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Protech Coilovers 
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GTM on order

Joined: Thu Jun 13, 2019 1:17 pm
Posts: 9
Location: Cumbria
GTM: Libra
Post Protech Coilovers
I have just fitted a pair of GTM Libra specific rear spring damper units from Protech. Simples. Until I lowered the car. There was NO clearance between the wheel and damper body. Realising there was a problem, I removed the springs and spaced the wheel from the hub until I got clearance through full suspension travel. It closes up noticeably on full bump. I will need 15 mm spacers, with corresponding wheel studs. This still gives clearance with the bodywork. However, there is minimal clearance between the 2 1/4 " ID spring supplied, and the engine mount bracketry. There were no clearance problems with the original AVO coilovers with 1 3/4" ID springs. Has anyone been here before. Protech are being very helpful and understanding, but insist that they have not had the problem before. The car is original and unmolested, built 2000. TIA, Peter


Thu Jul 22, 2021 2:07 pm
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GTM Nirvana
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Joined: Sun Oct 19, 2014 10:10 pm
Posts: 1015
Location: Bristol
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Post Re: Protech Coilovers
Hi Peter, I'm going to assume you are on the original suspension, not Z cars.
If after adding the wheel spacers you still have body clearance then you might be able to get clearance by adjusting the track width instead with the trailing arm adjusters. If you are lucky there may be enough adjustment on the outer mounts to move both outer mounts (both trailing arms) closer to the tub. This changes the angle so pushes the hub further out from the centreline of the car. If you do both by the same amount you won't change the camber. As the bottom mounts of the damper units connect towards the rear of the trailing arm doing this will make them lean in towards the top mounts and might just give you enough room at the wheel. If there isn't enough adjustment on the outers you may have to take the trailing arms off and wind the inners out a bit to give the same result but that is a bit of a pain as requires a fair bit of dismantling rather than just loosening the lock nut and turning the big 32mm sleeve bolts.

The way mine is set my wheels only just clear the bodywork (no spacers, ET37 wheels). In fact unless I put extra negative camber on when I use wider rear tyres (225/45/16) these do rub on the top of the arch. With 205/45/16 and normal negative amber (1.5 degrees) I have about 4mm clearance between tyre and bodywork on full bump and the inner part of the wheel misses the damper body/spring by around 8mm on full bump. I have 2 1/4" springs on my Gaz shocks.

What wheel offset do you have? If the ET is more than the typical 35-38mm of the GTM supplied wheels then this would also bring the wheels inboard a bit. I have some Elise S1 rear 16" wheels with ET of 25 IIRC and these push the wheel out similar to using 12mm spaces. If you are anywhere near Bristol you are welcome to try these to see if they help although they are shod with slicks right now!


Thu Jul 22, 2021 5:11 pm
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Ready for SVA

Joined: Sat May 05, 2012 9:24 am
Posts: 372
Location: Norwich
GTM: Libra
Post Re: Protech Coilovers
Yep i had it. It’s because the Protech are thicker (being alloy) than the AVO’s.
But also depends what wheels you have & what their offset is!
See here:
coilovers-t2608.html?hilit=Protech%20spacers&start=45

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Thu Jul 22, 2021 6:25 pm
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GTM on order

Joined: Thu Jun 13, 2019 1:17 pm
Posts: 9
Location: Cumbria
GTM: Libra
Post Re: Protech Coilovers
Sanzomat, as stated, the car is original spec on suspension, wheels and tyres. I will measure ET tomorrow. As Sven says, the Protechs, being alloy, are 42 mm od against the AVO 20 mm od on the extension. To gain clearance on the wheel rim we have spaced them out 15 mm. We thought about cranking out the trailing arms, but that could create drive shaft problems. Then we realised we also have spring clearance problems around the engine mount bracketry. The AVO springs were 1.9" id (not 1 3/4", that's the damper body). We have no clearance problems with the bodywork, even with 15 mm of spacer. I am not a fan of spacers ( memories of minis in the 60's) but they seem to be accepted practice nowadays.
Sven, thanks for that link, I had searched, but not found it. Protech were chosen as they listed GTM Libra specific coilovers, and delivered within the week. Mind you, £400+. What did you fit?


Thu Jul 22, 2021 8:29 pm
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GTM Nirvana
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Joined: Sun Oct 19, 2014 10:10 pm
Posts: 1015
Location: Bristol
GTM: Spyder
Post Re: Protech Coilovers
peterrainsley wrote:
We thought about cranking out the trailing arms, but that could create drive shaft problems.


I measured the plunge on the driveshafts to check this and there is still plenty spare even when you wind them right out (well, there is on mine!) This is with the PG1 gearbox and MGF driveshafts. might be different with R65/metro. Cranking out the trailing arms might give you the clearance you need at the engine mount too. Clearly wheel spacers won't!

When considering replacing shocks it is worth enquiring about refurbishment. They don't tend to advertise it but certainly both Gaz and Protech will refurb your existing dampers and it is usually a fraction of the cost of new ones but all the parts subject to wear get replaced so other than cosmetically they are as good as new.


Thu Jul 22, 2021 10:07 pm
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GTM on order

Joined: Thu Jun 13, 2019 1:17 pm
Posts: 9
Location: Cumbria
GTM: Libra
Post Re: Protech Coilovers
And here was me, in my nativity, thinking I was just going to bolt on a replacement pair of coilovers. Four bolts, job done. However, We have dialogue with Protech, and the way forward will probably be milling the extension body, 1.9" springs, an extra bump stop to reduce travel to original spec, and maybe spacers if we still need them. I don't really want to disturb the whole rear end to explore the drive shaft limits. I will let you know where we get. This car needs to be on the road.


Fri Jul 23, 2021 12:06 pm
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Joined: Wed Jul 31, 2013 11:47 am
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Location: Kano north Nigeria
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Post Re: Protech Coilovers
sanzomat wrote:
peterrainsley wrote:

When considering replacing shocks it is worth enquiring about refurbishment. They don't tend to advertise it but certainly both Gaz and Protech will refurb your existing dampers and it is usually a fraction of the cost of new ones but all the parts subject to wear get replaced so other than cosmetically they are as good as new.


I had AVO refurb a set of quite old dampers off my Jedi race car, so they also offer the service
John


Sat Jul 24, 2021 6:22 am
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On the Road

Joined: Sat Sep 29, 2007 3:45 pm
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Location: SL2 4JW
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Post Re: Protech Coilovers
peterrainsley wrote:
Has anyone been here before.


When I changed to Protech shocks from Avo 1.9s I encountered two problems. The offside spring fouled a bracket on the engine frame and I had to grind a mm to clear. Where the shocks bolts to the wishbone the Protechs have a ball where as the Gaz or Avo have a flat tube, again I had to grind half a mm on the underside of the ball to clear. No help to you but maybe someone else.

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Mon Jul 26, 2021 9:47 pm
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