torque arm and adding more height.

[high_tower]

i saw a website advertising torque arms 25mm shorter than standard. how much of an effect with this have ride height at the rear?

i have a standard height s and after getting a sit on a boxercup i realised i'd love to have mine a similar height but obviously without the huge price tag to go with new shocks and forks and ya da ya da ya da to make it a boxer cup.

are there any cheaper alternatives to lifting the bike to a 04 boxercup height or there abouts?

[andrew s]

Having a shorter torque arm will raise the back end but not by the 25mm. I cant remember the equation at the moment by how much it will raise the rear poss about 8mm but please dont quote me on that.

The 04 BCR uses the forks from a GS so it is also raised at the front as well as the back over standard and 03 BCR.

Andrew

[winger]

Don't get carried away with the height thing,the bike was made higher to give the cylinder heads more clearance for raceing in the Boxercup series,it' the relationship between the front and the back that make the difference.

BM have changed the spec over the years since introduction in 98,and rather than going into a long rambling they did this that and the other,your best option is to buy a Verholen ajustable arm(torque or paralever call it what you will),just make sure before fitting, to measure the rear of your bike first,when you've fitted the Verholen,ajust it accordingly raising the rear untill you find a setting that suits you,just remember you'll get to a stage when the steering will get very twichy and the front end will have a tendency to 'tuck'when you ride into slow corners,it's just a case of experimenting,the arm is very simple to ajust,go out riding and carry a spanner with you.

[iandunn1100ss]

+1 on the winger i have my torque full in because this suits my riding style but my not suit everyone. good way to change how the bike turns and tips in ,slight height change at the back but i had the seat reshaped so i could get my very short pins down.
ian

[throttlemeister]

The 04 BCR uses the forks from a GS so it is also raised at the front as well as the back over standard and 03 BCR.

The 03 BCR also is taller both in the front as in the back compared to a standard S. My Sport has the taller BCR suspension and it can be clearly seen on pictures of a standard compared to a sport/bcr.

With the standard S the top of the lower clamp is inside the fairing, on the sport or bcr the clamp is very much below the fairing.

The difference is about 1" over stock, front and back.

The only way to achieve this height on a standard S is to mount taller shocks.

Raising the back with the torque arm will change geometry as already mentioned, and thereby steering behavior. Change of clearance is minimal.

[winger]

E'rmmm well that ain't strictly true,don't go thinking that if you raise the rear with a short or Verholen arm and not have any hassle getting your feet on the floor,if your a short arse it's not an option,mine is a stock S,with the rear raised how i like it,i can con only just get my feet on the floor and i'm 6ft.

[jltownshend]

E'rmmm well that ain't strictly true,don't go thinking that if you raise the rear with a short or Verholen arm and not have any hassle getting your feet on the floor,if your a short arse it's not an option,mine is a stock S,with the rear raised how i like it,i can con only just get my feet on the floor and i'm 6ft.

Ermmm, welll that isn't strictly true either. We all have different body shapes (ie inside leg measurement)...

Pedantic?

John

[cc mac]

Is there a reliability issue when raising the ride height via the torque arm? I think I remember this being mentioned on a previous link. If it does not have any effect on reliability I might consider the adjustable torque arm myself.

[throttlemeister]

No, BMW delivers a shorter torque arm themselves for the Sport and the BCR.

[iandunn1100ss]

I am 5`6" and with a 29" inside leg , i have the torque arm on its shortest setting and the height adjuster on the ohlins up about 8mm and with the seat reshaped can get the balls of both feet down or as i normally do just put one foot down thats what suits me . i am tiny and still get on fine.
ian

[sandbar]

Is there a reliability issue when raising the ride height via the torque arm?

Yes.

'Gromit' had a link to a great Wikipedia page that explains it much better than I can. It is to do with the fact that BMW uses normal universal joints in the drive shaft rather than constant velocity joints.

sandbar

[throttlemeister]

If it does, it increases reliability as the short torque arm makes the shaft straight in normal riding position, so less stress on the ball joints.

[sandbar]

................as the short torque arm makes the shaft straight in normal riding position, so less stress on the ball joints.

Only with one particular shock length.

To be completely pedantic there is one ideal torque arm length for each shock length.

Straight is not the issue (it would be nice but not essential) - parallel is what you are looking for. If you have that, then it will stay parallel throughout suspension travel - well not quite because there is not a perfect parallelogram, but - hey! - it will be close and that is as good as it can get.

Here is the wikipedia link:

http://en.wikipedia.org/wiki/Universal_joint

The advantages are reduced vibration and because the rear wheel will not be pulsing then tyre wear will be improved.

There are quite a few examples of warranty claims being refused on rear drive problems because a different torque arm has been used.

sandbar

[throttlemeister]

Interesting!

[iandunn1100ss]

Had a slight oil leak before the torque went on now oil leak has gone for now so i am happy.
ian