RUF - Some comments
Posted: Fri Jul 20, 2007 9:42 pm
Part 2 in the series.... Thanks to Tiny 
RUF - some history
RUF is an acronym for "REARS UP FRONT" I Think the first well known person to do RUF was Glenn Wakefield, I guess around 1995. Glenn now runs Rocky Road Outfitters. He originally set them up in a SPOA application with "missing link" shackles.
Way back in the dusty dark ages around 1998 or something, Grimbo suggested we give it a go in his car. At that stage, We weren't aware of anyone who had done it in a SPUA application, but we might be wrong.
How/why does it work?
Rear suzuki sierra springs are 3" longer than front springs eye to eye. they also have more arch in them, and a much softer rate.
Front springs are very flat and have a high rate- approximately 220lb/" Rear springs are much softer at 150lb/"
These factors combine to allow a softer ride, move the front axle forward (more on that later) and permit more wheel travel than possible with front springs, so, all at once you might be able to clear a bigger tyre, have more wheel travel and a softer ride. These things don't often all happen together.
RUF permits about a 4" increase in suspension travel.
How is it done?
This is where the RUF thing splits into two. There are two approaches - "full" RUF and "partial" RUF.
Full RUF
Full RUF involves bolting the rear of the spring into the stock spring hanger. This moves the front axle forward as far as possible - about 40mm.
This wheelbase stretch has some compound effects. Not only does it get a large tyre out of the firewall, it also moves the centre of gravity backwards a bit, which makes the car feel less nose heavy and better balanced.
What's involved in Full RUF?
Because of the wheelbase stretch, a lot of work. As a minimum, the brake line brackets, bumpstop and shock absorber mount have to be moved. a longer front driveshaft is surprisingly not actually required, but is helpful (a coil sierra front driveshaft is the best fit, actually)
To get the maximum wheel travel, longer shock absorbers and brake lines are required, which will mean fabrication of new shock mounts.
Now to the chassis extension:
It might be possible to do full RUF without and actual chassis extension, but it would still take some clever reworking of the front spring hanger and bumpstop spacing to keep the shackle angle acceptable.
The first one I did was a full 100mm extension. The last one I did was 50mm or so and I think that the next one might be 35mm. It is a balance of bumpstop spacing, shackle length, and spring choice.
THe extension is easy enough to do on a NT car, harder and messier on a WT because of the wider spring spacing.
The extension can be engineered in Victoria without dramas.
If you had access to two chassis, it would be possible to do it with one cut and the front section from another chassis.
Here is a photo of an extension section, including the mount for a vitara power steering box which was moved forward to match the new axle location. The configuration of this extension was as specified by the engineer in this case. this car was a NT but we swapped the springs to NT spacing when the extension was done.
and from the other side:
And flexed up. (No bumpstops yet fitted in this case)
Here is a widetrack with stock manual steering. this car only has about 60mm of extension. The steering box was not moved forward. The tie rod and drag link do not interfere if 2" of bumpstop spacer are employed. If 1"or less of spacer are used, the tie rod and drag link will touch in a way that rubs the paint off, but there seem to be no long lasting effects in the cars I have set up.
Here is the same car with OME N76 shocks, custom mounts, bumpstop spacers, Full Ruf.
And here it is flexed up. The tyres are 33 9.5's
Partial RUF
Partial RUF involves redrilling the rear spring hanger to avoid the full wheelbase extension. This is one way of avoiding doing a chassis extension. This is really only applicable to WT cars as NT cars have a very small rear spring hanger which doesn't really allow it. Bumpstop spacing will be required to avoid inverting front shackles.
This modification will, if the right shocks are fitted, provide all the travel and ride improvements of full RUF, but not the balance point change or all the tyre clearance.
I can't help with this modification, I have never done it, but Patzuki has and might chime in with his findings. (and I know others have)
Disadvantages:
Lots of work to do "fully"
Requires parts - shocks, brake lines, driveshafts, springs,
Reduction in approach angle (the bigger tyres RUF allows mitigate most of this.
Requires an engineers certificate to be legal if an extension or chassis welding is performed.
It is hard to explain how totally this modification transforms the behaviour of a sierra.
