Shorter Paralever Arm

shards · Post by **shards** » Mon Mar 06, 2006 5:32 pm

Excuse me if this has been done before but....... I would like to lift up the front of my Rock for more clearance (for the under-hung Laser headers) and i understand that another model's Torque Arm achieves this. Is it the one from the GS? Are there any other implications - ie drive shaft angles etc?

Anyone done this?

Or can you point me to a web site?

Thanx, Steve

Post by **DJ Downunder** » Mon Mar 06, 2006 6:38 pm

Yes it is from the GS...it is a little shorter.

You will get a little more clearance...and...a steeper front end to make steering quicker...the bike will lean more on the side stand...
both wheels touch when on the center stand...also a bigger gap above the rear wheel and a higher seat.

The Boxer Cup bikes have this mod...no problems that I know of...many have done it...mostly the R1100S guys.

There are a few aftermarket ones avalable..even some that you can adjust the lenth...here's a pic of a nice one.

Let us know how you go with it.

DJ

[img]http://www.fototime.com/{EC3C8641-2B1B- ... icture.JPG[/img]

Boxerpunk · Post by **Boxerpunk** » Tue Mar 07, 2006 11:47 am

shards wrote:Excuse me if this has been done before but....... I would like to lift up the front of my Rock for more clearance (for the under-hung Laser headers)....

Lift up the front

Then you'll need a longer paralever-strut; haven't seen them so far.

Swiss Rockster · Post by **Swiss Rockster** » Tue Mar 14, 2006 2:04 pm

shards wrote:Excuse me if this has been done before but....... I would like to lift up the front of my Rock for more clearance (for the under-hung Laser headers) and i understand that another model's Torque Arm achieves this. Is it the one from the GS? Are there any other implications - ie drive shaft angles etc?

Anyone done this?

Or can you point me to a web site?

Thanx, Steve

The best thing you can do for uplifting is to install (and buy) Ohlins suspensions. Your bike will be better, higher, faster, safer, more comfortable. I've bought the Ohlins suspension and it's the best investissment I've ever made for my Rockster.

riceburner · Post by **riceburner** » Sun Apr 02, 2006 4:24 am

I fitted a custom made GS-length paralever arm to my Rock, ( just before it was written off.

). As DJ said, you loose the gap under the rear wheel when on the centre stand, but gain a bit of turn in.

No problems that I can think of, the engine, gearbox, shaft-drive and swingarm on the Rock is the same as the one on the GS anyway (save some cam & gearing differences I believe).

Ves · Post by **Ves** » Sat Jun 30, 2007 3:35 pm

Just put a GS torgue arm on the Rock.

Maybe I'm going to need to paint that thing black...

Anyway, the steering definitely feels more aggressive. I'm use to a sport bike and to me it just feels more right. Before it felt like I was steering a chopper.

Shortens the wheelbase by about 3/4" and went from 1.5 inches of space between rear tire and ground to less than 3/4" (yeah... when on the centerstand). My tire has a reasonable amount of wear, so I can see where, depending on the exact tire diameter and how much tread is left on it, you could loose just about all the space you have. Of course the fringe benefit is that it takes hardly any effort to get it on the centerstand now.

The extra seat height is definitely noticeable. I have a 36 inseam, standard seat, with an Airhawk pad on it and I'm comfortably flat footing it now.

Verdict... I like it...

Maybe the silver arm will grow on me...

riceburner · Post by **riceburner** » Sat Jun 30, 2007 4:35 pm

If you get a drive seal leak, the dealer might argue that the shorter paralever arm caused it. This is a bollox answer and should be treated as such.

Go for it.

fnfalman · Post by **fnfalman** » Sat Jun 30, 2007 8:37 pm

You should have invested into the Ohlins front & rear shocks. The Ohlins front allows for height adjustment so that you can quicken your steering PLUS the additional performances from the Ohlins themselves. I am still experimenting with dampening settings and height adjustments on my Ohlins shocks.

Ves · Post by **Ves** » Sat Jun 30, 2007 10:39 pm

fnfalman wrote:You should have invested into the Ohlins front & rear shocks. The Ohlins front allows for height adjustment so that you can quicken your steering PLUS the additional performances from the Ohlins themselves. I am still experimenting with dampening settings and height adjustments on my Ohlins shocks.

OOOOOOhhhhlin's.... droooolll.... some day...

