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stinkycheese
27th January 2009, 19:57
ive just read this on the GMC website;

"For those who do not know what torsion bars are, they are sprung steel bars with splines on both ends, one end fits in the radius arm which goes up and down with wheel travel and other end is fixed in the rear cross member. As the wheel goes up and down due to bumps the bar twists against the spring tension.

The problems that this lack of stiffer torsion bars create is that like a lot of front wheel drive cars and especially French cars, the rear suspension is set too high and too soft as standard. When you lower and stiffen the front this unbalanced situation is made worse. Sadly, many suppliers of these kits and supported by articles in motor magazines say the answer is to lower the rear suspension to make the car level again by just turning the torsion bars around on their splines. This is definitely not a solution but merely way of getting around a problem. Not many people understand the reason why it is not a proper fix.

The reason it is not a fix is that to make the cars sit lower you have to take tension off the bar, which exactly the opposite of what is necessary. Yes, it will lower the suspension to get it looking good and level with the front but that's all. If you put on some lowered uprated front springs you will make the handling worse unless you can fit uprated rear torsion bars. If you are more concerned with appearance then this modification is OK but if improved handling is required it is definitely not.

The only solution is to fit uprated torsion bars on the rear."

up until now i thought that lowering the standard torsion bar was fine, GMC seem to think otherwise, are they saying this to flog some aftermarket ones? :S

williamsvts
27th January 2009, 19:59
imo, GMC are a good company and he knows his shit. but they do put the message across that its there way or no way. thats my opinion lol

everyone get your guns out, im prepared to be shot down haha

VTR-120BHP
27th January 2009, 20:00
hmmmm im with you on this one..... someone explain :P

VTR-120BHP
27th January 2009, 20:01
imo, GMC are a good company and he knows his shit. but they do put the message across that its there way or no way. thats my opinion lol

everyone get your guns out, im prepared to be shot down haha


so is that "statement" correct ???

williamsvts
27th January 2009, 20:03
why would they sell the bilstien kits with lowered springs that suit standard torsion bars if its the wrong way to do it?
companies have to make money somehow and he'll make more selling to the general modifying scene aswell as competition than JUST racers. thats what i think.

VTEC-Saxo
27th January 2009, 20:06
hmm confused..

KamRacing
27th January 2009, 20:11
its all true though I dont understand what they mean by taking tension off the bar.

The torsion bar is the rear spring.
Its basically an uncoiled spring that works by resisting a twisting motion as the trailing arm moves.

When you uprate your front suspension you increase the spring rate at the front.
With standard torsion bars this means that you are dialling in understeer.

To sort this and create a 'great' handling car you need to increase the rear spring rate accordingly. This can only be done with bigger torsion bars.

Its a big expense that not many people are prepared to do, but the difference is amazing once done.

Kev

williamsvts
27th January 2009, 20:12
that depends on what rate front springs you go for though.

i dont get how the tension would alter either??

VTEC-Saxo
27th January 2009, 20:16
surly doing it the notches way would be the only way you could fuck things up..?

Curran
27th January 2009, 20:22
what is the spring rate of the standard torsion bars and front springs?

and how closely should the front and rear be matched?

bullit
27th January 2009, 20:33
gmc know their shit but they do like to sell stuff too

davidharvey
27th January 2009, 20:34
I am fairly new to saxo ownership and this forum, but I have spent way too many hours on here....

and my understanding its it not the only way to go, but is the best option.

Stefan
28th January 2009, 01:42
wow really confused :D

KamRacing
28th January 2009, 15:01
that depends on what rate front springs you go for though.

i dont get how the tension would alter either??

A standard spring would be around 90-100lb
A small increase isnt going to ruin the handling but when you are going towards 180lb + springs and coilover kits then it needs a upgrade at the rear.

I am fairly new to saxo ownership and this forum, but I have spent way too many hours on here....

and my understanding its it not the only way to go, but is the best option.

The other option is coilovers but if you wont pay £300 for torsion bars you will not pay £800 for a rear coilover conversion.

You can do a cheap fix with an antirollbar but all that does is reduce grip, rather than change the spring ratio.

EazyDayz
28th January 2009, 16:30
thanks for the help