Lowest Seat Height Possible on R1150RT?

[Aussiegazza]

I am a short ass and needed/wanted to lower the seat so that I did not need to slide off it to put my TOE down.

 

I first made up a new bracket that lowered the standard seat as much as possible:

 

 

Standard seat looked like this:

 

 

I have now put on a Sargent Low World Sport Performance seat. I can now get both big toes down at the same time. Note that the Sargent seat actually fits my modded mount better (less gap at the fuel tank):

 

 

I have now ordered BMW , R1150 RT , LOWERING SPRING KIT -25MM

Item Number CK SP-BM11-SSL029 from Hyperpro, as I want to be able to take my wife on the back safely.

 

As a hopefully useful resource, I will measure the various seat heights, and you can get an idea of the differences from the std lowest seat setting (800mm?).

 

Garry

Edited November 27, 2012 by Aussiegazza

[cavediver]

Aussiegazza, I can feel your pain. To use an old joke I should sue the state for building the road so close to my backside. As a new owner of an 2004 R1150RT I can bearly touch the ground with both feet. I'm going to order a sargent low seat in a couple of days. The brackets you made look good, I might try that myself.

 

Jack

[Quinn]

Another thing to try is to add thicker insoles to your boots. If it were still the 70s you could find platform shoes ala Kiss.

 

---

 

 

[Aussiegazza]

I can only assume that BMW measures its seat heights with a rider on the bike, as:

 

Standard seat with the mod was 800mm at the lowest seat point

Sargent seat (low) was 760mm.

 

Perhaps someone can measure the std lowest seat setting with the bike vertical and unloaded? I put a bit of wood across the seat and measured to the ground.

 

I will measure with -25mm springs and post when I get them.

 

Garry.

[Boffin]

One problem with the seat on the RT is its width. The vertical height to the seat is not the path your legs take, having to splay around that wide seat. A seat with a narrower nose can allow you to reach the ground more easily by slipping forward a little.

 

Andy

[tallman]

Garry,

 

BMW in the past did not measure the height with a rider.

Too much variety in size and weight.

 

Can't say that with certainty but to the best of recall, all BMW specs were unladen heights.

 

Adding 1/2" to soles is an ez mod.

[hopz]

Can someone please provide a brief/casual explanation about how the lowering kit works?

 

I did a brief search on this and found nothing useful...

[tallman]

I think it is merely a lowere spring replacement for the shock, not sure if it only works w/Hyper Pro or Wilbers of if it will work w/stock.

 

[Aussiegazza]

They are 1 inch shorter spring for the shocks.

[Richard_D]

You didn't make those brackets. It even has my sticker I put on it with my initials. Here's my thread. Busted ! http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Main=22137&Number=228851#Post228851

[Aussiegazza]

I made similar brackets but did not take a picture... I used your pic.

I will post a pic if I must.

I gve you credit in another of my threads and therefore did not think there would be an issue.

 

Edited November 29, 2012 by Aussiegazza

[Richard_D]

It's not an issue. I'm just having fun. I havn't been keeping up on here so forgive me if i came across the wrong way.

[cavediver]

Well thank you both, because I can use this. I just ordered a Sargent sport low seat last night and every 1/2" will help. I'll make the brakets over the weekend.

 

Jack

[Aussiegazza]

This is my bracket. I used nuts for extra strength and so I did not need to thread the aluminium. Also did not need to modify the rubber bumpers and the bike mounting bolts were further away from the inside edge:

 

 

These are the Hyperpro springs. will put them on this weekend if I can get a spring compressor:

 

 

Garry

Edited November 30, 2012 by Aussiegazza

[Aussiegazza]

The springs are actually purple in colour (you can order black). They are also progressive.

 

I have a hydraulic press, so I should be able to make up something to swap the coils over.

 

(as I have mill and lathe also).

 

I LOVE toys.

Edited November 30, 2012 by Aussiegazza

[Aussiegazza]

The rear is easiest to do. I had to ask an expert on how to get the spring off, but it is relatively easy to do.

 

There is an allen head grub screw in the follwoing picture. To remove the spring, loosen it, compress the spring and slide the sleeve it is attached to down slightly.

