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slimming down leaf springs ?

Posted: Mon Jan 27, 2014 9:58 am
by Vincent.vanGinneke
Hi all,

Would it be adviseable to slim down leafsprings (for my sidecar) in the lenght?
I've obtained a pair of (as told) T Ford (??) leaf springs but they are to wide, what I need is 4cm wide .
So I thought of angle grinding each blade one by one in the lenght.
Perhaps grind both sides to prevent warping to one side ?
Or not at all and look further for the right ones ?

advise is welcome.

zijspan aansluitingen.jpg

Posted: Mon Jan 27, 2014 11:35 am
by brenton.roy
That's a big job Vincent! If you are after advice, mine would be to pay someone else to do it. Probably someone you don't like.
There is a machine that mechanics use to grind car cylinder heads flat. You might be able to use something like that - and get the springs ground down as a unit, then tidy up the edges by hand and reassemble them.


Posted: Mon Jan 27, 2014 11:46 am
by Bob.Murphy
I hope you have a big Angle Grinder - I wouldn't use a 115mm one for that !

If the springs are too firm (after slimming) I have seen people grind as 'waist' into alternate leaves to make them more flexible.

I believe Mr Bradshaw designed that into the leaves on his early P&M Panther rear suspension design.

Having spent years fettling 'Series' Landrovers the best thing I ever did was fit modern Parabolic springs - 3 leaves on the back instead of 11 !

It was the first time I'd felt the suspension move :lol: .

I suspect a modern set of springs will be better than those old ones which may be Age Hardened.

Just my tuppence-worth.


Re: slimming down leaf springs ?

Posted: Mon Jan 27, 2014 12:04 pm
by adrie.degraaff
The best advise is; make new ones or have them made.
Buy the material (soft), there must be 10 mm between blades at the midle before the pin goes in, when ready bake the seperate blades in the oven on 200 degrees celcius.
We have done this in Ariel city.
When you find old springs; take them apart, round the blades with big hammer between 2 solid points (15cm) to the same 10 mm between blades.
The blades must be greased between when put together against noise.

Re: slimming down leaf springs ?

Posted: Mon Jan 27, 2014 12:50 pm
by Vincent.vanGinneke
Eat this .
Wetblast 010.jpg

Posted: Mon Jan 27, 2014 6:30 pm
by chris.vredenbregt
watch your foot...chris :oops:

Posted: Mon Jan 27, 2014 9:02 pm
by Steven.Carter
You have the beer Vincent handy between your legs to celebrate a successful grind.


Re: slimming down leaf springs ?

Posted: Tue Jan 28, 2014 5:57 pm
by Bob.Murphy
Vincent.vanGinneke wrote:Eat this

:lol: :lol: :lol:

Nice one ;) .

Another thought . . .

I recently replaced the front springs on my Ifor Williams HB510 Horse Trailer. Its a twin-axle with a gross weight of 2584 Kilos.

The front nearside cops all the sunken drain covers, broken kerbs, rocks at the side of the road and so-on when towing around the narrow roads we have here. The front N/S spring broke :roll: .

The springs are single leaf parabolics, they cost £36.20 each (including 20% VAT).

Ifor Williams make lots of trailers in different styles and capacities - there must be a parabolic spring that would suit your sidecar.

You seem to be going to a great deal of effort to modify something that may not give the result you want.

But keep the pictures coming I'm looking forward to seeing the build progress :D .


Re: slimming down leaf springs ?

Posted: Tue Jan 28, 2014 7:28 pm
by Vincent.vanGinneke
After posing for the pic I decided that it was to much work.....
This kind of spring would suit I guess.
From a pushbike trike transporter - Bakfiets-
Trike transportbike
transportfiets_271.jpg (36.34 KiB) Viewed 2329 times

Re: slimming down leaf springs ?

Posted: Wed Jan 29, 2014 10:53 am
by Bob.Murphy
Vincent.vanGinneke wrote: This kind of spring would suit I guess.

Is the spring you need bushed at both ends ??

Some have a bush at the leading edge but the rear is hooked through a pair of rollers to allow for the extension as it flattens under load - no swing shackles involved.

What are the dimensions ???