wishbones, just a thought for those scratch builders given how granada mk2 hubs are getting rarer.
Has anyone considered other more modern replacements for the Granada Mk2 front hubs?
Such as from other double wishbone RWD cars such as the Honda S2000, Nissan 350Z, Mazda RX-8 or (new) Mazda MX-5 etc?
While I ended up going for buying a chassis which will have Granada MK2 front hubs (or something close) I'd originally looked at using RX-8, from having the two side by side they are a million miles away, the RX-8's are designed for a low (although not GT40 low) good handling sports car with huge 323mm brakes the granada's er aren't.
RX-8's being rotaries tend to blow up by about 50k so there are plenty around and seem to go for about ~£30/side on ebay.
Down side is the RX-8's uprights are huge in comparison, the lower joint is the opposite way round to the granada and the rears don't have separate bearing carriers so can't use them easily. Upside is you might be able to use the upper wishbone as its quite a nice little alloy item.
Anyway as I said, a bit pointless should you already have granada upright designed wishbones, just a thought for those scratch builders given how granada mk2 hubs are getting rarer.
Adding to my previous post.
RX-8 (MX-5 very similar)
(new) MX-5 (RX-8 very similar)
S2000
KPI should be much better as designed for 225's tyres (in the case of the RX-8) ackerman may not be ideal as the RX-8 is much longer wheelbase but that IIRC that only makes it a bit less stable and more 'flickable'.
I take it back about the 350Z btw, its not suitable.
RX-8 (MX-5 very similar)
(new) MX-5 (RX-8 very similar)
S2000
KPI should be much better as designed for 225's tyres (in the case of the RX-8) ackerman may not be ideal as the RX-8 is much longer wheelbase but that IIRC that only makes it a bit less stable and more 'flickable'.
I take it back about the 350Z btw, its not suitable.
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Hi David
swapped mine to TVR Cerbera uprights came with discs and AP 4 pot calipers, a straight swap without modifying wishbones on my car which was based on a gtd setup. Have attached before and after I have bought a couple of pairs for @ £200 a pair with discs and calipers.
Forgot to say they are aluminium with steel top and bottom mounts which can easily be modified, hubs are Jeep easy to get bearings etc
swapped mine to TVR Cerbera uprights came with discs and AP 4 pot calipers, a straight swap without modifying wishbones on my car which was based on a gtd setup. Have attached before and after I have bought a couple of pairs for @ £200 a pair with discs and calipers.
Forgot to say they are aluminium with steel top and bottom mounts which can easily be modified, hubs are Jeep easy to get bearings etc
Attachments
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Hi Mark,
They look intresting...a couple of questions...
What diameter are the discs
Will 15" wheels fit on them
Are the control arms, the same height is the Granada
Are they lighter than the Granada uprights
Thanks
mick
They look intresting...a couple of questions...
What diameter are the discs
Will 15" wheels fit on them
Are the control arms, the same height is the Granada
Are they lighter than the Granada uprights
Thanks
mick
R3 is slightly different from the original (although meant to be slightly better handling), its going to be rarer if you're looking for bits, I have noted for the standard version:
Front Track 1496 mm / 58.9 in
Rear Track 1506 mm / 59.3 in
Also have these details which may or may not be of interest (from http://www.grabercars.com/phpbb2/viewtopic.php?p=1391&sid=cfc9106160dec1f2eebcbdb546936b96 )
RX-8
Front suspension
roll centre height 68mm
upper arm 8.46 inches
lower arm 13.35 inches
Rear suspension
roll centre height 96mm
upper arm 11.4 inches
lower arm 20.83 inches
Also MX-5 / Miata
Front suspension
roll centre height 61mm
camber gain in bump 0.91 degrees per inch mean rate
Scrub radius is zero
Rear suspension
roll centre height 120mm
camber gain in bump 0.21/0.58 degrees per inch initial/final rate
Passive rear steer toe in under cornering loads
Roll at 0.7g is 3.4 degrees (4.9 degrees per g)
Suggested suspension settings-
Static camber –0.625 front / -0.875 rear
Castor more than 5 degrees
Toe in 1/16inch front and rear
Not quite sure on those last two figures for the front/rear on the RX-8, they could be arm lengths but the rear is multi-link so it doesn't make a lot of sense.
