boxofbits Posted October 26, 2018 Report Share Posted October 26, 2018 Afternoon All Ive removed the front road spring on my TR4a and the free length of the spring is at odds with the manual by just over an inch. The free length is about 10” +\- whereas the manual states 11.1 “. Looks like they’ve shrunk under the weight of 100,000 miles! TR shop offer a set of TR6 springs which they say will do the job. Are they the same free length as the 4a as I would’ve thought with the 6 pot lump they might’ve been a heavier rating/ length? I’d need to change as a whole car set really so before I jump on the phone to order will the TR6 springs from TR Shop be suitable and not make it stand up like a Giraffe..! regards Kevin Quote Link to post Share on other sites
AndrewMAshton Posted October 26, 2018 Report Share Posted October 26, 2018 Hello Kevin, I have a brand new set that I bought from Racetorations, for the front and rear of the car, rear fitted, front uprated and lowered, 81/2" in length, looks like I will have to watch the speed bumps, cheers, Andrew PS Just checked the receipt, unfortunately no part number but I bought the springs and telescopic shockers at the same time, I also got them to rebuild my lever arms for the rear so all parts are matched. Quote Link to post Share on other sites
Malbaby Posted October 26, 2018 Report Share Posted October 26, 2018 Kevin....I would not use TR6 springs. What is wrong with your car's road height and ride comfort with your existing front springs ? Andrew...those Racestorations springs would be for track use, not touring comfort. Quote Link to post Share on other sites
DaveN Posted October 26, 2018 Report Share Posted October 26, 2018 Moss cat. lists tt4006 spring which is the same for the 6pot car. However for the 4a it says to use the alloy spacer 107682. That would add something like 2 inches I reckon. Quote Link to post Share on other sites
stuart Posted October 27, 2018 Report Share Posted October 27, 2018 12 hours ago, DaveN said: Moss cat. lists tt4006 spring which is the same for the 6pot car. However for the 4a it says to use the alloy spacer 107682. That would add something like 2 inches I reckon. In the latest Moss catalogue it doesnt say that Im afraid, thats for an early TR4 setup or later one using a lowered spring. I have found spacers fitted to a 4a but the ride height was all wrong anyway. Stuart. Quote Link to post Share on other sites
boxofbits Posted October 27, 2018 Author Report Share Posted October 27, 2018 20 hours ago, Malbaby said: Kevin....I would not use TR6 springs. What is wrong with your car's road height and ride comfort with your existing front springs ? Andrew...those Racestorations springs would be for track use, not touring comfort. Hi I spoke to the TR Shop on Friday and they advised that TR6 front springs are about the same. They have a set of TR6 springs, sold several sets of these particular sets and to date have had no negative feedback. I believe they said the rears are 25% stiffer. That'll make them about 155 lb which shouldn't be too drastic as the back end is very soft but on the other hand I don't want it too hard, too high, understeer or too twitchy over bumps etc! I wish I could get a new standard set tbh as the ride is about right. The reason for changing them is due to ride height differences around the car. I've checked the body to chassis gapping but it's not far enough out to make up the difference. Even if the free lengths turn out to be the same, they could differ in length under compression. Kevin Quote Link to post Share on other sites
DaveN Posted October 27, 2018 Report Share Posted October 27, 2018 7 hours ago, stuart said: In the latest Moss catalogue it doesnt say that Im afraid, thats for an early TR4 setup or later one using a lowered spring. I have found spacers fitted to a 4a but the ride height was all wrong anyway. Stuart. Apologies you are quite correct. I misread the 2/3/4 e cat for the 4a! I’m in the process of rebuilding mine hoping to gain a couple of inches ground clearance. Without I hope compromising the handling because I enjoy ragging it around the lanes. Time will tell! Quote Link to post Share on other sites