 

A large diameter, but thin circlip will be revealed. Take off the circlip and everything will fall apart:

 

 

Finished shock:

 

 

I measure the unloaded seat height at 755mm.

 

Being a progressive spring, I think the lowering effect will be felt when you are on the bike.

 

I may get the front done tomorrow.

Edited December 1, 2012 by Aussiegazza

[Aussiegazza]

Did the front shock. I used a car spring compressor after cutting off a bit of the tang that grips the spring near rhe bottom:

 

 

After taking it all apart, I found that I could have compressed from the other end, taken out the circlip, and it would have fallen apart:

 

 

I put it together on my press using the circlip approach and installed it.:

 

 

Do not have time to put the fairings on. Job for tomorrow.

 

Garry

[Aussiegazza]

Measured unladen after bouncing on it a bit.

 

745mm

 

I can get my 2 big toes JUST down at the same time.

 

So, went from somewhere above 800mm down to 745mm.

 

I may be able to gain a bit more by thinning the foam where my thighs contact to get my legs straighter (less bowed).

 

 

Cost about $650 for seat and $550 for springs from (bad) memory.

 

That's all folks!

 

Garry

 

[tallman]

Add 1/2 inch to your soles.

$50. Voila.

[biometrics]

Do I understand correctly that the replacement Purple springs cost you $550.00 ??? That seems like an awful lot of money for a set of springs... It would seem for not much more money that an aftermarket set of shocks might be a better investment... am I wrong in this assumption?

 

Thanks in advance, from another short legged guy...

 

-John

Edited December 4, 2012 by biometrics

[Aussiegazza]

I made an error in the price for the springs. They were $415AUS including $25 shipping.

 

The seat mount mod and the lower seat were the biggest bang for your buck.

 

After that, I think springs are the cheapest option to lower front and back to get a full inch lowering overall.

 

Many people complain that the std shocks are not up to scratch. Replace and you may get lowering and better shock control options.

 

Good aftermarket shocks are expensive though.

 

Check prices on-line.

 

Also I do wear boots with thick soles.

 

Garry

 

 

Edited December 5, 2012 by Aussiegazza

[Aussiegazza]

I do not like the 'comfort' of the Sargent low seat, which pushes into my hamstrings.

 

I have ordered a custom seat to be made out of my std seat, which should be available in Feb 13.

 

I will provide an update then.

 

Garry

[greggy]

Boy, can I relate. I recently purchased a used 1150RT and was seriously concerned about having to stand on my "tippy-toes" at stop signs. I purchased a nice Corbin seat of the scooter. Now I can put my feet flat on the ground but the new ergonomics make my knees aches after a 100 miles. Can't seem to win.

[Blondie]

Just a quick nod to Richard and Garry for the tip on how to lower the seat on my '04 R1150RT using homemade brackets.  That was really all I needed to get off my tiptoes, and it was way cheaper than a replacement seat or suspension mods.

 

Barry

[Bock2340]

Hello all, 

   I don't have an extreme problem with the seat height, but I am unable to flat foot it at stops which is my main concern.  Definitely different from my 1976 R90/6 though!  I'm looking at the brackets for the front seat mount, and I like them, but I'm wondering how many of you have also changed the rear seat bumpers to keep from sliding forward when riding.  I may end up just leaving the seat lower for my commute and moving to the center position for longer trips when I won't be doing the stop and go that I do in town.  If I can keep the seat flat while installing the adapter first made by Richard_D I'll definitely give it a try.  

   I have a 2004 by the way, but still have the '76.  Not sure I can give the old ride up, it's just too much fun.  Just hoping I have the time to give it the attention it needs to return to glory here in the near future  

 

[Blondie]

Glad you're still enjoying that R90/6.  I gotta get me one of those.

 

I haven't had a "sliding forward" issue after lowering the front using homemade brackets, but, if necessary, you could lower the rear a bit by shortening the studs and the rubber bumpers under  the seat.  If you don't like the result, you could use fresh rubber bumpers ... and hopefully the shortened studs would still work well enough with them.

 

Barry