Front Track 1496 mm / 58.9 in
Rear Track 1506 mm / 59.3 in
Also have these details which may or may not be of interest (from http://www.grabercars.com/phpbb2/viewtopic.php?p=1391&sid=cfc9106160dec1f2eebcbdb546936b96 )
RX-8
Front suspension
roll centre height 68mm
upper arm 8.46 inches
lower arm 13.35 inches
Rear suspension
roll centre height 96mm
upper arm 11.4 inches
lower arm 20.83 inches
Also MX-5 / Miata
Front suspension
roll centre height 61mm
camber gain in bump 0.91 degrees per inch mean rate
Scrub radius is zero
Rear suspension
roll centre height 120mm
camber gain in bump 0.21/0.58 degrees per inch initial/final rate
Passive rear steer toe in under cornering loads
Roll at 0.7g is 3.4 degrees (4.9 degrees per g)
Suggested suspension settings-
Static camber –0.625 front / -0.875 rear
Castor more than 5 degrees
Toe in 1/16inch front and rear
Not quite sure on those last two figures for the front/rear on the RX-8, they could be arm lengths but the rear is multi-link so it doesn't make a lot of sense.
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The 90-97 MX-5 I believe to have an KPI/SPI of 11º 20’ I don't know if that's the same as the newer one though. I also don't know which version the information above is from.
Visually the 2006+ MX-5's hubs/uprights are identical to the RX-8.
The RX-8 has a KPI/SPI of between 10º 52’ and 11º 02’ depending on if on 'normal' or 'sport' suspension setup. See http://www.williamperrine.com/RX_8_Manual_PDFs/9Suspension.pdf for *all* the RX-8 settings/measurements.
Also take into consideration that reducing tyre dia will also reduce the overall width (assuming you use the correct offset) *and* track if you want to keep the scrub radius the same. I don't know if anyone uses 18 inch tyres (std RX-8 size is 18*8JJ) on a GT40, I certainly thought they'd be a bit much.
Visually the 2006+ MX-5's hubs/uprights are identical to the RX-8.
The RX-8 has a KPI/SPI of between 10º 52’ and 11º 02’ depending on if on 'normal' or 'sport' suspension setup. See http://www.williamperrine.com/RX_8_Manual_PDFs/9Suspension.pdf for *all* the RX-8 settings/measurements.
Also take into consideration that reducing tyre dia will also reduce the overall width (assuming you use the correct offset) *and* track if you want to keep the scrub radius the same. I don't know if anyone uses 18 inch tyres (std RX-8 size is 18*8JJ) on a GT40, I certainly thought they'd be a bit much.
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After considering the TVR uprights I've discovered there are two different versions, the older ones with about 11 degrees SAI / KPI , and the later (2001+) with about 6 degrees SAI / KPI. There is an intermediate upright which is drilled for both. The TVR's aren't well regarded for their front end handling, IMO that's mostly due to a combination of high scrub radius and bump steer.
There is also a difference in the brakes, later ones have AP Racing CP6600 calipers and 323mm discs early ones I believe are CP5200 and require a spacer to use the larger discs.
I'm not sure about the earlier ones but with the later ones there is significant positive scrub, the originals are I believe ET40 offset 18in wheels. I calculated that to go with the 225/40R17 tyres I was considering I'd need about an ET70 to get zero scrub.
I bought some '05 TVR Tuscan S uprights/hubs which I was thinking to use but now I'm not so sure, it's going to be a pain to get the scrub anywhere near decent.
There is also a difference in the brakes, later ones have AP Racing CP6600 calipers and 323mm discs early ones I believe are CP5200 and require a spacer to use the larger discs.
I'm not sure about the earlier ones but with the later ones there is significant positive scrub, the originals are I believe ET40 offset 18in wheels. I calculated that to go with the 225/40R17 tyres I was considering I'd need about an ET70 to get zero scrub.
I bought some '05 TVR Tuscan S uprights/hubs which I was thinking to use but now I'm not so sure, it's going to be a pain to get the scrub anywhere near decent.
David, i have been playing about with some fd35 Mazda uprights for another project. They run zero scrub with correct mazda wheel offset and come with an ali fourpot caliper. Mx5 lower balljoint fits them .Excuse the state of them that is how they came.The hubs also have enough meat on them to redrill to a different pcd but they are close enough for the wobbly wheelnuts to work.
