Sorry for the stupid questions, I feel sure I know the answers but am asking out of caution...

'The book' states the builder should use dampers that are 13" open / 9" closed, with a 25mm extension.

Question 1 - I assume this is the same as 14" open /10" closed?
Question 2 - Can I mock up the maximum extents of movement in the suspension using 2 lengths of box section, one with 10" between the holes for the bolts (for 'most compressed' ) and one with 14" between the holes (for 'least compressed' ) ?

[Edited on 13/11/17 by jps]

[Edited on 13/11/17 by jps]

Hi JPS,

Good to hear from you!

Perhaps you missed this tread on the Haynes forum?
http://forums.haynes.co.uk/showthread.php?t=7246

To summarize and answer your questions:

Question1:
For a "book design" car (Sierra based), shocks should be 14'' open (or 13''+1'' extension), but still 9'' closed. But when it comes to Gaz Shocks, the 14'' open shocks come in 9.5'' closed only. That is what I have on my car. Body diam=2''.

Question2:
For your mock up, you can take a 14'' box section for the long ones, and either 9'' or 9.5'' for the short ones, according to what shock brand you are going to buy.

Springs should be 8'' long (2.5'' diam), different rates should be tried, even-though 350lb front and 250lb rear seems to be a good start (it worked for me that, is what I have on my car)

Hope the will help

The extension may be for the spring seat to clear the chassis ? It was very close on a Locost.

[Edited on 13/11/17 by big_wasa]

Similar to Sylvain - I have Gaz 14" x 9.5" shocks with 350lb front springs and at the moment 250lb rears but am changing the rears to 300lb this winter as I am often travelling two up with probably 30 stone of passengers on board, I am not sure if this will be my final set of springs but if I was solo then the 250lb ones would be the ones I would go for.

quote:

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Originally posted by voucht
Hi JPS,

Good to hear from you!

Perhaps you missed this tread on the Haynes forum?
http://forums.haynes.co.uk/showthread.php?t=7246

To summarize and answer your questions:

Question1:
For a "book design" car (Sierra based), shocks should be 14'' open (or 13''+1'' extension), but still 9'' closed. But when it comes to Gaz Shocks, the 14'' open shocks come in 9.5'' closed only. That is what I have on my car. Body diam=2''.

Question2:
For your mock up, you can take a 14'' box section for the long ones, and either 9'' or 9.5'' for the short ones, according to what shock brand you are going to buy.

Springs should be 8'' long (2.5'' diam), different rates should be tried, even-though 350lb front and 250lb rear seems to be a good start (it worked for me that, is what I have on my car)

Hope the will help

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I am using the following after much research (and recommendations from other users and forums);

From rallydesign;
4 x Gaz 14" Open, 9.5" Closed Length Coilover Shock (140/095/B12-2)
2 x 2 1/4", 400 Rate, 8" Free Length (RD1195/8)
2 x 2 1/4", 250 Rate, 9" Free Length (RD1189/9)
1 x C Spanner - Coil Over Spring Seat Adjuster (2 1/4" (RD207)

Please note I have a straight 6 BMW lump under the bonnet hence the 400lb springs up front. Car not road tested yet so springs may be changed.

Hi.

Just for conformation, what i supply for book roadster chassis is 14" open 9 1/2" closed.
The reason for the 13" + 1" was an attempt by author and designer to only allow one make off damper to be supplied / used. This can be ignored and just use 14" open units.

Cheers Matt

quote:

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Originally posted by procomp
Hi.

Just for conformation, what i supply for book roadster chassis is 14" open 9 1/2" closed.
The reason for the 13" + 1" was an attempt by author and designer to only allow one make off damper to be supplied / used. This can be ignored and just use 14" open units.

Cheers Matt

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quote:

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Originally posted by ianhurley20

quote:

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Originally posted by procomp
Hi.

Just for conformation, what i supply for book roadster chassis is 14" open 9 1/2" closed.
The reason for the 13" + 1" was an attempt by author and designer to only allow one make off damper to be supplied / used. This can be ignored and just use 14" open units.

Cheers Matt

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Thanks for that Matt - it explains a lot

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