Malbaby Posted October 27, 2018 Report Share Posted October 27, 2018 3 hours ago, boxofbits said: Hi I spoke to the TR Shop on Friday and they advised that TR6 front springs are about the same. They have a set of TR6 springs, sold several sets of these particular sets and to date have had no negative feedback. I believe they said the rears are 25% stiffer. That'll make them about 155 lb which shouldn't be too drastic as the back end is very soft but on the other hand I don't want it too hard, too high, understeer or too twitchy over bumps etc! I wish I could get a new standard set tbh as the ride is about right. The reason for changing them is due to ride height differences around the car. I've checked the body to chassis gapping but it's not far enough out to make up the difference. Even if the free lengths turn out to be the same, they could differ in length under compression. Kevin All TR springs are in the range approximately 300-320 lb/in. If you are happy with the present ride comfort and approx height, I would swap sides of the front springs first to see if there is any difference....or get the bare springs tested at a suspension workshop to compare compression rates, as most workshops have a dedicated compression measuring machine...If you would prefer a more comfortable ride, look at front springs at about 250 rating...Also keep in mind the weight of the driver in relation to ride height. Quote Link to post Share on other sites
boxofbits Posted October 27, 2018 Author Report Share Posted October 27, 2018 31 minutes ago, Malbaby said: All TR springs are in the range approximately 300-320 lb/in. If you are happy with the present ride comfort and approx height, I would swap sides of the front springs first to see if there is any difference....or get the bare springs tested at a suspension workshop to compare compression rates, as most workshops have a dedicated compression measuring machine...If you would prefer a more comfortable ride, look at front springs at about 250 rating...Also keep in mind the weight of the driver in relation to ride height. Hi Yes you are right the rates are higher than I had quoted...I think I may have been looking at the leaf spring rate and not coil springs though the manual I was referencing is not a factory manual and I will double check what rates it gave for the rear springs tomorrow. It quotes the front Spring free length of 11.1 " which is blatantly wrong! I came across a previous thread on here reference to a TR6 and the quoted length for the front spring is 10.03" which is identical to the free length on my 4a. In the thread started by Marco, it is also stated that standard springs, ordered as such from Moss or TR Shop appear to give an acceptable ride height and rates not too far removed from originals. The thread also states that Triumph fitted 3 different rear springs on IRS cars in an attempt to iron out issues with over pitching etc! I can't see there is much more rear weight other than a fuel pump and filter and heavier boot lid in a TR6 as opposed to the TR4a. Kevin Quote Link to post Share on other sites
stuart Posted October 28, 2018 Report Share Posted October 28, 2018 11 hours ago, boxofbits said: Hi Yes you are right the rates are higher than I had quoted...I think I may have been looking at the leaf spring rate and not coil springs though the manual I was referencing is not a factory manual and I will double check what rates it gave for the rear springs tomorrow. It quotes the front Spring free length of 11.1 " which is blatantly wrong! I came across a previous thread on here reference to a TR6 and the quoted length for the front spring is 10.03" which is identical to the free length on my 4a. In the thread started by Marco, it is also stated that standard springs, ordered as such from Moss or TR Shop appear to give an acceptable ride height and rates not too far removed from originals. The thread also states that Triumph fitted 3 different rear springs on IRS cars in an attempt to iron out issues with over pitching etc! I can't see there is much more rear weight other than a fuel pump and filter and heavier boot lid in a TR6 as opposed to the TR4a. Kevin There is actually a fair difference in weight at the rear of 6 over a 4a.Wings are heavier at the rear plus the three piece back panel and as you say the boot lid plus rear lamps. Stuart. Quote Link to post Share on other sites
boxofbits Posted October 28, 2018 Author Report Share Posted October 28, 2018 From Moss’s website it appears both the TR5 and TR6 shared a 350lb rear spring , with the TR4a at 280lb. From that I’d assume that when fitted to the 4a it should be very similar to a TR5 ride height at the rear hopefully. Kevin Quote Link to post Share on other sites
MikeyL Posted May 31, 2019 Report Share Posted May 31, 2019 My 67 4a IRS has front springs st 9.25” and rear st 11.5” is this normal? Quote Link to post Share on other sites
Malbaby Posted May 31, 2019 Report Share Posted May 31, 2019 The compression rate must be taken into account also, no matter what the height is. Quote Link to post Share on other sites
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