Spanking the Cow- The continuing saga of an R100GSPD at the Races

[Airhead Wrangler]

Originally Posted by Prutser

Do you know how much wheel travel you can get using the 1100 swingarm ?

HPN lists 245mm of travel for their models using the 1100 swingarm. The 1150 swingarm is a bit shorter and will give you less.

You need to modify the subframe a bit to allow your rear wheel to travel that high.

[Stagehand]

I wonder what a R12 or HP2 rear end would do?

Edit: Hp2 rear theoretiaclly allows for 250mm wheel travel.

[Clay Spinner]

Just watched your moment of glory on the video... brilliant! Hey... I bet many riders didn't even make the highlights!

[Prutser]

Originally Posted by Airhead Wrangler

HPN lists 245mm of travel for their models using the 1100 swingarm. The 1150 swingarm is a bit shorter and will give you less.

You need to modify the subframe a bit to allow your rear wheel to travel that high.

Thanks AW.
I was just wondering. Never heard how much travel they could get out of the 1100 swing arm.(in an Airhead frame)
Not really impressive !

The unsprung weight would be the thing that worries me the most.

[gsd4me]

Originally Posted by Stagehand

here's the video: My moment of glory forever preserved at six minutes, forty seconds in.


http://www.youtube.com/watch?v=Fhy5KPsKPAg

Classic . There can`t be too many people that have ever done that; got their foot stuck in one, maybe, but a front wheel?

[Stagehand]

And a back wheel as well now that you mention it! Haha! It took myself and two redshirts to lift it out :lol

[Airhead Wrangler]

Originally Posted by Prutser

Thanks AW.
I was just wondering. Never heard how much travel they could get out of the 1100 swing arm.(in an Airhead frame)
Not really impressive !

The unsprung weight would be the thing that worries me the most.

It's heavier, but not THAT much heavier. Weight could be mitigated a bit by installing an excel tube type rim instead of the monster tubeless cross spoke rim. Also keep in mind that it's already quite a bit longer and the shorter stroke shock means that that weight of the shock is only "semi-unsprung", less effect of its inertia when trying to move the wheel. I added up all the weights of various rear end setups a while back based on the weights listed in the parts fiche which actually seem to be pretty accurate:

R1100GS
final drive 16.7
paralever rod 1.3
swingarm 7.8
drive shaft 5.2
rear wheel 14.7
disc 2.0
caliper 1.8
shock 10.0

59.5 lbs total


R100GS or GSPD
rear wheel 14.2
swingarm w/ all bearings, pins, lower boot 6.2
tie rod 1.0
driveshaft 4.4
final drive 17.8
brake shoes, cam, lever 1.9
shock 8.4

53.9 total



R80G/S, R80ST
swingarm w/ bearings and pivot pins 7.3 lbs
driveshaft 3.9
final drive 16.2
rear wheel 13.0
brake pads, cam, lever 1.4
shock 6.3

48.1 total




HP2
final drive 17.4
swingarm 9.6
paralever tie rod .9
rear wheel 11.3
driveshaft 4.8
rear disc 2.1
rear caliper 2.1
shock 4.9 (I find that very hard to believe)

53.1 lbs total

[LoJack]

Cool!

Hp2 had an air shock, didn't it? That might explain the weight.

[Prutser]

[QUOTE=Airhead Wrangler;19942531]It's heavier, but not THAT much heavier. Weight could be mitigated a bit by installing an excel tube type rim instead of the monster tubeless cross spoke rim. Also keep in mind that it's already quite a bit longer and the shorter stroke shock means that that weight of the shock is only "semi-unsprung", less effect of its inertia when trying to move the wheel. I added up all the weights of various rear end setups a while back based on the weights listed in the parts fiche which actually seem to be pretty accurate:

I have been thinking about re-builing an R65GS.
And just like Stagehand am thinking about what to do.

But would really like more travel than the 245 from the 1100 swing.
Have been comparing some parts to a few weeks ago.
Found a lot more weight differances between the 1100 and the ST stuff.

@Jason: did you bottom out the mono from Paul with that amount of travel.

[Airhead Wrangler]

Originally Posted by Prutser

But would really like more travel than the 245 from the 1100 swing.
Have been comparing some parts to a few weeks ago.
Found a lot more weight differances between the 1100 and the ST stuff.

How much travel are you looking for? I think once you factor in driveshaft angles and shaft clearance issues inside the swingarms, there's really no way to get any more travel without lengthening the swingarm beyond 100mm. Not to say that's not possible, but the longer you go the more likely you are to high center the engine on something - breakover angle and all that.

[Stagehand]

I only cased the bike once that I am sure of. That was sort of an extreme circumstance, and one wouldnt bottom or case as long as the suspension is right. Rooney's front and rear wheels both had 300mm of travel.

The slightly added weight of a late model rear end could be mitigated by the fact you dont have to extend both a swingarm and a driveshaft. Thats nice, all that work is done at least.

One would want to lace an 18" rear on the rear anyway, so you'd probably put a lighter rim on anyway.


Why do we think we are limited to 245 rear travel with the 1100? Is that the angle limit of the shaft? I seem to think it will do more than that if you hang the right shock on it. It will just a be a custom one, but then, you'd be making your own top mount anyway, so you will be anyway, right? Unless you just try and use the 1100 shock as well with a differnet spring, but then how you mount the shock might give you some different room, too... it really gets kinda mind blowing, quickly.

[Airhead Wrangler]

Originally Posted by Stagehand

Why do we think we are limited to 245 rear travel with the 1100? Is that the angle limit of the shaft? I seem to think it will do more than that if you hang the right shock on it.

That was just an assumption on my part. HPN listed 245mm for their bike that uses the 1100 swingarm and it seems like they push everything as far as they possibly can. I haven't actually measured and assembled and tried to break it. Someone give me measurements and I'll CAD it up. Anybody have all these parts laying around??

[the_babaji]

A cow grate, ah, how fitting.

Sent from my GT-I9000 using Tapatalk 2

[Stagehand]

I also did a down and dirty measurement of the R100 paralever and the GS1150 I have in the barn, and the 1150 was 2.5 inches longer. Pivot center to axle center.

I'm saying if the rear is 100mm longer it can get more travel than if its 50mm longer.

I remember somebody saying that 100mm longer was a fair number to aim for, but it had no data backing it up. Just a number compromising additional travel and an over-long wheelbase.

[Stagehand]

Originally Posted by the_babaji

A cow grate, ah, how fitting.

Sent from my GT-I9000 using Tapatalk 2

I thought that was pretty funny, also :lol