TR4a Solid Axle or IRS advise please

[michael pridham]

Hi Folks,

Looking to buy a TR4a but unsure of which to buy either the solid axle or IRS model as iam a newby to the TR4 scene, any advise please and any pitfalls.

Thanks

Michael

[John Morrison]

Sure folk will give conflicting answers, but for my money,

a TR4 trumps a TR4a everytime.

 

Simpler, stonger and by definition more reliable.

 

John.

[RogerH]

Hi Michael,

if you want a TR4A then the most common in the UK have the IRS. The live axle was popular in the USA and some have come home but not many by comparison.

 

If you are also interested in the TR4 then live axle is the only offering and as John comments is very popular.

TR4 owners say they handle better than the 4A.

Owners of the 4A aren't bothered and still go like the clappers.

 

Roger

[chas8218TR4]

Solid axle every time for me, preferably a 4, but I have no experience of a solid axle 4a.

 

ChasV8

[BrianC]

Unless you actually want IRS then a TR4 is far preferable to a live-axle TR4A as the chassis is stronger.

Other than that, differences between TR4 and TR4A are mainly cosmetic so choose what you like the look of (or can afford!)

[TR 2100]

Michael,

 

Be aware that live axle TR4As are not common. As Roger points out,

they were not available in the UK, so they will be a US import.

(nothing wrong with that in my book, but likely to affect value)

 

Also, I stand to be corrected, but the 4A chassis is more susceptible

to flexing due to the different design.

But - a live axle 4A still has the 4A chassis, NOT the TR4 chassis,

so comparisons are not straightforward.

 

Again, as pointed out by Roger, TR4 owners swear the 4 is better.

TR4A owners aren't bothered.

Go figure !

 

ANY TR is a helluvalot better than NO TR.

 

AlanR

Edited September 27, 2016 by TR 2100

[Mark1965TR4aBRG]

4a looks nicer in my opinion both inside and out, but for sure the solid axle has is advantages.

 

If I were doing it again I'd do a 5, but that doesn't really help much.

 

I'm near Cambridge if you'd like a ride in a 4a albeit some what improved from standard. I'm also 20mins from TRGB so you could if they have one try the live axle 4..

[michael pridham]

4a looks nicer in my opinion both inside and out, but for sure the solid axle has is advantages.

 

If I were doing it again I'd do a 5, but that doesn't really help much.

 

I'm near Cambridge if you'd like a ride in a 4a albeit some what improved from standard. I'm also 20mins from TRGB so you could if they have one try the live axle 4..

Thanks for all of your replies keep them coming please.

Michael

[ChrisR-4A]

Hi Michael, solid axle on 4a chassis is the worst of both worlds. Less comfortable ride and weaker chassis.

Nothing wrong with a well sorted IRS 4A,

Think tele dampers, poly bushes and for a quieter smoother ride then CV Driveshafts.

Where abouts are you?

Chris

[Alec Pringle]

For out and out roadholding, the 4 has the edge - particularly if judiciously tweaked and stiffened.

 

For long distance fast touring the 4A IRS can offer improved ride comfort, especially when laden.

 

The 4A live axle can produce a good compromise, and often enough at an advantageous purchase price.

 

Suspension and transmission modifications should be approached with care, and particularly with the IRS cars - too many of the so-called 'upgrades' offered over the years should have been consigned straight from supplier to recycling skip, saving all the effort of fitting to the car . . . . . .

 

Cheers

 

Alec

[michael pridham]

Hi Michael, solid axle on 4a chassis is the worst of both worlds. Less comfortable ride and weaker chassis.

Nothing wrong with a well sorted IRS 4A,

Think tele dampers, poly bushes and for a quieter smoother ride then CV Driveshafts.

Where abouts are you?

Chris

Chris,

I live in Lincoln

[Guest ntc]

I have said it before ( horse and cart) when was the last time you saw a modern with a live axle.

[boxofbits]

Hi Michael

 

My experience of road driving in a TR4a is pleasing drive with no real issues, and in theory an independent suspension set-up should work better than a live axle.

 

But if you are thinking of doing serious track days of eventing, then the TR4 is the one to go for in my opinion.

 

Regards

 

Kevin

[Kiwifrog]

Sure folk will give conflicting answers, but for my money,

a TR4 trumps a TR4a everytime.

 

Simpler, stonger and by definition more reliable.

 

John.

