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Triumph TR6 - Gas Shocks?
|What is the opinion out there regarding the use of aftermarket gas shock conversion kits to "improve" handling and comfort" I ve seen many types listed in suppliers and e-bay but have seen little literature/opinion on their value...any comments out there in LBC land? (sounds like a good winter project to me :-))|
There are some old threads on this. If I recall there is one choice that is not that great for structural strength.
|There are four basic conversions types out there that I know of. One is the one that Rick references. It is a pair of mount plates that sandwich the inner fender well between and will transmit loads directly into the sheet metal, not a good idea at all. Another uses a bracket that goes from the lever shock mount to the bottom of the boot floor, another bracket that goes from the boot floor to the boot side of the inner fender well and a third bracket for the shock that is mounted against the inner fender well. Much better, but it does constitute a rather convoluted load path. Next, there is what amounts to a one piece, no drilling type. It has a mount plate that bolts to the lever shock mount plate and a cantilevered arm, reinforced with gussets, that reachs up into the inner fender well. This last type is probably what you have seen. There are two common themes with these. One is that they all take you to a tube shock instead of the lever shock, the other is that they do decrease the amount of clearance on the inside of the wheel/tire. If you are running wider wheel/tire conbos, this could present a problem for you.|
The fourth tube shock conversion is from Revington TR in the UK. These are now offered up by Roadster Factory and I know from discussion with Dave that they have sold at least one of these set ups. This kit places the shock inside the rear spring, but installation is more involved. Gusset plates and an upper mount plate have to be welded in place, the trailing arm needs to be drilled for the lower mounts and the hole in the spring pan area has to be enlarged for the shock. The shocks themselves are adjustable AVO race units. It does require stiffer rear springs, 420 lb-inch units at a minimum. That's about all I can tell you about this one so far. Despite the extra work, this conversion strikes me as the best thought out of the bunch. It has a nice straight load and travel path and it does not decrease wheel/tire clearance. Roadster is supposed to get a report on the installation once it is complete, so there should be more information on this one available in the not too distant future.
My own position is that for the first three, I would just as soon stick with lever shocks and have found the heavy duty rebuilt ones from Apple to be good and am aware that now Moss Europe and a few of the other UK suppliers are offering up uprated levers. So for me it is either stick with levers or take the plunge and go the Revington conversion route.
|Well done Steve!|
|Thanks all, most educational (Steve..you should go into publishing :-))|
I think I will put this project on hold until I get Brian H to take a spin and offer his feedback on the cars handling characteristics...second opinion from a TR6 surgeon!
|Hi Bob and others,|
Steve has given a comprehensive answer, but I would like to put in a plug for the 3rd. system he describes, the "one piece" type.
I have used this for 6 or 7 years on my irs TR4a, which has the same suspension, very pleased.
Points in it's favour
1) Mounts with original bolts in original position, feeds loads into chassis in same place as original.
2)I have had no clearance problems , even with 205/50x15 race tires.(Taller profile tires may be different but I don't think so.)
3) Simple, not expensive, sold with KYB non adjustable shocks if you have stock springs, or Spax adjustables if you have lower or firmer springs.
4) Installs in 30 minutes, for both sides, changes back for originality just as easily.
The Revington solution does also sound good, but seems to require very hard springs you may not want.
(I might consider making a copy of the steel adaptor in aluminium, 6061 or similar alloy, to reduce weight, in which case I would sell the steel set.)
Anyway, it seems to me to work very well.
Like Simon, I used the third type and am pleased with the results. Very quick & simple to install and I find the ride feels a little tighter. The beauty of this setup, like Steve said is that if you don't like it you unbolt it and reinstall the old levers. When my car arrived in May, it had the mounting plates for the first type of setup that Steve described still in place but the lever shocks had been reinstalled. I removed that setup completely and trashed it. It was really junk and not a good idea structurally. I'm happy with my KYB gas conversion.
|On converting the steel adapter to aluminum, I don't know that I would recommend that. 6061 has an advantage over the higher strength aluminums such as 2124, 7050 and 7x75 family in that it is weldable, but to get back to "-T6" properties, you would need to do post weld soultion and precipitation heat treatments. Other wise you take significant property knockdowns in the weld heat affected zone. You would also have to bump up the size to maintian the same strength as the steel. Plus aluminum for all intents and purposes has no endurance limit compared with steel. |
I would recommend sticking with the steel unless you just have to have a weight decrease, then if you must go Ti 6-4 such as that covered by AMS 4911. Good as welded strength, similar to the mild steel in the current bracket as long as the welding is done properly and density is ~.16 lb/in cubed vs ~.30lb/in cubed for the steel and good endurance limit to boot.
|Steve- More pencils in that pocket protector?|
Really I am jealous of you knowledge!
|Must agree with Simom and Bob,|
I have the one piece "third choice" and even with a
KYB shock it handles well. Will change to Koni or Spax this winter with antisepated better performance.
This thread was discussed between 05/12/2004 and 08/12/2004
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