Hope this helps.
Steve.
RUF - some history
RUF is an acronym for "REARS UP FRONT" I Think the first well known person to do RUF was Glenn Wakefield, I guess around 1995. Glenn now runs Rocky Road Outfitters. He originally set them up in a SPOA application with "missing link" shackles.
Way back in the dusty dark ages around 1998 or something, Grimbo suggested we give it a go in his car. At that stage, We weren't aware of anyone who had done it in a SPUA application, but we might be wrong.
How/why does it work?
Rear suzuki sierra springs are 3" longer than front springs eye to eye. they also have more arch in them, and a much softer rate.
Front springs are very flat and have a high rate- approximately 220lb/" Rear springs are much softer at 150lb/"
These factors combine to allow a softer ride, move the front axle forward (more on that later) and permit more wheel travel than possible with front springs, so, all at once you might be able to clear a bigger tyre, have more wheel travel and a softer ride. These things don't often all happen together.
RUF permits about a 4" increase in suspension travel.
How is it done?
This is where the RUF thing splits into two. There are two approaches - "full" RUF and "partial" RUF.
Full RUF
Full RUF involves bolting the rear of the spring into the stock spring hanger. This moves the front axle forward as far as possible - about 40mm.
This wheelbase stretch has some compound effects. Not only does it get a large tyre out of the firewall, it also moves the centre of gravity backwards a bit, which makes the car feel less nose heavy and better balanced.
What's involved in Full RUF?
Because of the wheelbase stretch, a lot of work. As a minimum, the brake line brackets, bumpstop and shock absorber mount have to be moved. a longer front driveshaft is surprisingly not actually required, but is helpful (a coil sierra front driveshaft is the best fit, actually)
To get the maximum wheel travel, longer shock absorbers and brake lines are required, which will mean fabrication of new shock mounts.
Now to the chassis extension:
It might be possible to do full RUF without and actual chassis extension, but it would still take some clever reworking of the front spring hanger and bumpstop spacing to keep the shackle angle acceptable.
The first one I did was a full 100mm extension. The last one I did was 50mm or so and I think that the next one might be 35mm. It is a balance of bumpstop spacing, shackle length, and spring choice.
THe extension is easy enough to do on a NT car, harder and messier on a WT because of the wider spring spacing.
The extension can be engineered in Victoria without dramas.
If you had access to two chassis, it would be possible to do it with one cut and the front section from another chassis.
Here is a photo of an extension section, including the mount for a vitara power steering box which was moved forward to match the new axle location. The configuration of this extension was as specified by the engineer in this case. this car was a NT but we swapped the springs to NT spacing when the extension was done.
and from the other side:
And flexed up. (No bumpstops yet fitted in this case)
Here is a widetrack with stock manual steering. this car only has about 60mm of extension. The steering box was not moved forward. The tie rod and drag link do not interfere if 2" of bumpstop spacer are employed. If 1"or less of spacer are used, the tie rod and drag link will touch in a way that rubs the paint off, but there seem to be no long lasting effects in the cars I have set up.
Here is the same car with OME N76 shocks, custom mounts, bumpstop spacers, Full Ruf.
And here it is flexed up. The tyres are 33 9.5's
Partial RUF
Partial RUF involves redrilling the rear spring hanger to avoid the full wheelbase extension. This is one way of avoiding doing a chassis extension. This is really only applicable to WT cars as NT cars have a very small rear spring hanger which doesn't really allow it. Bumpstop spacing will be required to avoid inverting front shackles.
This modification will, if the right shocks are fitted, provide all the travel and ride improvements of full RUF, but not the balance point change or all the tyre clearance.
I can't help with this modification, I have never done it, but Patzuki has and might chime in with his findings. (and I know others have)
Disadvantages:
Lots of work to do "fully"
Requires parts - shocks, brake lines, driveshafts, springs,
Reduction in approach angle (the bigger tyres RUF allows mitigate most of this.
Requires an engineers certificate to be legal if an extension or chassis welding is performed.
It is hard to explain how totally this modification transforms the behaviour of a sierra.
Hope this helps.
Steve.
, gregs, oh i mean his doctors hairdressers car, was number 2 