 

 

+1

[MichaelH]

Hi Michael,

If you are going to compete with it, I have experience of both racing and rallying a 4A and a 4

The advantage of the 4A is that it has more rear suspension travel and makes a good road rallying car, the 4 has more competition history and if you want to race the 4 is easier to make into a rollerskate

mind you the 5s and 6s which are IRS are pretty quick

One final word: the 4 chassis is inherently longer lived that the later cars because it has a simple ladder construction whereas the later cars chassis is boxed in and rots from the inside

Still I have a 4 and a 4A and love them both

Good luck in your choice

MichaelH

Edited September 27, 2016 by MichaelH

[stuart]

Hi Michael, solid axle on 4a chassis is the worst of both worlds. Less comfortable ride and weaker chassis.

Nothing wrong with a well sorted IRS 4A,

Think tele dampers, poly bushes and for a quieter smoother ride then CV Driveshafts.

Where abouts are you?

Chris

Cobblers and anyone who has driven mine (Solid axle 4a) will tell you the way that is set up beats both a 4 and an IRS 4a hands down. It depends on how its built in the first place.

Stuart.

[Peter Cobbold]

Semi-trailing arms move the wheels at all sorts of strange toe and camber angles unless the springs are made really stiff. If only a solid axle had been available on the 6......

Peter

[BlueTR3A-5EKT]

Semi-trailing arms move the wheels at all sorts of strange toe and camber angles unless the springs are made really stiff. If only a solid axle had been available on the 6......

Peter

This has been done - I saw a TR250 in the US with the solid axle set up - They grafted the entire rear chassis section and axle/spring set up from a TR4A

 

DIY Cut the back chassis legs off a TR4A, or adapt your TR6 hassis with bits from CTM perhaps.

Get a solid axle from a TR4-4A

Get a pair of leaf springs from same car or have them made up from single bar rather than laminated. - Midland Road Springs? http://leafsprings.co.uk/shop/

The devil will be the brackets to attach the front of the spring to the usually rotted trailing arm chassis rail. It bolts in the same place as the outer bracket of an IRS on TR4A solid axle. Looks like a bent trailing arm bracket. Back end uses a shackle that is about 1/2" longer than TR2/3/4.

Rear shocks car be levers with special links or tubes with some bracket arrangement...

 

Or go the whole hog and create a space frame with IRS like this http://www.britishracecar.com/DennisDeLap-TVR-2200.htm

You will lose the ability to fit in the golf bats in the boot.

Peter W

[Peter Cobbold]

This has been done - I saw a TR250 in the US with the solid axle set up - They grafted the entire rear chassis section and axle/spring set up from a TR4A

 

DIY Cut the back chassis legs off a TR4A, or adapt your TR6 hassis with bits from CTM perhaps.

Get a solid axle from a TR4-4A

Get a pair of leaf springs from same car or have them made up from single bar rather than laminated. - Midland Road Springs? http://leafsprings.co.uk/shop/

The devil will be the brackets to attach the front of the spring to the usually rotted trailing arm chassis rail. It bolts in the same place as the outer bracket of an IRS on TR4A solid axle. Looks like a bent trailing arm bracket. Back end uses a shackle that is about 1/2" longer than TR2/3/4.

Rear shocks car be levers with special links or tubes with some bracket arrangement...

 

Or go the whole hog and create a space frame with IRS like this http://www.britishracecar.com/DennisDeLap-TVR-2200.htm

You will lose the ability to fit in the golf bats in the boot.

Peter W

Thanks Peter, bookmarked....for when the 6 needs a new chassis Peter

[TR4A1965]

I have recently rebuilt my TR4A IRS and used Koni shocks.

 

They made such a difference as the car used to scuttle around corners.

 

Whilst it was fun getting to know how far you could push the car in the bend with the armstrong levers the Koni conversion has made all the difference.

 

You can steam in to a bend with confidence and the car is as solid as a rock. The road holding is amazing and I love it.

 

I don't think the original lever set up was this good:-)???

 

I spoke to the original owner who stated that the IRS set up was useless and worse than his previous TR3.

 

He put this down to the fact that there was no Koni shock absorber conversion available at the time for the TR4A.

 

There was a conversion available for the TR3 when he had it.

 

For him, his new TR4A was a bit of a let down by comparison.

 

Best

 

Paul.

[ChrisR-4A]

Chris,

I live in Lincoln

Hi Michael, I'm at Rochford Essex so a bit too far.

 

Still you have quite a few different views now which should help you decide. Either chassis could make a good car, rust is the biggest problem now all these cars are over 50 years old and the 4A chassis is more prone than the 4's so an average to good 4 could be less work and cheaper to fix. A 4a hood & frame is easier to use but can be retrofitted to a 4 or you may find a car with a Surrey top which is the same for both models and is preferred by many owners.

Good luck , Chris