You know what though, I just realized this

:idea::idea: , adjusting shock ride height DOES NOT do the same thing as using a shorter arm. Look at this illustration of the rear suspension:

When you put on a shorter arm, point B (where the arm connects to the rear wheel) moves forward, and the rear wheel pivots down and forward by pivoting about point A. Point E (where the shock connects to the swingarm) doesn't move, point A doesn't move, and there is no pivoting of the swingarm (line A-C) about point C.

But, when you increase ride height by increasing preload or using a shock's ride height adjustment, points A and E pivot about point C, and B pivots about D. So, in that case the rear wheel is basically pivoting about points C and D.

What's the difference? When the rear wheel pivots about A, it is pivoting about a much smaller radius than when it pivots about C and D, which means that for a 1 inch movement down it will move forward significantly more than the same 1 inch adjustment if done with the shock setting... Or put another way, if you do the shock adjustment, you would have to raise the rear of the bike much more than 1 inch to get the wheelbase to be 1 inch shorter.

Wow, I never thought about that... that's cool...

Rog(UK) - Yorkshire Dales · Sun Jul 01, 2007 4:27 am

Nice explanation, Ves. Do I spot a Mechanical Engineer?

Ride safely,

Rog

Ves · Post by **Ves** » Sun Jul 01, 2007 8:08 am

Rog(UK) - Yorkshire Dales wrote:Nice explanation, Ves. Do I spot a Mechanical Engineer?

Ride safely,

Rog

It shows huh?

Yup, guilty as charged.

Post by **OU812** » Sun Jul 01, 2007 5:51 pm

Ves, you da Man! I would do the same, but if it makes my legs to appear shorter, well you know I barley touch the ground now.

Post by **iowabeakster** » Sun Jul 01, 2007 8:55 pm

nice explanation Ves! cool indeed!

Ves · Post by **Ves** » Mon Jul 02, 2007 7:12 am

Special thanks to my publisher doug, for making this possible, we couldn't do it without you. I also want to thank my wife and children for their continued support and for having the patience to put up with my Engineering mentality and.... What?...

I didn't win the Nobel Peace Prize?...

Seriously, glad I can make a contribution to a great board. And thanks to fnfalman for the thought provoking comments.

Boxerpunk · Post by **Boxerpunk** » Mon Jul 02, 2007 3:33 pm

shards wrote:Or can you point me to a web site?

Here's a nice adjustable one from Boxer-design:

http://www.boxer-design.us/paraleverstrutr1150radv.htm

Or just a shorter one from Boxer-design:

http://www.boxer-design.us/zaraleveerr1150radv.htm

And an adjustable one from Van Harten (Dutch):

http://www.vanharten.nl/site/specialpar ... .php?id=57

Ves · Post by **Ves** » Fri Jul 06, 2007 7:17 am

Let me tell you folks... Having the short arm on there now for a week, I can emphatically say that it's like I'm riding a different bike. The difference in the handling is huge. I find myself going into corners faster, the bike flicks over easier, and it seems to have lost none of it's overall stability. It just has that connected to the front wheel feel.

For the money, I can not think of a single thing I could have done to that motorcycle that would have such a positive effect on handling. If you can handle the 3/4"-or-so additional seat height, and you like a sharp responsive bike, do this mod... That's all there is to it.

Post by **DJ Downunder** » Fri Jul 06, 2007 8:40 am

That's great Ves...are you sure it's not a placebo effect....

Just kidding..

...I've wanted to do mine for years..One day I'll pick up a GS arm cheap and I'll do it also.

My only concern was the bike leaning over too far on the side stand and both wheels touching while on the center stand...but they can be fixed.

DJ

Ves · Post by **Ves** » Fri Jul 06, 2007 5:38 pm

DJ Downunder wrote:...

My only concern was the bike leaning over too far on the side stand and both wheels touching while on the center stand...but they can be fixed.

DJ

So far neither one has been a problem, but depending on how level the ground is where I park, I have had both wheels touching.

riceburner · Post by **riceburner** » Sat Jul 07, 2007 6:40 pm

DJ Downunder wrote:That's great Ves...are you sure it's not a placebo effect....

Just kidding.. ...I've wanted to do mine for years..One day I'll pick up a GS arm cheap and I'll do it also.

My only concern was the bike leaning over too far on the side stand and both wheels touching while on the center stand...but they can be fixed.

DJ

DO it.

Although both wheels touch on the main stand, it's ONLY just touching - if your tyres are in any way worn then only one will touch. Even with new tyres one of them won't be taking any weight. The bike won't roll off the stand.

Post by **two wheel tango** » Wed Jul 11, 2007 9:03 am

That Van Harten paralever looks cool. Wonder if its available in the US.

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