Bob
Bob
Good shout. Mid-engined reasonably powerful (276hp) RWD about the right weight (1000-1300Kg) with good size wheels(16 or 17in)/tyres (225 or 235)/brakes (294 or 314) that's well known for being a superb handing car.
Do you know the KPI on them?
I believe the RX-7 is 114.3mm/5.
Bit rare unfortunately but I'd imagine potentially still available new as they've (only!) been out of production 11 years.
Do you know the KPI on them?
I believe the RX-7 is 114.3mm/5.
Bit rare unfortunately but I'd imagine potentially still available new as they've (only!) been out of production 11 years.
They are not expensive and are easily found, from memory they were £75 for the pair complete off the bay of thieves. I will put a stick of inches over them for you and measure the kpi .
http://www.ebay.co.uk/itm/RX7-Mazda...arts_Vehicles_CarParts_SM&hash=item232ca8b5f4
Bob
http://www.ebay.co.uk/itm/RX7-Mazda...arts_Vehicles_CarParts_SM&hash=item232ca8b5f4
Bob
Interestingly enough while I'd mentioned it earlier while I was looking at suspension geometry I overlaid the RX-8 front suspension mounting points (which I just happened to have from a previous musing) with my model of the GTs40. While they don't line up, they're close enough that if you were doing a scratch build on a budget laugh grabbing the whole front end (rack, arms, uprights, brakes) would really not be a bad place to start and would gain you a touch of extra foot room too. Extra 2in track on the 'originals' which shouldn't be significant to affect anything.
Downside is non-replaceable ball joints in all the arms and they're not cheap (~£200 per arm).
laugh grabbing the whole front end (rack, arms, uprights, brakes) would really not be a bad place to start and would gain you a touch of extra foot room too. Extra 2in track on the 'originals' which shouldn't be significant to affect anything.
Downside is non-replaceable ball joints in all the arms and they're not cheap (~£200 per arm).
FDs hubs I have here are 10 deg kingpin inc. as best I can measure with a protractor and rule.
Bob
The best KPI angle I have found for the GTDs is 14.7 degrees, but of course that also supposes that the wheel offsets , ackerman etc etc all work together, Frank
Mike Pass
Supporter
Don't forget to check for bump steer when mixing and matching various bits and pieces. If your steering arms are a different length than your wishbones the arc they move through will be different and the effective length change will also be different and this can lead to bump steer. If the steering direction changes as the suspension moves up and down then you have bump steer and the car will be nasty to drive as it will try to change direction every time you hit a bump or hollow.
Check for bump steer by fastening a cheap laser pointer to the hub, remove the spring and shock absorber and plot the movement of the laser spot on a wall or piece of board as you move the suspension up and down. Do this particularly for the main used range of the suspension. The line produced should be straight and vertical. Because everything in a wishbone suspension moves in an arc there will always be a small amount of bump steer but you can get rid of the worst effects.
The simplest start point is to choose a steering rack where the steering arm pivots are in the same plane as the wishbone pickups. However in most cases moving the entire rack up and down and front to rear will get the situation to an acceptable point.
It is also useful to do an accurate model of your setup made from thin plywood and use this to see where the roll centre of your arrangement actually is and how it moves as the suspension rises and falls. Keeping the roll centre movement as small as possible will help in making your car feel nice to drive.
Cheers
Mike
Check for bump steer by fastening a cheap laser pointer to the hub, remove the spring and shock absorber and plot the movement of the laser spot on a wall or piece of board as you move the suspension up and down. Do this particularly for the main used range of the suspension. The line produced should be straight and vertical. Because everything in a wishbone suspension moves in an arc there will always be a small amount of bump steer but you can get rid of the worst effects.
The simplest start point is to choose a steering rack where the steering arm pivots are in the same plane as the wishbone pickups. However in most cases moving the entire rack up and down and front to rear will get the situation to an acceptable point.
It is also useful to do an accurate model of your setup made from thin plywood and use this to see where the roll centre of your arrangement actually is and how it moves as the suspension rises and falls. Keeping the roll centre movement as small as possible will help in making your car feel nice to drive.
Cheers
Mike
